odmp stakeholder workshop report hydrological model
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882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 129
OKAVANGO DELTA MANAGEMENT PLAN
HYDROLOGY AND WATER RESOURCES
Maximum Depth of Overland Flow
STAKEHOLDER WORKSHOP11 th February 2005
PROCEEDINGS
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List of Contents
1 BACKGROUND
2 PROGRAMME3 PRESENTATIONS AND DISCUSSION
31 Introductions
32 Integrated Hydrologic Model
321 Introduction
322 Conceptual Model
323 Evapotranspiration
324 Surface Waters
325 SubSurface Waters
326 Outputs
4 SCENARIOS
41 Introduction
42 Hydrologic Inputs
43 Presentation of Results
44 Baseline
45 Upstream Water Resources Developments 451 Introduction
452 Dams in Angola
453 Irrigation
46 Abstractions from Delta
47 Climate Change
48 Management Planning
5 DISCUSSION
51 Introduction
52 Database Management
53 Integrated Hydrologic Model
54 Scenarios
55 Presentation of Results
56 Stakeholdersrsquo Responses
6 CONCLUSIONS
61 Summary 62 Recommendations
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1 INTRODUCTION
11 BackgroundThe Hydrology and Water Resources is one of the twelve components comprising theOkavango Delta Management Plan project The project and the componentcommenced in May 2003
The development objective of the Okavango Delta Management Plan is integratedresource management for the Okavango Delta that will ensure its long termconservation and that will provide benefits for the present and future well-being of thepeople through sustainable use of its natural resources
In line with this development objective the immediate objectives for the Hydrologyand Water Resources component are improved water resources planning andmonitoring and evaluation in the Okavango Delta based on an enhanced capacity of the Department of Water Affairs Corresponding to these objectives the outputs of the component are
(1) A comprehensive quality controlled database comprising existing climatichydrologic surface water ground water and sediment data for theOkavango Delta
(2) Recommendations on the improvement and expansion of the OkavangoDelta monitoring network
(3) A digital Topographic Model of the delta
(4) An Integrated Hydrologic Model for the delta
(5) The analyses of the impacts of water resources scenarios for the OkavangoDelta Management Plan
(6) Capability within DWA to maintain and operate the Integrated HydrologicModel for the establishment and implementation of the ODMP
While all aspects of the component were discussed the Workshop focussed onoutputs (4) and (5) the Integrated Hydrologic Model and its application to impacts of water resources developments in the delta and the basin upstream with commentsand discussion on the model and the format of the presentation of the outputs
12 ObjectiveThe Hydrology and Water Resources workshop was convened to
bull Inform project partner institutions and the community about the role of the integrated hydrologic model in management planning
bull Afford the project partner institutions and the community theopportunity to comment on the outputs of the model and to suggestways in which the outputs or result can be made usable by them
bull Afford the project partner institutions and the community theopportunity to suggest management scenarios relevant to their respective institutions
bull Ensure that this component is community driven or encompasses theviews of the majority of the stakeholders from the beginning
bull
Guarantee ownership commitment and sustainability of the projectbull Minimise risk during implementation of entire management planning
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13 ProgrammeThe programme for the one day Workshop is presented in Annex 1 The first sessioncovered the background to the establishment and the implementation of thecomponent in DWA the recommendations for improved hydrologic monitoring in thedelta and their pending implementation and data collection and management
This was followed by a description of the Integrated Hydrologic Modelling system andits set up to represent the hydrology of the Okavango Delta The next four presentations covered the application of the model to represent existingdevelopments in the delta and the basin upstream and hydrologic conditions as theywould be in the delta given the implementation of a range of potential water resourcesdevelopments Each presentation was followed by a discussion session
The team implementing the component comprises DWA staff and national andinternational consultants An important output from the component is capacitybuilding in DWA to maintain and operate the Integrated Hydrologic Model Thisentails technology transfer from the consultants to the DWA staff The technologytransfer is carried out in a three pronged approach
bull A series of formal training courses in DWA Gaborone on the mainelements of integrated hydrologic modelling
bull On-the-job training whereby the DWA staff learn by doing setting upand applying the model under the guidance and supervision of theconsultants
bull Overseas training most likely MSc courses in recognised internationalhydrologic institutions
DWA has assigned four permanent staff members to work full time on ODMP Aspart of the technology transfer process each of these four staff presented an aspect
of the model application in the WorkshopThe presentation of the model and its application was followed by an open discussionby the participants Each sector was given a slot to allow the representatives to voicetheir particular comments
The model results at this stage are preliminary and the focus was more on are thehydrologic and water resources development data appropriate and is thepresentation format of the results meaningful and useful to the respective ODMPsectors in the context of the Okavango Delta Management Plan
14 ParticipationThe list of participants is given in Annex 2 Despite an early dispatch of invitationletters in advance to representatives of the different components it became apparentthat most components were not represented at the workshop Most notableabsences were from the technically oriented components such as SustainableLivestock Management Vegetation Resources Management Waste Managementetc
Of the components that were present it appeared that these representatives were notfamiliar with the project or are not dealing with the project on a daily basis judgingfrom their contribution to the discussions on the role of the Hydrology and Water Resources component It appears that project partner institutions still have acombined workload of their routine work and new duties related to ODMP Thisadded responsibility is somewhat too great and affects the ability of project officers todeliver efficiently and effectively
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Each component should identify a suitable person to act as a focal point for liaisonwith the Hydrology and Water Resources component and this person should attendfuture such workshops and meetings
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2 PRESENTATIONS AND DISCUSSION
21 IntroductionsSelected slides from those employed in the respective presentations are included inAnnex 3 and illustrate the text of the presentations in the following sections
The introductory presentations covered the component background implementationdata collection and processing and monitoring proposals As such they generatedlimited discussion One suggestion was that as most of the stakeholders were fromsectors other than water a glossary should be included to cover the use of technicalterms
22 Integrated Hydrologic Model
221 Introduction
The Introduction to the Integrated Hydrologic Model set out the approach tomathematical modelling in the context of the hydrology of the delta The key flowprocesses above in and below the delta are shown in slide 1 Given the criticallinkages among the atmospheric surface and ground waters it is necessary todevelop an Integrated Hydrological Model which integrates the essential physicalphenomena controlling the delta As such the model requires a basis in physicalprocesses as opposed to a conceptual model which has an idealised representation
It is not the intention to set up a detailed model The available data do not justify thisand the project resources are not available The model will be somewhat schematicbut nonetheless capable of describing the essential processes such as the overallflow pattern among the distributaries flooding and drainage of seasonal swampareas The model will not be capable of predicting the small scale vegetation andmorphological changes which appear to have a significant impact on the overall flowpattern
Water and its distribution in space and time is the fundamental physical basis for management of the ecosystem Management criteria for the delta could include
bull Maintain present flood extent and duration
bull Maintain current pattern of flows through the delta
bull Minimise adverse impacts on any part of the interconnected hydrologicalsystem
The distinct environments and key hydrologic phenomena were presented illustratingthe complex interactions among the atmospheric surface and subsurfacecomponents of the wetland
In order to have a realistic representation of these key phenomena and their interactions and to make quantitative prediction of the potential effects of changes inwater use it is necessary to employ an Integrated Hydrologic Model The systemselected is MIKE SHE developed by DHI Water and Environment Denmark Thegeneric system (the software can be applied to any hydrologic system) is marketedcommercially and is applied to hundreds of catchments and wetlands worldwide
The key features of the software package are (slide 2)
bull Physically based with a realistic representation of the hydrologic
phenomena based on the laws of physics
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(slide 3) The vegetation dynamics are based on remotely sensed data with limitedground verification (see slides 4 and 5) The relationship between the extent of surface water and the rate of evapotranspiration is shown for the normally andseasonally flooded areas in slide 6
224 Surface Waters
The surface water flows are dependent on the topography of the delta which hasbeen described by a digital elevation model of the Ramsar area with a 30m resolutionbased on aerial radar altimetry and remote sensing and a limited number of channelcross sections available at gauging stations and surveyed by researchers
The key characteristics of the delta are the numerous bifurcations or defluences (asopposed to confluences) extensive spills to the flood plains and swamps andhydraulic connections among the spill areas and slow flood wave propagation(around four months from upstream to downstream) with a high variation in the extentof flooding (slide 7)
The surface waters of the delta are described by a full hydrodynamic representationof the flows in the main rivers and channels and by a distributed kinematicrepresentation of the flows over the flood plains and through the swamps Thedescriptions are fully coupled (slide 8) and enable the representation of theessentially one dimensional flows through the channels giving definition to the flowand the spreading and distributed storage over the flood plain (slide 9)
225 SubSurface Waters
Infiltration rates are significant on the predominantly sandy soils in the early stages of the flood season The infiltration raises the ground water levels up to the flood water level This increases the water available to plants which in turn increasestranspiration from the leaf surfaces to the atmosphere (slide 10)
An essential component is the inclusion of the critical unsaturated root zone the zonefrom which plants draw water and transpire to the atmosphere Together withevaporation from open water this is represents the main loss of water in the deltaThe evapotranspiration component simulates both the hydrologic and vegetationdynamics (slide 11)
The ground water component is important to account for the local effects of groundwater on the water balance ie recharge and discharge and evapotranspirationlosses Only the surficial ground water aquifer is represented (slide 12)
Detailed ground water studies show infiltration and recharge of fresh water lensesembedded in older saline ground water Given the low topographical relief limited
ground water flow is directed towards local depressions (slide 13) Model water balance tests indicate that there is no significant ground water flow from the delta nor are there data to support such flow hypotheses Consequently there is no flowacross the subsurface model boundary
226 Outputs
The outputs from the model are designed to support broad based managementplanning in the Okavango Delta The outputs are presented in grid or map formatshowing the spatial variation in the parameters over the delta time series (plots of various parameters against time) and summary tables of results The outputs may besummarised as
bull The actual evaporation from open water and the transpiration fromvegetation
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bull Surface water levels and flows through the rivers and over the floodedswamp areas and the extent of flooding
bull The moisture content of the soil
bull The ground water levels and flows
bull The overall water balance including inflows outflows and changes insurface and subsurface storage for the delta and selected areas of thedelta
bull Sediment transport along the main channels of the delta showingpatterns of erosion and deposition
The Integrated Hydrologic Model does have practical certain limitations and it isimportant that these are recognised by the stakeholders and management planners
Channel Switching
While the model can predict the impact of cutting and dredging a new channel
through the delta and the impact of closing an existing channel through theencroachment of vegetation it is not able to predict the occurrence of the formation of new channels and the realignment of existing channels which may be initiated by themovement patterns of large mammals and vegetation growth
Certain trends in sedimentation and channel development and decay may bepredicted by the application of sediment transport to the model Work on this areahas just commenced Detailed analyses of selected reaches and areas of the deltamay be carried out through the application of two dimensional morphological modelsThis is beyond the scope of the present component activities
Level of Detail and Accuracy
While the technology exists to simulate the hydrologic behaviour of the delta at a highlevel of detail (previous applications have been made at the level of individualcultivated fields) this is constrained by
bull The resources available to the component do not permit thedevelopment of submodels which could enable the study of a particular area of the delta below the present one square kilometre resolution
bull The available data do not justify high expectations on the level of accuracy with respect to absolute water levels and quantitiesRecommendations have been made for improved data collection andmanagement which when available could justify further modeldevelopment
The key issue at this stage is that the Integrated Hydrologic Model represents theessential hydrologic phenomena in an integrated manner such that it may be appliedwith confidence to the assessment of the impacts of future water resourcesdevelopments on the delta hydrology for the purposes of the management plan
Physical Phenomena
The model simulates physical hydrological phenomena only Studies have revealedin particular the importance of the interdependency of physical and biologicalphenomena for example the movement of large mammals opening new flow pathsthrough the vegetation sedimentation and vegetation in closing existing channels
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bull The data should reflect how the delta may recover in a period of normal inflows after a dry period
The long term inflow in terms of volume per annum from 1933 to date is shown inslide 14 for both Mukwe in Namibia and Mohembo in Botswana Whereas at Mukwethe river is more or less confined to the gauged channel at Mohembo the river has
broadened out with a wide flood plain It is not possible to gauge the flows over theflood plain and Mohembo will not represent the total discharge This is most clearlyevinced in the high flow years 199899 and 200001
An anomaly appears in the data from around 1950 to 1980 where the total inflow atMohembo appears higher than Mukwe As there is no significant inflow to the river between the two gauges this can only be explained by gauging errors The seriesafter 1980 is more consistent with Mukwe showing a higher inflow than Mohembo
The period from 1992 to 1997 represents the sequence of the five lowest inflowyears and is therefore chosen to provide the input data to analyse the impacts under critical conditions for both the existing state and possible future states with water resources developments
The following five year period from 1997 to 2002 represents relatively normalhydrologic conditions in the delta and has been used to assess how the delta mayrecover after a sequence of dry years (see slide 15)
A high inflow period could also be selected eg 1987 to 1992 to assess the impactsunder high inflow conditions It is not planned to analyse this period as
bull The conditions will not be critical to a management planning exercise
bull The number of impacts which have to be assessed in terms of flowsdepths etc will be further increased
Appropriate time series of inputs (inflows precipitation etc) have been prepared and
applied to the existing state of the delta The model results are used as a baselineagainst which future developments are assessed for their impacts The inputs aremodified to represent conditions which may prevail under future conditions
To summarise while the inflows to the delta will be dynamic ranging over two fiveyear periods representing critical dry and normal average hydrologic conditions theexisting and future states will be static This implies that for the duration of the fiveyear model run period the population for instance will not be increasing no newdams or irrigation schemes are built etc
At present the Baseline and Scenario Conditions have been simulated for the criticaldry hydrologic input period from October 1992 to October 1997 Summary results arepresented and discussed in the following sections Slides illustrating the outputs arepresented in Annex 3
233 Presentation of Results
In order to assist the stakeholders assess the outputs and their implications for their particular sectors a common format for the presentation is adopted The resolutionof the model in space is one kilometre and in time four hours In order to limit thesize of the output files the results are output with a temporal resolution of one weekfor surface flows and the unsaturated zone while the slower responding ground water results are output every two months of the five year period
For the purpose of presenting summary data the delta is divided into five zonesaccording to the probability of flooding as assessed from 15 years of satellite images(source J McCarthy Stockholm University) with the Panhandle treated as a fifth
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separate zone (slide 16) The probability delta area and a zone description are givenin the table
Model Area (km 2) 28782 Description
Zone 1 - 01gtFPgt0 19322 rarely flooded
Zone 2 - 05gtFPgt01 3534 occasionally flooded
Zone 3 - 09gtFPgt05 2328 seasonally flooded
Zone 4 - 1gtFPgt09 2152 normally flooded
Zone 5 - Panhandle 1446 Panhandle
(1) Animated sequence of flooding in the delta showing the monthly variation inflooded area and depth (The AVI format file is available from DWA sizearound 110Mb)
(2) Map based on the one kilometre grid showing the minimum depth of water in the delta for the five dry years
(3) Time series showing the variation in the depth of flooding over the five year period The depth is averaged for each of five zones (see table)
(4) Map based on the one kilometre grid showing the minimum level of soilmoisture in the root zone (the zone from which plants draw water) in thedelta over the five dry years
(5) Map based on the one kilometre grid showing the maximum depth toground water in the delta over the five dry years
(6) Summary tables are prepared showing the following
bull Water balance showing inflows outflows and storage changes
bull Baseline conditions and impacts for the surface water soilmoisture and ground water for the entire delta and for each of the five zones
A wide range of outputs of all hydrologic parameters in various formats is possibleand can be tailored to the needs of the individual stakeholders It is possible also toselect different zones to calculate average time series and summary results Theabove selection has been made by the component as samples of what may be usefuland meaningful to the stakeholders and to generate discussion
24 Baseline
Surface Water
The animated depth of flow sequence (slide 17) shows the expansion and contractionof the flooded area and depth as the sequence of flood waves for each of the fiveyears propagates through the Panhandle and spreads out through the delta Slide 18shows the detail for the lower envelope of flooding for the upper delta Each squareis one square kilometre
Time series of the depth of surface water are shown for each of the five zones in slide19 The Panhandle is the first area affected by the flood wave from upstream andbeing relatively confined within a flood plain around 20km wide has the maximumrange from the seasonal wet to dry periods around 06m through the five dry yearsAs the flood wave propagates through the delta the range in water levels declines
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The accumulated impact of the drought years is also felt more as there is a generaldecline in the flood depth
As the summary table (slide 20) shows the area flooded ranges from 1513km 2 to12077km 2 while the depth ranges from 0 to around 5m The average depth in thenormally flooded area ranges from 011m to 092m
SubSurface Water
The distribution of the soil moisture content is shown as a deficit below saturatedlevel as the lower envelope (maximum deficit) for the five year period in slide 21The average deficit ranges from 056m in the rarely flooded area to 012m in thenormally flooded area
The depth to ground water over the delta area is shown for the lower envelope(maximum depth) over the five year period in slide 22 The depth ranges from anaverage of 188m in the rarely flooded area to 037m in the normally flooded area
Water Balance
The overall water balance for the Baseline and Scenarios is shown in slide 23Negative values indicate an inflow to the delta (eg precipitation and river inflow) whilepositive values indicate an outflow (eg evapotranspiration and river outflows) TheTotal should be zero the small value indicates a very minor continuity error Thenegative overland and subsurface storage changes indicate a decline in storage inthese levels
25 Upstream Water Resources Developments
251 Introduction
To date no significant water resources developments have taken place upstream inAngola and Namibia In the past plans have been made for the construction of damsfor irrigation and hydropower Anticipating that these plans may be revived theWERRD project has run a number of scenarios using a modified rainfall-runoff modelof the basin (Pitman model Rhodes University) including a scenario for all planneddams
A number of sources describes potential irrigation in the upstream basin in Angolaand Namibia These have been reviewed and a potential scenario compiled basedon
bull Irrigation demand based on 15000m 3haa with a 25 return flow
bull Irrigated area in Angola 54500ha in Namibia 7500ha
bull Angola grows vegetables in winter (June to October) Namibia growsmaize in summer (December to April)
The corresponding runoff from the upstream basin has been applied under twoscenarios Dams in Angola and Irrigation as inflow to the delta upstream The twopotential developments are kept separate for the purpose of initial appraisal in order that the impact from each can be identified This will assist in minimising the adverseimpacts from these developments
252 Dams in Angola
The impact of the previously planned hydropower dams in Angola on the inflow to the
delta is presented in slide 24 Hydropower development does not consume waterbut stores water in the flood period for release in the dry period This results in a
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redistribution of the natural hydrograph flood flows are reduced while dry seasonflows are increased (The impact appears only to be significant in 1993 and 1996 ndashthis needs further investigation)
The impact of the dams on the surface and subsurface waters of the delta is minimalgiven the limited apparent impact in three out of the five dry years and the fact that
there is no nett water loss in the basin upstream
253 Irrigation
The impact of the potential irrigation scenario on the inflow to the delta is shown inslide 25 The impact is greatest in the dry period when water is withdrawn for therelatively large area of winter crops in Angola The summer withdrawals for irrigationin Namibia are significantly less
Correspondingly the impact on the delta in the flood period is minimal while in thedry period the overland depth of flow is reduced particularly in the Panhandle andnormally flooded areas and the minimum flood extent is reduced by 660km 2 or 40of the present dry period area (slide 26)
26 Abstractions from DeltaWater for largely local domestic use is abstracted from both the surface and groundwaters of the delta The surface water abstractions are based on water rights issuedby DWA (ie the amount which may legitimately be withdrawn ndash actual withdrawals arenot monitored and may be greater or less than allowed) Ground water abstractionsare based on the demands projected from historic information to the present day
In terms of the inflows to the delta (river flows from the basin upstream andprecipitation over the basin the abstractions and corresponding impacts are minimalSurface water abstraction represents 0006 of the inflow and ground water 02In the five dry years analysed the minimum flooded area is reduced by 025Future scenario runs will simulate the impact of abstractions with projected increasedpopulation and rates of consumption to the notional year 2025
27 Climate ChangePotential climate change will have an impact on the delta in respect of inflows fromthe basin upstream and the climate over the delta The WERRD project has run aglobal climate model HadCM3 1 to predict the changed precipitation and temperatureover the basin For the upstream basin the Pitman rainfall-runoff model has beenapplied to predict the modified inflows upstream of the delta (slide 27) The modifiedprecipitation and temperature over the delta have been used as direct inputs to theIntegrated Hydrologic Model (slide 28)
The impact of the climate change scenario is highly significant in both the flood anddry seasons River inflows to the delta are reduced by 38 and precipitation over the delta by 9 Temperature increases by 22ordmC
The corresponding impact on flow depths is shown on the reduced depths the impacton the minimum depths is shown for the Panhandle and normally flooded areas inslide 29 and in each of the five zones through the five year run period in slide 30The reduction in depth averages 003m over the entire delta and the minimumflooded area is almost halved
1 httpwwwmet-officegovukresearchhadleycentremodelsHadCM3html
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28 Management PlanningThe model analyses are carried out to assess the impacts of possible future basinconditions on the delta for the purposes of management planning An iterativeprocess is envisaged with a series of bilateral meetings with the Stakeholders andcommon Workshops in which the inputs and outputs are presented to and discussedwith the stakeholders The outputs can migrate towards a presentation format that isboth meaningful and relevant to the stakeholders
The Hydrology and Water Resources component will only analyse the impacts on thewaters of the delta DWA and its consultants do not have the capability or theresources to analyse the impacts on the wildlife vegetation livestock fisheries or tourists It is up to these respective sectors to assess these impacts based on thechanged delta hydrology
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3 DISCUSSION
31 IntroductionThe following sections record the comments made on the foregoing presentationsand the responses given by the hydrology team (in italics)
32 Database Management(1) What is lithology Remember that as much as you are speaking to experts
you are also speaking to non-experts
The point is well taken A glossary will be prepared to explain technical terms
(2) The presentations are too fast and we need details of the graphs for example
This point is also noted presentations should emphasise important pointsSelected slides from the Workshop are included in Annex 3 and a full report is being prepared of both the Integrated Hydrologic Model and the
preliminary scenario analysis These should be studied by thestakeholders in advance of further (bilateral) discussions
(3) Is there a slide to show locations of critical rainfall and flow stations so thatwe could appreciate all the difficulties encountered We would appreciatemuch if we could have locations of all your data sources
The locations of the existing and proposed gauging stations is available inDWA in GIS format The key source for this and information from other sectors and stakeholders will be the Okavango Delta Information System
implemented in HOORC
33 Integrated Hydrologic Model(1) I like your conceptual model but what is applicable in Europe may not
necessarily be applicable here also
The conceptual model is fundamental to the development of a numerical model The conceptual model is strictly formulated for the Okavango Deltabased on available data and scientific publications on the subject Theconceptual model has no relation to European or other climatic conditions
(2) Your evapotranspiration rates are higher than those from Class A pan whenactually the reverse should be true This should be looked into
Actual rates of evapotranspiration (ET) are not necessarily lower than panevaporation owing to a number of factors including pan correction methodcombined free surface ET and vegetation transpiration in flood plains and actual location in the delta versus the location of pan measurements If new documented field data on ET losses are available the hydrology teamwould be happy compare these to model simulations
(3) Is there any physical evidence of flooding
The assessment of the observed flood extent has been based mainly on ananalysis of satellite images from 1984 to 2000 (J McCarthy StockholmUniversity) and DWA water level observations
(4) How do you parameterize your flow in respect to flow resistance
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The Manning resistance coefficient is used to describe the resistance toflow in the river channels and over the flood plains Values for overland flow are distributed according to three vegetation zones based onvegetation mapping (S Ringrose HOORC) Values in the river channelsare ascribed based on channel vegetation descriptions (Dr CK NaiduDWA) Adjustments are made to give a good match with observed flood extent overall water balance and downstream discharges
(5) Your climate input data comprise rainfall evapotranspiration etc fromMaun and Shakawe To what extent can one use a physically based modelwith such a coarse resolution Could we conclude that this is an empiricalmodel
MIKE SHE is a physically based model which implies that the model parameters have a clear physical interpretation as opposed to lumped conceptual models Data measured in single locations may be used toassign parameter values but the parameters used at the current grid scaleof 1km 2 should be regarded as lsquoefficientrsquo parameters representing the
aggregated responseThe lack of input data on distributed rainfall or any other model input doesnot imply that the MIKE SHE model is empirical Maun and Shakawe arethe only two stations in and adjacent to the delta with reliable data Thedelta is not a conventional catchment area where the runoff from individual subcatchments is essential to arrive at the combined flow in themainstream Overland flows mix the runoff from the subcatchments and evapotranspiration dominates Thus a high resolution of the rainfall data isnot of major importance in a general flow model of the delta Nonethelessrecommendations for improved monitoring include rehabilitation of the eight DCPs which measure rainfall and the installation of an additional eight automatic gauges in the delta
(6) Our confidence on the model cannot be based on your numbers
This particular comment was based on relatively consistent outflows for theBaseline and Scenarios This was owing to the nature of the downstreamboundary condition which has since been improved and now shows avariation
The flow leaving the delta (and the model) has passed through anextremely complex hydrologic system flood propagation flow splits among distributaries spills to vast flood plains and swamps evapotranspirationand infiltration The measurement of the discharge upstream is subject toerrors of at least 10 (say 50m 3 s at the flood peak) Differences between
the model computations and the observations cannot better this(7) What resolution should we have confidence on as it pertains to your
model
Given the complexity of the area and the available data model resultsshould not be interpreted looking at single grid values Interpretation based on delta zones or subsystems is more appropriate Five zones based onflood probability have been applied in the scenario demonstration runs and others may be devised according to stakeholdersrsquo needs The minimumarea should cover several square kilometres
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34 Scenarios(1) You have run the scenarios based on dry period(s) Could you please
revise this You might be missing out on recharge to groundwater as aresult of high floods A single high flood could recharge an aquifer for thenext twenty years for example
It is the intention to run the model for a period of normal flows to see how the delta recovers from a drought As suggested the model will also be runfor high floods (this is also important for sediment transport in the delta)
(2) In taking the dry period as critical you have to consider floods as alsocritical Floods need to be covered as well
The delta is not under stress during high flow periods and the impacts of water resources developments will not be so keenly felt and therefore not critical to management planning See also response to (1) above
(3) People are more worried about the switching of channels Maybe thisaspect needs to come out in your model outputs as well
The introduction of sediment transport to the model (which has just commenced) will give an indication of possible future switches and redistribution of delta flows Switching and realignment of channels has achaotic component (the butterfly effect on global climate is akin to ahippopotamus going walkabout in the delta) and accurate predictions aresimply not possible
(4) Looking at the modelrsquos level of resolution critical management issues willnot be answered
The component has been conceived and ToR written (in 200102) toaddress the broad scale management planning issues (water resources
developments upstream climate change abstractions from the delta reed cutting and dredging) On this basis the model approach has been set outand the model set up and applied Preliminary applications suggest that the main threats to the delta will arise from upstream irrigation and climatechange These are the critical management issues related to hydrology
(5) Channel blockages impacts need to be covered in detail Channel switchingis another fundamental management issue
The model can simulate the impact of channel blockages and channel switching As discussed in (3) above the model cannot predict theseoccurrences
(6) You mentioned that your model could handle sediment transport Do youhave something on sediment transport now
An approach to introducing sediment transport to the model has beendrafted (pending report on the Integrated Hydrologic Model)
(7) You seem not to be representing your conditions
See response to (6) above
35 Presentation of Results(1) You canrsquot have a reduction of flow by 40 and yet have no impact on the
outflow This gives me the confidence of your model
See response to (4) above
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(2) The difference in long-term average discharge between observed andsimulations should not be taken to be insignificant This should becombined with other scenarios to better appreciate its impact
It is important in the preliminary stage to separate the impacts fromindividual water resources developments to obtain a good understanding of
which are critical and which are not A limited number of combinationscenarios may be run at a later stage once these can be defined and agreed by the management planners and stakeholders
(3) It would be good to combine all the scenarios as well
See (2) above
(4) It would be interesting also to look at frequency and duration of flooding
The impact on the duration of flooding can be assessed through the timeseries plots for different zones An estimate can also be made on theimpact of the scenarios on the frequency of flooding
(5) What is the model doing as it pertains to erosion and sedimentation
Sediment transport is being introduced to the model This will enable theassessment of the broad pattern of erosion and deposition through themain river channels along which the bed load is conveyed from the basinupstream
(6) The issue of land use change has to be incorporated into the model
To introduce the impact of land use changes in the basin upstream requiresthe application of a water resources planning model to the upstream basinThis is not within the present scope of ODMP which is relying on theoutputs of basinwide projects such as Sharing Water and WERRD (bothcompleted) and possibly in the future TwinBas (ongoing) If ODMP
partners suggest particular potential land use changes within the deltawhich have an impact on the hydrology these may be simulated using theIntegrated Hydrologic Model
(7) The presentations have mostly been technical I would like to suggest thatwe make handouts available after the workshop so that the participantscould have ample time to go over them and later submit their suggestionscomments and or questions
This document represents a full report on the proceedings Further comments from ODMP partners are welcome that our further work may more closely meet the needs of delta management planning Further discussions will be held with the stakeholders on the ongoing model applications possibly on a bilateral basis to obtain a closer understanding of particular needs and ways to meet these needs
36 Stakeholdersrsquo Responses
Wildlife
(1) We need drying flood plain map to better track movement of wild animals
The drying and wetting of the flood plains was presented as animated sequences in the Workshop for all scenarios with a monthly time step Afiner temporal resolution can be prepared (down to four hours) though the
spatial resolution is limited to one kilometre squares
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(2) We would appreciate information on correlations between the distribution of elephants population and extent of flooding close to the buffalo fence
The HampWR component can provide information on the waters of the deltaIt is up to the individual partners to analyse this information for their ownneeds The HampWR component cannot be expected to carry out all the
analyses for the management planThe integration of information from all ODMP components will be carried out within the Okavango Delta Information System implemented inHOORC (also with support from Danida)
Fisheries
(1) Water quality is very critical as this have impact on fish populationdynamics Sedimentation is also critical as it has a bearing on fishpopulations
Sedimentation is indeed critical to fish populations as fine organic richsediment is washed out from the flood plain into the channels by the flood waters resulting in oxygen depletion
The MIKE SHE integrated hydrologic modelling system has the capability tosimulate water quality This is not within the present scope of ODMPSystematic data (including DO and SOD) do not exist at present on whichto develop such a model Improved monitoring recommendations includethe introduction of systematic sampling and analysis at the key inflow station of Mohembo and monthly in-situ measurements of salinity and pH at around 20 discharge stations throughout the delta
Water Affairs
(1) Is MIKE SHE an instrument or whatMIKE SHE is one of a suite of water and environmental software packagesdeveloped and marketed commercially by DHI Water and EnvironmentThe MIKE SHE package is the most advanced generic (can be applied toany system) hydrologic software available MIKE SHE has a consistent development history over thirty years and has been applied to hundreds of hydrologic systems worldwide
(2) Can the model predict channel shifts
The sediment transport model will predict erosion and deposition leading tochannel aggradation and eventual closure The delta morphology isinherently unstable and chaotic and no model can predict channel abandonment with higher certainty than what is constrained by natural variability (chaos) Nonetheless the impact of major channel shifts can be
predicted as well as possible management measures to mitigate suchshifts
(3) Mr Dikgomo mentioned that Hydrology and Water Resources component isone of the twelve What are the other eleven components
The CTA may best respond to this question though it is suggested that representatives from participating organisations take the trouble to informthemselves of the ODMP structure objectives and outputs before attending such fora
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Land Board
(1) Is it possible for the model to give us depth of water table within at least500 metres from the delta This can help us with land use This will alsohelp us determine how far we can avoid pollution in land allocations
The spatial resolution of the model is one square kilometre The model cangive the various hydrologic parameters such a depth to ground water withinthe general area (within a few square kilometres) This should be quiteadequate for the purpose of broad based management planning
(2) Can the model add value to Tawana land board land use and managementplan (2004-2029)
The Hydrology and Water Resources component is concerned withhydrology and water resources The outputs from the component arehydrologic data and predictions for the delta It is up to the various sectorsand components of the management plan to assess the impact of thesehydrologic parameters for their own purposes The HampWR component can
assist in the interpretation of the hydrologic dataTourism
(1) There are lodges and camps located close to the river channels Can themodel be able to help on the implications of pollution
The model can simulate the pattern of flow in the delta which may give auseful indication of the movement of pollution though not the output whichmay be given by a water quality model (advection dispersion decay etc)
General
(1) This component (Hydrology and Water Resources) is so detached from therest It should relocate to MaunThe component is located in Gaborone as the capital has better infrastructure Progress on the component would be constrained by thelimited infrastructure in Maun
(2) To what extent is your data real time series that it could be relied upon
The data available from the delta at present are poor largely owing todifficulties in access and disturbance of gauging stations by humans and large mammalian wildlife Lack of systematic use of the data to date havealso contributed to neglect Improved monitoring is necessary for management planning and an improved hydrologic model with finer
resolution and greater accuracy Recommendations have been prepared for DWA to improve hydrologic monitoring and it is hoped these can beimplemented in the course of 2005
(3) The presentations are too technical When will ODMP reach out to usSomeone mentioned that communication and or information disseminationis a problem Why cant we find other Batswana who could do the job toconvey the information in an audience screened and targeted way
The hydrology of the delta is complex and requires a complex model for arealistic simulation of the processes The presentations were intended togive all participants an understanding that the model is indeed capable of simulating the key hydrologic phenomena of the delta It is hoped that this
has been achieved though it is recognised that the depth of understanding
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will depend upon the level of the individual participantrsquos hydrologic knowledge
The DWA staff assigned to ODMP will gradually take over presentations insuch fora as part of the process of technology transfer which is anessential part of the component
Lessons have been learnt from this Workshop A second and possibly third Workshop will be planned along with bilateral meetings with the individual Stakeholders hopefully improving the communication to the diverse
participants (see Conclusions)
(4) Communications and networking is lagging behind but its pro-activeness isso crucial The component would simplify information and relay it tocommunity andor stakeholders
The HampWR component looks forward to this component being activatedand to cooperating with the Communications and Networking component in
presenting results of the hydrologic analyses meaningful to all
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4 CONCLUSIONS
41 SummaryProf Francis Sefe from the consultantsrsquo team summarised the Workshop discussionas follows
(1) There were discussions on both spatial and temporal resolutions of themodel which need clarification
(2) It was observed that data quality and availability is a constraint to accuratemodelling of the hydrology of the delta and providing physical evidence toback the model conclusions
(3) In the selection of scenarios it is critical to understand that the individualscenarios are not stand alone
(4) The choice of what constitutes the baseline scenario was discussed It hasto be emphasised that the inclusion of exceptional floods is also importantand hence not only the dry period should be used
(5) The presentation was multifaceted
(6) People could not easily locate any landmark features on the map Thisneed not be Villages could be labelled and even the rivers themselves
(7) Though water quality is not in the scope of the current modelling water quality is very important and this has to be looked into in the future
(8) Ground water fluctuations at the periphery of the delta need to be lookedinto
(9) Various stakeholders have difficulty interpreting the results This is a critical
issue that needs to be addressed The target audience should reasonablybe able to assimilate the information relayed to them
42 RecommendationsThe following recommendations are made with regard to the future interactionbetween the Hydrology and Water Resources component and the other ODMPparticipants
(1) While the introductions to the set up and application of the IntegratedHydrologic Model attempted to convey the complexity of the deltahydrology and its computer based representation further effort needs to bemade to present the model and its results in a manner which is fullycomprehensible to the Stakeholders most of whom do not have in depthhydrologic knowledge
(2) It was originally believed that presentation of the model to Stakeholders in acombined forum would allow the interchange of ideas and knowledgeamong the Stakeholders as well as with the Hydrology and Water Resources component The resulting discussion tended to be dominatedby those with technical hydrologic knowledge at the expense of thosewithout The next round of discussions should be on a bilateral basis suchthat the discussions can proceed at a level appropriate for the individualStakeholders and their needs in respect of hydrology and water resources
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(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
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ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
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ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
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Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
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Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
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ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
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List of Contents
1 BACKGROUND
2 PROGRAMME3 PRESENTATIONS AND DISCUSSION
31 Introductions
32 Integrated Hydrologic Model
321 Introduction
322 Conceptual Model
323 Evapotranspiration
324 Surface Waters
325 SubSurface Waters
326 Outputs
4 SCENARIOS
41 Introduction
42 Hydrologic Inputs
43 Presentation of Results
44 Baseline
45 Upstream Water Resources Developments 451 Introduction
452 Dams in Angola
453 Irrigation
46 Abstractions from Delta
47 Climate Change
48 Management Planning
5 DISCUSSION
51 Introduction
52 Database Management
53 Integrated Hydrologic Model
54 Scenarios
55 Presentation of Results
56 Stakeholdersrsquo Responses
6 CONCLUSIONS
61 Summary 62 Recommendations
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1 INTRODUCTION
11 BackgroundThe Hydrology and Water Resources is one of the twelve components comprising theOkavango Delta Management Plan project The project and the componentcommenced in May 2003
The development objective of the Okavango Delta Management Plan is integratedresource management for the Okavango Delta that will ensure its long termconservation and that will provide benefits for the present and future well-being of thepeople through sustainable use of its natural resources
In line with this development objective the immediate objectives for the Hydrologyand Water Resources component are improved water resources planning andmonitoring and evaluation in the Okavango Delta based on an enhanced capacity of the Department of Water Affairs Corresponding to these objectives the outputs of the component are
(1) A comprehensive quality controlled database comprising existing climatichydrologic surface water ground water and sediment data for theOkavango Delta
(2) Recommendations on the improvement and expansion of the OkavangoDelta monitoring network
(3) A digital Topographic Model of the delta
(4) An Integrated Hydrologic Model for the delta
(5) The analyses of the impacts of water resources scenarios for the OkavangoDelta Management Plan
(6) Capability within DWA to maintain and operate the Integrated HydrologicModel for the establishment and implementation of the ODMP
While all aspects of the component were discussed the Workshop focussed onoutputs (4) and (5) the Integrated Hydrologic Model and its application to impacts of water resources developments in the delta and the basin upstream with commentsand discussion on the model and the format of the presentation of the outputs
12 ObjectiveThe Hydrology and Water Resources workshop was convened to
bull Inform project partner institutions and the community about the role of the integrated hydrologic model in management planning
bull Afford the project partner institutions and the community theopportunity to comment on the outputs of the model and to suggestways in which the outputs or result can be made usable by them
bull Afford the project partner institutions and the community theopportunity to suggest management scenarios relevant to their respective institutions
bull Ensure that this component is community driven or encompasses theviews of the majority of the stakeholders from the beginning
bull
Guarantee ownership commitment and sustainability of the projectbull Minimise risk during implementation of entire management planning
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13 ProgrammeThe programme for the one day Workshop is presented in Annex 1 The first sessioncovered the background to the establishment and the implementation of thecomponent in DWA the recommendations for improved hydrologic monitoring in thedelta and their pending implementation and data collection and management
This was followed by a description of the Integrated Hydrologic Modelling system andits set up to represent the hydrology of the Okavango Delta The next four presentations covered the application of the model to represent existingdevelopments in the delta and the basin upstream and hydrologic conditions as theywould be in the delta given the implementation of a range of potential water resourcesdevelopments Each presentation was followed by a discussion session
The team implementing the component comprises DWA staff and national andinternational consultants An important output from the component is capacitybuilding in DWA to maintain and operate the Integrated Hydrologic Model Thisentails technology transfer from the consultants to the DWA staff The technologytransfer is carried out in a three pronged approach
bull A series of formal training courses in DWA Gaborone on the mainelements of integrated hydrologic modelling
bull On-the-job training whereby the DWA staff learn by doing setting upand applying the model under the guidance and supervision of theconsultants
bull Overseas training most likely MSc courses in recognised internationalhydrologic institutions
DWA has assigned four permanent staff members to work full time on ODMP Aspart of the technology transfer process each of these four staff presented an aspect
of the model application in the WorkshopThe presentation of the model and its application was followed by an open discussionby the participants Each sector was given a slot to allow the representatives to voicetheir particular comments
The model results at this stage are preliminary and the focus was more on are thehydrologic and water resources development data appropriate and is thepresentation format of the results meaningful and useful to the respective ODMPsectors in the context of the Okavango Delta Management Plan
14 ParticipationThe list of participants is given in Annex 2 Despite an early dispatch of invitationletters in advance to representatives of the different components it became apparentthat most components were not represented at the workshop Most notableabsences were from the technically oriented components such as SustainableLivestock Management Vegetation Resources Management Waste Managementetc
Of the components that were present it appeared that these representatives were notfamiliar with the project or are not dealing with the project on a daily basis judgingfrom their contribution to the discussions on the role of the Hydrology and Water Resources component It appears that project partner institutions still have acombined workload of their routine work and new duties related to ODMP Thisadded responsibility is somewhat too great and affects the ability of project officers todeliver efficiently and effectively
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Each component should identify a suitable person to act as a focal point for liaisonwith the Hydrology and Water Resources component and this person should attendfuture such workshops and meetings
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2 PRESENTATIONS AND DISCUSSION
21 IntroductionsSelected slides from those employed in the respective presentations are included inAnnex 3 and illustrate the text of the presentations in the following sections
The introductory presentations covered the component background implementationdata collection and processing and monitoring proposals As such they generatedlimited discussion One suggestion was that as most of the stakeholders were fromsectors other than water a glossary should be included to cover the use of technicalterms
22 Integrated Hydrologic Model
221 Introduction
The Introduction to the Integrated Hydrologic Model set out the approach tomathematical modelling in the context of the hydrology of the delta The key flowprocesses above in and below the delta are shown in slide 1 Given the criticallinkages among the atmospheric surface and ground waters it is necessary todevelop an Integrated Hydrological Model which integrates the essential physicalphenomena controlling the delta As such the model requires a basis in physicalprocesses as opposed to a conceptual model which has an idealised representation
It is not the intention to set up a detailed model The available data do not justify thisand the project resources are not available The model will be somewhat schematicbut nonetheless capable of describing the essential processes such as the overallflow pattern among the distributaries flooding and drainage of seasonal swampareas The model will not be capable of predicting the small scale vegetation andmorphological changes which appear to have a significant impact on the overall flowpattern
Water and its distribution in space and time is the fundamental physical basis for management of the ecosystem Management criteria for the delta could include
bull Maintain present flood extent and duration
bull Maintain current pattern of flows through the delta
bull Minimise adverse impacts on any part of the interconnected hydrologicalsystem
The distinct environments and key hydrologic phenomena were presented illustratingthe complex interactions among the atmospheric surface and subsurfacecomponents of the wetland
In order to have a realistic representation of these key phenomena and their interactions and to make quantitative prediction of the potential effects of changes inwater use it is necessary to employ an Integrated Hydrologic Model The systemselected is MIKE SHE developed by DHI Water and Environment Denmark Thegeneric system (the software can be applied to any hydrologic system) is marketedcommercially and is applied to hundreds of catchments and wetlands worldwide
The key features of the software package are (slide 2)
bull Physically based with a realistic representation of the hydrologic
phenomena based on the laws of physics
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(slide 3) The vegetation dynamics are based on remotely sensed data with limitedground verification (see slides 4 and 5) The relationship between the extent of surface water and the rate of evapotranspiration is shown for the normally andseasonally flooded areas in slide 6
224 Surface Waters
The surface water flows are dependent on the topography of the delta which hasbeen described by a digital elevation model of the Ramsar area with a 30m resolutionbased on aerial radar altimetry and remote sensing and a limited number of channelcross sections available at gauging stations and surveyed by researchers
The key characteristics of the delta are the numerous bifurcations or defluences (asopposed to confluences) extensive spills to the flood plains and swamps andhydraulic connections among the spill areas and slow flood wave propagation(around four months from upstream to downstream) with a high variation in the extentof flooding (slide 7)
The surface waters of the delta are described by a full hydrodynamic representationof the flows in the main rivers and channels and by a distributed kinematicrepresentation of the flows over the flood plains and through the swamps Thedescriptions are fully coupled (slide 8) and enable the representation of theessentially one dimensional flows through the channels giving definition to the flowand the spreading and distributed storage over the flood plain (slide 9)
225 SubSurface Waters
Infiltration rates are significant on the predominantly sandy soils in the early stages of the flood season The infiltration raises the ground water levels up to the flood water level This increases the water available to plants which in turn increasestranspiration from the leaf surfaces to the atmosphere (slide 10)
An essential component is the inclusion of the critical unsaturated root zone the zonefrom which plants draw water and transpire to the atmosphere Together withevaporation from open water this is represents the main loss of water in the deltaThe evapotranspiration component simulates both the hydrologic and vegetationdynamics (slide 11)
The ground water component is important to account for the local effects of groundwater on the water balance ie recharge and discharge and evapotranspirationlosses Only the surficial ground water aquifer is represented (slide 12)
Detailed ground water studies show infiltration and recharge of fresh water lensesembedded in older saline ground water Given the low topographical relief limited
ground water flow is directed towards local depressions (slide 13) Model water balance tests indicate that there is no significant ground water flow from the delta nor are there data to support such flow hypotheses Consequently there is no flowacross the subsurface model boundary
226 Outputs
The outputs from the model are designed to support broad based managementplanning in the Okavango Delta The outputs are presented in grid or map formatshowing the spatial variation in the parameters over the delta time series (plots of various parameters against time) and summary tables of results The outputs may besummarised as
bull The actual evaporation from open water and the transpiration fromvegetation
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bull Surface water levels and flows through the rivers and over the floodedswamp areas and the extent of flooding
bull The moisture content of the soil
bull The ground water levels and flows
bull The overall water balance including inflows outflows and changes insurface and subsurface storage for the delta and selected areas of thedelta
bull Sediment transport along the main channels of the delta showingpatterns of erosion and deposition
The Integrated Hydrologic Model does have practical certain limitations and it isimportant that these are recognised by the stakeholders and management planners
Channel Switching
While the model can predict the impact of cutting and dredging a new channel
through the delta and the impact of closing an existing channel through theencroachment of vegetation it is not able to predict the occurrence of the formation of new channels and the realignment of existing channels which may be initiated by themovement patterns of large mammals and vegetation growth
Certain trends in sedimentation and channel development and decay may bepredicted by the application of sediment transport to the model Work on this areahas just commenced Detailed analyses of selected reaches and areas of the deltamay be carried out through the application of two dimensional morphological modelsThis is beyond the scope of the present component activities
Level of Detail and Accuracy
While the technology exists to simulate the hydrologic behaviour of the delta at a highlevel of detail (previous applications have been made at the level of individualcultivated fields) this is constrained by
bull The resources available to the component do not permit thedevelopment of submodels which could enable the study of a particular area of the delta below the present one square kilometre resolution
bull The available data do not justify high expectations on the level of accuracy with respect to absolute water levels and quantitiesRecommendations have been made for improved data collection andmanagement which when available could justify further modeldevelopment
The key issue at this stage is that the Integrated Hydrologic Model represents theessential hydrologic phenomena in an integrated manner such that it may be appliedwith confidence to the assessment of the impacts of future water resourcesdevelopments on the delta hydrology for the purposes of the management plan
Physical Phenomena
The model simulates physical hydrological phenomena only Studies have revealedin particular the importance of the interdependency of physical and biologicalphenomena for example the movement of large mammals opening new flow pathsthrough the vegetation sedimentation and vegetation in closing existing channels
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bull The data should reflect how the delta may recover in a period of normal inflows after a dry period
The long term inflow in terms of volume per annum from 1933 to date is shown inslide 14 for both Mukwe in Namibia and Mohembo in Botswana Whereas at Mukwethe river is more or less confined to the gauged channel at Mohembo the river has
broadened out with a wide flood plain It is not possible to gauge the flows over theflood plain and Mohembo will not represent the total discharge This is most clearlyevinced in the high flow years 199899 and 200001
An anomaly appears in the data from around 1950 to 1980 where the total inflow atMohembo appears higher than Mukwe As there is no significant inflow to the river between the two gauges this can only be explained by gauging errors The seriesafter 1980 is more consistent with Mukwe showing a higher inflow than Mohembo
The period from 1992 to 1997 represents the sequence of the five lowest inflowyears and is therefore chosen to provide the input data to analyse the impacts under critical conditions for both the existing state and possible future states with water resources developments
The following five year period from 1997 to 2002 represents relatively normalhydrologic conditions in the delta and has been used to assess how the delta mayrecover after a sequence of dry years (see slide 15)
A high inflow period could also be selected eg 1987 to 1992 to assess the impactsunder high inflow conditions It is not planned to analyse this period as
bull The conditions will not be critical to a management planning exercise
bull The number of impacts which have to be assessed in terms of flowsdepths etc will be further increased
Appropriate time series of inputs (inflows precipitation etc) have been prepared and
applied to the existing state of the delta The model results are used as a baselineagainst which future developments are assessed for their impacts The inputs aremodified to represent conditions which may prevail under future conditions
To summarise while the inflows to the delta will be dynamic ranging over two fiveyear periods representing critical dry and normal average hydrologic conditions theexisting and future states will be static This implies that for the duration of the fiveyear model run period the population for instance will not be increasing no newdams or irrigation schemes are built etc
At present the Baseline and Scenario Conditions have been simulated for the criticaldry hydrologic input period from October 1992 to October 1997 Summary results arepresented and discussed in the following sections Slides illustrating the outputs arepresented in Annex 3
233 Presentation of Results
In order to assist the stakeholders assess the outputs and their implications for their particular sectors a common format for the presentation is adopted The resolutionof the model in space is one kilometre and in time four hours In order to limit thesize of the output files the results are output with a temporal resolution of one weekfor surface flows and the unsaturated zone while the slower responding ground water results are output every two months of the five year period
For the purpose of presenting summary data the delta is divided into five zonesaccording to the probability of flooding as assessed from 15 years of satellite images(source J McCarthy Stockholm University) with the Panhandle treated as a fifth
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separate zone (slide 16) The probability delta area and a zone description are givenin the table
Model Area (km 2) 28782 Description
Zone 1 - 01gtFPgt0 19322 rarely flooded
Zone 2 - 05gtFPgt01 3534 occasionally flooded
Zone 3 - 09gtFPgt05 2328 seasonally flooded
Zone 4 - 1gtFPgt09 2152 normally flooded
Zone 5 - Panhandle 1446 Panhandle
(1) Animated sequence of flooding in the delta showing the monthly variation inflooded area and depth (The AVI format file is available from DWA sizearound 110Mb)
(2) Map based on the one kilometre grid showing the minimum depth of water in the delta for the five dry years
(3) Time series showing the variation in the depth of flooding over the five year period The depth is averaged for each of five zones (see table)
(4) Map based on the one kilometre grid showing the minimum level of soilmoisture in the root zone (the zone from which plants draw water) in thedelta over the five dry years
(5) Map based on the one kilometre grid showing the maximum depth toground water in the delta over the five dry years
(6) Summary tables are prepared showing the following
bull Water balance showing inflows outflows and storage changes
bull Baseline conditions and impacts for the surface water soilmoisture and ground water for the entire delta and for each of the five zones
A wide range of outputs of all hydrologic parameters in various formats is possibleand can be tailored to the needs of the individual stakeholders It is possible also toselect different zones to calculate average time series and summary results Theabove selection has been made by the component as samples of what may be usefuland meaningful to the stakeholders and to generate discussion
24 Baseline
Surface Water
The animated depth of flow sequence (slide 17) shows the expansion and contractionof the flooded area and depth as the sequence of flood waves for each of the fiveyears propagates through the Panhandle and spreads out through the delta Slide 18shows the detail for the lower envelope of flooding for the upper delta Each squareis one square kilometre
Time series of the depth of surface water are shown for each of the five zones in slide19 The Panhandle is the first area affected by the flood wave from upstream andbeing relatively confined within a flood plain around 20km wide has the maximumrange from the seasonal wet to dry periods around 06m through the five dry yearsAs the flood wave propagates through the delta the range in water levels declines
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The accumulated impact of the drought years is also felt more as there is a generaldecline in the flood depth
As the summary table (slide 20) shows the area flooded ranges from 1513km 2 to12077km 2 while the depth ranges from 0 to around 5m The average depth in thenormally flooded area ranges from 011m to 092m
SubSurface Water
The distribution of the soil moisture content is shown as a deficit below saturatedlevel as the lower envelope (maximum deficit) for the five year period in slide 21The average deficit ranges from 056m in the rarely flooded area to 012m in thenormally flooded area
The depth to ground water over the delta area is shown for the lower envelope(maximum depth) over the five year period in slide 22 The depth ranges from anaverage of 188m in the rarely flooded area to 037m in the normally flooded area
Water Balance
The overall water balance for the Baseline and Scenarios is shown in slide 23Negative values indicate an inflow to the delta (eg precipitation and river inflow) whilepositive values indicate an outflow (eg evapotranspiration and river outflows) TheTotal should be zero the small value indicates a very minor continuity error Thenegative overland and subsurface storage changes indicate a decline in storage inthese levels
25 Upstream Water Resources Developments
251 Introduction
To date no significant water resources developments have taken place upstream inAngola and Namibia In the past plans have been made for the construction of damsfor irrigation and hydropower Anticipating that these plans may be revived theWERRD project has run a number of scenarios using a modified rainfall-runoff modelof the basin (Pitman model Rhodes University) including a scenario for all planneddams
A number of sources describes potential irrigation in the upstream basin in Angolaand Namibia These have been reviewed and a potential scenario compiled basedon
bull Irrigation demand based on 15000m 3haa with a 25 return flow
bull Irrigated area in Angola 54500ha in Namibia 7500ha
bull Angola grows vegetables in winter (June to October) Namibia growsmaize in summer (December to April)
The corresponding runoff from the upstream basin has been applied under twoscenarios Dams in Angola and Irrigation as inflow to the delta upstream The twopotential developments are kept separate for the purpose of initial appraisal in order that the impact from each can be identified This will assist in minimising the adverseimpacts from these developments
252 Dams in Angola
The impact of the previously planned hydropower dams in Angola on the inflow to the
delta is presented in slide 24 Hydropower development does not consume waterbut stores water in the flood period for release in the dry period This results in a
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redistribution of the natural hydrograph flood flows are reduced while dry seasonflows are increased (The impact appears only to be significant in 1993 and 1996 ndashthis needs further investigation)
The impact of the dams on the surface and subsurface waters of the delta is minimalgiven the limited apparent impact in three out of the five dry years and the fact that
there is no nett water loss in the basin upstream
253 Irrigation
The impact of the potential irrigation scenario on the inflow to the delta is shown inslide 25 The impact is greatest in the dry period when water is withdrawn for therelatively large area of winter crops in Angola The summer withdrawals for irrigationin Namibia are significantly less
Correspondingly the impact on the delta in the flood period is minimal while in thedry period the overland depth of flow is reduced particularly in the Panhandle andnormally flooded areas and the minimum flood extent is reduced by 660km 2 or 40of the present dry period area (slide 26)
26 Abstractions from DeltaWater for largely local domestic use is abstracted from both the surface and groundwaters of the delta The surface water abstractions are based on water rights issuedby DWA (ie the amount which may legitimately be withdrawn ndash actual withdrawals arenot monitored and may be greater or less than allowed) Ground water abstractionsare based on the demands projected from historic information to the present day
In terms of the inflows to the delta (river flows from the basin upstream andprecipitation over the basin the abstractions and corresponding impacts are minimalSurface water abstraction represents 0006 of the inflow and ground water 02In the five dry years analysed the minimum flooded area is reduced by 025Future scenario runs will simulate the impact of abstractions with projected increasedpopulation and rates of consumption to the notional year 2025
27 Climate ChangePotential climate change will have an impact on the delta in respect of inflows fromthe basin upstream and the climate over the delta The WERRD project has run aglobal climate model HadCM3 1 to predict the changed precipitation and temperatureover the basin For the upstream basin the Pitman rainfall-runoff model has beenapplied to predict the modified inflows upstream of the delta (slide 27) The modifiedprecipitation and temperature over the delta have been used as direct inputs to theIntegrated Hydrologic Model (slide 28)
The impact of the climate change scenario is highly significant in both the flood anddry seasons River inflows to the delta are reduced by 38 and precipitation over the delta by 9 Temperature increases by 22ordmC
The corresponding impact on flow depths is shown on the reduced depths the impacton the minimum depths is shown for the Panhandle and normally flooded areas inslide 29 and in each of the five zones through the five year run period in slide 30The reduction in depth averages 003m over the entire delta and the minimumflooded area is almost halved
1 httpwwwmet-officegovukresearchhadleycentremodelsHadCM3html
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28 Management PlanningThe model analyses are carried out to assess the impacts of possible future basinconditions on the delta for the purposes of management planning An iterativeprocess is envisaged with a series of bilateral meetings with the Stakeholders andcommon Workshops in which the inputs and outputs are presented to and discussedwith the stakeholders The outputs can migrate towards a presentation format that isboth meaningful and relevant to the stakeholders
The Hydrology and Water Resources component will only analyse the impacts on thewaters of the delta DWA and its consultants do not have the capability or theresources to analyse the impacts on the wildlife vegetation livestock fisheries or tourists It is up to these respective sectors to assess these impacts based on thechanged delta hydrology
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3 DISCUSSION
31 IntroductionThe following sections record the comments made on the foregoing presentationsand the responses given by the hydrology team (in italics)
32 Database Management(1) What is lithology Remember that as much as you are speaking to experts
you are also speaking to non-experts
The point is well taken A glossary will be prepared to explain technical terms
(2) The presentations are too fast and we need details of the graphs for example
This point is also noted presentations should emphasise important pointsSelected slides from the Workshop are included in Annex 3 and a full report is being prepared of both the Integrated Hydrologic Model and the
preliminary scenario analysis These should be studied by thestakeholders in advance of further (bilateral) discussions
(3) Is there a slide to show locations of critical rainfall and flow stations so thatwe could appreciate all the difficulties encountered We would appreciatemuch if we could have locations of all your data sources
The locations of the existing and proposed gauging stations is available inDWA in GIS format The key source for this and information from other sectors and stakeholders will be the Okavango Delta Information System
implemented in HOORC
33 Integrated Hydrologic Model(1) I like your conceptual model but what is applicable in Europe may not
necessarily be applicable here also
The conceptual model is fundamental to the development of a numerical model The conceptual model is strictly formulated for the Okavango Deltabased on available data and scientific publications on the subject Theconceptual model has no relation to European or other climatic conditions
(2) Your evapotranspiration rates are higher than those from Class A pan whenactually the reverse should be true This should be looked into
Actual rates of evapotranspiration (ET) are not necessarily lower than panevaporation owing to a number of factors including pan correction methodcombined free surface ET and vegetation transpiration in flood plains and actual location in the delta versus the location of pan measurements If new documented field data on ET losses are available the hydrology teamwould be happy compare these to model simulations
(3) Is there any physical evidence of flooding
The assessment of the observed flood extent has been based mainly on ananalysis of satellite images from 1984 to 2000 (J McCarthy StockholmUniversity) and DWA water level observations
(4) How do you parameterize your flow in respect to flow resistance
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The Manning resistance coefficient is used to describe the resistance toflow in the river channels and over the flood plains Values for overland flow are distributed according to three vegetation zones based onvegetation mapping (S Ringrose HOORC) Values in the river channelsare ascribed based on channel vegetation descriptions (Dr CK NaiduDWA) Adjustments are made to give a good match with observed flood extent overall water balance and downstream discharges
(5) Your climate input data comprise rainfall evapotranspiration etc fromMaun and Shakawe To what extent can one use a physically based modelwith such a coarse resolution Could we conclude that this is an empiricalmodel
MIKE SHE is a physically based model which implies that the model parameters have a clear physical interpretation as opposed to lumped conceptual models Data measured in single locations may be used toassign parameter values but the parameters used at the current grid scaleof 1km 2 should be regarded as lsquoefficientrsquo parameters representing the
aggregated responseThe lack of input data on distributed rainfall or any other model input doesnot imply that the MIKE SHE model is empirical Maun and Shakawe arethe only two stations in and adjacent to the delta with reliable data Thedelta is not a conventional catchment area where the runoff from individual subcatchments is essential to arrive at the combined flow in themainstream Overland flows mix the runoff from the subcatchments and evapotranspiration dominates Thus a high resolution of the rainfall data isnot of major importance in a general flow model of the delta Nonethelessrecommendations for improved monitoring include rehabilitation of the eight DCPs which measure rainfall and the installation of an additional eight automatic gauges in the delta
(6) Our confidence on the model cannot be based on your numbers
This particular comment was based on relatively consistent outflows for theBaseline and Scenarios This was owing to the nature of the downstreamboundary condition which has since been improved and now shows avariation
The flow leaving the delta (and the model) has passed through anextremely complex hydrologic system flood propagation flow splits among distributaries spills to vast flood plains and swamps evapotranspirationand infiltration The measurement of the discharge upstream is subject toerrors of at least 10 (say 50m 3 s at the flood peak) Differences between
the model computations and the observations cannot better this(7) What resolution should we have confidence on as it pertains to your
model
Given the complexity of the area and the available data model resultsshould not be interpreted looking at single grid values Interpretation based on delta zones or subsystems is more appropriate Five zones based onflood probability have been applied in the scenario demonstration runs and others may be devised according to stakeholdersrsquo needs The minimumarea should cover several square kilometres
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34 Scenarios(1) You have run the scenarios based on dry period(s) Could you please
revise this You might be missing out on recharge to groundwater as aresult of high floods A single high flood could recharge an aquifer for thenext twenty years for example
It is the intention to run the model for a period of normal flows to see how the delta recovers from a drought As suggested the model will also be runfor high floods (this is also important for sediment transport in the delta)
(2) In taking the dry period as critical you have to consider floods as alsocritical Floods need to be covered as well
The delta is not under stress during high flow periods and the impacts of water resources developments will not be so keenly felt and therefore not critical to management planning See also response to (1) above
(3) People are more worried about the switching of channels Maybe thisaspect needs to come out in your model outputs as well
The introduction of sediment transport to the model (which has just commenced) will give an indication of possible future switches and redistribution of delta flows Switching and realignment of channels has achaotic component (the butterfly effect on global climate is akin to ahippopotamus going walkabout in the delta) and accurate predictions aresimply not possible
(4) Looking at the modelrsquos level of resolution critical management issues willnot be answered
The component has been conceived and ToR written (in 200102) toaddress the broad scale management planning issues (water resources
developments upstream climate change abstractions from the delta reed cutting and dredging) On this basis the model approach has been set outand the model set up and applied Preliminary applications suggest that the main threats to the delta will arise from upstream irrigation and climatechange These are the critical management issues related to hydrology
(5) Channel blockages impacts need to be covered in detail Channel switchingis another fundamental management issue
The model can simulate the impact of channel blockages and channel switching As discussed in (3) above the model cannot predict theseoccurrences
(6) You mentioned that your model could handle sediment transport Do youhave something on sediment transport now
An approach to introducing sediment transport to the model has beendrafted (pending report on the Integrated Hydrologic Model)
(7) You seem not to be representing your conditions
See response to (6) above
35 Presentation of Results(1) You canrsquot have a reduction of flow by 40 and yet have no impact on the
outflow This gives me the confidence of your model
See response to (4) above
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(2) The difference in long-term average discharge between observed andsimulations should not be taken to be insignificant This should becombined with other scenarios to better appreciate its impact
It is important in the preliminary stage to separate the impacts fromindividual water resources developments to obtain a good understanding of
which are critical and which are not A limited number of combinationscenarios may be run at a later stage once these can be defined and agreed by the management planners and stakeholders
(3) It would be good to combine all the scenarios as well
See (2) above
(4) It would be interesting also to look at frequency and duration of flooding
The impact on the duration of flooding can be assessed through the timeseries plots for different zones An estimate can also be made on theimpact of the scenarios on the frequency of flooding
(5) What is the model doing as it pertains to erosion and sedimentation
Sediment transport is being introduced to the model This will enable theassessment of the broad pattern of erosion and deposition through themain river channels along which the bed load is conveyed from the basinupstream
(6) The issue of land use change has to be incorporated into the model
To introduce the impact of land use changes in the basin upstream requiresthe application of a water resources planning model to the upstream basinThis is not within the present scope of ODMP which is relying on theoutputs of basinwide projects such as Sharing Water and WERRD (bothcompleted) and possibly in the future TwinBas (ongoing) If ODMP
partners suggest particular potential land use changes within the deltawhich have an impact on the hydrology these may be simulated using theIntegrated Hydrologic Model
(7) The presentations have mostly been technical I would like to suggest thatwe make handouts available after the workshop so that the participantscould have ample time to go over them and later submit their suggestionscomments and or questions
This document represents a full report on the proceedings Further comments from ODMP partners are welcome that our further work may more closely meet the needs of delta management planning Further discussions will be held with the stakeholders on the ongoing model applications possibly on a bilateral basis to obtain a closer understanding of particular needs and ways to meet these needs
36 Stakeholdersrsquo Responses
Wildlife
(1) We need drying flood plain map to better track movement of wild animals
The drying and wetting of the flood plains was presented as animated sequences in the Workshop for all scenarios with a monthly time step Afiner temporal resolution can be prepared (down to four hours) though the
spatial resolution is limited to one kilometre squares
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(2) We would appreciate information on correlations between the distribution of elephants population and extent of flooding close to the buffalo fence
The HampWR component can provide information on the waters of the deltaIt is up to the individual partners to analyse this information for their ownneeds The HampWR component cannot be expected to carry out all the
analyses for the management planThe integration of information from all ODMP components will be carried out within the Okavango Delta Information System implemented inHOORC (also with support from Danida)
Fisheries
(1) Water quality is very critical as this have impact on fish populationdynamics Sedimentation is also critical as it has a bearing on fishpopulations
Sedimentation is indeed critical to fish populations as fine organic richsediment is washed out from the flood plain into the channels by the flood waters resulting in oxygen depletion
The MIKE SHE integrated hydrologic modelling system has the capability tosimulate water quality This is not within the present scope of ODMPSystematic data (including DO and SOD) do not exist at present on whichto develop such a model Improved monitoring recommendations includethe introduction of systematic sampling and analysis at the key inflow station of Mohembo and monthly in-situ measurements of salinity and pH at around 20 discharge stations throughout the delta
Water Affairs
(1) Is MIKE SHE an instrument or whatMIKE SHE is one of a suite of water and environmental software packagesdeveloped and marketed commercially by DHI Water and EnvironmentThe MIKE SHE package is the most advanced generic (can be applied toany system) hydrologic software available MIKE SHE has a consistent development history over thirty years and has been applied to hundreds of hydrologic systems worldwide
(2) Can the model predict channel shifts
The sediment transport model will predict erosion and deposition leading tochannel aggradation and eventual closure The delta morphology isinherently unstable and chaotic and no model can predict channel abandonment with higher certainty than what is constrained by natural variability (chaos) Nonetheless the impact of major channel shifts can be
predicted as well as possible management measures to mitigate suchshifts
(3) Mr Dikgomo mentioned that Hydrology and Water Resources component isone of the twelve What are the other eleven components
The CTA may best respond to this question though it is suggested that representatives from participating organisations take the trouble to informthemselves of the ODMP structure objectives and outputs before attending such fora
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Land Board
(1) Is it possible for the model to give us depth of water table within at least500 metres from the delta This can help us with land use This will alsohelp us determine how far we can avoid pollution in land allocations
The spatial resolution of the model is one square kilometre The model cangive the various hydrologic parameters such a depth to ground water withinthe general area (within a few square kilometres) This should be quiteadequate for the purpose of broad based management planning
(2) Can the model add value to Tawana land board land use and managementplan (2004-2029)
The Hydrology and Water Resources component is concerned withhydrology and water resources The outputs from the component arehydrologic data and predictions for the delta It is up to the various sectorsand components of the management plan to assess the impact of thesehydrologic parameters for their own purposes The HampWR component can
assist in the interpretation of the hydrologic dataTourism
(1) There are lodges and camps located close to the river channels Can themodel be able to help on the implications of pollution
The model can simulate the pattern of flow in the delta which may give auseful indication of the movement of pollution though not the output whichmay be given by a water quality model (advection dispersion decay etc)
General
(1) This component (Hydrology and Water Resources) is so detached from therest It should relocate to MaunThe component is located in Gaborone as the capital has better infrastructure Progress on the component would be constrained by thelimited infrastructure in Maun
(2) To what extent is your data real time series that it could be relied upon
The data available from the delta at present are poor largely owing todifficulties in access and disturbance of gauging stations by humans and large mammalian wildlife Lack of systematic use of the data to date havealso contributed to neglect Improved monitoring is necessary for management planning and an improved hydrologic model with finer
resolution and greater accuracy Recommendations have been prepared for DWA to improve hydrologic monitoring and it is hoped these can beimplemented in the course of 2005
(3) The presentations are too technical When will ODMP reach out to usSomeone mentioned that communication and or information disseminationis a problem Why cant we find other Batswana who could do the job toconvey the information in an audience screened and targeted way
The hydrology of the delta is complex and requires a complex model for arealistic simulation of the processes The presentations were intended togive all participants an understanding that the model is indeed capable of simulating the key hydrologic phenomena of the delta It is hoped that this
has been achieved though it is recognised that the depth of understanding
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will depend upon the level of the individual participantrsquos hydrologic knowledge
The DWA staff assigned to ODMP will gradually take over presentations insuch fora as part of the process of technology transfer which is anessential part of the component
Lessons have been learnt from this Workshop A second and possibly third Workshop will be planned along with bilateral meetings with the individual Stakeholders hopefully improving the communication to the diverse
participants (see Conclusions)
(4) Communications and networking is lagging behind but its pro-activeness isso crucial The component would simplify information and relay it tocommunity andor stakeholders
The HampWR component looks forward to this component being activatedand to cooperating with the Communications and Networking component in
presenting results of the hydrologic analyses meaningful to all
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4 CONCLUSIONS
41 SummaryProf Francis Sefe from the consultantsrsquo team summarised the Workshop discussionas follows
(1) There were discussions on both spatial and temporal resolutions of themodel which need clarification
(2) It was observed that data quality and availability is a constraint to accuratemodelling of the hydrology of the delta and providing physical evidence toback the model conclusions
(3) In the selection of scenarios it is critical to understand that the individualscenarios are not stand alone
(4) The choice of what constitutes the baseline scenario was discussed It hasto be emphasised that the inclusion of exceptional floods is also importantand hence not only the dry period should be used
(5) The presentation was multifaceted
(6) People could not easily locate any landmark features on the map Thisneed not be Villages could be labelled and even the rivers themselves
(7) Though water quality is not in the scope of the current modelling water quality is very important and this has to be looked into in the future
(8) Ground water fluctuations at the periphery of the delta need to be lookedinto
(9) Various stakeholders have difficulty interpreting the results This is a critical
issue that needs to be addressed The target audience should reasonablybe able to assimilate the information relayed to them
42 RecommendationsThe following recommendations are made with regard to the future interactionbetween the Hydrology and Water Resources component and the other ODMPparticipants
(1) While the introductions to the set up and application of the IntegratedHydrologic Model attempted to convey the complexity of the deltahydrology and its computer based representation further effort needs to bemade to present the model and its results in a manner which is fullycomprehensible to the Stakeholders most of whom do not have in depthhydrologic knowledge
(2) It was originally believed that presentation of the model to Stakeholders in acombined forum would allow the interchange of ideas and knowledgeamong the Stakeholders as well as with the Hydrology and Water Resources component The resulting discussion tended to be dominatedby those with technical hydrologic knowledge at the expense of thosewithout The next round of discussions should be on a bilateral basis suchthat the discussions can proceed at a level appropriate for the individualStakeholders and their needs in respect of hydrology and water resources
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(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
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ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
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ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
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Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
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Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
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ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
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1 INTRODUCTION
11 BackgroundThe Hydrology and Water Resources is one of the twelve components comprising theOkavango Delta Management Plan project The project and the componentcommenced in May 2003
The development objective of the Okavango Delta Management Plan is integratedresource management for the Okavango Delta that will ensure its long termconservation and that will provide benefits for the present and future well-being of thepeople through sustainable use of its natural resources
In line with this development objective the immediate objectives for the Hydrologyand Water Resources component are improved water resources planning andmonitoring and evaluation in the Okavango Delta based on an enhanced capacity of the Department of Water Affairs Corresponding to these objectives the outputs of the component are
(1) A comprehensive quality controlled database comprising existing climatichydrologic surface water ground water and sediment data for theOkavango Delta
(2) Recommendations on the improvement and expansion of the OkavangoDelta monitoring network
(3) A digital Topographic Model of the delta
(4) An Integrated Hydrologic Model for the delta
(5) The analyses of the impacts of water resources scenarios for the OkavangoDelta Management Plan
(6) Capability within DWA to maintain and operate the Integrated HydrologicModel for the establishment and implementation of the ODMP
While all aspects of the component were discussed the Workshop focussed onoutputs (4) and (5) the Integrated Hydrologic Model and its application to impacts of water resources developments in the delta and the basin upstream with commentsand discussion on the model and the format of the presentation of the outputs
12 ObjectiveThe Hydrology and Water Resources workshop was convened to
bull Inform project partner institutions and the community about the role of the integrated hydrologic model in management planning
bull Afford the project partner institutions and the community theopportunity to comment on the outputs of the model and to suggestways in which the outputs or result can be made usable by them
bull Afford the project partner institutions and the community theopportunity to suggest management scenarios relevant to their respective institutions
bull Ensure that this component is community driven or encompasses theviews of the majority of the stakeholders from the beginning
bull
Guarantee ownership commitment and sustainability of the projectbull Minimise risk during implementation of entire management planning
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13 ProgrammeThe programme for the one day Workshop is presented in Annex 1 The first sessioncovered the background to the establishment and the implementation of thecomponent in DWA the recommendations for improved hydrologic monitoring in thedelta and their pending implementation and data collection and management
This was followed by a description of the Integrated Hydrologic Modelling system andits set up to represent the hydrology of the Okavango Delta The next four presentations covered the application of the model to represent existingdevelopments in the delta and the basin upstream and hydrologic conditions as theywould be in the delta given the implementation of a range of potential water resourcesdevelopments Each presentation was followed by a discussion session
The team implementing the component comprises DWA staff and national andinternational consultants An important output from the component is capacitybuilding in DWA to maintain and operate the Integrated Hydrologic Model Thisentails technology transfer from the consultants to the DWA staff The technologytransfer is carried out in a three pronged approach
bull A series of formal training courses in DWA Gaborone on the mainelements of integrated hydrologic modelling
bull On-the-job training whereby the DWA staff learn by doing setting upand applying the model under the guidance and supervision of theconsultants
bull Overseas training most likely MSc courses in recognised internationalhydrologic institutions
DWA has assigned four permanent staff members to work full time on ODMP Aspart of the technology transfer process each of these four staff presented an aspect
of the model application in the WorkshopThe presentation of the model and its application was followed by an open discussionby the participants Each sector was given a slot to allow the representatives to voicetheir particular comments
The model results at this stage are preliminary and the focus was more on are thehydrologic and water resources development data appropriate and is thepresentation format of the results meaningful and useful to the respective ODMPsectors in the context of the Okavango Delta Management Plan
14 ParticipationThe list of participants is given in Annex 2 Despite an early dispatch of invitationletters in advance to representatives of the different components it became apparentthat most components were not represented at the workshop Most notableabsences were from the technically oriented components such as SustainableLivestock Management Vegetation Resources Management Waste Managementetc
Of the components that were present it appeared that these representatives were notfamiliar with the project or are not dealing with the project on a daily basis judgingfrom their contribution to the discussions on the role of the Hydrology and Water Resources component It appears that project partner institutions still have acombined workload of their routine work and new duties related to ODMP Thisadded responsibility is somewhat too great and affects the ability of project officers todeliver efficiently and effectively
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Each component should identify a suitable person to act as a focal point for liaisonwith the Hydrology and Water Resources component and this person should attendfuture such workshops and meetings
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2 PRESENTATIONS AND DISCUSSION
21 IntroductionsSelected slides from those employed in the respective presentations are included inAnnex 3 and illustrate the text of the presentations in the following sections
The introductory presentations covered the component background implementationdata collection and processing and monitoring proposals As such they generatedlimited discussion One suggestion was that as most of the stakeholders were fromsectors other than water a glossary should be included to cover the use of technicalterms
22 Integrated Hydrologic Model
221 Introduction
The Introduction to the Integrated Hydrologic Model set out the approach tomathematical modelling in the context of the hydrology of the delta The key flowprocesses above in and below the delta are shown in slide 1 Given the criticallinkages among the atmospheric surface and ground waters it is necessary todevelop an Integrated Hydrological Model which integrates the essential physicalphenomena controlling the delta As such the model requires a basis in physicalprocesses as opposed to a conceptual model which has an idealised representation
It is not the intention to set up a detailed model The available data do not justify thisand the project resources are not available The model will be somewhat schematicbut nonetheless capable of describing the essential processes such as the overallflow pattern among the distributaries flooding and drainage of seasonal swampareas The model will not be capable of predicting the small scale vegetation andmorphological changes which appear to have a significant impact on the overall flowpattern
Water and its distribution in space and time is the fundamental physical basis for management of the ecosystem Management criteria for the delta could include
bull Maintain present flood extent and duration
bull Maintain current pattern of flows through the delta
bull Minimise adverse impacts on any part of the interconnected hydrologicalsystem
The distinct environments and key hydrologic phenomena were presented illustratingthe complex interactions among the atmospheric surface and subsurfacecomponents of the wetland
In order to have a realistic representation of these key phenomena and their interactions and to make quantitative prediction of the potential effects of changes inwater use it is necessary to employ an Integrated Hydrologic Model The systemselected is MIKE SHE developed by DHI Water and Environment Denmark Thegeneric system (the software can be applied to any hydrologic system) is marketedcommercially and is applied to hundreds of catchments and wetlands worldwide
The key features of the software package are (slide 2)
bull Physically based with a realistic representation of the hydrologic
phenomena based on the laws of physics
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(slide 3) The vegetation dynamics are based on remotely sensed data with limitedground verification (see slides 4 and 5) The relationship between the extent of surface water and the rate of evapotranspiration is shown for the normally andseasonally flooded areas in slide 6
224 Surface Waters
The surface water flows are dependent on the topography of the delta which hasbeen described by a digital elevation model of the Ramsar area with a 30m resolutionbased on aerial radar altimetry and remote sensing and a limited number of channelcross sections available at gauging stations and surveyed by researchers
The key characteristics of the delta are the numerous bifurcations or defluences (asopposed to confluences) extensive spills to the flood plains and swamps andhydraulic connections among the spill areas and slow flood wave propagation(around four months from upstream to downstream) with a high variation in the extentof flooding (slide 7)
The surface waters of the delta are described by a full hydrodynamic representationof the flows in the main rivers and channels and by a distributed kinematicrepresentation of the flows over the flood plains and through the swamps Thedescriptions are fully coupled (slide 8) and enable the representation of theessentially one dimensional flows through the channels giving definition to the flowand the spreading and distributed storage over the flood plain (slide 9)
225 SubSurface Waters
Infiltration rates are significant on the predominantly sandy soils in the early stages of the flood season The infiltration raises the ground water levels up to the flood water level This increases the water available to plants which in turn increasestranspiration from the leaf surfaces to the atmosphere (slide 10)
An essential component is the inclusion of the critical unsaturated root zone the zonefrom which plants draw water and transpire to the atmosphere Together withevaporation from open water this is represents the main loss of water in the deltaThe evapotranspiration component simulates both the hydrologic and vegetationdynamics (slide 11)
The ground water component is important to account for the local effects of groundwater on the water balance ie recharge and discharge and evapotranspirationlosses Only the surficial ground water aquifer is represented (slide 12)
Detailed ground water studies show infiltration and recharge of fresh water lensesembedded in older saline ground water Given the low topographical relief limited
ground water flow is directed towards local depressions (slide 13) Model water balance tests indicate that there is no significant ground water flow from the delta nor are there data to support such flow hypotheses Consequently there is no flowacross the subsurface model boundary
226 Outputs
The outputs from the model are designed to support broad based managementplanning in the Okavango Delta The outputs are presented in grid or map formatshowing the spatial variation in the parameters over the delta time series (plots of various parameters against time) and summary tables of results The outputs may besummarised as
bull The actual evaporation from open water and the transpiration fromvegetation
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bull Surface water levels and flows through the rivers and over the floodedswamp areas and the extent of flooding
bull The moisture content of the soil
bull The ground water levels and flows
bull The overall water balance including inflows outflows and changes insurface and subsurface storage for the delta and selected areas of thedelta
bull Sediment transport along the main channels of the delta showingpatterns of erosion and deposition
The Integrated Hydrologic Model does have practical certain limitations and it isimportant that these are recognised by the stakeholders and management planners
Channel Switching
While the model can predict the impact of cutting and dredging a new channel
through the delta and the impact of closing an existing channel through theencroachment of vegetation it is not able to predict the occurrence of the formation of new channels and the realignment of existing channels which may be initiated by themovement patterns of large mammals and vegetation growth
Certain trends in sedimentation and channel development and decay may bepredicted by the application of sediment transport to the model Work on this areahas just commenced Detailed analyses of selected reaches and areas of the deltamay be carried out through the application of two dimensional morphological modelsThis is beyond the scope of the present component activities
Level of Detail and Accuracy
While the technology exists to simulate the hydrologic behaviour of the delta at a highlevel of detail (previous applications have been made at the level of individualcultivated fields) this is constrained by
bull The resources available to the component do not permit thedevelopment of submodels which could enable the study of a particular area of the delta below the present one square kilometre resolution
bull The available data do not justify high expectations on the level of accuracy with respect to absolute water levels and quantitiesRecommendations have been made for improved data collection andmanagement which when available could justify further modeldevelopment
The key issue at this stage is that the Integrated Hydrologic Model represents theessential hydrologic phenomena in an integrated manner such that it may be appliedwith confidence to the assessment of the impacts of future water resourcesdevelopments on the delta hydrology for the purposes of the management plan
Physical Phenomena
The model simulates physical hydrological phenomena only Studies have revealedin particular the importance of the interdependency of physical and biologicalphenomena for example the movement of large mammals opening new flow pathsthrough the vegetation sedimentation and vegetation in closing existing channels
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bull The data should reflect how the delta may recover in a period of normal inflows after a dry period
The long term inflow in terms of volume per annum from 1933 to date is shown inslide 14 for both Mukwe in Namibia and Mohembo in Botswana Whereas at Mukwethe river is more or less confined to the gauged channel at Mohembo the river has
broadened out with a wide flood plain It is not possible to gauge the flows over theflood plain and Mohembo will not represent the total discharge This is most clearlyevinced in the high flow years 199899 and 200001
An anomaly appears in the data from around 1950 to 1980 where the total inflow atMohembo appears higher than Mukwe As there is no significant inflow to the river between the two gauges this can only be explained by gauging errors The seriesafter 1980 is more consistent with Mukwe showing a higher inflow than Mohembo
The period from 1992 to 1997 represents the sequence of the five lowest inflowyears and is therefore chosen to provide the input data to analyse the impacts under critical conditions for both the existing state and possible future states with water resources developments
The following five year period from 1997 to 2002 represents relatively normalhydrologic conditions in the delta and has been used to assess how the delta mayrecover after a sequence of dry years (see slide 15)
A high inflow period could also be selected eg 1987 to 1992 to assess the impactsunder high inflow conditions It is not planned to analyse this period as
bull The conditions will not be critical to a management planning exercise
bull The number of impacts which have to be assessed in terms of flowsdepths etc will be further increased
Appropriate time series of inputs (inflows precipitation etc) have been prepared and
applied to the existing state of the delta The model results are used as a baselineagainst which future developments are assessed for their impacts The inputs aremodified to represent conditions which may prevail under future conditions
To summarise while the inflows to the delta will be dynamic ranging over two fiveyear periods representing critical dry and normal average hydrologic conditions theexisting and future states will be static This implies that for the duration of the fiveyear model run period the population for instance will not be increasing no newdams or irrigation schemes are built etc
At present the Baseline and Scenario Conditions have been simulated for the criticaldry hydrologic input period from October 1992 to October 1997 Summary results arepresented and discussed in the following sections Slides illustrating the outputs arepresented in Annex 3
233 Presentation of Results
In order to assist the stakeholders assess the outputs and their implications for their particular sectors a common format for the presentation is adopted The resolutionof the model in space is one kilometre and in time four hours In order to limit thesize of the output files the results are output with a temporal resolution of one weekfor surface flows and the unsaturated zone while the slower responding ground water results are output every two months of the five year period
For the purpose of presenting summary data the delta is divided into five zonesaccording to the probability of flooding as assessed from 15 years of satellite images(source J McCarthy Stockholm University) with the Panhandle treated as a fifth
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separate zone (slide 16) The probability delta area and a zone description are givenin the table
Model Area (km 2) 28782 Description
Zone 1 - 01gtFPgt0 19322 rarely flooded
Zone 2 - 05gtFPgt01 3534 occasionally flooded
Zone 3 - 09gtFPgt05 2328 seasonally flooded
Zone 4 - 1gtFPgt09 2152 normally flooded
Zone 5 - Panhandle 1446 Panhandle
(1) Animated sequence of flooding in the delta showing the monthly variation inflooded area and depth (The AVI format file is available from DWA sizearound 110Mb)
(2) Map based on the one kilometre grid showing the minimum depth of water in the delta for the five dry years
(3) Time series showing the variation in the depth of flooding over the five year period The depth is averaged for each of five zones (see table)
(4) Map based on the one kilometre grid showing the minimum level of soilmoisture in the root zone (the zone from which plants draw water) in thedelta over the five dry years
(5) Map based on the one kilometre grid showing the maximum depth toground water in the delta over the five dry years
(6) Summary tables are prepared showing the following
bull Water balance showing inflows outflows and storage changes
bull Baseline conditions and impacts for the surface water soilmoisture and ground water for the entire delta and for each of the five zones
A wide range of outputs of all hydrologic parameters in various formats is possibleand can be tailored to the needs of the individual stakeholders It is possible also toselect different zones to calculate average time series and summary results Theabove selection has been made by the component as samples of what may be usefuland meaningful to the stakeholders and to generate discussion
24 Baseline
Surface Water
The animated depth of flow sequence (slide 17) shows the expansion and contractionof the flooded area and depth as the sequence of flood waves for each of the fiveyears propagates through the Panhandle and spreads out through the delta Slide 18shows the detail for the lower envelope of flooding for the upper delta Each squareis one square kilometre
Time series of the depth of surface water are shown for each of the five zones in slide19 The Panhandle is the first area affected by the flood wave from upstream andbeing relatively confined within a flood plain around 20km wide has the maximumrange from the seasonal wet to dry periods around 06m through the five dry yearsAs the flood wave propagates through the delta the range in water levels declines
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The accumulated impact of the drought years is also felt more as there is a generaldecline in the flood depth
As the summary table (slide 20) shows the area flooded ranges from 1513km 2 to12077km 2 while the depth ranges from 0 to around 5m The average depth in thenormally flooded area ranges from 011m to 092m
SubSurface Water
The distribution of the soil moisture content is shown as a deficit below saturatedlevel as the lower envelope (maximum deficit) for the five year period in slide 21The average deficit ranges from 056m in the rarely flooded area to 012m in thenormally flooded area
The depth to ground water over the delta area is shown for the lower envelope(maximum depth) over the five year period in slide 22 The depth ranges from anaverage of 188m in the rarely flooded area to 037m in the normally flooded area
Water Balance
The overall water balance for the Baseline and Scenarios is shown in slide 23Negative values indicate an inflow to the delta (eg precipitation and river inflow) whilepositive values indicate an outflow (eg evapotranspiration and river outflows) TheTotal should be zero the small value indicates a very minor continuity error Thenegative overland and subsurface storage changes indicate a decline in storage inthese levels
25 Upstream Water Resources Developments
251 Introduction
To date no significant water resources developments have taken place upstream inAngola and Namibia In the past plans have been made for the construction of damsfor irrigation and hydropower Anticipating that these plans may be revived theWERRD project has run a number of scenarios using a modified rainfall-runoff modelof the basin (Pitman model Rhodes University) including a scenario for all planneddams
A number of sources describes potential irrigation in the upstream basin in Angolaand Namibia These have been reviewed and a potential scenario compiled basedon
bull Irrigation demand based on 15000m 3haa with a 25 return flow
bull Irrigated area in Angola 54500ha in Namibia 7500ha
bull Angola grows vegetables in winter (June to October) Namibia growsmaize in summer (December to April)
The corresponding runoff from the upstream basin has been applied under twoscenarios Dams in Angola and Irrigation as inflow to the delta upstream The twopotential developments are kept separate for the purpose of initial appraisal in order that the impact from each can be identified This will assist in minimising the adverseimpacts from these developments
252 Dams in Angola
The impact of the previously planned hydropower dams in Angola on the inflow to the
delta is presented in slide 24 Hydropower development does not consume waterbut stores water in the flood period for release in the dry period This results in a
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redistribution of the natural hydrograph flood flows are reduced while dry seasonflows are increased (The impact appears only to be significant in 1993 and 1996 ndashthis needs further investigation)
The impact of the dams on the surface and subsurface waters of the delta is minimalgiven the limited apparent impact in three out of the five dry years and the fact that
there is no nett water loss in the basin upstream
253 Irrigation
The impact of the potential irrigation scenario on the inflow to the delta is shown inslide 25 The impact is greatest in the dry period when water is withdrawn for therelatively large area of winter crops in Angola The summer withdrawals for irrigationin Namibia are significantly less
Correspondingly the impact on the delta in the flood period is minimal while in thedry period the overland depth of flow is reduced particularly in the Panhandle andnormally flooded areas and the minimum flood extent is reduced by 660km 2 or 40of the present dry period area (slide 26)
26 Abstractions from DeltaWater for largely local domestic use is abstracted from both the surface and groundwaters of the delta The surface water abstractions are based on water rights issuedby DWA (ie the amount which may legitimately be withdrawn ndash actual withdrawals arenot monitored and may be greater or less than allowed) Ground water abstractionsare based on the demands projected from historic information to the present day
In terms of the inflows to the delta (river flows from the basin upstream andprecipitation over the basin the abstractions and corresponding impacts are minimalSurface water abstraction represents 0006 of the inflow and ground water 02In the five dry years analysed the minimum flooded area is reduced by 025Future scenario runs will simulate the impact of abstractions with projected increasedpopulation and rates of consumption to the notional year 2025
27 Climate ChangePotential climate change will have an impact on the delta in respect of inflows fromthe basin upstream and the climate over the delta The WERRD project has run aglobal climate model HadCM3 1 to predict the changed precipitation and temperatureover the basin For the upstream basin the Pitman rainfall-runoff model has beenapplied to predict the modified inflows upstream of the delta (slide 27) The modifiedprecipitation and temperature over the delta have been used as direct inputs to theIntegrated Hydrologic Model (slide 28)
The impact of the climate change scenario is highly significant in both the flood anddry seasons River inflows to the delta are reduced by 38 and precipitation over the delta by 9 Temperature increases by 22ordmC
The corresponding impact on flow depths is shown on the reduced depths the impacton the minimum depths is shown for the Panhandle and normally flooded areas inslide 29 and in each of the five zones through the five year run period in slide 30The reduction in depth averages 003m over the entire delta and the minimumflooded area is almost halved
1 httpwwwmet-officegovukresearchhadleycentremodelsHadCM3html
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28 Management PlanningThe model analyses are carried out to assess the impacts of possible future basinconditions on the delta for the purposes of management planning An iterativeprocess is envisaged with a series of bilateral meetings with the Stakeholders andcommon Workshops in which the inputs and outputs are presented to and discussedwith the stakeholders The outputs can migrate towards a presentation format that isboth meaningful and relevant to the stakeholders
The Hydrology and Water Resources component will only analyse the impacts on thewaters of the delta DWA and its consultants do not have the capability or theresources to analyse the impacts on the wildlife vegetation livestock fisheries or tourists It is up to these respective sectors to assess these impacts based on thechanged delta hydrology
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3 DISCUSSION
31 IntroductionThe following sections record the comments made on the foregoing presentationsand the responses given by the hydrology team (in italics)
32 Database Management(1) What is lithology Remember that as much as you are speaking to experts
you are also speaking to non-experts
The point is well taken A glossary will be prepared to explain technical terms
(2) The presentations are too fast and we need details of the graphs for example
This point is also noted presentations should emphasise important pointsSelected slides from the Workshop are included in Annex 3 and a full report is being prepared of both the Integrated Hydrologic Model and the
preliminary scenario analysis These should be studied by thestakeholders in advance of further (bilateral) discussions
(3) Is there a slide to show locations of critical rainfall and flow stations so thatwe could appreciate all the difficulties encountered We would appreciatemuch if we could have locations of all your data sources
The locations of the existing and proposed gauging stations is available inDWA in GIS format The key source for this and information from other sectors and stakeholders will be the Okavango Delta Information System
implemented in HOORC
33 Integrated Hydrologic Model(1) I like your conceptual model but what is applicable in Europe may not
necessarily be applicable here also
The conceptual model is fundamental to the development of a numerical model The conceptual model is strictly formulated for the Okavango Deltabased on available data and scientific publications on the subject Theconceptual model has no relation to European or other climatic conditions
(2) Your evapotranspiration rates are higher than those from Class A pan whenactually the reverse should be true This should be looked into
Actual rates of evapotranspiration (ET) are not necessarily lower than panevaporation owing to a number of factors including pan correction methodcombined free surface ET and vegetation transpiration in flood plains and actual location in the delta versus the location of pan measurements If new documented field data on ET losses are available the hydrology teamwould be happy compare these to model simulations
(3) Is there any physical evidence of flooding
The assessment of the observed flood extent has been based mainly on ananalysis of satellite images from 1984 to 2000 (J McCarthy StockholmUniversity) and DWA water level observations
(4) How do you parameterize your flow in respect to flow resistance
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The Manning resistance coefficient is used to describe the resistance toflow in the river channels and over the flood plains Values for overland flow are distributed according to three vegetation zones based onvegetation mapping (S Ringrose HOORC) Values in the river channelsare ascribed based on channel vegetation descriptions (Dr CK NaiduDWA) Adjustments are made to give a good match with observed flood extent overall water balance and downstream discharges
(5) Your climate input data comprise rainfall evapotranspiration etc fromMaun and Shakawe To what extent can one use a physically based modelwith such a coarse resolution Could we conclude that this is an empiricalmodel
MIKE SHE is a physically based model which implies that the model parameters have a clear physical interpretation as opposed to lumped conceptual models Data measured in single locations may be used toassign parameter values but the parameters used at the current grid scaleof 1km 2 should be regarded as lsquoefficientrsquo parameters representing the
aggregated responseThe lack of input data on distributed rainfall or any other model input doesnot imply that the MIKE SHE model is empirical Maun and Shakawe arethe only two stations in and adjacent to the delta with reliable data Thedelta is not a conventional catchment area where the runoff from individual subcatchments is essential to arrive at the combined flow in themainstream Overland flows mix the runoff from the subcatchments and evapotranspiration dominates Thus a high resolution of the rainfall data isnot of major importance in a general flow model of the delta Nonethelessrecommendations for improved monitoring include rehabilitation of the eight DCPs which measure rainfall and the installation of an additional eight automatic gauges in the delta
(6) Our confidence on the model cannot be based on your numbers
This particular comment was based on relatively consistent outflows for theBaseline and Scenarios This was owing to the nature of the downstreamboundary condition which has since been improved and now shows avariation
The flow leaving the delta (and the model) has passed through anextremely complex hydrologic system flood propagation flow splits among distributaries spills to vast flood plains and swamps evapotranspirationand infiltration The measurement of the discharge upstream is subject toerrors of at least 10 (say 50m 3 s at the flood peak) Differences between
the model computations and the observations cannot better this(7) What resolution should we have confidence on as it pertains to your
model
Given the complexity of the area and the available data model resultsshould not be interpreted looking at single grid values Interpretation based on delta zones or subsystems is more appropriate Five zones based onflood probability have been applied in the scenario demonstration runs and others may be devised according to stakeholdersrsquo needs The minimumarea should cover several square kilometres
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34 Scenarios(1) You have run the scenarios based on dry period(s) Could you please
revise this You might be missing out on recharge to groundwater as aresult of high floods A single high flood could recharge an aquifer for thenext twenty years for example
It is the intention to run the model for a period of normal flows to see how the delta recovers from a drought As suggested the model will also be runfor high floods (this is also important for sediment transport in the delta)
(2) In taking the dry period as critical you have to consider floods as alsocritical Floods need to be covered as well
The delta is not under stress during high flow periods and the impacts of water resources developments will not be so keenly felt and therefore not critical to management planning See also response to (1) above
(3) People are more worried about the switching of channels Maybe thisaspect needs to come out in your model outputs as well
The introduction of sediment transport to the model (which has just commenced) will give an indication of possible future switches and redistribution of delta flows Switching and realignment of channels has achaotic component (the butterfly effect on global climate is akin to ahippopotamus going walkabout in the delta) and accurate predictions aresimply not possible
(4) Looking at the modelrsquos level of resolution critical management issues willnot be answered
The component has been conceived and ToR written (in 200102) toaddress the broad scale management planning issues (water resources
developments upstream climate change abstractions from the delta reed cutting and dredging) On this basis the model approach has been set outand the model set up and applied Preliminary applications suggest that the main threats to the delta will arise from upstream irrigation and climatechange These are the critical management issues related to hydrology
(5) Channel blockages impacts need to be covered in detail Channel switchingis another fundamental management issue
The model can simulate the impact of channel blockages and channel switching As discussed in (3) above the model cannot predict theseoccurrences
(6) You mentioned that your model could handle sediment transport Do youhave something on sediment transport now
An approach to introducing sediment transport to the model has beendrafted (pending report on the Integrated Hydrologic Model)
(7) You seem not to be representing your conditions
See response to (6) above
35 Presentation of Results(1) You canrsquot have a reduction of flow by 40 and yet have no impact on the
outflow This gives me the confidence of your model
See response to (4) above
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(2) The difference in long-term average discharge between observed andsimulations should not be taken to be insignificant This should becombined with other scenarios to better appreciate its impact
It is important in the preliminary stage to separate the impacts fromindividual water resources developments to obtain a good understanding of
which are critical and which are not A limited number of combinationscenarios may be run at a later stage once these can be defined and agreed by the management planners and stakeholders
(3) It would be good to combine all the scenarios as well
See (2) above
(4) It would be interesting also to look at frequency and duration of flooding
The impact on the duration of flooding can be assessed through the timeseries plots for different zones An estimate can also be made on theimpact of the scenarios on the frequency of flooding
(5) What is the model doing as it pertains to erosion and sedimentation
Sediment transport is being introduced to the model This will enable theassessment of the broad pattern of erosion and deposition through themain river channels along which the bed load is conveyed from the basinupstream
(6) The issue of land use change has to be incorporated into the model
To introduce the impact of land use changes in the basin upstream requiresthe application of a water resources planning model to the upstream basinThis is not within the present scope of ODMP which is relying on theoutputs of basinwide projects such as Sharing Water and WERRD (bothcompleted) and possibly in the future TwinBas (ongoing) If ODMP
partners suggest particular potential land use changes within the deltawhich have an impact on the hydrology these may be simulated using theIntegrated Hydrologic Model
(7) The presentations have mostly been technical I would like to suggest thatwe make handouts available after the workshop so that the participantscould have ample time to go over them and later submit their suggestionscomments and or questions
This document represents a full report on the proceedings Further comments from ODMP partners are welcome that our further work may more closely meet the needs of delta management planning Further discussions will be held with the stakeholders on the ongoing model applications possibly on a bilateral basis to obtain a closer understanding of particular needs and ways to meet these needs
36 Stakeholdersrsquo Responses
Wildlife
(1) We need drying flood plain map to better track movement of wild animals
The drying and wetting of the flood plains was presented as animated sequences in the Workshop for all scenarios with a monthly time step Afiner temporal resolution can be prepared (down to four hours) though the
spatial resolution is limited to one kilometre squares
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(2) We would appreciate information on correlations between the distribution of elephants population and extent of flooding close to the buffalo fence
The HampWR component can provide information on the waters of the deltaIt is up to the individual partners to analyse this information for their ownneeds The HampWR component cannot be expected to carry out all the
analyses for the management planThe integration of information from all ODMP components will be carried out within the Okavango Delta Information System implemented inHOORC (also with support from Danida)
Fisheries
(1) Water quality is very critical as this have impact on fish populationdynamics Sedimentation is also critical as it has a bearing on fishpopulations
Sedimentation is indeed critical to fish populations as fine organic richsediment is washed out from the flood plain into the channels by the flood waters resulting in oxygen depletion
The MIKE SHE integrated hydrologic modelling system has the capability tosimulate water quality This is not within the present scope of ODMPSystematic data (including DO and SOD) do not exist at present on whichto develop such a model Improved monitoring recommendations includethe introduction of systematic sampling and analysis at the key inflow station of Mohembo and monthly in-situ measurements of salinity and pH at around 20 discharge stations throughout the delta
Water Affairs
(1) Is MIKE SHE an instrument or whatMIKE SHE is one of a suite of water and environmental software packagesdeveloped and marketed commercially by DHI Water and EnvironmentThe MIKE SHE package is the most advanced generic (can be applied toany system) hydrologic software available MIKE SHE has a consistent development history over thirty years and has been applied to hundreds of hydrologic systems worldwide
(2) Can the model predict channel shifts
The sediment transport model will predict erosion and deposition leading tochannel aggradation and eventual closure The delta morphology isinherently unstable and chaotic and no model can predict channel abandonment with higher certainty than what is constrained by natural variability (chaos) Nonetheless the impact of major channel shifts can be
predicted as well as possible management measures to mitigate suchshifts
(3) Mr Dikgomo mentioned that Hydrology and Water Resources component isone of the twelve What are the other eleven components
The CTA may best respond to this question though it is suggested that representatives from participating organisations take the trouble to informthemselves of the ODMP structure objectives and outputs before attending such fora
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Land Board
(1) Is it possible for the model to give us depth of water table within at least500 metres from the delta This can help us with land use This will alsohelp us determine how far we can avoid pollution in land allocations
The spatial resolution of the model is one square kilometre The model cangive the various hydrologic parameters such a depth to ground water withinthe general area (within a few square kilometres) This should be quiteadequate for the purpose of broad based management planning
(2) Can the model add value to Tawana land board land use and managementplan (2004-2029)
The Hydrology and Water Resources component is concerned withhydrology and water resources The outputs from the component arehydrologic data and predictions for the delta It is up to the various sectorsand components of the management plan to assess the impact of thesehydrologic parameters for their own purposes The HampWR component can
assist in the interpretation of the hydrologic dataTourism
(1) There are lodges and camps located close to the river channels Can themodel be able to help on the implications of pollution
The model can simulate the pattern of flow in the delta which may give auseful indication of the movement of pollution though not the output whichmay be given by a water quality model (advection dispersion decay etc)
General
(1) This component (Hydrology and Water Resources) is so detached from therest It should relocate to MaunThe component is located in Gaborone as the capital has better infrastructure Progress on the component would be constrained by thelimited infrastructure in Maun
(2) To what extent is your data real time series that it could be relied upon
The data available from the delta at present are poor largely owing todifficulties in access and disturbance of gauging stations by humans and large mammalian wildlife Lack of systematic use of the data to date havealso contributed to neglect Improved monitoring is necessary for management planning and an improved hydrologic model with finer
resolution and greater accuracy Recommendations have been prepared for DWA to improve hydrologic monitoring and it is hoped these can beimplemented in the course of 2005
(3) The presentations are too technical When will ODMP reach out to usSomeone mentioned that communication and or information disseminationis a problem Why cant we find other Batswana who could do the job toconvey the information in an audience screened and targeted way
The hydrology of the delta is complex and requires a complex model for arealistic simulation of the processes The presentations were intended togive all participants an understanding that the model is indeed capable of simulating the key hydrologic phenomena of the delta It is hoped that this
has been achieved though it is recognised that the depth of understanding
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will depend upon the level of the individual participantrsquos hydrologic knowledge
The DWA staff assigned to ODMP will gradually take over presentations insuch fora as part of the process of technology transfer which is anessential part of the component
Lessons have been learnt from this Workshop A second and possibly third Workshop will be planned along with bilateral meetings with the individual Stakeholders hopefully improving the communication to the diverse
participants (see Conclusions)
(4) Communications and networking is lagging behind but its pro-activeness isso crucial The component would simplify information and relay it tocommunity andor stakeholders
The HampWR component looks forward to this component being activatedand to cooperating with the Communications and Networking component in
presenting results of the hydrologic analyses meaningful to all
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4 CONCLUSIONS
41 SummaryProf Francis Sefe from the consultantsrsquo team summarised the Workshop discussionas follows
(1) There were discussions on both spatial and temporal resolutions of themodel which need clarification
(2) It was observed that data quality and availability is a constraint to accuratemodelling of the hydrology of the delta and providing physical evidence toback the model conclusions
(3) In the selection of scenarios it is critical to understand that the individualscenarios are not stand alone
(4) The choice of what constitutes the baseline scenario was discussed It hasto be emphasised that the inclusion of exceptional floods is also importantand hence not only the dry period should be used
(5) The presentation was multifaceted
(6) People could not easily locate any landmark features on the map Thisneed not be Villages could be labelled and even the rivers themselves
(7) Though water quality is not in the scope of the current modelling water quality is very important and this has to be looked into in the future
(8) Ground water fluctuations at the periphery of the delta need to be lookedinto
(9) Various stakeholders have difficulty interpreting the results This is a critical
issue that needs to be addressed The target audience should reasonablybe able to assimilate the information relayed to them
42 RecommendationsThe following recommendations are made with regard to the future interactionbetween the Hydrology and Water Resources component and the other ODMPparticipants
(1) While the introductions to the set up and application of the IntegratedHydrologic Model attempted to convey the complexity of the deltahydrology and its computer based representation further effort needs to bemade to present the model and its results in a manner which is fullycomprehensible to the Stakeholders most of whom do not have in depthhydrologic knowledge
(2) It was originally believed that presentation of the model to Stakeholders in acombined forum would allow the interchange of ideas and knowledgeamong the Stakeholders as well as with the Hydrology and Water Resources component The resulting discussion tended to be dominatedby those with technical hydrologic knowledge at the expense of thosewithout The next round of discussions should be on a bilateral basis suchthat the discussions can proceed at a level appropriate for the individualStakeholders and their needs in respect of hydrology and water resources
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(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
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ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
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ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
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Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
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Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
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ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
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13 ProgrammeThe programme for the one day Workshop is presented in Annex 1 The first sessioncovered the background to the establishment and the implementation of thecomponent in DWA the recommendations for improved hydrologic monitoring in thedelta and their pending implementation and data collection and management
This was followed by a description of the Integrated Hydrologic Modelling system andits set up to represent the hydrology of the Okavango Delta The next four presentations covered the application of the model to represent existingdevelopments in the delta and the basin upstream and hydrologic conditions as theywould be in the delta given the implementation of a range of potential water resourcesdevelopments Each presentation was followed by a discussion session
The team implementing the component comprises DWA staff and national andinternational consultants An important output from the component is capacitybuilding in DWA to maintain and operate the Integrated Hydrologic Model Thisentails technology transfer from the consultants to the DWA staff The technologytransfer is carried out in a three pronged approach
bull A series of formal training courses in DWA Gaborone on the mainelements of integrated hydrologic modelling
bull On-the-job training whereby the DWA staff learn by doing setting upand applying the model under the guidance and supervision of theconsultants
bull Overseas training most likely MSc courses in recognised internationalhydrologic institutions
DWA has assigned four permanent staff members to work full time on ODMP Aspart of the technology transfer process each of these four staff presented an aspect
of the model application in the WorkshopThe presentation of the model and its application was followed by an open discussionby the participants Each sector was given a slot to allow the representatives to voicetheir particular comments
The model results at this stage are preliminary and the focus was more on are thehydrologic and water resources development data appropriate and is thepresentation format of the results meaningful and useful to the respective ODMPsectors in the context of the Okavango Delta Management Plan
14 ParticipationThe list of participants is given in Annex 2 Despite an early dispatch of invitationletters in advance to representatives of the different components it became apparentthat most components were not represented at the workshop Most notableabsences were from the technically oriented components such as SustainableLivestock Management Vegetation Resources Management Waste Managementetc
Of the components that were present it appeared that these representatives were notfamiliar with the project or are not dealing with the project on a daily basis judgingfrom their contribution to the discussions on the role of the Hydrology and Water Resources component It appears that project partner institutions still have acombined workload of their routine work and new duties related to ODMP Thisadded responsibility is somewhat too great and affects the ability of project officers todeliver efficiently and effectively
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Each component should identify a suitable person to act as a focal point for liaisonwith the Hydrology and Water Resources component and this person should attendfuture such workshops and meetings
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2 PRESENTATIONS AND DISCUSSION
21 IntroductionsSelected slides from those employed in the respective presentations are included inAnnex 3 and illustrate the text of the presentations in the following sections
The introductory presentations covered the component background implementationdata collection and processing and monitoring proposals As such they generatedlimited discussion One suggestion was that as most of the stakeholders were fromsectors other than water a glossary should be included to cover the use of technicalterms
22 Integrated Hydrologic Model
221 Introduction
The Introduction to the Integrated Hydrologic Model set out the approach tomathematical modelling in the context of the hydrology of the delta The key flowprocesses above in and below the delta are shown in slide 1 Given the criticallinkages among the atmospheric surface and ground waters it is necessary todevelop an Integrated Hydrological Model which integrates the essential physicalphenomena controlling the delta As such the model requires a basis in physicalprocesses as opposed to a conceptual model which has an idealised representation
It is not the intention to set up a detailed model The available data do not justify thisand the project resources are not available The model will be somewhat schematicbut nonetheless capable of describing the essential processes such as the overallflow pattern among the distributaries flooding and drainage of seasonal swampareas The model will not be capable of predicting the small scale vegetation andmorphological changes which appear to have a significant impact on the overall flowpattern
Water and its distribution in space and time is the fundamental physical basis for management of the ecosystem Management criteria for the delta could include
bull Maintain present flood extent and duration
bull Maintain current pattern of flows through the delta
bull Minimise adverse impacts on any part of the interconnected hydrologicalsystem
The distinct environments and key hydrologic phenomena were presented illustratingthe complex interactions among the atmospheric surface and subsurfacecomponents of the wetland
In order to have a realistic representation of these key phenomena and their interactions and to make quantitative prediction of the potential effects of changes inwater use it is necessary to employ an Integrated Hydrologic Model The systemselected is MIKE SHE developed by DHI Water and Environment Denmark Thegeneric system (the software can be applied to any hydrologic system) is marketedcommercially and is applied to hundreds of catchments and wetlands worldwide
The key features of the software package are (slide 2)
bull Physically based with a realistic representation of the hydrologic
phenomena based on the laws of physics
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(slide 3) The vegetation dynamics are based on remotely sensed data with limitedground verification (see slides 4 and 5) The relationship between the extent of surface water and the rate of evapotranspiration is shown for the normally andseasonally flooded areas in slide 6
224 Surface Waters
The surface water flows are dependent on the topography of the delta which hasbeen described by a digital elevation model of the Ramsar area with a 30m resolutionbased on aerial radar altimetry and remote sensing and a limited number of channelcross sections available at gauging stations and surveyed by researchers
The key characteristics of the delta are the numerous bifurcations or defluences (asopposed to confluences) extensive spills to the flood plains and swamps andhydraulic connections among the spill areas and slow flood wave propagation(around four months from upstream to downstream) with a high variation in the extentof flooding (slide 7)
The surface waters of the delta are described by a full hydrodynamic representationof the flows in the main rivers and channels and by a distributed kinematicrepresentation of the flows over the flood plains and through the swamps Thedescriptions are fully coupled (slide 8) and enable the representation of theessentially one dimensional flows through the channels giving definition to the flowand the spreading and distributed storage over the flood plain (slide 9)
225 SubSurface Waters
Infiltration rates are significant on the predominantly sandy soils in the early stages of the flood season The infiltration raises the ground water levels up to the flood water level This increases the water available to plants which in turn increasestranspiration from the leaf surfaces to the atmosphere (slide 10)
An essential component is the inclusion of the critical unsaturated root zone the zonefrom which plants draw water and transpire to the atmosphere Together withevaporation from open water this is represents the main loss of water in the deltaThe evapotranspiration component simulates both the hydrologic and vegetationdynamics (slide 11)
The ground water component is important to account for the local effects of groundwater on the water balance ie recharge and discharge and evapotranspirationlosses Only the surficial ground water aquifer is represented (slide 12)
Detailed ground water studies show infiltration and recharge of fresh water lensesembedded in older saline ground water Given the low topographical relief limited
ground water flow is directed towards local depressions (slide 13) Model water balance tests indicate that there is no significant ground water flow from the delta nor are there data to support such flow hypotheses Consequently there is no flowacross the subsurface model boundary
226 Outputs
The outputs from the model are designed to support broad based managementplanning in the Okavango Delta The outputs are presented in grid or map formatshowing the spatial variation in the parameters over the delta time series (plots of various parameters against time) and summary tables of results The outputs may besummarised as
bull The actual evaporation from open water and the transpiration fromvegetation
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bull Surface water levels and flows through the rivers and over the floodedswamp areas and the extent of flooding
bull The moisture content of the soil
bull The ground water levels and flows
bull The overall water balance including inflows outflows and changes insurface and subsurface storage for the delta and selected areas of thedelta
bull Sediment transport along the main channels of the delta showingpatterns of erosion and deposition
The Integrated Hydrologic Model does have practical certain limitations and it isimportant that these are recognised by the stakeholders and management planners
Channel Switching
While the model can predict the impact of cutting and dredging a new channel
through the delta and the impact of closing an existing channel through theencroachment of vegetation it is not able to predict the occurrence of the formation of new channels and the realignment of existing channels which may be initiated by themovement patterns of large mammals and vegetation growth
Certain trends in sedimentation and channel development and decay may bepredicted by the application of sediment transport to the model Work on this areahas just commenced Detailed analyses of selected reaches and areas of the deltamay be carried out through the application of two dimensional morphological modelsThis is beyond the scope of the present component activities
Level of Detail and Accuracy
While the technology exists to simulate the hydrologic behaviour of the delta at a highlevel of detail (previous applications have been made at the level of individualcultivated fields) this is constrained by
bull The resources available to the component do not permit thedevelopment of submodels which could enable the study of a particular area of the delta below the present one square kilometre resolution
bull The available data do not justify high expectations on the level of accuracy with respect to absolute water levels and quantitiesRecommendations have been made for improved data collection andmanagement which when available could justify further modeldevelopment
The key issue at this stage is that the Integrated Hydrologic Model represents theessential hydrologic phenomena in an integrated manner such that it may be appliedwith confidence to the assessment of the impacts of future water resourcesdevelopments on the delta hydrology for the purposes of the management plan
Physical Phenomena
The model simulates physical hydrological phenomena only Studies have revealedin particular the importance of the interdependency of physical and biologicalphenomena for example the movement of large mammals opening new flow pathsthrough the vegetation sedimentation and vegetation in closing existing channels
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bull The data should reflect how the delta may recover in a period of normal inflows after a dry period
The long term inflow in terms of volume per annum from 1933 to date is shown inslide 14 for both Mukwe in Namibia and Mohembo in Botswana Whereas at Mukwethe river is more or less confined to the gauged channel at Mohembo the river has
broadened out with a wide flood plain It is not possible to gauge the flows over theflood plain and Mohembo will not represent the total discharge This is most clearlyevinced in the high flow years 199899 and 200001
An anomaly appears in the data from around 1950 to 1980 where the total inflow atMohembo appears higher than Mukwe As there is no significant inflow to the river between the two gauges this can only be explained by gauging errors The seriesafter 1980 is more consistent with Mukwe showing a higher inflow than Mohembo
The period from 1992 to 1997 represents the sequence of the five lowest inflowyears and is therefore chosen to provide the input data to analyse the impacts under critical conditions for both the existing state and possible future states with water resources developments
The following five year period from 1997 to 2002 represents relatively normalhydrologic conditions in the delta and has been used to assess how the delta mayrecover after a sequence of dry years (see slide 15)
A high inflow period could also be selected eg 1987 to 1992 to assess the impactsunder high inflow conditions It is not planned to analyse this period as
bull The conditions will not be critical to a management planning exercise
bull The number of impacts which have to be assessed in terms of flowsdepths etc will be further increased
Appropriate time series of inputs (inflows precipitation etc) have been prepared and
applied to the existing state of the delta The model results are used as a baselineagainst which future developments are assessed for their impacts The inputs aremodified to represent conditions which may prevail under future conditions
To summarise while the inflows to the delta will be dynamic ranging over two fiveyear periods representing critical dry and normal average hydrologic conditions theexisting and future states will be static This implies that for the duration of the fiveyear model run period the population for instance will not be increasing no newdams or irrigation schemes are built etc
At present the Baseline and Scenario Conditions have been simulated for the criticaldry hydrologic input period from October 1992 to October 1997 Summary results arepresented and discussed in the following sections Slides illustrating the outputs arepresented in Annex 3
233 Presentation of Results
In order to assist the stakeholders assess the outputs and their implications for their particular sectors a common format for the presentation is adopted The resolutionof the model in space is one kilometre and in time four hours In order to limit thesize of the output files the results are output with a temporal resolution of one weekfor surface flows and the unsaturated zone while the slower responding ground water results are output every two months of the five year period
For the purpose of presenting summary data the delta is divided into five zonesaccording to the probability of flooding as assessed from 15 years of satellite images(source J McCarthy Stockholm University) with the Panhandle treated as a fifth
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separate zone (slide 16) The probability delta area and a zone description are givenin the table
Model Area (km 2) 28782 Description
Zone 1 - 01gtFPgt0 19322 rarely flooded
Zone 2 - 05gtFPgt01 3534 occasionally flooded
Zone 3 - 09gtFPgt05 2328 seasonally flooded
Zone 4 - 1gtFPgt09 2152 normally flooded
Zone 5 - Panhandle 1446 Panhandle
(1) Animated sequence of flooding in the delta showing the monthly variation inflooded area and depth (The AVI format file is available from DWA sizearound 110Mb)
(2) Map based on the one kilometre grid showing the minimum depth of water in the delta for the five dry years
(3) Time series showing the variation in the depth of flooding over the five year period The depth is averaged for each of five zones (see table)
(4) Map based on the one kilometre grid showing the minimum level of soilmoisture in the root zone (the zone from which plants draw water) in thedelta over the five dry years
(5) Map based on the one kilometre grid showing the maximum depth toground water in the delta over the five dry years
(6) Summary tables are prepared showing the following
bull Water balance showing inflows outflows and storage changes
bull Baseline conditions and impacts for the surface water soilmoisture and ground water for the entire delta and for each of the five zones
A wide range of outputs of all hydrologic parameters in various formats is possibleand can be tailored to the needs of the individual stakeholders It is possible also toselect different zones to calculate average time series and summary results Theabove selection has been made by the component as samples of what may be usefuland meaningful to the stakeholders and to generate discussion
24 Baseline
Surface Water
The animated depth of flow sequence (slide 17) shows the expansion and contractionof the flooded area and depth as the sequence of flood waves for each of the fiveyears propagates through the Panhandle and spreads out through the delta Slide 18shows the detail for the lower envelope of flooding for the upper delta Each squareis one square kilometre
Time series of the depth of surface water are shown for each of the five zones in slide19 The Panhandle is the first area affected by the flood wave from upstream andbeing relatively confined within a flood plain around 20km wide has the maximumrange from the seasonal wet to dry periods around 06m through the five dry yearsAs the flood wave propagates through the delta the range in water levels declines
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The accumulated impact of the drought years is also felt more as there is a generaldecline in the flood depth
As the summary table (slide 20) shows the area flooded ranges from 1513km 2 to12077km 2 while the depth ranges from 0 to around 5m The average depth in thenormally flooded area ranges from 011m to 092m
SubSurface Water
The distribution of the soil moisture content is shown as a deficit below saturatedlevel as the lower envelope (maximum deficit) for the five year period in slide 21The average deficit ranges from 056m in the rarely flooded area to 012m in thenormally flooded area
The depth to ground water over the delta area is shown for the lower envelope(maximum depth) over the five year period in slide 22 The depth ranges from anaverage of 188m in the rarely flooded area to 037m in the normally flooded area
Water Balance
The overall water balance for the Baseline and Scenarios is shown in slide 23Negative values indicate an inflow to the delta (eg precipitation and river inflow) whilepositive values indicate an outflow (eg evapotranspiration and river outflows) TheTotal should be zero the small value indicates a very minor continuity error Thenegative overland and subsurface storage changes indicate a decline in storage inthese levels
25 Upstream Water Resources Developments
251 Introduction
To date no significant water resources developments have taken place upstream inAngola and Namibia In the past plans have been made for the construction of damsfor irrigation and hydropower Anticipating that these plans may be revived theWERRD project has run a number of scenarios using a modified rainfall-runoff modelof the basin (Pitman model Rhodes University) including a scenario for all planneddams
A number of sources describes potential irrigation in the upstream basin in Angolaand Namibia These have been reviewed and a potential scenario compiled basedon
bull Irrigation demand based on 15000m 3haa with a 25 return flow
bull Irrigated area in Angola 54500ha in Namibia 7500ha
bull Angola grows vegetables in winter (June to October) Namibia growsmaize in summer (December to April)
The corresponding runoff from the upstream basin has been applied under twoscenarios Dams in Angola and Irrigation as inflow to the delta upstream The twopotential developments are kept separate for the purpose of initial appraisal in order that the impact from each can be identified This will assist in minimising the adverseimpacts from these developments
252 Dams in Angola
The impact of the previously planned hydropower dams in Angola on the inflow to the
delta is presented in slide 24 Hydropower development does not consume waterbut stores water in the flood period for release in the dry period This results in a
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redistribution of the natural hydrograph flood flows are reduced while dry seasonflows are increased (The impact appears only to be significant in 1993 and 1996 ndashthis needs further investigation)
The impact of the dams on the surface and subsurface waters of the delta is minimalgiven the limited apparent impact in three out of the five dry years and the fact that
there is no nett water loss in the basin upstream
253 Irrigation
The impact of the potential irrigation scenario on the inflow to the delta is shown inslide 25 The impact is greatest in the dry period when water is withdrawn for therelatively large area of winter crops in Angola The summer withdrawals for irrigationin Namibia are significantly less
Correspondingly the impact on the delta in the flood period is minimal while in thedry period the overland depth of flow is reduced particularly in the Panhandle andnormally flooded areas and the minimum flood extent is reduced by 660km 2 or 40of the present dry period area (slide 26)
26 Abstractions from DeltaWater for largely local domestic use is abstracted from both the surface and groundwaters of the delta The surface water abstractions are based on water rights issuedby DWA (ie the amount which may legitimately be withdrawn ndash actual withdrawals arenot monitored and may be greater or less than allowed) Ground water abstractionsare based on the demands projected from historic information to the present day
In terms of the inflows to the delta (river flows from the basin upstream andprecipitation over the basin the abstractions and corresponding impacts are minimalSurface water abstraction represents 0006 of the inflow and ground water 02In the five dry years analysed the minimum flooded area is reduced by 025Future scenario runs will simulate the impact of abstractions with projected increasedpopulation and rates of consumption to the notional year 2025
27 Climate ChangePotential climate change will have an impact on the delta in respect of inflows fromthe basin upstream and the climate over the delta The WERRD project has run aglobal climate model HadCM3 1 to predict the changed precipitation and temperatureover the basin For the upstream basin the Pitman rainfall-runoff model has beenapplied to predict the modified inflows upstream of the delta (slide 27) The modifiedprecipitation and temperature over the delta have been used as direct inputs to theIntegrated Hydrologic Model (slide 28)
The impact of the climate change scenario is highly significant in both the flood anddry seasons River inflows to the delta are reduced by 38 and precipitation over the delta by 9 Temperature increases by 22ordmC
The corresponding impact on flow depths is shown on the reduced depths the impacton the minimum depths is shown for the Panhandle and normally flooded areas inslide 29 and in each of the five zones through the five year run period in slide 30The reduction in depth averages 003m over the entire delta and the minimumflooded area is almost halved
1 httpwwwmet-officegovukresearchhadleycentremodelsHadCM3html
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28 Management PlanningThe model analyses are carried out to assess the impacts of possible future basinconditions on the delta for the purposes of management planning An iterativeprocess is envisaged with a series of bilateral meetings with the Stakeholders andcommon Workshops in which the inputs and outputs are presented to and discussedwith the stakeholders The outputs can migrate towards a presentation format that isboth meaningful and relevant to the stakeholders
The Hydrology and Water Resources component will only analyse the impacts on thewaters of the delta DWA and its consultants do not have the capability or theresources to analyse the impacts on the wildlife vegetation livestock fisheries or tourists It is up to these respective sectors to assess these impacts based on thechanged delta hydrology
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3 DISCUSSION
31 IntroductionThe following sections record the comments made on the foregoing presentationsand the responses given by the hydrology team (in italics)
32 Database Management(1) What is lithology Remember that as much as you are speaking to experts
you are also speaking to non-experts
The point is well taken A glossary will be prepared to explain technical terms
(2) The presentations are too fast and we need details of the graphs for example
This point is also noted presentations should emphasise important pointsSelected slides from the Workshop are included in Annex 3 and a full report is being prepared of both the Integrated Hydrologic Model and the
preliminary scenario analysis These should be studied by thestakeholders in advance of further (bilateral) discussions
(3) Is there a slide to show locations of critical rainfall and flow stations so thatwe could appreciate all the difficulties encountered We would appreciatemuch if we could have locations of all your data sources
The locations of the existing and proposed gauging stations is available inDWA in GIS format The key source for this and information from other sectors and stakeholders will be the Okavango Delta Information System
implemented in HOORC
33 Integrated Hydrologic Model(1) I like your conceptual model but what is applicable in Europe may not
necessarily be applicable here also
The conceptual model is fundamental to the development of a numerical model The conceptual model is strictly formulated for the Okavango Deltabased on available data and scientific publications on the subject Theconceptual model has no relation to European or other climatic conditions
(2) Your evapotranspiration rates are higher than those from Class A pan whenactually the reverse should be true This should be looked into
Actual rates of evapotranspiration (ET) are not necessarily lower than panevaporation owing to a number of factors including pan correction methodcombined free surface ET and vegetation transpiration in flood plains and actual location in the delta versus the location of pan measurements If new documented field data on ET losses are available the hydrology teamwould be happy compare these to model simulations
(3) Is there any physical evidence of flooding
The assessment of the observed flood extent has been based mainly on ananalysis of satellite images from 1984 to 2000 (J McCarthy StockholmUniversity) and DWA water level observations
(4) How do you parameterize your flow in respect to flow resistance
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The Manning resistance coefficient is used to describe the resistance toflow in the river channels and over the flood plains Values for overland flow are distributed according to three vegetation zones based onvegetation mapping (S Ringrose HOORC) Values in the river channelsare ascribed based on channel vegetation descriptions (Dr CK NaiduDWA) Adjustments are made to give a good match with observed flood extent overall water balance and downstream discharges
(5) Your climate input data comprise rainfall evapotranspiration etc fromMaun and Shakawe To what extent can one use a physically based modelwith such a coarse resolution Could we conclude that this is an empiricalmodel
MIKE SHE is a physically based model which implies that the model parameters have a clear physical interpretation as opposed to lumped conceptual models Data measured in single locations may be used toassign parameter values but the parameters used at the current grid scaleof 1km 2 should be regarded as lsquoefficientrsquo parameters representing the
aggregated responseThe lack of input data on distributed rainfall or any other model input doesnot imply that the MIKE SHE model is empirical Maun and Shakawe arethe only two stations in and adjacent to the delta with reliable data Thedelta is not a conventional catchment area where the runoff from individual subcatchments is essential to arrive at the combined flow in themainstream Overland flows mix the runoff from the subcatchments and evapotranspiration dominates Thus a high resolution of the rainfall data isnot of major importance in a general flow model of the delta Nonethelessrecommendations for improved monitoring include rehabilitation of the eight DCPs which measure rainfall and the installation of an additional eight automatic gauges in the delta
(6) Our confidence on the model cannot be based on your numbers
This particular comment was based on relatively consistent outflows for theBaseline and Scenarios This was owing to the nature of the downstreamboundary condition which has since been improved and now shows avariation
The flow leaving the delta (and the model) has passed through anextremely complex hydrologic system flood propagation flow splits among distributaries spills to vast flood plains and swamps evapotranspirationand infiltration The measurement of the discharge upstream is subject toerrors of at least 10 (say 50m 3 s at the flood peak) Differences between
the model computations and the observations cannot better this(7) What resolution should we have confidence on as it pertains to your
model
Given the complexity of the area and the available data model resultsshould not be interpreted looking at single grid values Interpretation based on delta zones or subsystems is more appropriate Five zones based onflood probability have been applied in the scenario demonstration runs and others may be devised according to stakeholdersrsquo needs The minimumarea should cover several square kilometres
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34 Scenarios(1) You have run the scenarios based on dry period(s) Could you please
revise this You might be missing out on recharge to groundwater as aresult of high floods A single high flood could recharge an aquifer for thenext twenty years for example
It is the intention to run the model for a period of normal flows to see how the delta recovers from a drought As suggested the model will also be runfor high floods (this is also important for sediment transport in the delta)
(2) In taking the dry period as critical you have to consider floods as alsocritical Floods need to be covered as well
The delta is not under stress during high flow periods and the impacts of water resources developments will not be so keenly felt and therefore not critical to management planning See also response to (1) above
(3) People are more worried about the switching of channels Maybe thisaspect needs to come out in your model outputs as well
The introduction of sediment transport to the model (which has just commenced) will give an indication of possible future switches and redistribution of delta flows Switching and realignment of channels has achaotic component (the butterfly effect on global climate is akin to ahippopotamus going walkabout in the delta) and accurate predictions aresimply not possible
(4) Looking at the modelrsquos level of resolution critical management issues willnot be answered
The component has been conceived and ToR written (in 200102) toaddress the broad scale management planning issues (water resources
developments upstream climate change abstractions from the delta reed cutting and dredging) On this basis the model approach has been set outand the model set up and applied Preliminary applications suggest that the main threats to the delta will arise from upstream irrigation and climatechange These are the critical management issues related to hydrology
(5) Channel blockages impacts need to be covered in detail Channel switchingis another fundamental management issue
The model can simulate the impact of channel blockages and channel switching As discussed in (3) above the model cannot predict theseoccurrences
(6) You mentioned that your model could handle sediment transport Do youhave something on sediment transport now
An approach to introducing sediment transport to the model has beendrafted (pending report on the Integrated Hydrologic Model)
(7) You seem not to be representing your conditions
See response to (6) above
35 Presentation of Results(1) You canrsquot have a reduction of flow by 40 and yet have no impact on the
outflow This gives me the confidence of your model
See response to (4) above
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(2) The difference in long-term average discharge between observed andsimulations should not be taken to be insignificant This should becombined with other scenarios to better appreciate its impact
It is important in the preliminary stage to separate the impacts fromindividual water resources developments to obtain a good understanding of
which are critical and which are not A limited number of combinationscenarios may be run at a later stage once these can be defined and agreed by the management planners and stakeholders
(3) It would be good to combine all the scenarios as well
See (2) above
(4) It would be interesting also to look at frequency and duration of flooding
The impact on the duration of flooding can be assessed through the timeseries plots for different zones An estimate can also be made on theimpact of the scenarios on the frequency of flooding
(5) What is the model doing as it pertains to erosion and sedimentation
Sediment transport is being introduced to the model This will enable theassessment of the broad pattern of erosion and deposition through themain river channels along which the bed load is conveyed from the basinupstream
(6) The issue of land use change has to be incorporated into the model
To introduce the impact of land use changes in the basin upstream requiresthe application of a water resources planning model to the upstream basinThis is not within the present scope of ODMP which is relying on theoutputs of basinwide projects such as Sharing Water and WERRD (bothcompleted) and possibly in the future TwinBas (ongoing) If ODMP
partners suggest particular potential land use changes within the deltawhich have an impact on the hydrology these may be simulated using theIntegrated Hydrologic Model
(7) The presentations have mostly been technical I would like to suggest thatwe make handouts available after the workshop so that the participantscould have ample time to go over them and later submit their suggestionscomments and or questions
This document represents a full report on the proceedings Further comments from ODMP partners are welcome that our further work may more closely meet the needs of delta management planning Further discussions will be held with the stakeholders on the ongoing model applications possibly on a bilateral basis to obtain a closer understanding of particular needs and ways to meet these needs
36 Stakeholdersrsquo Responses
Wildlife
(1) We need drying flood plain map to better track movement of wild animals
The drying and wetting of the flood plains was presented as animated sequences in the Workshop for all scenarios with a monthly time step Afiner temporal resolution can be prepared (down to four hours) though the
spatial resolution is limited to one kilometre squares
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(2) We would appreciate information on correlations between the distribution of elephants population and extent of flooding close to the buffalo fence
The HampWR component can provide information on the waters of the deltaIt is up to the individual partners to analyse this information for their ownneeds The HampWR component cannot be expected to carry out all the
analyses for the management planThe integration of information from all ODMP components will be carried out within the Okavango Delta Information System implemented inHOORC (also with support from Danida)
Fisheries
(1) Water quality is very critical as this have impact on fish populationdynamics Sedimentation is also critical as it has a bearing on fishpopulations
Sedimentation is indeed critical to fish populations as fine organic richsediment is washed out from the flood plain into the channels by the flood waters resulting in oxygen depletion
The MIKE SHE integrated hydrologic modelling system has the capability tosimulate water quality This is not within the present scope of ODMPSystematic data (including DO and SOD) do not exist at present on whichto develop such a model Improved monitoring recommendations includethe introduction of systematic sampling and analysis at the key inflow station of Mohembo and monthly in-situ measurements of salinity and pH at around 20 discharge stations throughout the delta
Water Affairs
(1) Is MIKE SHE an instrument or whatMIKE SHE is one of a suite of water and environmental software packagesdeveloped and marketed commercially by DHI Water and EnvironmentThe MIKE SHE package is the most advanced generic (can be applied toany system) hydrologic software available MIKE SHE has a consistent development history over thirty years and has been applied to hundreds of hydrologic systems worldwide
(2) Can the model predict channel shifts
The sediment transport model will predict erosion and deposition leading tochannel aggradation and eventual closure The delta morphology isinherently unstable and chaotic and no model can predict channel abandonment with higher certainty than what is constrained by natural variability (chaos) Nonetheless the impact of major channel shifts can be
predicted as well as possible management measures to mitigate suchshifts
(3) Mr Dikgomo mentioned that Hydrology and Water Resources component isone of the twelve What are the other eleven components
The CTA may best respond to this question though it is suggested that representatives from participating organisations take the trouble to informthemselves of the ODMP structure objectives and outputs before attending such fora
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Land Board
(1) Is it possible for the model to give us depth of water table within at least500 metres from the delta This can help us with land use This will alsohelp us determine how far we can avoid pollution in land allocations
The spatial resolution of the model is one square kilometre The model cangive the various hydrologic parameters such a depth to ground water withinthe general area (within a few square kilometres) This should be quiteadequate for the purpose of broad based management planning
(2) Can the model add value to Tawana land board land use and managementplan (2004-2029)
The Hydrology and Water Resources component is concerned withhydrology and water resources The outputs from the component arehydrologic data and predictions for the delta It is up to the various sectorsand components of the management plan to assess the impact of thesehydrologic parameters for their own purposes The HampWR component can
assist in the interpretation of the hydrologic dataTourism
(1) There are lodges and camps located close to the river channels Can themodel be able to help on the implications of pollution
The model can simulate the pattern of flow in the delta which may give auseful indication of the movement of pollution though not the output whichmay be given by a water quality model (advection dispersion decay etc)
General
(1) This component (Hydrology and Water Resources) is so detached from therest It should relocate to MaunThe component is located in Gaborone as the capital has better infrastructure Progress on the component would be constrained by thelimited infrastructure in Maun
(2) To what extent is your data real time series that it could be relied upon
The data available from the delta at present are poor largely owing todifficulties in access and disturbance of gauging stations by humans and large mammalian wildlife Lack of systematic use of the data to date havealso contributed to neglect Improved monitoring is necessary for management planning and an improved hydrologic model with finer
resolution and greater accuracy Recommendations have been prepared for DWA to improve hydrologic monitoring and it is hoped these can beimplemented in the course of 2005
(3) The presentations are too technical When will ODMP reach out to usSomeone mentioned that communication and or information disseminationis a problem Why cant we find other Batswana who could do the job toconvey the information in an audience screened and targeted way
The hydrology of the delta is complex and requires a complex model for arealistic simulation of the processes The presentations were intended togive all participants an understanding that the model is indeed capable of simulating the key hydrologic phenomena of the delta It is hoped that this
has been achieved though it is recognised that the depth of understanding
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will depend upon the level of the individual participantrsquos hydrologic knowledge
The DWA staff assigned to ODMP will gradually take over presentations insuch fora as part of the process of technology transfer which is anessential part of the component
Lessons have been learnt from this Workshop A second and possibly third Workshop will be planned along with bilateral meetings with the individual Stakeholders hopefully improving the communication to the diverse
participants (see Conclusions)
(4) Communications and networking is lagging behind but its pro-activeness isso crucial The component would simplify information and relay it tocommunity andor stakeholders
The HampWR component looks forward to this component being activatedand to cooperating with the Communications and Networking component in
presenting results of the hydrologic analyses meaningful to all
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4 CONCLUSIONS
41 SummaryProf Francis Sefe from the consultantsrsquo team summarised the Workshop discussionas follows
(1) There were discussions on both spatial and temporal resolutions of themodel which need clarification
(2) It was observed that data quality and availability is a constraint to accuratemodelling of the hydrology of the delta and providing physical evidence toback the model conclusions
(3) In the selection of scenarios it is critical to understand that the individualscenarios are not stand alone
(4) The choice of what constitutes the baseline scenario was discussed It hasto be emphasised that the inclusion of exceptional floods is also importantand hence not only the dry period should be used
(5) The presentation was multifaceted
(6) People could not easily locate any landmark features on the map Thisneed not be Villages could be labelled and even the rivers themselves
(7) Though water quality is not in the scope of the current modelling water quality is very important and this has to be looked into in the future
(8) Ground water fluctuations at the periphery of the delta need to be lookedinto
(9) Various stakeholders have difficulty interpreting the results This is a critical
issue that needs to be addressed The target audience should reasonablybe able to assimilate the information relayed to them
42 RecommendationsThe following recommendations are made with regard to the future interactionbetween the Hydrology and Water Resources component and the other ODMPparticipants
(1) While the introductions to the set up and application of the IntegratedHydrologic Model attempted to convey the complexity of the deltahydrology and its computer based representation further effort needs to bemade to present the model and its results in a manner which is fullycomprehensible to the Stakeholders most of whom do not have in depthhydrologic knowledge
(2) It was originally believed that presentation of the model to Stakeholders in acombined forum would allow the interchange of ideas and knowledgeamong the Stakeholders as well as with the Hydrology and Water Resources component The resulting discussion tended to be dominatedby those with technical hydrologic knowledge at the expense of thosewithout The next round of discussions should be on a bilateral basis suchthat the discussions can proceed at a level appropriate for the individualStakeholders and their needs in respect of hydrology and water resources
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(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
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ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
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ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
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Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
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Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
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ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
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Each component should identify a suitable person to act as a focal point for liaisonwith the Hydrology and Water Resources component and this person should attendfuture such workshops and meetings
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2 PRESENTATIONS AND DISCUSSION
21 IntroductionsSelected slides from those employed in the respective presentations are included inAnnex 3 and illustrate the text of the presentations in the following sections
The introductory presentations covered the component background implementationdata collection and processing and monitoring proposals As such they generatedlimited discussion One suggestion was that as most of the stakeholders were fromsectors other than water a glossary should be included to cover the use of technicalterms
22 Integrated Hydrologic Model
221 Introduction
The Introduction to the Integrated Hydrologic Model set out the approach tomathematical modelling in the context of the hydrology of the delta The key flowprocesses above in and below the delta are shown in slide 1 Given the criticallinkages among the atmospheric surface and ground waters it is necessary todevelop an Integrated Hydrological Model which integrates the essential physicalphenomena controlling the delta As such the model requires a basis in physicalprocesses as opposed to a conceptual model which has an idealised representation
It is not the intention to set up a detailed model The available data do not justify thisand the project resources are not available The model will be somewhat schematicbut nonetheless capable of describing the essential processes such as the overallflow pattern among the distributaries flooding and drainage of seasonal swampareas The model will not be capable of predicting the small scale vegetation andmorphological changes which appear to have a significant impact on the overall flowpattern
Water and its distribution in space and time is the fundamental physical basis for management of the ecosystem Management criteria for the delta could include
bull Maintain present flood extent and duration
bull Maintain current pattern of flows through the delta
bull Minimise adverse impacts on any part of the interconnected hydrologicalsystem
The distinct environments and key hydrologic phenomena were presented illustratingthe complex interactions among the atmospheric surface and subsurfacecomponents of the wetland
In order to have a realistic representation of these key phenomena and their interactions and to make quantitative prediction of the potential effects of changes inwater use it is necessary to employ an Integrated Hydrologic Model The systemselected is MIKE SHE developed by DHI Water and Environment Denmark Thegeneric system (the software can be applied to any hydrologic system) is marketedcommercially and is applied to hundreds of catchments and wetlands worldwide
The key features of the software package are (slide 2)
bull Physically based with a realistic representation of the hydrologic
phenomena based on the laws of physics
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(slide 3) The vegetation dynamics are based on remotely sensed data with limitedground verification (see slides 4 and 5) The relationship between the extent of surface water and the rate of evapotranspiration is shown for the normally andseasonally flooded areas in slide 6
224 Surface Waters
The surface water flows are dependent on the topography of the delta which hasbeen described by a digital elevation model of the Ramsar area with a 30m resolutionbased on aerial radar altimetry and remote sensing and a limited number of channelcross sections available at gauging stations and surveyed by researchers
The key characteristics of the delta are the numerous bifurcations or defluences (asopposed to confluences) extensive spills to the flood plains and swamps andhydraulic connections among the spill areas and slow flood wave propagation(around four months from upstream to downstream) with a high variation in the extentof flooding (slide 7)
The surface waters of the delta are described by a full hydrodynamic representationof the flows in the main rivers and channels and by a distributed kinematicrepresentation of the flows over the flood plains and through the swamps Thedescriptions are fully coupled (slide 8) and enable the representation of theessentially one dimensional flows through the channels giving definition to the flowand the spreading and distributed storage over the flood plain (slide 9)
225 SubSurface Waters
Infiltration rates are significant on the predominantly sandy soils in the early stages of the flood season The infiltration raises the ground water levels up to the flood water level This increases the water available to plants which in turn increasestranspiration from the leaf surfaces to the atmosphere (slide 10)
An essential component is the inclusion of the critical unsaturated root zone the zonefrom which plants draw water and transpire to the atmosphere Together withevaporation from open water this is represents the main loss of water in the deltaThe evapotranspiration component simulates both the hydrologic and vegetationdynamics (slide 11)
The ground water component is important to account for the local effects of groundwater on the water balance ie recharge and discharge and evapotranspirationlosses Only the surficial ground water aquifer is represented (slide 12)
Detailed ground water studies show infiltration and recharge of fresh water lensesembedded in older saline ground water Given the low topographical relief limited
ground water flow is directed towards local depressions (slide 13) Model water balance tests indicate that there is no significant ground water flow from the delta nor are there data to support such flow hypotheses Consequently there is no flowacross the subsurface model boundary
226 Outputs
The outputs from the model are designed to support broad based managementplanning in the Okavango Delta The outputs are presented in grid or map formatshowing the spatial variation in the parameters over the delta time series (plots of various parameters against time) and summary tables of results The outputs may besummarised as
bull The actual evaporation from open water and the transpiration fromvegetation
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bull Surface water levels and flows through the rivers and over the floodedswamp areas and the extent of flooding
bull The moisture content of the soil
bull The ground water levels and flows
bull The overall water balance including inflows outflows and changes insurface and subsurface storage for the delta and selected areas of thedelta
bull Sediment transport along the main channels of the delta showingpatterns of erosion and deposition
The Integrated Hydrologic Model does have practical certain limitations and it isimportant that these are recognised by the stakeholders and management planners
Channel Switching
While the model can predict the impact of cutting and dredging a new channel
through the delta and the impact of closing an existing channel through theencroachment of vegetation it is not able to predict the occurrence of the formation of new channels and the realignment of existing channels which may be initiated by themovement patterns of large mammals and vegetation growth
Certain trends in sedimentation and channel development and decay may bepredicted by the application of sediment transport to the model Work on this areahas just commenced Detailed analyses of selected reaches and areas of the deltamay be carried out through the application of two dimensional morphological modelsThis is beyond the scope of the present component activities
Level of Detail and Accuracy
While the technology exists to simulate the hydrologic behaviour of the delta at a highlevel of detail (previous applications have been made at the level of individualcultivated fields) this is constrained by
bull The resources available to the component do not permit thedevelopment of submodels which could enable the study of a particular area of the delta below the present one square kilometre resolution
bull The available data do not justify high expectations on the level of accuracy with respect to absolute water levels and quantitiesRecommendations have been made for improved data collection andmanagement which when available could justify further modeldevelopment
The key issue at this stage is that the Integrated Hydrologic Model represents theessential hydrologic phenomena in an integrated manner such that it may be appliedwith confidence to the assessment of the impacts of future water resourcesdevelopments on the delta hydrology for the purposes of the management plan
Physical Phenomena
The model simulates physical hydrological phenomena only Studies have revealedin particular the importance of the interdependency of physical and biologicalphenomena for example the movement of large mammals opening new flow pathsthrough the vegetation sedimentation and vegetation in closing existing channels
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bull The data should reflect how the delta may recover in a period of normal inflows after a dry period
The long term inflow in terms of volume per annum from 1933 to date is shown inslide 14 for both Mukwe in Namibia and Mohembo in Botswana Whereas at Mukwethe river is more or less confined to the gauged channel at Mohembo the river has
broadened out with a wide flood plain It is not possible to gauge the flows over theflood plain and Mohembo will not represent the total discharge This is most clearlyevinced in the high flow years 199899 and 200001
An anomaly appears in the data from around 1950 to 1980 where the total inflow atMohembo appears higher than Mukwe As there is no significant inflow to the river between the two gauges this can only be explained by gauging errors The seriesafter 1980 is more consistent with Mukwe showing a higher inflow than Mohembo
The period from 1992 to 1997 represents the sequence of the five lowest inflowyears and is therefore chosen to provide the input data to analyse the impacts under critical conditions for both the existing state and possible future states with water resources developments
The following five year period from 1997 to 2002 represents relatively normalhydrologic conditions in the delta and has been used to assess how the delta mayrecover after a sequence of dry years (see slide 15)
A high inflow period could also be selected eg 1987 to 1992 to assess the impactsunder high inflow conditions It is not planned to analyse this period as
bull The conditions will not be critical to a management planning exercise
bull The number of impacts which have to be assessed in terms of flowsdepths etc will be further increased
Appropriate time series of inputs (inflows precipitation etc) have been prepared and
applied to the existing state of the delta The model results are used as a baselineagainst which future developments are assessed for their impacts The inputs aremodified to represent conditions which may prevail under future conditions
To summarise while the inflows to the delta will be dynamic ranging over two fiveyear periods representing critical dry and normal average hydrologic conditions theexisting and future states will be static This implies that for the duration of the fiveyear model run period the population for instance will not be increasing no newdams or irrigation schemes are built etc
At present the Baseline and Scenario Conditions have been simulated for the criticaldry hydrologic input period from October 1992 to October 1997 Summary results arepresented and discussed in the following sections Slides illustrating the outputs arepresented in Annex 3
233 Presentation of Results
In order to assist the stakeholders assess the outputs and their implications for their particular sectors a common format for the presentation is adopted The resolutionof the model in space is one kilometre and in time four hours In order to limit thesize of the output files the results are output with a temporal resolution of one weekfor surface flows and the unsaturated zone while the slower responding ground water results are output every two months of the five year period
For the purpose of presenting summary data the delta is divided into five zonesaccording to the probability of flooding as assessed from 15 years of satellite images(source J McCarthy Stockholm University) with the Panhandle treated as a fifth
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separate zone (slide 16) The probability delta area and a zone description are givenin the table
Model Area (km 2) 28782 Description
Zone 1 - 01gtFPgt0 19322 rarely flooded
Zone 2 - 05gtFPgt01 3534 occasionally flooded
Zone 3 - 09gtFPgt05 2328 seasonally flooded
Zone 4 - 1gtFPgt09 2152 normally flooded
Zone 5 - Panhandle 1446 Panhandle
(1) Animated sequence of flooding in the delta showing the monthly variation inflooded area and depth (The AVI format file is available from DWA sizearound 110Mb)
(2) Map based on the one kilometre grid showing the minimum depth of water in the delta for the five dry years
(3) Time series showing the variation in the depth of flooding over the five year period The depth is averaged for each of five zones (see table)
(4) Map based on the one kilometre grid showing the minimum level of soilmoisture in the root zone (the zone from which plants draw water) in thedelta over the five dry years
(5) Map based on the one kilometre grid showing the maximum depth toground water in the delta over the five dry years
(6) Summary tables are prepared showing the following
bull Water balance showing inflows outflows and storage changes
bull Baseline conditions and impacts for the surface water soilmoisture and ground water for the entire delta and for each of the five zones
A wide range of outputs of all hydrologic parameters in various formats is possibleand can be tailored to the needs of the individual stakeholders It is possible also toselect different zones to calculate average time series and summary results Theabove selection has been made by the component as samples of what may be usefuland meaningful to the stakeholders and to generate discussion
24 Baseline
Surface Water
The animated depth of flow sequence (slide 17) shows the expansion and contractionof the flooded area and depth as the sequence of flood waves for each of the fiveyears propagates through the Panhandle and spreads out through the delta Slide 18shows the detail for the lower envelope of flooding for the upper delta Each squareis one square kilometre
Time series of the depth of surface water are shown for each of the five zones in slide19 The Panhandle is the first area affected by the flood wave from upstream andbeing relatively confined within a flood plain around 20km wide has the maximumrange from the seasonal wet to dry periods around 06m through the five dry yearsAs the flood wave propagates through the delta the range in water levels declines
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The accumulated impact of the drought years is also felt more as there is a generaldecline in the flood depth
As the summary table (slide 20) shows the area flooded ranges from 1513km 2 to12077km 2 while the depth ranges from 0 to around 5m The average depth in thenormally flooded area ranges from 011m to 092m
SubSurface Water
The distribution of the soil moisture content is shown as a deficit below saturatedlevel as the lower envelope (maximum deficit) for the five year period in slide 21The average deficit ranges from 056m in the rarely flooded area to 012m in thenormally flooded area
The depth to ground water over the delta area is shown for the lower envelope(maximum depth) over the five year period in slide 22 The depth ranges from anaverage of 188m in the rarely flooded area to 037m in the normally flooded area
Water Balance
The overall water balance for the Baseline and Scenarios is shown in slide 23Negative values indicate an inflow to the delta (eg precipitation and river inflow) whilepositive values indicate an outflow (eg evapotranspiration and river outflows) TheTotal should be zero the small value indicates a very minor continuity error Thenegative overland and subsurface storage changes indicate a decline in storage inthese levels
25 Upstream Water Resources Developments
251 Introduction
To date no significant water resources developments have taken place upstream inAngola and Namibia In the past plans have been made for the construction of damsfor irrigation and hydropower Anticipating that these plans may be revived theWERRD project has run a number of scenarios using a modified rainfall-runoff modelof the basin (Pitman model Rhodes University) including a scenario for all planneddams
A number of sources describes potential irrigation in the upstream basin in Angolaand Namibia These have been reviewed and a potential scenario compiled basedon
bull Irrigation demand based on 15000m 3haa with a 25 return flow
bull Irrigated area in Angola 54500ha in Namibia 7500ha
bull Angola grows vegetables in winter (June to October) Namibia growsmaize in summer (December to April)
The corresponding runoff from the upstream basin has been applied under twoscenarios Dams in Angola and Irrigation as inflow to the delta upstream The twopotential developments are kept separate for the purpose of initial appraisal in order that the impact from each can be identified This will assist in minimising the adverseimpacts from these developments
252 Dams in Angola
The impact of the previously planned hydropower dams in Angola on the inflow to the
delta is presented in slide 24 Hydropower development does not consume waterbut stores water in the flood period for release in the dry period This results in a
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redistribution of the natural hydrograph flood flows are reduced while dry seasonflows are increased (The impact appears only to be significant in 1993 and 1996 ndashthis needs further investigation)
The impact of the dams on the surface and subsurface waters of the delta is minimalgiven the limited apparent impact in three out of the five dry years and the fact that
there is no nett water loss in the basin upstream
253 Irrigation
The impact of the potential irrigation scenario on the inflow to the delta is shown inslide 25 The impact is greatest in the dry period when water is withdrawn for therelatively large area of winter crops in Angola The summer withdrawals for irrigationin Namibia are significantly less
Correspondingly the impact on the delta in the flood period is minimal while in thedry period the overland depth of flow is reduced particularly in the Panhandle andnormally flooded areas and the minimum flood extent is reduced by 660km 2 or 40of the present dry period area (slide 26)
26 Abstractions from DeltaWater for largely local domestic use is abstracted from both the surface and groundwaters of the delta The surface water abstractions are based on water rights issuedby DWA (ie the amount which may legitimately be withdrawn ndash actual withdrawals arenot monitored and may be greater or less than allowed) Ground water abstractionsare based on the demands projected from historic information to the present day
In terms of the inflows to the delta (river flows from the basin upstream andprecipitation over the basin the abstractions and corresponding impacts are minimalSurface water abstraction represents 0006 of the inflow and ground water 02In the five dry years analysed the minimum flooded area is reduced by 025Future scenario runs will simulate the impact of abstractions with projected increasedpopulation and rates of consumption to the notional year 2025
27 Climate ChangePotential climate change will have an impact on the delta in respect of inflows fromthe basin upstream and the climate over the delta The WERRD project has run aglobal climate model HadCM3 1 to predict the changed precipitation and temperatureover the basin For the upstream basin the Pitman rainfall-runoff model has beenapplied to predict the modified inflows upstream of the delta (slide 27) The modifiedprecipitation and temperature over the delta have been used as direct inputs to theIntegrated Hydrologic Model (slide 28)
The impact of the climate change scenario is highly significant in both the flood anddry seasons River inflows to the delta are reduced by 38 and precipitation over the delta by 9 Temperature increases by 22ordmC
The corresponding impact on flow depths is shown on the reduced depths the impacton the minimum depths is shown for the Panhandle and normally flooded areas inslide 29 and in each of the five zones through the five year run period in slide 30The reduction in depth averages 003m over the entire delta and the minimumflooded area is almost halved
1 httpwwwmet-officegovukresearchhadleycentremodelsHadCM3html
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28 Management PlanningThe model analyses are carried out to assess the impacts of possible future basinconditions on the delta for the purposes of management planning An iterativeprocess is envisaged with a series of bilateral meetings with the Stakeholders andcommon Workshops in which the inputs and outputs are presented to and discussedwith the stakeholders The outputs can migrate towards a presentation format that isboth meaningful and relevant to the stakeholders
The Hydrology and Water Resources component will only analyse the impacts on thewaters of the delta DWA and its consultants do not have the capability or theresources to analyse the impacts on the wildlife vegetation livestock fisheries or tourists It is up to these respective sectors to assess these impacts based on thechanged delta hydrology
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3 DISCUSSION
31 IntroductionThe following sections record the comments made on the foregoing presentationsand the responses given by the hydrology team (in italics)
32 Database Management(1) What is lithology Remember that as much as you are speaking to experts
you are also speaking to non-experts
The point is well taken A glossary will be prepared to explain technical terms
(2) The presentations are too fast and we need details of the graphs for example
This point is also noted presentations should emphasise important pointsSelected slides from the Workshop are included in Annex 3 and a full report is being prepared of both the Integrated Hydrologic Model and the
preliminary scenario analysis These should be studied by thestakeholders in advance of further (bilateral) discussions
(3) Is there a slide to show locations of critical rainfall and flow stations so thatwe could appreciate all the difficulties encountered We would appreciatemuch if we could have locations of all your data sources
The locations of the existing and proposed gauging stations is available inDWA in GIS format The key source for this and information from other sectors and stakeholders will be the Okavango Delta Information System
implemented in HOORC
33 Integrated Hydrologic Model(1) I like your conceptual model but what is applicable in Europe may not
necessarily be applicable here also
The conceptual model is fundamental to the development of a numerical model The conceptual model is strictly formulated for the Okavango Deltabased on available data and scientific publications on the subject Theconceptual model has no relation to European or other climatic conditions
(2) Your evapotranspiration rates are higher than those from Class A pan whenactually the reverse should be true This should be looked into
Actual rates of evapotranspiration (ET) are not necessarily lower than panevaporation owing to a number of factors including pan correction methodcombined free surface ET and vegetation transpiration in flood plains and actual location in the delta versus the location of pan measurements If new documented field data on ET losses are available the hydrology teamwould be happy compare these to model simulations
(3) Is there any physical evidence of flooding
The assessment of the observed flood extent has been based mainly on ananalysis of satellite images from 1984 to 2000 (J McCarthy StockholmUniversity) and DWA water level observations
(4) How do you parameterize your flow in respect to flow resistance
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The Manning resistance coefficient is used to describe the resistance toflow in the river channels and over the flood plains Values for overland flow are distributed according to three vegetation zones based onvegetation mapping (S Ringrose HOORC) Values in the river channelsare ascribed based on channel vegetation descriptions (Dr CK NaiduDWA) Adjustments are made to give a good match with observed flood extent overall water balance and downstream discharges
(5) Your climate input data comprise rainfall evapotranspiration etc fromMaun and Shakawe To what extent can one use a physically based modelwith such a coarse resolution Could we conclude that this is an empiricalmodel
MIKE SHE is a physically based model which implies that the model parameters have a clear physical interpretation as opposed to lumped conceptual models Data measured in single locations may be used toassign parameter values but the parameters used at the current grid scaleof 1km 2 should be regarded as lsquoefficientrsquo parameters representing the
aggregated responseThe lack of input data on distributed rainfall or any other model input doesnot imply that the MIKE SHE model is empirical Maun and Shakawe arethe only two stations in and adjacent to the delta with reliable data Thedelta is not a conventional catchment area where the runoff from individual subcatchments is essential to arrive at the combined flow in themainstream Overland flows mix the runoff from the subcatchments and evapotranspiration dominates Thus a high resolution of the rainfall data isnot of major importance in a general flow model of the delta Nonethelessrecommendations for improved monitoring include rehabilitation of the eight DCPs which measure rainfall and the installation of an additional eight automatic gauges in the delta
(6) Our confidence on the model cannot be based on your numbers
This particular comment was based on relatively consistent outflows for theBaseline and Scenarios This was owing to the nature of the downstreamboundary condition which has since been improved and now shows avariation
The flow leaving the delta (and the model) has passed through anextremely complex hydrologic system flood propagation flow splits among distributaries spills to vast flood plains and swamps evapotranspirationand infiltration The measurement of the discharge upstream is subject toerrors of at least 10 (say 50m 3 s at the flood peak) Differences between
the model computations and the observations cannot better this(7) What resolution should we have confidence on as it pertains to your
model
Given the complexity of the area and the available data model resultsshould not be interpreted looking at single grid values Interpretation based on delta zones or subsystems is more appropriate Five zones based onflood probability have been applied in the scenario demonstration runs and others may be devised according to stakeholdersrsquo needs The minimumarea should cover several square kilometres
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34 Scenarios(1) You have run the scenarios based on dry period(s) Could you please
revise this You might be missing out on recharge to groundwater as aresult of high floods A single high flood could recharge an aquifer for thenext twenty years for example
It is the intention to run the model for a period of normal flows to see how the delta recovers from a drought As suggested the model will also be runfor high floods (this is also important for sediment transport in the delta)
(2) In taking the dry period as critical you have to consider floods as alsocritical Floods need to be covered as well
The delta is not under stress during high flow periods and the impacts of water resources developments will not be so keenly felt and therefore not critical to management planning See also response to (1) above
(3) People are more worried about the switching of channels Maybe thisaspect needs to come out in your model outputs as well
The introduction of sediment transport to the model (which has just commenced) will give an indication of possible future switches and redistribution of delta flows Switching and realignment of channels has achaotic component (the butterfly effect on global climate is akin to ahippopotamus going walkabout in the delta) and accurate predictions aresimply not possible
(4) Looking at the modelrsquos level of resolution critical management issues willnot be answered
The component has been conceived and ToR written (in 200102) toaddress the broad scale management planning issues (water resources
developments upstream climate change abstractions from the delta reed cutting and dredging) On this basis the model approach has been set outand the model set up and applied Preliminary applications suggest that the main threats to the delta will arise from upstream irrigation and climatechange These are the critical management issues related to hydrology
(5) Channel blockages impacts need to be covered in detail Channel switchingis another fundamental management issue
The model can simulate the impact of channel blockages and channel switching As discussed in (3) above the model cannot predict theseoccurrences
(6) You mentioned that your model could handle sediment transport Do youhave something on sediment transport now
An approach to introducing sediment transport to the model has beendrafted (pending report on the Integrated Hydrologic Model)
(7) You seem not to be representing your conditions
See response to (6) above
35 Presentation of Results(1) You canrsquot have a reduction of flow by 40 and yet have no impact on the
outflow This gives me the confidence of your model
See response to (4) above
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(2) The difference in long-term average discharge between observed andsimulations should not be taken to be insignificant This should becombined with other scenarios to better appreciate its impact
It is important in the preliminary stage to separate the impacts fromindividual water resources developments to obtain a good understanding of
which are critical and which are not A limited number of combinationscenarios may be run at a later stage once these can be defined and agreed by the management planners and stakeholders
(3) It would be good to combine all the scenarios as well
See (2) above
(4) It would be interesting also to look at frequency and duration of flooding
The impact on the duration of flooding can be assessed through the timeseries plots for different zones An estimate can also be made on theimpact of the scenarios on the frequency of flooding
(5) What is the model doing as it pertains to erosion and sedimentation
Sediment transport is being introduced to the model This will enable theassessment of the broad pattern of erosion and deposition through themain river channels along which the bed load is conveyed from the basinupstream
(6) The issue of land use change has to be incorporated into the model
To introduce the impact of land use changes in the basin upstream requiresthe application of a water resources planning model to the upstream basinThis is not within the present scope of ODMP which is relying on theoutputs of basinwide projects such as Sharing Water and WERRD (bothcompleted) and possibly in the future TwinBas (ongoing) If ODMP
partners suggest particular potential land use changes within the deltawhich have an impact on the hydrology these may be simulated using theIntegrated Hydrologic Model
(7) The presentations have mostly been technical I would like to suggest thatwe make handouts available after the workshop so that the participantscould have ample time to go over them and later submit their suggestionscomments and or questions
This document represents a full report on the proceedings Further comments from ODMP partners are welcome that our further work may more closely meet the needs of delta management planning Further discussions will be held with the stakeholders on the ongoing model applications possibly on a bilateral basis to obtain a closer understanding of particular needs and ways to meet these needs
36 Stakeholdersrsquo Responses
Wildlife
(1) We need drying flood plain map to better track movement of wild animals
The drying and wetting of the flood plains was presented as animated sequences in the Workshop for all scenarios with a monthly time step Afiner temporal resolution can be prepared (down to four hours) though the
spatial resolution is limited to one kilometre squares
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(2) We would appreciate information on correlations between the distribution of elephants population and extent of flooding close to the buffalo fence
The HampWR component can provide information on the waters of the deltaIt is up to the individual partners to analyse this information for their ownneeds The HampWR component cannot be expected to carry out all the
analyses for the management planThe integration of information from all ODMP components will be carried out within the Okavango Delta Information System implemented inHOORC (also with support from Danida)
Fisheries
(1) Water quality is very critical as this have impact on fish populationdynamics Sedimentation is also critical as it has a bearing on fishpopulations
Sedimentation is indeed critical to fish populations as fine organic richsediment is washed out from the flood plain into the channels by the flood waters resulting in oxygen depletion
The MIKE SHE integrated hydrologic modelling system has the capability tosimulate water quality This is not within the present scope of ODMPSystematic data (including DO and SOD) do not exist at present on whichto develop such a model Improved monitoring recommendations includethe introduction of systematic sampling and analysis at the key inflow station of Mohembo and monthly in-situ measurements of salinity and pH at around 20 discharge stations throughout the delta
Water Affairs
(1) Is MIKE SHE an instrument or whatMIKE SHE is one of a suite of water and environmental software packagesdeveloped and marketed commercially by DHI Water and EnvironmentThe MIKE SHE package is the most advanced generic (can be applied toany system) hydrologic software available MIKE SHE has a consistent development history over thirty years and has been applied to hundreds of hydrologic systems worldwide
(2) Can the model predict channel shifts
The sediment transport model will predict erosion and deposition leading tochannel aggradation and eventual closure The delta morphology isinherently unstable and chaotic and no model can predict channel abandonment with higher certainty than what is constrained by natural variability (chaos) Nonetheless the impact of major channel shifts can be
predicted as well as possible management measures to mitigate suchshifts
(3) Mr Dikgomo mentioned that Hydrology and Water Resources component isone of the twelve What are the other eleven components
The CTA may best respond to this question though it is suggested that representatives from participating organisations take the trouble to informthemselves of the ODMP structure objectives and outputs before attending such fora
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Land Board
(1) Is it possible for the model to give us depth of water table within at least500 metres from the delta This can help us with land use This will alsohelp us determine how far we can avoid pollution in land allocations
The spatial resolution of the model is one square kilometre The model cangive the various hydrologic parameters such a depth to ground water withinthe general area (within a few square kilometres) This should be quiteadequate for the purpose of broad based management planning
(2) Can the model add value to Tawana land board land use and managementplan (2004-2029)
The Hydrology and Water Resources component is concerned withhydrology and water resources The outputs from the component arehydrologic data and predictions for the delta It is up to the various sectorsand components of the management plan to assess the impact of thesehydrologic parameters for their own purposes The HampWR component can
assist in the interpretation of the hydrologic dataTourism
(1) There are lodges and camps located close to the river channels Can themodel be able to help on the implications of pollution
The model can simulate the pattern of flow in the delta which may give auseful indication of the movement of pollution though not the output whichmay be given by a water quality model (advection dispersion decay etc)
General
(1) This component (Hydrology and Water Resources) is so detached from therest It should relocate to MaunThe component is located in Gaborone as the capital has better infrastructure Progress on the component would be constrained by thelimited infrastructure in Maun
(2) To what extent is your data real time series that it could be relied upon
The data available from the delta at present are poor largely owing todifficulties in access and disturbance of gauging stations by humans and large mammalian wildlife Lack of systematic use of the data to date havealso contributed to neglect Improved monitoring is necessary for management planning and an improved hydrologic model with finer
resolution and greater accuracy Recommendations have been prepared for DWA to improve hydrologic monitoring and it is hoped these can beimplemented in the course of 2005
(3) The presentations are too technical When will ODMP reach out to usSomeone mentioned that communication and or information disseminationis a problem Why cant we find other Batswana who could do the job toconvey the information in an audience screened and targeted way
The hydrology of the delta is complex and requires a complex model for arealistic simulation of the processes The presentations were intended togive all participants an understanding that the model is indeed capable of simulating the key hydrologic phenomena of the delta It is hoped that this
has been achieved though it is recognised that the depth of understanding
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will depend upon the level of the individual participantrsquos hydrologic knowledge
The DWA staff assigned to ODMP will gradually take over presentations insuch fora as part of the process of technology transfer which is anessential part of the component
Lessons have been learnt from this Workshop A second and possibly third Workshop will be planned along with bilateral meetings with the individual Stakeholders hopefully improving the communication to the diverse
participants (see Conclusions)
(4) Communications and networking is lagging behind but its pro-activeness isso crucial The component would simplify information and relay it tocommunity andor stakeholders
The HampWR component looks forward to this component being activatedand to cooperating with the Communications and Networking component in
presenting results of the hydrologic analyses meaningful to all
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4 CONCLUSIONS
41 SummaryProf Francis Sefe from the consultantsrsquo team summarised the Workshop discussionas follows
(1) There were discussions on both spatial and temporal resolutions of themodel which need clarification
(2) It was observed that data quality and availability is a constraint to accuratemodelling of the hydrology of the delta and providing physical evidence toback the model conclusions
(3) In the selection of scenarios it is critical to understand that the individualscenarios are not stand alone
(4) The choice of what constitutes the baseline scenario was discussed It hasto be emphasised that the inclusion of exceptional floods is also importantand hence not only the dry period should be used
(5) The presentation was multifaceted
(6) People could not easily locate any landmark features on the map Thisneed not be Villages could be labelled and even the rivers themselves
(7) Though water quality is not in the scope of the current modelling water quality is very important and this has to be looked into in the future
(8) Ground water fluctuations at the periphery of the delta need to be lookedinto
(9) Various stakeholders have difficulty interpreting the results This is a critical
issue that needs to be addressed The target audience should reasonablybe able to assimilate the information relayed to them
42 RecommendationsThe following recommendations are made with regard to the future interactionbetween the Hydrology and Water Resources component and the other ODMPparticipants
(1) While the introductions to the set up and application of the IntegratedHydrologic Model attempted to convey the complexity of the deltahydrology and its computer based representation further effort needs to bemade to present the model and its results in a manner which is fullycomprehensible to the Stakeholders most of whom do not have in depthhydrologic knowledge
(2) It was originally believed that presentation of the model to Stakeholders in acombined forum would allow the interchange of ideas and knowledgeamong the Stakeholders as well as with the Hydrology and Water Resources component The resulting discussion tended to be dominatedby those with technical hydrologic knowledge at the expense of thosewithout The next round of discussions should be on a bilateral basis suchthat the discussions can proceed at a level appropriate for the individualStakeholders and their needs in respect of hydrology and water resources
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(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
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ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
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ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
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Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
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Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
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ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
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2 PRESENTATIONS AND DISCUSSION
21 IntroductionsSelected slides from those employed in the respective presentations are included inAnnex 3 and illustrate the text of the presentations in the following sections
The introductory presentations covered the component background implementationdata collection and processing and monitoring proposals As such they generatedlimited discussion One suggestion was that as most of the stakeholders were fromsectors other than water a glossary should be included to cover the use of technicalterms
22 Integrated Hydrologic Model
221 Introduction
The Introduction to the Integrated Hydrologic Model set out the approach tomathematical modelling in the context of the hydrology of the delta The key flowprocesses above in and below the delta are shown in slide 1 Given the criticallinkages among the atmospheric surface and ground waters it is necessary todevelop an Integrated Hydrological Model which integrates the essential physicalphenomena controlling the delta As such the model requires a basis in physicalprocesses as opposed to a conceptual model which has an idealised representation
It is not the intention to set up a detailed model The available data do not justify thisand the project resources are not available The model will be somewhat schematicbut nonetheless capable of describing the essential processes such as the overallflow pattern among the distributaries flooding and drainage of seasonal swampareas The model will not be capable of predicting the small scale vegetation andmorphological changes which appear to have a significant impact on the overall flowpattern
Water and its distribution in space and time is the fundamental physical basis for management of the ecosystem Management criteria for the delta could include
bull Maintain present flood extent and duration
bull Maintain current pattern of flows through the delta
bull Minimise adverse impacts on any part of the interconnected hydrologicalsystem
The distinct environments and key hydrologic phenomena were presented illustratingthe complex interactions among the atmospheric surface and subsurfacecomponents of the wetland
In order to have a realistic representation of these key phenomena and their interactions and to make quantitative prediction of the potential effects of changes inwater use it is necessary to employ an Integrated Hydrologic Model The systemselected is MIKE SHE developed by DHI Water and Environment Denmark Thegeneric system (the software can be applied to any hydrologic system) is marketedcommercially and is applied to hundreds of catchments and wetlands worldwide
The key features of the software package are (slide 2)
bull Physically based with a realistic representation of the hydrologic
phenomena based on the laws of physics
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Hydrology and Water Resources Okavango Delta Management Plan
(slide 3) The vegetation dynamics are based on remotely sensed data with limitedground verification (see slides 4 and 5) The relationship between the extent of surface water and the rate of evapotranspiration is shown for the normally andseasonally flooded areas in slide 6
224 Surface Waters
The surface water flows are dependent on the topography of the delta which hasbeen described by a digital elevation model of the Ramsar area with a 30m resolutionbased on aerial radar altimetry and remote sensing and a limited number of channelcross sections available at gauging stations and surveyed by researchers
The key characteristics of the delta are the numerous bifurcations or defluences (asopposed to confluences) extensive spills to the flood plains and swamps andhydraulic connections among the spill areas and slow flood wave propagation(around four months from upstream to downstream) with a high variation in the extentof flooding (slide 7)
The surface waters of the delta are described by a full hydrodynamic representationof the flows in the main rivers and channels and by a distributed kinematicrepresentation of the flows over the flood plains and through the swamps Thedescriptions are fully coupled (slide 8) and enable the representation of theessentially one dimensional flows through the channels giving definition to the flowand the spreading and distributed storage over the flood plain (slide 9)
225 SubSurface Waters
Infiltration rates are significant on the predominantly sandy soils in the early stages of the flood season The infiltration raises the ground water levels up to the flood water level This increases the water available to plants which in turn increasestranspiration from the leaf surfaces to the atmosphere (slide 10)
An essential component is the inclusion of the critical unsaturated root zone the zonefrom which plants draw water and transpire to the atmosphere Together withevaporation from open water this is represents the main loss of water in the deltaThe evapotranspiration component simulates both the hydrologic and vegetationdynamics (slide 11)
The ground water component is important to account for the local effects of groundwater on the water balance ie recharge and discharge and evapotranspirationlosses Only the surficial ground water aquifer is represented (slide 12)
Detailed ground water studies show infiltration and recharge of fresh water lensesembedded in older saline ground water Given the low topographical relief limited
ground water flow is directed towards local depressions (slide 13) Model water balance tests indicate that there is no significant ground water flow from the delta nor are there data to support such flow hypotheses Consequently there is no flowacross the subsurface model boundary
226 Outputs
The outputs from the model are designed to support broad based managementplanning in the Okavango Delta The outputs are presented in grid or map formatshowing the spatial variation in the parameters over the delta time series (plots of various parameters against time) and summary tables of results The outputs may besummarised as
bull The actual evaporation from open water and the transpiration fromvegetation
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bull Surface water levels and flows through the rivers and over the floodedswamp areas and the extent of flooding
bull The moisture content of the soil
bull The ground water levels and flows
bull The overall water balance including inflows outflows and changes insurface and subsurface storage for the delta and selected areas of thedelta
bull Sediment transport along the main channels of the delta showingpatterns of erosion and deposition
The Integrated Hydrologic Model does have practical certain limitations and it isimportant that these are recognised by the stakeholders and management planners
Channel Switching
While the model can predict the impact of cutting and dredging a new channel
through the delta and the impact of closing an existing channel through theencroachment of vegetation it is not able to predict the occurrence of the formation of new channels and the realignment of existing channels which may be initiated by themovement patterns of large mammals and vegetation growth
Certain trends in sedimentation and channel development and decay may bepredicted by the application of sediment transport to the model Work on this areahas just commenced Detailed analyses of selected reaches and areas of the deltamay be carried out through the application of two dimensional morphological modelsThis is beyond the scope of the present component activities
Level of Detail and Accuracy
While the technology exists to simulate the hydrologic behaviour of the delta at a highlevel of detail (previous applications have been made at the level of individualcultivated fields) this is constrained by
bull The resources available to the component do not permit thedevelopment of submodels which could enable the study of a particular area of the delta below the present one square kilometre resolution
bull The available data do not justify high expectations on the level of accuracy with respect to absolute water levels and quantitiesRecommendations have been made for improved data collection andmanagement which when available could justify further modeldevelopment
The key issue at this stage is that the Integrated Hydrologic Model represents theessential hydrologic phenomena in an integrated manner such that it may be appliedwith confidence to the assessment of the impacts of future water resourcesdevelopments on the delta hydrology for the purposes of the management plan
Physical Phenomena
The model simulates physical hydrological phenomena only Studies have revealedin particular the importance of the interdependency of physical and biologicalphenomena for example the movement of large mammals opening new flow pathsthrough the vegetation sedimentation and vegetation in closing existing channels
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bull The data should reflect how the delta may recover in a period of normal inflows after a dry period
The long term inflow in terms of volume per annum from 1933 to date is shown inslide 14 for both Mukwe in Namibia and Mohembo in Botswana Whereas at Mukwethe river is more or less confined to the gauged channel at Mohembo the river has
broadened out with a wide flood plain It is not possible to gauge the flows over theflood plain and Mohembo will not represent the total discharge This is most clearlyevinced in the high flow years 199899 and 200001
An anomaly appears in the data from around 1950 to 1980 where the total inflow atMohembo appears higher than Mukwe As there is no significant inflow to the river between the two gauges this can only be explained by gauging errors The seriesafter 1980 is more consistent with Mukwe showing a higher inflow than Mohembo
The period from 1992 to 1997 represents the sequence of the five lowest inflowyears and is therefore chosen to provide the input data to analyse the impacts under critical conditions for both the existing state and possible future states with water resources developments
The following five year period from 1997 to 2002 represents relatively normalhydrologic conditions in the delta and has been used to assess how the delta mayrecover after a sequence of dry years (see slide 15)
A high inflow period could also be selected eg 1987 to 1992 to assess the impactsunder high inflow conditions It is not planned to analyse this period as
bull The conditions will not be critical to a management planning exercise
bull The number of impacts which have to be assessed in terms of flowsdepths etc will be further increased
Appropriate time series of inputs (inflows precipitation etc) have been prepared and
applied to the existing state of the delta The model results are used as a baselineagainst which future developments are assessed for their impacts The inputs aremodified to represent conditions which may prevail under future conditions
To summarise while the inflows to the delta will be dynamic ranging over two fiveyear periods representing critical dry and normal average hydrologic conditions theexisting and future states will be static This implies that for the duration of the fiveyear model run period the population for instance will not be increasing no newdams or irrigation schemes are built etc
At present the Baseline and Scenario Conditions have been simulated for the criticaldry hydrologic input period from October 1992 to October 1997 Summary results arepresented and discussed in the following sections Slides illustrating the outputs arepresented in Annex 3
233 Presentation of Results
In order to assist the stakeholders assess the outputs and their implications for their particular sectors a common format for the presentation is adopted The resolutionof the model in space is one kilometre and in time four hours In order to limit thesize of the output files the results are output with a temporal resolution of one weekfor surface flows and the unsaturated zone while the slower responding ground water results are output every two months of the five year period
For the purpose of presenting summary data the delta is divided into five zonesaccording to the probability of flooding as assessed from 15 years of satellite images(source J McCarthy Stockholm University) with the Panhandle treated as a fifth
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separate zone (slide 16) The probability delta area and a zone description are givenin the table
Model Area (km 2) 28782 Description
Zone 1 - 01gtFPgt0 19322 rarely flooded
Zone 2 - 05gtFPgt01 3534 occasionally flooded
Zone 3 - 09gtFPgt05 2328 seasonally flooded
Zone 4 - 1gtFPgt09 2152 normally flooded
Zone 5 - Panhandle 1446 Panhandle
(1) Animated sequence of flooding in the delta showing the monthly variation inflooded area and depth (The AVI format file is available from DWA sizearound 110Mb)
(2) Map based on the one kilometre grid showing the minimum depth of water in the delta for the five dry years
(3) Time series showing the variation in the depth of flooding over the five year period The depth is averaged for each of five zones (see table)
(4) Map based on the one kilometre grid showing the minimum level of soilmoisture in the root zone (the zone from which plants draw water) in thedelta over the five dry years
(5) Map based on the one kilometre grid showing the maximum depth toground water in the delta over the five dry years
(6) Summary tables are prepared showing the following
bull Water balance showing inflows outflows and storage changes
bull Baseline conditions and impacts for the surface water soilmoisture and ground water for the entire delta and for each of the five zones
A wide range of outputs of all hydrologic parameters in various formats is possibleand can be tailored to the needs of the individual stakeholders It is possible also toselect different zones to calculate average time series and summary results Theabove selection has been made by the component as samples of what may be usefuland meaningful to the stakeholders and to generate discussion
24 Baseline
Surface Water
The animated depth of flow sequence (slide 17) shows the expansion and contractionof the flooded area and depth as the sequence of flood waves for each of the fiveyears propagates through the Panhandle and spreads out through the delta Slide 18shows the detail for the lower envelope of flooding for the upper delta Each squareis one square kilometre
Time series of the depth of surface water are shown for each of the five zones in slide19 The Panhandle is the first area affected by the flood wave from upstream andbeing relatively confined within a flood plain around 20km wide has the maximumrange from the seasonal wet to dry periods around 06m through the five dry yearsAs the flood wave propagates through the delta the range in water levels declines
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The accumulated impact of the drought years is also felt more as there is a generaldecline in the flood depth
As the summary table (slide 20) shows the area flooded ranges from 1513km 2 to12077km 2 while the depth ranges from 0 to around 5m The average depth in thenormally flooded area ranges from 011m to 092m
SubSurface Water
The distribution of the soil moisture content is shown as a deficit below saturatedlevel as the lower envelope (maximum deficit) for the five year period in slide 21The average deficit ranges from 056m in the rarely flooded area to 012m in thenormally flooded area
The depth to ground water over the delta area is shown for the lower envelope(maximum depth) over the five year period in slide 22 The depth ranges from anaverage of 188m in the rarely flooded area to 037m in the normally flooded area
Water Balance
The overall water balance for the Baseline and Scenarios is shown in slide 23Negative values indicate an inflow to the delta (eg precipitation and river inflow) whilepositive values indicate an outflow (eg evapotranspiration and river outflows) TheTotal should be zero the small value indicates a very minor continuity error Thenegative overland and subsurface storage changes indicate a decline in storage inthese levels
25 Upstream Water Resources Developments
251 Introduction
To date no significant water resources developments have taken place upstream inAngola and Namibia In the past plans have been made for the construction of damsfor irrigation and hydropower Anticipating that these plans may be revived theWERRD project has run a number of scenarios using a modified rainfall-runoff modelof the basin (Pitman model Rhodes University) including a scenario for all planneddams
A number of sources describes potential irrigation in the upstream basin in Angolaand Namibia These have been reviewed and a potential scenario compiled basedon
bull Irrigation demand based on 15000m 3haa with a 25 return flow
bull Irrigated area in Angola 54500ha in Namibia 7500ha
bull Angola grows vegetables in winter (June to October) Namibia growsmaize in summer (December to April)
The corresponding runoff from the upstream basin has been applied under twoscenarios Dams in Angola and Irrigation as inflow to the delta upstream The twopotential developments are kept separate for the purpose of initial appraisal in order that the impact from each can be identified This will assist in minimising the adverseimpacts from these developments
252 Dams in Angola
The impact of the previously planned hydropower dams in Angola on the inflow to the
delta is presented in slide 24 Hydropower development does not consume waterbut stores water in the flood period for release in the dry period This results in a
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redistribution of the natural hydrograph flood flows are reduced while dry seasonflows are increased (The impact appears only to be significant in 1993 and 1996 ndashthis needs further investigation)
The impact of the dams on the surface and subsurface waters of the delta is minimalgiven the limited apparent impact in three out of the five dry years and the fact that
there is no nett water loss in the basin upstream
253 Irrigation
The impact of the potential irrigation scenario on the inflow to the delta is shown inslide 25 The impact is greatest in the dry period when water is withdrawn for therelatively large area of winter crops in Angola The summer withdrawals for irrigationin Namibia are significantly less
Correspondingly the impact on the delta in the flood period is minimal while in thedry period the overland depth of flow is reduced particularly in the Panhandle andnormally flooded areas and the minimum flood extent is reduced by 660km 2 or 40of the present dry period area (slide 26)
26 Abstractions from DeltaWater for largely local domestic use is abstracted from both the surface and groundwaters of the delta The surface water abstractions are based on water rights issuedby DWA (ie the amount which may legitimately be withdrawn ndash actual withdrawals arenot monitored and may be greater or less than allowed) Ground water abstractionsare based on the demands projected from historic information to the present day
In terms of the inflows to the delta (river flows from the basin upstream andprecipitation over the basin the abstractions and corresponding impacts are minimalSurface water abstraction represents 0006 of the inflow and ground water 02In the five dry years analysed the minimum flooded area is reduced by 025Future scenario runs will simulate the impact of abstractions with projected increasedpopulation and rates of consumption to the notional year 2025
27 Climate ChangePotential climate change will have an impact on the delta in respect of inflows fromthe basin upstream and the climate over the delta The WERRD project has run aglobal climate model HadCM3 1 to predict the changed precipitation and temperatureover the basin For the upstream basin the Pitman rainfall-runoff model has beenapplied to predict the modified inflows upstream of the delta (slide 27) The modifiedprecipitation and temperature over the delta have been used as direct inputs to theIntegrated Hydrologic Model (slide 28)
The impact of the climate change scenario is highly significant in both the flood anddry seasons River inflows to the delta are reduced by 38 and precipitation over the delta by 9 Temperature increases by 22ordmC
The corresponding impact on flow depths is shown on the reduced depths the impacton the minimum depths is shown for the Panhandle and normally flooded areas inslide 29 and in each of the five zones through the five year run period in slide 30The reduction in depth averages 003m over the entire delta and the minimumflooded area is almost halved
1 httpwwwmet-officegovukresearchhadleycentremodelsHadCM3html
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28 Management PlanningThe model analyses are carried out to assess the impacts of possible future basinconditions on the delta for the purposes of management planning An iterativeprocess is envisaged with a series of bilateral meetings with the Stakeholders andcommon Workshops in which the inputs and outputs are presented to and discussedwith the stakeholders The outputs can migrate towards a presentation format that isboth meaningful and relevant to the stakeholders
The Hydrology and Water Resources component will only analyse the impacts on thewaters of the delta DWA and its consultants do not have the capability or theresources to analyse the impacts on the wildlife vegetation livestock fisheries or tourists It is up to these respective sectors to assess these impacts based on thechanged delta hydrology
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3 DISCUSSION
31 IntroductionThe following sections record the comments made on the foregoing presentationsand the responses given by the hydrology team (in italics)
32 Database Management(1) What is lithology Remember that as much as you are speaking to experts
you are also speaking to non-experts
The point is well taken A glossary will be prepared to explain technical terms
(2) The presentations are too fast and we need details of the graphs for example
This point is also noted presentations should emphasise important pointsSelected slides from the Workshop are included in Annex 3 and a full report is being prepared of both the Integrated Hydrologic Model and the
preliminary scenario analysis These should be studied by thestakeholders in advance of further (bilateral) discussions
(3) Is there a slide to show locations of critical rainfall and flow stations so thatwe could appreciate all the difficulties encountered We would appreciatemuch if we could have locations of all your data sources
The locations of the existing and proposed gauging stations is available inDWA in GIS format The key source for this and information from other sectors and stakeholders will be the Okavango Delta Information System
implemented in HOORC
33 Integrated Hydrologic Model(1) I like your conceptual model but what is applicable in Europe may not
necessarily be applicable here also
The conceptual model is fundamental to the development of a numerical model The conceptual model is strictly formulated for the Okavango Deltabased on available data and scientific publications on the subject Theconceptual model has no relation to European or other climatic conditions
(2) Your evapotranspiration rates are higher than those from Class A pan whenactually the reverse should be true This should be looked into
Actual rates of evapotranspiration (ET) are not necessarily lower than panevaporation owing to a number of factors including pan correction methodcombined free surface ET and vegetation transpiration in flood plains and actual location in the delta versus the location of pan measurements If new documented field data on ET losses are available the hydrology teamwould be happy compare these to model simulations
(3) Is there any physical evidence of flooding
The assessment of the observed flood extent has been based mainly on ananalysis of satellite images from 1984 to 2000 (J McCarthy StockholmUniversity) and DWA water level observations
(4) How do you parameterize your flow in respect to flow resistance
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The Manning resistance coefficient is used to describe the resistance toflow in the river channels and over the flood plains Values for overland flow are distributed according to three vegetation zones based onvegetation mapping (S Ringrose HOORC) Values in the river channelsare ascribed based on channel vegetation descriptions (Dr CK NaiduDWA) Adjustments are made to give a good match with observed flood extent overall water balance and downstream discharges
(5) Your climate input data comprise rainfall evapotranspiration etc fromMaun and Shakawe To what extent can one use a physically based modelwith such a coarse resolution Could we conclude that this is an empiricalmodel
MIKE SHE is a physically based model which implies that the model parameters have a clear physical interpretation as opposed to lumped conceptual models Data measured in single locations may be used toassign parameter values but the parameters used at the current grid scaleof 1km 2 should be regarded as lsquoefficientrsquo parameters representing the
aggregated responseThe lack of input data on distributed rainfall or any other model input doesnot imply that the MIKE SHE model is empirical Maun and Shakawe arethe only two stations in and adjacent to the delta with reliable data Thedelta is not a conventional catchment area where the runoff from individual subcatchments is essential to arrive at the combined flow in themainstream Overland flows mix the runoff from the subcatchments and evapotranspiration dominates Thus a high resolution of the rainfall data isnot of major importance in a general flow model of the delta Nonethelessrecommendations for improved monitoring include rehabilitation of the eight DCPs which measure rainfall and the installation of an additional eight automatic gauges in the delta
(6) Our confidence on the model cannot be based on your numbers
This particular comment was based on relatively consistent outflows for theBaseline and Scenarios This was owing to the nature of the downstreamboundary condition which has since been improved and now shows avariation
The flow leaving the delta (and the model) has passed through anextremely complex hydrologic system flood propagation flow splits among distributaries spills to vast flood plains and swamps evapotranspirationand infiltration The measurement of the discharge upstream is subject toerrors of at least 10 (say 50m 3 s at the flood peak) Differences between
the model computations and the observations cannot better this(7) What resolution should we have confidence on as it pertains to your
model
Given the complexity of the area and the available data model resultsshould not be interpreted looking at single grid values Interpretation based on delta zones or subsystems is more appropriate Five zones based onflood probability have been applied in the scenario demonstration runs and others may be devised according to stakeholdersrsquo needs The minimumarea should cover several square kilometres
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34 Scenarios(1) You have run the scenarios based on dry period(s) Could you please
revise this You might be missing out on recharge to groundwater as aresult of high floods A single high flood could recharge an aquifer for thenext twenty years for example
It is the intention to run the model for a period of normal flows to see how the delta recovers from a drought As suggested the model will also be runfor high floods (this is also important for sediment transport in the delta)
(2) In taking the dry period as critical you have to consider floods as alsocritical Floods need to be covered as well
The delta is not under stress during high flow periods and the impacts of water resources developments will not be so keenly felt and therefore not critical to management planning See also response to (1) above
(3) People are more worried about the switching of channels Maybe thisaspect needs to come out in your model outputs as well
The introduction of sediment transport to the model (which has just commenced) will give an indication of possible future switches and redistribution of delta flows Switching and realignment of channels has achaotic component (the butterfly effect on global climate is akin to ahippopotamus going walkabout in the delta) and accurate predictions aresimply not possible
(4) Looking at the modelrsquos level of resolution critical management issues willnot be answered
The component has been conceived and ToR written (in 200102) toaddress the broad scale management planning issues (water resources
developments upstream climate change abstractions from the delta reed cutting and dredging) On this basis the model approach has been set outand the model set up and applied Preliminary applications suggest that the main threats to the delta will arise from upstream irrigation and climatechange These are the critical management issues related to hydrology
(5) Channel blockages impacts need to be covered in detail Channel switchingis another fundamental management issue
The model can simulate the impact of channel blockages and channel switching As discussed in (3) above the model cannot predict theseoccurrences
(6) You mentioned that your model could handle sediment transport Do youhave something on sediment transport now
An approach to introducing sediment transport to the model has beendrafted (pending report on the Integrated Hydrologic Model)
(7) You seem not to be representing your conditions
See response to (6) above
35 Presentation of Results(1) You canrsquot have a reduction of flow by 40 and yet have no impact on the
outflow This gives me the confidence of your model
See response to (4) above
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(2) The difference in long-term average discharge between observed andsimulations should not be taken to be insignificant This should becombined with other scenarios to better appreciate its impact
It is important in the preliminary stage to separate the impacts fromindividual water resources developments to obtain a good understanding of
which are critical and which are not A limited number of combinationscenarios may be run at a later stage once these can be defined and agreed by the management planners and stakeholders
(3) It would be good to combine all the scenarios as well
See (2) above
(4) It would be interesting also to look at frequency and duration of flooding
The impact on the duration of flooding can be assessed through the timeseries plots for different zones An estimate can also be made on theimpact of the scenarios on the frequency of flooding
(5) What is the model doing as it pertains to erosion and sedimentation
Sediment transport is being introduced to the model This will enable theassessment of the broad pattern of erosion and deposition through themain river channels along which the bed load is conveyed from the basinupstream
(6) The issue of land use change has to be incorporated into the model
To introduce the impact of land use changes in the basin upstream requiresthe application of a water resources planning model to the upstream basinThis is not within the present scope of ODMP which is relying on theoutputs of basinwide projects such as Sharing Water and WERRD (bothcompleted) and possibly in the future TwinBas (ongoing) If ODMP
partners suggest particular potential land use changes within the deltawhich have an impact on the hydrology these may be simulated using theIntegrated Hydrologic Model
(7) The presentations have mostly been technical I would like to suggest thatwe make handouts available after the workshop so that the participantscould have ample time to go over them and later submit their suggestionscomments and or questions
This document represents a full report on the proceedings Further comments from ODMP partners are welcome that our further work may more closely meet the needs of delta management planning Further discussions will be held with the stakeholders on the ongoing model applications possibly on a bilateral basis to obtain a closer understanding of particular needs and ways to meet these needs
36 Stakeholdersrsquo Responses
Wildlife
(1) We need drying flood plain map to better track movement of wild animals
The drying and wetting of the flood plains was presented as animated sequences in the Workshop for all scenarios with a monthly time step Afiner temporal resolution can be prepared (down to four hours) though the
spatial resolution is limited to one kilometre squares
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(2) We would appreciate information on correlations between the distribution of elephants population and extent of flooding close to the buffalo fence
The HampWR component can provide information on the waters of the deltaIt is up to the individual partners to analyse this information for their ownneeds The HampWR component cannot be expected to carry out all the
analyses for the management planThe integration of information from all ODMP components will be carried out within the Okavango Delta Information System implemented inHOORC (also with support from Danida)
Fisheries
(1) Water quality is very critical as this have impact on fish populationdynamics Sedimentation is also critical as it has a bearing on fishpopulations
Sedimentation is indeed critical to fish populations as fine organic richsediment is washed out from the flood plain into the channels by the flood waters resulting in oxygen depletion
The MIKE SHE integrated hydrologic modelling system has the capability tosimulate water quality This is not within the present scope of ODMPSystematic data (including DO and SOD) do not exist at present on whichto develop such a model Improved monitoring recommendations includethe introduction of systematic sampling and analysis at the key inflow station of Mohembo and monthly in-situ measurements of salinity and pH at around 20 discharge stations throughout the delta
Water Affairs
(1) Is MIKE SHE an instrument or whatMIKE SHE is one of a suite of water and environmental software packagesdeveloped and marketed commercially by DHI Water and EnvironmentThe MIKE SHE package is the most advanced generic (can be applied toany system) hydrologic software available MIKE SHE has a consistent development history over thirty years and has been applied to hundreds of hydrologic systems worldwide
(2) Can the model predict channel shifts
The sediment transport model will predict erosion and deposition leading tochannel aggradation and eventual closure The delta morphology isinherently unstable and chaotic and no model can predict channel abandonment with higher certainty than what is constrained by natural variability (chaos) Nonetheless the impact of major channel shifts can be
predicted as well as possible management measures to mitigate suchshifts
(3) Mr Dikgomo mentioned that Hydrology and Water Resources component isone of the twelve What are the other eleven components
The CTA may best respond to this question though it is suggested that representatives from participating organisations take the trouble to informthemselves of the ODMP structure objectives and outputs before attending such fora
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Land Board
(1) Is it possible for the model to give us depth of water table within at least500 metres from the delta This can help us with land use This will alsohelp us determine how far we can avoid pollution in land allocations
The spatial resolution of the model is one square kilometre The model cangive the various hydrologic parameters such a depth to ground water withinthe general area (within a few square kilometres) This should be quiteadequate for the purpose of broad based management planning
(2) Can the model add value to Tawana land board land use and managementplan (2004-2029)
The Hydrology and Water Resources component is concerned withhydrology and water resources The outputs from the component arehydrologic data and predictions for the delta It is up to the various sectorsand components of the management plan to assess the impact of thesehydrologic parameters for their own purposes The HampWR component can
assist in the interpretation of the hydrologic dataTourism
(1) There are lodges and camps located close to the river channels Can themodel be able to help on the implications of pollution
The model can simulate the pattern of flow in the delta which may give auseful indication of the movement of pollution though not the output whichmay be given by a water quality model (advection dispersion decay etc)
General
(1) This component (Hydrology and Water Resources) is so detached from therest It should relocate to MaunThe component is located in Gaborone as the capital has better infrastructure Progress on the component would be constrained by thelimited infrastructure in Maun
(2) To what extent is your data real time series that it could be relied upon
The data available from the delta at present are poor largely owing todifficulties in access and disturbance of gauging stations by humans and large mammalian wildlife Lack of systematic use of the data to date havealso contributed to neglect Improved monitoring is necessary for management planning and an improved hydrologic model with finer
resolution and greater accuracy Recommendations have been prepared for DWA to improve hydrologic monitoring and it is hoped these can beimplemented in the course of 2005
(3) The presentations are too technical When will ODMP reach out to usSomeone mentioned that communication and or information disseminationis a problem Why cant we find other Batswana who could do the job toconvey the information in an audience screened and targeted way
The hydrology of the delta is complex and requires a complex model for arealistic simulation of the processes The presentations were intended togive all participants an understanding that the model is indeed capable of simulating the key hydrologic phenomena of the delta It is hoped that this
has been achieved though it is recognised that the depth of understanding
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will depend upon the level of the individual participantrsquos hydrologic knowledge
The DWA staff assigned to ODMP will gradually take over presentations insuch fora as part of the process of technology transfer which is anessential part of the component
Lessons have been learnt from this Workshop A second and possibly third Workshop will be planned along with bilateral meetings with the individual Stakeholders hopefully improving the communication to the diverse
participants (see Conclusions)
(4) Communications and networking is lagging behind but its pro-activeness isso crucial The component would simplify information and relay it tocommunity andor stakeholders
The HampWR component looks forward to this component being activatedand to cooperating with the Communications and Networking component in
presenting results of the hydrologic analyses meaningful to all
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4 CONCLUSIONS
41 SummaryProf Francis Sefe from the consultantsrsquo team summarised the Workshop discussionas follows
(1) There were discussions on both spatial and temporal resolutions of themodel which need clarification
(2) It was observed that data quality and availability is a constraint to accuratemodelling of the hydrology of the delta and providing physical evidence toback the model conclusions
(3) In the selection of scenarios it is critical to understand that the individualscenarios are not stand alone
(4) The choice of what constitutes the baseline scenario was discussed It hasto be emphasised that the inclusion of exceptional floods is also importantand hence not only the dry period should be used
(5) The presentation was multifaceted
(6) People could not easily locate any landmark features on the map Thisneed not be Villages could be labelled and even the rivers themselves
(7) Though water quality is not in the scope of the current modelling water quality is very important and this has to be looked into in the future
(8) Ground water fluctuations at the periphery of the delta need to be lookedinto
(9) Various stakeholders have difficulty interpreting the results This is a critical
issue that needs to be addressed The target audience should reasonablybe able to assimilate the information relayed to them
42 RecommendationsThe following recommendations are made with regard to the future interactionbetween the Hydrology and Water Resources component and the other ODMPparticipants
(1) While the introductions to the set up and application of the IntegratedHydrologic Model attempted to convey the complexity of the deltahydrology and its computer based representation further effort needs to bemade to present the model and its results in a manner which is fullycomprehensible to the Stakeholders most of whom do not have in depthhydrologic knowledge
(2) It was originally believed that presentation of the model to Stakeholders in acombined forum would allow the interchange of ideas and knowledgeamong the Stakeholders as well as with the Hydrology and Water Resources component The resulting discussion tended to be dominatedby those with technical hydrologic knowledge at the expense of thosewithout The next round of discussions should be on a bilateral basis suchthat the discussions can proceed at a level appropriate for the individualStakeholders and their needs in respect of hydrology and water resources
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(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
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ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
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ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
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Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
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Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
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ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
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(slide 3) The vegetation dynamics are based on remotely sensed data with limitedground verification (see slides 4 and 5) The relationship between the extent of surface water and the rate of evapotranspiration is shown for the normally andseasonally flooded areas in slide 6
224 Surface Waters
The surface water flows are dependent on the topography of the delta which hasbeen described by a digital elevation model of the Ramsar area with a 30m resolutionbased on aerial radar altimetry and remote sensing and a limited number of channelcross sections available at gauging stations and surveyed by researchers
The key characteristics of the delta are the numerous bifurcations or defluences (asopposed to confluences) extensive spills to the flood plains and swamps andhydraulic connections among the spill areas and slow flood wave propagation(around four months from upstream to downstream) with a high variation in the extentof flooding (slide 7)
The surface waters of the delta are described by a full hydrodynamic representationof the flows in the main rivers and channels and by a distributed kinematicrepresentation of the flows over the flood plains and through the swamps Thedescriptions are fully coupled (slide 8) and enable the representation of theessentially one dimensional flows through the channels giving definition to the flowand the spreading and distributed storage over the flood plain (slide 9)
225 SubSurface Waters
Infiltration rates are significant on the predominantly sandy soils in the early stages of the flood season The infiltration raises the ground water levels up to the flood water level This increases the water available to plants which in turn increasestranspiration from the leaf surfaces to the atmosphere (slide 10)
An essential component is the inclusion of the critical unsaturated root zone the zonefrom which plants draw water and transpire to the atmosphere Together withevaporation from open water this is represents the main loss of water in the deltaThe evapotranspiration component simulates both the hydrologic and vegetationdynamics (slide 11)
The ground water component is important to account for the local effects of groundwater on the water balance ie recharge and discharge and evapotranspirationlosses Only the surficial ground water aquifer is represented (slide 12)
Detailed ground water studies show infiltration and recharge of fresh water lensesembedded in older saline ground water Given the low topographical relief limited
ground water flow is directed towards local depressions (slide 13) Model water balance tests indicate that there is no significant ground water flow from the delta nor are there data to support such flow hypotheses Consequently there is no flowacross the subsurface model boundary
226 Outputs
The outputs from the model are designed to support broad based managementplanning in the Okavango Delta The outputs are presented in grid or map formatshowing the spatial variation in the parameters over the delta time series (plots of various parameters against time) and summary tables of results The outputs may besummarised as
bull The actual evaporation from open water and the transpiration fromvegetation
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bull Surface water levels and flows through the rivers and over the floodedswamp areas and the extent of flooding
bull The moisture content of the soil
bull The ground water levels and flows
bull The overall water balance including inflows outflows and changes insurface and subsurface storage for the delta and selected areas of thedelta
bull Sediment transport along the main channels of the delta showingpatterns of erosion and deposition
The Integrated Hydrologic Model does have practical certain limitations and it isimportant that these are recognised by the stakeholders and management planners
Channel Switching
While the model can predict the impact of cutting and dredging a new channel
through the delta and the impact of closing an existing channel through theencroachment of vegetation it is not able to predict the occurrence of the formation of new channels and the realignment of existing channels which may be initiated by themovement patterns of large mammals and vegetation growth
Certain trends in sedimentation and channel development and decay may bepredicted by the application of sediment transport to the model Work on this areahas just commenced Detailed analyses of selected reaches and areas of the deltamay be carried out through the application of two dimensional morphological modelsThis is beyond the scope of the present component activities
Level of Detail and Accuracy
While the technology exists to simulate the hydrologic behaviour of the delta at a highlevel of detail (previous applications have been made at the level of individualcultivated fields) this is constrained by
bull The resources available to the component do not permit thedevelopment of submodels which could enable the study of a particular area of the delta below the present one square kilometre resolution
bull The available data do not justify high expectations on the level of accuracy with respect to absolute water levels and quantitiesRecommendations have been made for improved data collection andmanagement which when available could justify further modeldevelopment
The key issue at this stage is that the Integrated Hydrologic Model represents theessential hydrologic phenomena in an integrated manner such that it may be appliedwith confidence to the assessment of the impacts of future water resourcesdevelopments on the delta hydrology for the purposes of the management plan
Physical Phenomena
The model simulates physical hydrological phenomena only Studies have revealedin particular the importance of the interdependency of physical and biologicalphenomena for example the movement of large mammals opening new flow pathsthrough the vegetation sedimentation and vegetation in closing existing channels
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bull The data should reflect how the delta may recover in a period of normal inflows after a dry period
The long term inflow in terms of volume per annum from 1933 to date is shown inslide 14 for both Mukwe in Namibia and Mohembo in Botswana Whereas at Mukwethe river is more or less confined to the gauged channel at Mohembo the river has
broadened out with a wide flood plain It is not possible to gauge the flows over theflood plain and Mohembo will not represent the total discharge This is most clearlyevinced in the high flow years 199899 and 200001
An anomaly appears in the data from around 1950 to 1980 where the total inflow atMohembo appears higher than Mukwe As there is no significant inflow to the river between the two gauges this can only be explained by gauging errors The seriesafter 1980 is more consistent with Mukwe showing a higher inflow than Mohembo
The period from 1992 to 1997 represents the sequence of the five lowest inflowyears and is therefore chosen to provide the input data to analyse the impacts under critical conditions for both the existing state and possible future states with water resources developments
The following five year period from 1997 to 2002 represents relatively normalhydrologic conditions in the delta and has been used to assess how the delta mayrecover after a sequence of dry years (see slide 15)
A high inflow period could also be selected eg 1987 to 1992 to assess the impactsunder high inflow conditions It is not planned to analyse this period as
bull The conditions will not be critical to a management planning exercise
bull The number of impacts which have to be assessed in terms of flowsdepths etc will be further increased
Appropriate time series of inputs (inflows precipitation etc) have been prepared and
applied to the existing state of the delta The model results are used as a baselineagainst which future developments are assessed for their impacts The inputs aremodified to represent conditions which may prevail under future conditions
To summarise while the inflows to the delta will be dynamic ranging over two fiveyear periods representing critical dry and normal average hydrologic conditions theexisting and future states will be static This implies that for the duration of the fiveyear model run period the population for instance will not be increasing no newdams or irrigation schemes are built etc
At present the Baseline and Scenario Conditions have been simulated for the criticaldry hydrologic input period from October 1992 to October 1997 Summary results arepresented and discussed in the following sections Slides illustrating the outputs arepresented in Annex 3
233 Presentation of Results
In order to assist the stakeholders assess the outputs and their implications for their particular sectors a common format for the presentation is adopted The resolutionof the model in space is one kilometre and in time four hours In order to limit thesize of the output files the results are output with a temporal resolution of one weekfor surface flows and the unsaturated zone while the slower responding ground water results are output every two months of the five year period
For the purpose of presenting summary data the delta is divided into five zonesaccording to the probability of flooding as assessed from 15 years of satellite images(source J McCarthy Stockholm University) with the Panhandle treated as a fifth
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separate zone (slide 16) The probability delta area and a zone description are givenin the table
Model Area (km 2) 28782 Description
Zone 1 - 01gtFPgt0 19322 rarely flooded
Zone 2 - 05gtFPgt01 3534 occasionally flooded
Zone 3 - 09gtFPgt05 2328 seasonally flooded
Zone 4 - 1gtFPgt09 2152 normally flooded
Zone 5 - Panhandle 1446 Panhandle
(1) Animated sequence of flooding in the delta showing the monthly variation inflooded area and depth (The AVI format file is available from DWA sizearound 110Mb)
(2) Map based on the one kilometre grid showing the minimum depth of water in the delta for the five dry years
(3) Time series showing the variation in the depth of flooding over the five year period The depth is averaged for each of five zones (see table)
(4) Map based on the one kilometre grid showing the minimum level of soilmoisture in the root zone (the zone from which plants draw water) in thedelta over the five dry years
(5) Map based on the one kilometre grid showing the maximum depth toground water in the delta over the five dry years
(6) Summary tables are prepared showing the following
bull Water balance showing inflows outflows and storage changes
bull Baseline conditions and impacts for the surface water soilmoisture and ground water for the entire delta and for each of the five zones
A wide range of outputs of all hydrologic parameters in various formats is possibleand can be tailored to the needs of the individual stakeholders It is possible also toselect different zones to calculate average time series and summary results Theabove selection has been made by the component as samples of what may be usefuland meaningful to the stakeholders and to generate discussion
24 Baseline
Surface Water
The animated depth of flow sequence (slide 17) shows the expansion and contractionof the flooded area and depth as the sequence of flood waves for each of the fiveyears propagates through the Panhandle and spreads out through the delta Slide 18shows the detail for the lower envelope of flooding for the upper delta Each squareis one square kilometre
Time series of the depth of surface water are shown for each of the five zones in slide19 The Panhandle is the first area affected by the flood wave from upstream andbeing relatively confined within a flood plain around 20km wide has the maximumrange from the seasonal wet to dry periods around 06m through the five dry yearsAs the flood wave propagates through the delta the range in water levels declines
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The accumulated impact of the drought years is also felt more as there is a generaldecline in the flood depth
As the summary table (slide 20) shows the area flooded ranges from 1513km 2 to12077km 2 while the depth ranges from 0 to around 5m The average depth in thenormally flooded area ranges from 011m to 092m
SubSurface Water
The distribution of the soil moisture content is shown as a deficit below saturatedlevel as the lower envelope (maximum deficit) for the five year period in slide 21The average deficit ranges from 056m in the rarely flooded area to 012m in thenormally flooded area
The depth to ground water over the delta area is shown for the lower envelope(maximum depth) over the five year period in slide 22 The depth ranges from anaverage of 188m in the rarely flooded area to 037m in the normally flooded area
Water Balance
The overall water balance for the Baseline and Scenarios is shown in slide 23Negative values indicate an inflow to the delta (eg precipitation and river inflow) whilepositive values indicate an outflow (eg evapotranspiration and river outflows) TheTotal should be zero the small value indicates a very minor continuity error Thenegative overland and subsurface storage changes indicate a decline in storage inthese levels
25 Upstream Water Resources Developments
251 Introduction
To date no significant water resources developments have taken place upstream inAngola and Namibia In the past plans have been made for the construction of damsfor irrigation and hydropower Anticipating that these plans may be revived theWERRD project has run a number of scenarios using a modified rainfall-runoff modelof the basin (Pitman model Rhodes University) including a scenario for all planneddams
A number of sources describes potential irrigation in the upstream basin in Angolaand Namibia These have been reviewed and a potential scenario compiled basedon
bull Irrigation demand based on 15000m 3haa with a 25 return flow
bull Irrigated area in Angola 54500ha in Namibia 7500ha
bull Angola grows vegetables in winter (June to October) Namibia growsmaize in summer (December to April)
The corresponding runoff from the upstream basin has been applied under twoscenarios Dams in Angola and Irrigation as inflow to the delta upstream The twopotential developments are kept separate for the purpose of initial appraisal in order that the impact from each can be identified This will assist in minimising the adverseimpacts from these developments
252 Dams in Angola
The impact of the previously planned hydropower dams in Angola on the inflow to the
delta is presented in slide 24 Hydropower development does not consume waterbut stores water in the flood period for release in the dry period This results in a
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redistribution of the natural hydrograph flood flows are reduced while dry seasonflows are increased (The impact appears only to be significant in 1993 and 1996 ndashthis needs further investigation)
The impact of the dams on the surface and subsurface waters of the delta is minimalgiven the limited apparent impact in three out of the five dry years and the fact that
there is no nett water loss in the basin upstream
253 Irrigation
The impact of the potential irrigation scenario on the inflow to the delta is shown inslide 25 The impact is greatest in the dry period when water is withdrawn for therelatively large area of winter crops in Angola The summer withdrawals for irrigationin Namibia are significantly less
Correspondingly the impact on the delta in the flood period is minimal while in thedry period the overland depth of flow is reduced particularly in the Panhandle andnormally flooded areas and the minimum flood extent is reduced by 660km 2 or 40of the present dry period area (slide 26)
26 Abstractions from DeltaWater for largely local domestic use is abstracted from both the surface and groundwaters of the delta The surface water abstractions are based on water rights issuedby DWA (ie the amount which may legitimately be withdrawn ndash actual withdrawals arenot monitored and may be greater or less than allowed) Ground water abstractionsare based on the demands projected from historic information to the present day
In terms of the inflows to the delta (river flows from the basin upstream andprecipitation over the basin the abstractions and corresponding impacts are minimalSurface water abstraction represents 0006 of the inflow and ground water 02In the five dry years analysed the minimum flooded area is reduced by 025Future scenario runs will simulate the impact of abstractions with projected increasedpopulation and rates of consumption to the notional year 2025
27 Climate ChangePotential climate change will have an impact on the delta in respect of inflows fromthe basin upstream and the climate over the delta The WERRD project has run aglobal climate model HadCM3 1 to predict the changed precipitation and temperatureover the basin For the upstream basin the Pitman rainfall-runoff model has beenapplied to predict the modified inflows upstream of the delta (slide 27) The modifiedprecipitation and temperature over the delta have been used as direct inputs to theIntegrated Hydrologic Model (slide 28)
The impact of the climate change scenario is highly significant in both the flood anddry seasons River inflows to the delta are reduced by 38 and precipitation over the delta by 9 Temperature increases by 22ordmC
The corresponding impact on flow depths is shown on the reduced depths the impacton the minimum depths is shown for the Panhandle and normally flooded areas inslide 29 and in each of the five zones through the five year run period in slide 30The reduction in depth averages 003m over the entire delta and the minimumflooded area is almost halved
1 httpwwwmet-officegovukresearchhadleycentremodelsHadCM3html
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28 Management PlanningThe model analyses are carried out to assess the impacts of possible future basinconditions on the delta for the purposes of management planning An iterativeprocess is envisaged with a series of bilateral meetings with the Stakeholders andcommon Workshops in which the inputs and outputs are presented to and discussedwith the stakeholders The outputs can migrate towards a presentation format that isboth meaningful and relevant to the stakeholders
The Hydrology and Water Resources component will only analyse the impacts on thewaters of the delta DWA and its consultants do not have the capability or theresources to analyse the impacts on the wildlife vegetation livestock fisheries or tourists It is up to these respective sectors to assess these impacts based on thechanged delta hydrology
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3 DISCUSSION
31 IntroductionThe following sections record the comments made on the foregoing presentationsand the responses given by the hydrology team (in italics)
32 Database Management(1) What is lithology Remember that as much as you are speaking to experts
you are also speaking to non-experts
The point is well taken A glossary will be prepared to explain technical terms
(2) The presentations are too fast and we need details of the graphs for example
This point is also noted presentations should emphasise important pointsSelected slides from the Workshop are included in Annex 3 and a full report is being prepared of both the Integrated Hydrologic Model and the
preliminary scenario analysis These should be studied by thestakeholders in advance of further (bilateral) discussions
(3) Is there a slide to show locations of critical rainfall and flow stations so thatwe could appreciate all the difficulties encountered We would appreciatemuch if we could have locations of all your data sources
The locations of the existing and proposed gauging stations is available inDWA in GIS format The key source for this and information from other sectors and stakeholders will be the Okavango Delta Information System
implemented in HOORC
33 Integrated Hydrologic Model(1) I like your conceptual model but what is applicable in Europe may not
necessarily be applicable here also
The conceptual model is fundamental to the development of a numerical model The conceptual model is strictly formulated for the Okavango Deltabased on available data and scientific publications on the subject Theconceptual model has no relation to European or other climatic conditions
(2) Your evapotranspiration rates are higher than those from Class A pan whenactually the reverse should be true This should be looked into
Actual rates of evapotranspiration (ET) are not necessarily lower than panevaporation owing to a number of factors including pan correction methodcombined free surface ET and vegetation transpiration in flood plains and actual location in the delta versus the location of pan measurements If new documented field data on ET losses are available the hydrology teamwould be happy compare these to model simulations
(3) Is there any physical evidence of flooding
The assessment of the observed flood extent has been based mainly on ananalysis of satellite images from 1984 to 2000 (J McCarthy StockholmUniversity) and DWA water level observations
(4) How do you parameterize your flow in respect to flow resistance
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The Manning resistance coefficient is used to describe the resistance toflow in the river channels and over the flood plains Values for overland flow are distributed according to three vegetation zones based onvegetation mapping (S Ringrose HOORC) Values in the river channelsare ascribed based on channel vegetation descriptions (Dr CK NaiduDWA) Adjustments are made to give a good match with observed flood extent overall water balance and downstream discharges
(5) Your climate input data comprise rainfall evapotranspiration etc fromMaun and Shakawe To what extent can one use a physically based modelwith such a coarse resolution Could we conclude that this is an empiricalmodel
MIKE SHE is a physically based model which implies that the model parameters have a clear physical interpretation as opposed to lumped conceptual models Data measured in single locations may be used toassign parameter values but the parameters used at the current grid scaleof 1km 2 should be regarded as lsquoefficientrsquo parameters representing the
aggregated responseThe lack of input data on distributed rainfall or any other model input doesnot imply that the MIKE SHE model is empirical Maun and Shakawe arethe only two stations in and adjacent to the delta with reliable data Thedelta is not a conventional catchment area where the runoff from individual subcatchments is essential to arrive at the combined flow in themainstream Overland flows mix the runoff from the subcatchments and evapotranspiration dominates Thus a high resolution of the rainfall data isnot of major importance in a general flow model of the delta Nonethelessrecommendations for improved monitoring include rehabilitation of the eight DCPs which measure rainfall and the installation of an additional eight automatic gauges in the delta
(6) Our confidence on the model cannot be based on your numbers
This particular comment was based on relatively consistent outflows for theBaseline and Scenarios This was owing to the nature of the downstreamboundary condition which has since been improved and now shows avariation
The flow leaving the delta (and the model) has passed through anextremely complex hydrologic system flood propagation flow splits among distributaries spills to vast flood plains and swamps evapotranspirationand infiltration The measurement of the discharge upstream is subject toerrors of at least 10 (say 50m 3 s at the flood peak) Differences between
the model computations and the observations cannot better this(7) What resolution should we have confidence on as it pertains to your
model
Given the complexity of the area and the available data model resultsshould not be interpreted looking at single grid values Interpretation based on delta zones or subsystems is more appropriate Five zones based onflood probability have been applied in the scenario demonstration runs and others may be devised according to stakeholdersrsquo needs The minimumarea should cover several square kilometres
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34 Scenarios(1) You have run the scenarios based on dry period(s) Could you please
revise this You might be missing out on recharge to groundwater as aresult of high floods A single high flood could recharge an aquifer for thenext twenty years for example
It is the intention to run the model for a period of normal flows to see how the delta recovers from a drought As suggested the model will also be runfor high floods (this is also important for sediment transport in the delta)
(2) In taking the dry period as critical you have to consider floods as alsocritical Floods need to be covered as well
The delta is not under stress during high flow periods and the impacts of water resources developments will not be so keenly felt and therefore not critical to management planning See also response to (1) above
(3) People are more worried about the switching of channels Maybe thisaspect needs to come out in your model outputs as well
The introduction of sediment transport to the model (which has just commenced) will give an indication of possible future switches and redistribution of delta flows Switching and realignment of channels has achaotic component (the butterfly effect on global climate is akin to ahippopotamus going walkabout in the delta) and accurate predictions aresimply not possible
(4) Looking at the modelrsquos level of resolution critical management issues willnot be answered
The component has been conceived and ToR written (in 200102) toaddress the broad scale management planning issues (water resources
developments upstream climate change abstractions from the delta reed cutting and dredging) On this basis the model approach has been set outand the model set up and applied Preliminary applications suggest that the main threats to the delta will arise from upstream irrigation and climatechange These are the critical management issues related to hydrology
(5) Channel blockages impacts need to be covered in detail Channel switchingis another fundamental management issue
The model can simulate the impact of channel blockages and channel switching As discussed in (3) above the model cannot predict theseoccurrences
(6) You mentioned that your model could handle sediment transport Do youhave something on sediment transport now
An approach to introducing sediment transport to the model has beendrafted (pending report on the Integrated Hydrologic Model)
(7) You seem not to be representing your conditions
See response to (6) above
35 Presentation of Results(1) You canrsquot have a reduction of flow by 40 and yet have no impact on the
outflow This gives me the confidence of your model
See response to (4) above
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(2) The difference in long-term average discharge between observed andsimulations should not be taken to be insignificant This should becombined with other scenarios to better appreciate its impact
It is important in the preliminary stage to separate the impacts fromindividual water resources developments to obtain a good understanding of
which are critical and which are not A limited number of combinationscenarios may be run at a later stage once these can be defined and agreed by the management planners and stakeholders
(3) It would be good to combine all the scenarios as well
See (2) above
(4) It would be interesting also to look at frequency and duration of flooding
The impact on the duration of flooding can be assessed through the timeseries plots for different zones An estimate can also be made on theimpact of the scenarios on the frequency of flooding
(5) What is the model doing as it pertains to erosion and sedimentation
Sediment transport is being introduced to the model This will enable theassessment of the broad pattern of erosion and deposition through themain river channels along which the bed load is conveyed from the basinupstream
(6) The issue of land use change has to be incorporated into the model
To introduce the impact of land use changes in the basin upstream requiresthe application of a water resources planning model to the upstream basinThis is not within the present scope of ODMP which is relying on theoutputs of basinwide projects such as Sharing Water and WERRD (bothcompleted) and possibly in the future TwinBas (ongoing) If ODMP
partners suggest particular potential land use changes within the deltawhich have an impact on the hydrology these may be simulated using theIntegrated Hydrologic Model
(7) The presentations have mostly been technical I would like to suggest thatwe make handouts available after the workshop so that the participantscould have ample time to go over them and later submit their suggestionscomments and or questions
This document represents a full report on the proceedings Further comments from ODMP partners are welcome that our further work may more closely meet the needs of delta management planning Further discussions will be held with the stakeholders on the ongoing model applications possibly on a bilateral basis to obtain a closer understanding of particular needs and ways to meet these needs
36 Stakeholdersrsquo Responses
Wildlife
(1) We need drying flood plain map to better track movement of wild animals
The drying and wetting of the flood plains was presented as animated sequences in the Workshop for all scenarios with a monthly time step Afiner temporal resolution can be prepared (down to four hours) though the
spatial resolution is limited to one kilometre squares
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(2) We would appreciate information on correlations between the distribution of elephants population and extent of flooding close to the buffalo fence
The HampWR component can provide information on the waters of the deltaIt is up to the individual partners to analyse this information for their ownneeds The HampWR component cannot be expected to carry out all the
analyses for the management planThe integration of information from all ODMP components will be carried out within the Okavango Delta Information System implemented inHOORC (also with support from Danida)
Fisheries
(1) Water quality is very critical as this have impact on fish populationdynamics Sedimentation is also critical as it has a bearing on fishpopulations
Sedimentation is indeed critical to fish populations as fine organic richsediment is washed out from the flood plain into the channels by the flood waters resulting in oxygen depletion
The MIKE SHE integrated hydrologic modelling system has the capability tosimulate water quality This is not within the present scope of ODMPSystematic data (including DO and SOD) do not exist at present on whichto develop such a model Improved monitoring recommendations includethe introduction of systematic sampling and analysis at the key inflow station of Mohembo and monthly in-situ measurements of salinity and pH at around 20 discharge stations throughout the delta
Water Affairs
(1) Is MIKE SHE an instrument or whatMIKE SHE is one of a suite of water and environmental software packagesdeveloped and marketed commercially by DHI Water and EnvironmentThe MIKE SHE package is the most advanced generic (can be applied toany system) hydrologic software available MIKE SHE has a consistent development history over thirty years and has been applied to hundreds of hydrologic systems worldwide
(2) Can the model predict channel shifts
The sediment transport model will predict erosion and deposition leading tochannel aggradation and eventual closure The delta morphology isinherently unstable and chaotic and no model can predict channel abandonment with higher certainty than what is constrained by natural variability (chaos) Nonetheless the impact of major channel shifts can be
predicted as well as possible management measures to mitigate suchshifts
(3) Mr Dikgomo mentioned that Hydrology and Water Resources component isone of the twelve What are the other eleven components
The CTA may best respond to this question though it is suggested that representatives from participating organisations take the trouble to informthemselves of the ODMP structure objectives and outputs before attending such fora
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Land Board
(1) Is it possible for the model to give us depth of water table within at least500 metres from the delta This can help us with land use This will alsohelp us determine how far we can avoid pollution in land allocations
The spatial resolution of the model is one square kilometre The model cangive the various hydrologic parameters such a depth to ground water withinthe general area (within a few square kilometres) This should be quiteadequate for the purpose of broad based management planning
(2) Can the model add value to Tawana land board land use and managementplan (2004-2029)
The Hydrology and Water Resources component is concerned withhydrology and water resources The outputs from the component arehydrologic data and predictions for the delta It is up to the various sectorsand components of the management plan to assess the impact of thesehydrologic parameters for their own purposes The HampWR component can
assist in the interpretation of the hydrologic dataTourism
(1) There are lodges and camps located close to the river channels Can themodel be able to help on the implications of pollution
The model can simulate the pattern of flow in the delta which may give auseful indication of the movement of pollution though not the output whichmay be given by a water quality model (advection dispersion decay etc)
General
(1) This component (Hydrology and Water Resources) is so detached from therest It should relocate to MaunThe component is located in Gaborone as the capital has better infrastructure Progress on the component would be constrained by thelimited infrastructure in Maun
(2) To what extent is your data real time series that it could be relied upon
The data available from the delta at present are poor largely owing todifficulties in access and disturbance of gauging stations by humans and large mammalian wildlife Lack of systematic use of the data to date havealso contributed to neglect Improved monitoring is necessary for management planning and an improved hydrologic model with finer
resolution and greater accuracy Recommendations have been prepared for DWA to improve hydrologic monitoring and it is hoped these can beimplemented in the course of 2005
(3) The presentations are too technical When will ODMP reach out to usSomeone mentioned that communication and or information disseminationis a problem Why cant we find other Batswana who could do the job toconvey the information in an audience screened and targeted way
The hydrology of the delta is complex and requires a complex model for arealistic simulation of the processes The presentations were intended togive all participants an understanding that the model is indeed capable of simulating the key hydrologic phenomena of the delta It is hoped that this
has been achieved though it is recognised that the depth of understanding
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will depend upon the level of the individual participantrsquos hydrologic knowledge
The DWA staff assigned to ODMP will gradually take over presentations insuch fora as part of the process of technology transfer which is anessential part of the component
Lessons have been learnt from this Workshop A second and possibly third Workshop will be planned along with bilateral meetings with the individual Stakeholders hopefully improving the communication to the diverse
participants (see Conclusions)
(4) Communications and networking is lagging behind but its pro-activeness isso crucial The component would simplify information and relay it tocommunity andor stakeholders
The HampWR component looks forward to this component being activatedand to cooperating with the Communications and Networking component in
presenting results of the hydrologic analyses meaningful to all
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4 CONCLUSIONS
41 SummaryProf Francis Sefe from the consultantsrsquo team summarised the Workshop discussionas follows
(1) There were discussions on both spatial and temporal resolutions of themodel which need clarification
(2) It was observed that data quality and availability is a constraint to accuratemodelling of the hydrology of the delta and providing physical evidence toback the model conclusions
(3) In the selection of scenarios it is critical to understand that the individualscenarios are not stand alone
(4) The choice of what constitutes the baseline scenario was discussed It hasto be emphasised that the inclusion of exceptional floods is also importantand hence not only the dry period should be used
(5) The presentation was multifaceted
(6) People could not easily locate any landmark features on the map Thisneed not be Villages could be labelled and even the rivers themselves
(7) Though water quality is not in the scope of the current modelling water quality is very important and this has to be looked into in the future
(8) Ground water fluctuations at the periphery of the delta need to be lookedinto
(9) Various stakeholders have difficulty interpreting the results This is a critical
issue that needs to be addressed The target audience should reasonablybe able to assimilate the information relayed to them
42 RecommendationsThe following recommendations are made with regard to the future interactionbetween the Hydrology and Water Resources component and the other ODMPparticipants
(1) While the introductions to the set up and application of the IntegratedHydrologic Model attempted to convey the complexity of the deltahydrology and its computer based representation further effort needs to bemade to present the model and its results in a manner which is fullycomprehensible to the Stakeholders most of whom do not have in depthhydrologic knowledge
(2) It was originally believed that presentation of the model to Stakeholders in acombined forum would allow the interchange of ideas and knowledgeamong the Stakeholders as well as with the Hydrology and Water Resources component The resulting discussion tended to be dominatedby those with technical hydrologic knowledge at the expense of thosewithout The next round of discussions should be on a bilateral basis suchthat the discussions can proceed at a level appropriate for the individualStakeholders and their needs in respect of hydrology and water resources
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(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
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ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
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ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
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Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
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Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
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ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
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(slide 3) The vegetation dynamics are based on remotely sensed data with limitedground verification (see slides 4 and 5) The relationship between the extent of surface water and the rate of evapotranspiration is shown for the normally andseasonally flooded areas in slide 6
224 Surface Waters
The surface water flows are dependent on the topography of the delta which hasbeen described by a digital elevation model of the Ramsar area with a 30m resolutionbased on aerial radar altimetry and remote sensing and a limited number of channelcross sections available at gauging stations and surveyed by researchers
The key characteristics of the delta are the numerous bifurcations or defluences (asopposed to confluences) extensive spills to the flood plains and swamps andhydraulic connections among the spill areas and slow flood wave propagation(around four months from upstream to downstream) with a high variation in the extentof flooding (slide 7)
The surface waters of the delta are described by a full hydrodynamic representationof the flows in the main rivers and channels and by a distributed kinematicrepresentation of the flows over the flood plains and through the swamps Thedescriptions are fully coupled (slide 8) and enable the representation of theessentially one dimensional flows through the channels giving definition to the flowand the spreading and distributed storage over the flood plain (slide 9)
225 SubSurface Waters
Infiltration rates are significant on the predominantly sandy soils in the early stages of the flood season The infiltration raises the ground water levels up to the flood water level This increases the water available to plants which in turn increasestranspiration from the leaf surfaces to the atmosphere (slide 10)
An essential component is the inclusion of the critical unsaturated root zone the zonefrom which plants draw water and transpire to the atmosphere Together withevaporation from open water this is represents the main loss of water in the deltaThe evapotranspiration component simulates both the hydrologic and vegetationdynamics (slide 11)
The ground water component is important to account for the local effects of groundwater on the water balance ie recharge and discharge and evapotranspirationlosses Only the surficial ground water aquifer is represented (slide 12)
Detailed ground water studies show infiltration and recharge of fresh water lensesembedded in older saline ground water Given the low topographical relief limited
ground water flow is directed towards local depressions (slide 13) Model water balance tests indicate that there is no significant ground water flow from the delta nor are there data to support such flow hypotheses Consequently there is no flowacross the subsurface model boundary
226 Outputs
The outputs from the model are designed to support broad based managementplanning in the Okavango Delta The outputs are presented in grid or map formatshowing the spatial variation in the parameters over the delta time series (plots of various parameters against time) and summary tables of results The outputs may besummarised as
bull The actual evaporation from open water and the transpiration fromvegetation
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bull Surface water levels and flows through the rivers and over the floodedswamp areas and the extent of flooding
bull The moisture content of the soil
bull The ground water levels and flows
bull The overall water balance including inflows outflows and changes insurface and subsurface storage for the delta and selected areas of thedelta
bull Sediment transport along the main channels of the delta showingpatterns of erosion and deposition
The Integrated Hydrologic Model does have practical certain limitations and it isimportant that these are recognised by the stakeholders and management planners
Channel Switching
While the model can predict the impact of cutting and dredging a new channel
through the delta and the impact of closing an existing channel through theencroachment of vegetation it is not able to predict the occurrence of the formation of new channels and the realignment of existing channels which may be initiated by themovement patterns of large mammals and vegetation growth
Certain trends in sedimentation and channel development and decay may bepredicted by the application of sediment transport to the model Work on this areahas just commenced Detailed analyses of selected reaches and areas of the deltamay be carried out through the application of two dimensional morphological modelsThis is beyond the scope of the present component activities
Level of Detail and Accuracy
While the technology exists to simulate the hydrologic behaviour of the delta at a highlevel of detail (previous applications have been made at the level of individualcultivated fields) this is constrained by
bull The resources available to the component do not permit thedevelopment of submodels which could enable the study of a particular area of the delta below the present one square kilometre resolution
bull The available data do not justify high expectations on the level of accuracy with respect to absolute water levels and quantitiesRecommendations have been made for improved data collection andmanagement which when available could justify further modeldevelopment
The key issue at this stage is that the Integrated Hydrologic Model represents theessential hydrologic phenomena in an integrated manner such that it may be appliedwith confidence to the assessment of the impacts of future water resourcesdevelopments on the delta hydrology for the purposes of the management plan
Physical Phenomena
The model simulates physical hydrological phenomena only Studies have revealedin particular the importance of the interdependency of physical and biologicalphenomena for example the movement of large mammals opening new flow pathsthrough the vegetation sedimentation and vegetation in closing existing channels
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bull The data should reflect how the delta may recover in a period of normal inflows after a dry period
The long term inflow in terms of volume per annum from 1933 to date is shown inslide 14 for both Mukwe in Namibia and Mohembo in Botswana Whereas at Mukwethe river is more or less confined to the gauged channel at Mohembo the river has
broadened out with a wide flood plain It is not possible to gauge the flows over theflood plain and Mohembo will not represent the total discharge This is most clearlyevinced in the high flow years 199899 and 200001
An anomaly appears in the data from around 1950 to 1980 where the total inflow atMohembo appears higher than Mukwe As there is no significant inflow to the river between the two gauges this can only be explained by gauging errors The seriesafter 1980 is more consistent with Mukwe showing a higher inflow than Mohembo
The period from 1992 to 1997 represents the sequence of the five lowest inflowyears and is therefore chosen to provide the input data to analyse the impacts under critical conditions for both the existing state and possible future states with water resources developments
The following five year period from 1997 to 2002 represents relatively normalhydrologic conditions in the delta and has been used to assess how the delta mayrecover after a sequence of dry years (see slide 15)
A high inflow period could also be selected eg 1987 to 1992 to assess the impactsunder high inflow conditions It is not planned to analyse this period as
bull The conditions will not be critical to a management planning exercise
bull The number of impacts which have to be assessed in terms of flowsdepths etc will be further increased
Appropriate time series of inputs (inflows precipitation etc) have been prepared and
applied to the existing state of the delta The model results are used as a baselineagainst which future developments are assessed for their impacts The inputs aremodified to represent conditions which may prevail under future conditions
To summarise while the inflows to the delta will be dynamic ranging over two fiveyear periods representing critical dry and normal average hydrologic conditions theexisting and future states will be static This implies that for the duration of the fiveyear model run period the population for instance will not be increasing no newdams or irrigation schemes are built etc
At present the Baseline and Scenario Conditions have been simulated for the criticaldry hydrologic input period from October 1992 to October 1997 Summary results arepresented and discussed in the following sections Slides illustrating the outputs arepresented in Annex 3
233 Presentation of Results
In order to assist the stakeholders assess the outputs and their implications for their particular sectors a common format for the presentation is adopted The resolutionof the model in space is one kilometre and in time four hours In order to limit thesize of the output files the results are output with a temporal resolution of one weekfor surface flows and the unsaturated zone while the slower responding ground water results are output every two months of the five year period
For the purpose of presenting summary data the delta is divided into five zonesaccording to the probability of flooding as assessed from 15 years of satellite images(source J McCarthy Stockholm University) with the Panhandle treated as a fifth
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separate zone (slide 16) The probability delta area and a zone description are givenin the table
Model Area (km 2) 28782 Description
Zone 1 - 01gtFPgt0 19322 rarely flooded
Zone 2 - 05gtFPgt01 3534 occasionally flooded
Zone 3 - 09gtFPgt05 2328 seasonally flooded
Zone 4 - 1gtFPgt09 2152 normally flooded
Zone 5 - Panhandle 1446 Panhandle
(1) Animated sequence of flooding in the delta showing the monthly variation inflooded area and depth (The AVI format file is available from DWA sizearound 110Mb)
(2) Map based on the one kilometre grid showing the minimum depth of water in the delta for the five dry years
(3) Time series showing the variation in the depth of flooding over the five year period The depth is averaged for each of five zones (see table)
(4) Map based on the one kilometre grid showing the minimum level of soilmoisture in the root zone (the zone from which plants draw water) in thedelta over the five dry years
(5) Map based on the one kilometre grid showing the maximum depth toground water in the delta over the five dry years
(6) Summary tables are prepared showing the following
bull Water balance showing inflows outflows and storage changes
bull Baseline conditions and impacts for the surface water soilmoisture and ground water for the entire delta and for each of the five zones
A wide range of outputs of all hydrologic parameters in various formats is possibleand can be tailored to the needs of the individual stakeholders It is possible also toselect different zones to calculate average time series and summary results Theabove selection has been made by the component as samples of what may be usefuland meaningful to the stakeholders and to generate discussion
24 Baseline
Surface Water
The animated depth of flow sequence (slide 17) shows the expansion and contractionof the flooded area and depth as the sequence of flood waves for each of the fiveyears propagates through the Panhandle and spreads out through the delta Slide 18shows the detail for the lower envelope of flooding for the upper delta Each squareis one square kilometre
Time series of the depth of surface water are shown for each of the five zones in slide19 The Panhandle is the first area affected by the flood wave from upstream andbeing relatively confined within a flood plain around 20km wide has the maximumrange from the seasonal wet to dry periods around 06m through the five dry yearsAs the flood wave propagates through the delta the range in water levels declines
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The accumulated impact of the drought years is also felt more as there is a generaldecline in the flood depth
As the summary table (slide 20) shows the area flooded ranges from 1513km 2 to12077km 2 while the depth ranges from 0 to around 5m The average depth in thenormally flooded area ranges from 011m to 092m
SubSurface Water
The distribution of the soil moisture content is shown as a deficit below saturatedlevel as the lower envelope (maximum deficit) for the five year period in slide 21The average deficit ranges from 056m in the rarely flooded area to 012m in thenormally flooded area
The depth to ground water over the delta area is shown for the lower envelope(maximum depth) over the five year period in slide 22 The depth ranges from anaverage of 188m in the rarely flooded area to 037m in the normally flooded area
Water Balance
The overall water balance for the Baseline and Scenarios is shown in slide 23Negative values indicate an inflow to the delta (eg precipitation and river inflow) whilepositive values indicate an outflow (eg evapotranspiration and river outflows) TheTotal should be zero the small value indicates a very minor continuity error Thenegative overland and subsurface storage changes indicate a decline in storage inthese levels
25 Upstream Water Resources Developments
251 Introduction
To date no significant water resources developments have taken place upstream inAngola and Namibia In the past plans have been made for the construction of damsfor irrigation and hydropower Anticipating that these plans may be revived theWERRD project has run a number of scenarios using a modified rainfall-runoff modelof the basin (Pitman model Rhodes University) including a scenario for all planneddams
A number of sources describes potential irrigation in the upstream basin in Angolaand Namibia These have been reviewed and a potential scenario compiled basedon
bull Irrigation demand based on 15000m 3haa with a 25 return flow
bull Irrigated area in Angola 54500ha in Namibia 7500ha
bull Angola grows vegetables in winter (June to October) Namibia growsmaize in summer (December to April)
The corresponding runoff from the upstream basin has been applied under twoscenarios Dams in Angola and Irrigation as inflow to the delta upstream The twopotential developments are kept separate for the purpose of initial appraisal in order that the impact from each can be identified This will assist in minimising the adverseimpacts from these developments
252 Dams in Angola
The impact of the previously planned hydropower dams in Angola on the inflow to the
delta is presented in slide 24 Hydropower development does not consume waterbut stores water in the flood period for release in the dry period This results in a
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redistribution of the natural hydrograph flood flows are reduced while dry seasonflows are increased (The impact appears only to be significant in 1993 and 1996 ndashthis needs further investigation)
The impact of the dams on the surface and subsurface waters of the delta is minimalgiven the limited apparent impact in three out of the five dry years and the fact that
there is no nett water loss in the basin upstream
253 Irrigation
The impact of the potential irrigation scenario on the inflow to the delta is shown inslide 25 The impact is greatest in the dry period when water is withdrawn for therelatively large area of winter crops in Angola The summer withdrawals for irrigationin Namibia are significantly less
Correspondingly the impact on the delta in the flood period is minimal while in thedry period the overland depth of flow is reduced particularly in the Panhandle andnormally flooded areas and the minimum flood extent is reduced by 660km 2 or 40of the present dry period area (slide 26)
26 Abstractions from DeltaWater for largely local domestic use is abstracted from both the surface and groundwaters of the delta The surface water abstractions are based on water rights issuedby DWA (ie the amount which may legitimately be withdrawn ndash actual withdrawals arenot monitored and may be greater or less than allowed) Ground water abstractionsare based on the demands projected from historic information to the present day
In terms of the inflows to the delta (river flows from the basin upstream andprecipitation over the basin the abstractions and corresponding impacts are minimalSurface water abstraction represents 0006 of the inflow and ground water 02In the five dry years analysed the minimum flooded area is reduced by 025Future scenario runs will simulate the impact of abstractions with projected increasedpopulation and rates of consumption to the notional year 2025
27 Climate ChangePotential climate change will have an impact on the delta in respect of inflows fromthe basin upstream and the climate over the delta The WERRD project has run aglobal climate model HadCM3 1 to predict the changed precipitation and temperatureover the basin For the upstream basin the Pitman rainfall-runoff model has beenapplied to predict the modified inflows upstream of the delta (slide 27) The modifiedprecipitation and temperature over the delta have been used as direct inputs to theIntegrated Hydrologic Model (slide 28)
The impact of the climate change scenario is highly significant in both the flood anddry seasons River inflows to the delta are reduced by 38 and precipitation over the delta by 9 Temperature increases by 22ordmC
The corresponding impact on flow depths is shown on the reduced depths the impacton the minimum depths is shown for the Panhandle and normally flooded areas inslide 29 and in each of the five zones through the five year run period in slide 30The reduction in depth averages 003m over the entire delta and the minimumflooded area is almost halved
1 httpwwwmet-officegovukresearchhadleycentremodelsHadCM3html
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28 Management PlanningThe model analyses are carried out to assess the impacts of possible future basinconditions on the delta for the purposes of management planning An iterativeprocess is envisaged with a series of bilateral meetings with the Stakeholders andcommon Workshops in which the inputs and outputs are presented to and discussedwith the stakeholders The outputs can migrate towards a presentation format that isboth meaningful and relevant to the stakeholders
The Hydrology and Water Resources component will only analyse the impacts on thewaters of the delta DWA and its consultants do not have the capability or theresources to analyse the impacts on the wildlife vegetation livestock fisheries or tourists It is up to these respective sectors to assess these impacts based on thechanged delta hydrology
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3 DISCUSSION
31 IntroductionThe following sections record the comments made on the foregoing presentationsand the responses given by the hydrology team (in italics)
32 Database Management(1) What is lithology Remember that as much as you are speaking to experts
you are also speaking to non-experts
The point is well taken A glossary will be prepared to explain technical terms
(2) The presentations are too fast and we need details of the graphs for example
This point is also noted presentations should emphasise important pointsSelected slides from the Workshop are included in Annex 3 and a full report is being prepared of both the Integrated Hydrologic Model and the
preliminary scenario analysis These should be studied by thestakeholders in advance of further (bilateral) discussions
(3) Is there a slide to show locations of critical rainfall and flow stations so thatwe could appreciate all the difficulties encountered We would appreciatemuch if we could have locations of all your data sources
The locations of the existing and proposed gauging stations is available inDWA in GIS format The key source for this and information from other sectors and stakeholders will be the Okavango Delta Information System
implemented in HOORC
33 Integrated Hydrologic Model(1) I like your conceptual model but what is applicable in Europe may not
necessarily be applicable here also
The conceptual model is fundamental to the development of a numerical model The conceptual model is strictly formulated for the Okavango Deltabased on available data and scientific publications on the subject Theconceptual model has no relation to European or other climatic conditions
(2) Your evapotranspiration rates are higher than those from Class A pan whenactually the reverse should be true This should be looked into
Actual rates of evapotranspiration (ET) are not necessarily lower than panevaporation owing to a number of factors including pan correction methodcombined free surface ET and vegetation transpiration in flood plains and actual location in the delta versus the location of pan measurements If new documented field data on ET losses are available the hydrology teamwould be happy compare these to model simulations
(3) Is there any physical evidence of flooding
The assessment of the observed flood extent has been based mainly on ananalysis of satellite images from 1984 to 2000 (J McCarthy StockholmUniversity) and DWA water level observations
(4) How do you parameterize your flow in respect to flow resistance
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The Manning resistance coefficient is used to describe the resistance toflow in the river channels and over the flood plains Values for overland flow are distributed according to three vegetation zones based onvegetation mapping (S Ringrose HOORC) Values in the river channelsare ascribed based on channel vegetation descriptions (Dr CK NaiduDWA) Adjustments are made to give a good match with observed flood extent overall water balance and downstream discharges
(5) Your climate input data comprise rainfall evapotranspiration etc fromMaun and Shakawe To what extent can one use a physically based modelwith such a coarse resolution Could we conclude that this is an empiricalmodel
MIKE SHE is a physically based model which implies that the model parameters have a clear physical interpretation as opposed to lumped conceptual models Data measured in single locations may be used toassign parameter values but the parameters used at the current grid scaleof 1km 2 should be regarded as lsquoefficientrsquo parameters representing the
aggregated responseThe lack of input data on distributed rainfall or any other model input doesnot imply that the MIKE SHE model is empirical Maun and Shakawe arethe only two stations in and adjacent to the delta with reliable data Thedelta is not a conventional catchment area where the runoff from individual subcatchments is essential to arrive at the combined flow in themainstream Overland flows mix the runoff from the subcatchments and evapotranspiration dominates Thus a high resolution of the rainfall data isnot of major importance in a general flow model of the delta Nonethelessrecommendations for improved monitoring include rehabilitation of the eight DCPs which measure rainfall and the installation of an additional eight automatic gauges in the delta
(6) Our confidence on the model cannot be based on your numbers
This particular comment was based on relatively consistent outflows for theBaseline and Scenarios This was owing to the nature of the downstreamboundary condition which has since been improved and now shows avariation
The flow leaving the delta (and the model) has passed through anextremely complex hydrologic system flood propagation flow splits among distributaries spills to vast flood plains and swamps evapotranspirationand infiltration The measurement of the discharge upstream is subject toerrors of at least 10 (say 50m 3 s at the flood peak) Differences between
the model computations and the observations cannot better this(7) What resolution should we have confidence on as it pertains to your
model
Given the complexity of the area and the available data model resultsshould not be interpreted looking at single grid values Interpretation based on delta zones or subsystems is more appropriate Five zones based onflood probability have been applied in the scenario demonstration runs and others may be devised according to stakeholdersrsquo needs The minimumarea should cover several square kilometres
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34 Scenarios(1) You have run the scenarios based on dry period(s) Could you please
revise this You might be missing out on recharge to groundwater as aresult of high floods A single high flood could recharge an aquifer for thenext twenty years for example
It is the intention to run the model for a period of normal flows to see how the delta recovers from a drought As suggested the model will also be runfor high floods (this is also important for sediment transport in the delta)
(2) In taking the dry period as critical you have to consider floods as alsocritical Floods need to be covered as well
The delta is not under stress during high flow periods and the impacts of water resources developments will not be so keenly felt and therefore not critical to management planning See also response to (1) above
(3) People are more worried about the switching of channels Maybe thisaspect needs to come out in your model outputs as well
The introduction of sediment transport to the model (which has just commenced) will give an indication of possible future switches and redistribution of delta flows Switching and realignment of channels has achaotic component (the butterfly effect on global climate is akin to ahippopotamus going walkabout in the delta) and accurate predictions aresimply not possible
(4) Looking at the modelrsquos level of resolution critical management issues willnot be answered
The component has been conceived and ToR written (in 200102) toaddress the broad scale management planning issues (water resources
developments upstream climate change abstractions from the delta reed cutting and dredging) On this basis the model approach has been set outand the model set up and applied Preliminary applications suggest that the main threats to the delta will arise from upstream irrigation and climatechange These are the critical management issues related to hydrology
(5) Channel blockages impacts need to be covered in detail Channel switchingis another fundamental management issue
The model can simulate the impact of channel blockages and channel switching As discussed in (3) above the model cannot predict theseoccurrences
(6) You mentioned that your model could handle sediment transport Do youhave something on sediment transport now
An approach to introducing sediment transport to the model has beendrafted (pending report on the Integrated Hydrologic Model)
(7) You seem not to be representing your conditions
See response to (6) above
35 Presentation of Results(1) You canrsquot have a reduction of flow by 40 and yet have no impact on the
outflow This gives me the confidence of your model
See response to (4) above
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(2) The difference in long-term average discharge between observed andsimulations should not be taken to be insignificant This should becombined with other scenarios to better appreciate its impact
It is important in the preliminary stage to separate the impacts fromindividual water resources developments to obtain a good understanding of
which are critical and which are not A limited number of combinationscenarios may be run at a later stage once these can be defined and agreed by the management planners and stakeholders
(3) It would be good to combine all the scenarios as well
See (2) above
(4) It would be interesting also to look at frequency and duration of flooding
The impact on the duration of flooding can be assessed through the timeseries plots for different zones An estimate can also be made on theimpact of the scenarios on the frequency of flooding
(5) What is the model doing as it pertains to erosion and sedimentation
Sediment transport is being introduced to the model This will enable theassessment of the broad pattern of erosion and deposition through themain river channels along which the bed load is conveyed from the basinupstream
(6) The issue of land use change has to be incorporated into the model
To introduce the impact of land use changes in the basin upstream requiresthe application of a water resources planning model to the upstream basinThis is not within the present scope of ODMP which is relying on theoutputs of basinwide projects such as Sharing Water and WERRD (bothcompleted) and possibly in the future TwinBas (ongoing) If ODMP
partners suggest particular potential land use changes within the deltawhich have an impact on the hydrology these may be simulated using theIntegrated Hydrologic Model
(7) The presentations have mostly been technical I would like to suggest thatwe make handouts available after the workshop so that the participantscould have ample time to go over them and later submit their suggestionscomments and or questions
This document represents a full report on the proceedings Further comments from ODMP partners are welcome that our further work may more closely meet the needs of delta management planning Further discussions will be held with the stakeholders on the ongoing model applications possibly on a bilateral basis to obtain a closer understanding of particular needs and ways to meet these needs
36 Stakeholdersrsquo Responses
Wildlife
(1) We need drying flood plain map to better track movement of wild animals
The drying and wetting of the flood plains was presented as animated sequences in the Workshop for all scenarios with a monthly time step Afiner temporal resolution can be prepared (down to four hours) though the
spatial resolution is limited to one kilometre squares
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(2) We would appreciate information on correlations between the distribution of elephants population and extent of flooding close to the buffalo fence
The HampWR component can provide information on the waters of the deltaIt is up to the individual partners to analyse this information for their ownneeds The HampWR component cannot be expected to carry out all the
analyses for the management planThe integration of information from all ODMP components will be carried out within the Okavango Delta Information System implemented inHOORC (also with support from Danida)
Fisheries
(1) Water quality is very critical as this have impact on fish populationdynamics Sedimentation is also critical as it has a bearing on fishpopulations
Sedimentation is indeed critical to fish populations as fine organic richsediment is washed out from the flood plain into the channels by the flood waters resulting in oxygen depletion
The MIKE SHE integrated hydrologic modelling system has the capability tosimulate water quality This is not within the present scope of ODMPSystematic data (including DO and SOD) do not exist at present on whichto develop such a model Improved monitoring recommendations includethe introduction of systematic sampling and analysis at the key inflow station of Mohembo and monthly in-situ measurements of salinity and pH at around 20 discharge stations throughout the delta
Water Affairs
(1) Is MIKE SHE an instrument or whatMIKE SHE is one of a suite of water and environmental software packagesdeveloped and marketed commercially by DHI Water and EnvironmentThe MIKE SHE package is the most advanced generic (can be applied toany system) hydrologic software available MIKE SHE has a consistent development history over thirty years and has been applied to hundreds of hydrologic systems worldwide
(2) Can the model predict channel shifts
The sediment transport model will predict erosion and deposition leading tochannel aggradation and eventual closure The delta morphology isinherently unstable and chaotic and no model can predict channel abandonment with higher certainty than what is constrained by natural variability (chaos) Nonetheless the impact of major channel shifts can be
predicted as well as possible management measures to mitigate suchshifts
(3) Mr Dikgomo mentioned that Hydrology and Water Resources component isone of the twelve What are the other eleven components
The CTA may best respond to this question though it is suggested that representatives from participating organisations take the trouble to informthemselves of the ODMP structure objectives and outputs before attending such fora
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Land Board
(1) Is it possible for the model to give us depth of water table within at least500 metres from the delta This can help us with land use This will alsohelp us determine how far we can avoid pollution in land allocations
The spatial resolution of the model is one square kilometre The model cangive the various hydrologic parameters such a depth to ground water withinthe general area (within a few square kilometres) This should be quiteadequate for the purpose of broad based management planning
(2) Can the model add value to Tawana land board land use and managementplan (2004-2029)
The Hydrology and Water Resources component is concerned withhydrology and water resources The outputs from the component arehydrologic data and predictions for the delta It is up to the various sectorsand components of the management plan to assess the impact of thesehydrologic parameters for their own purposes The HampWR component can
assist in the interpretation of the hydrologic dataTourism
(1) There are lodges and camps located close to the river channels Can themodel be able to help on the implications of pollution
The model can simulate the pattern of flow in the delta which may give auseful indication of the movement of pollution though not the output whichmay be given by a water quality model (advection dispersion decay etc)
General
(1) This component (Hydrology and Water Resources) is so detached from therest It should relocate to MaunThe component is located in Gaborone as the capital has better infrastructure Progress on the component would be constrained by thelimited infrastructure in Maun
(2) To what extent is your data real time series that it could be relied upon
The data available from the delta at present are poor largely owing todifficulties in access and disturbance of gauging stations by humans and large mammalian wildlife Lack of systematic use of the data to date havealso contributed to neglect Improved monitoring is necessary for management planning and an improved hydrologic model with finer
resolution and greater accuracy Recommendations have been prepared for DWA to improve hydrologic monitoring and it is hoped these can beimplemented in the course of 2005
(3) The presentations are too technical When will ODMP reach out to usSomeone mentioned that communication and or information disseminationis a problem Why cant we find other Batswana who could do the job toconvey the information in an audience screened and targeted way
The hydrology of the delta is complex and requires a complex model for arealistic simulation of the processes The presentations were intended togive all participants an understanding that the model is indeed capable of simulating the key hydrologic phenomena of the delta It is hoped that this
has been achieved though it is recognised that the depth of understanding
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will depend upon the level of the individual participantrsquos hydrologic knowledge
The DWA staff assigned to ODMP will gradually take over presentations insuch fora as part of the process of technology transfer which is anessential part of the component
Lessons have been learnt from this Workshop A second and possibly third Workshop will be planned along with bilateral meetings with the individual Stakeholders hopefully improving the communication to the diverse
participants (see Conclusions)
(4) Communications and networking is lagging behind but its pro-activeness isso crucial The component would simplify information and relay it tocommunity andor stakeholders
The HampWR component looks forward to this component being activatedand to cooperating with the Communications and Networking component in
presenting results of the hydrologic analyses meaningful to all
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4 CONCLUSIONS
41 SummaryProf Francis Sefe from the consultantsrsquo team summarised the Workshop discussionas follows
(1) There were discussions on both spatial and temporal resolutions of themodel which need clarification
(2) It was observed that data quality and availability is a constraint to accuratemodelling of the hydrology of the delta and providing physical evidence toback the model conclusions
(3) In the selection of scenarios it is critical to understand that the individualscenarios are not stand alone
(4) The choice of what constitutes the baseline scenario was discussed It hasto be emphasised that the inclusion of exceptional floods is also importantand hence not only the dry period should be used
(5) The presentation was multifaceted
(6) People could not easily locate any landmark features on the map Thisneed not be Villages could be labelled and even the rivers themselves
(7) Though water quality is not in the scope of the current modelling water quality is very important and this has to be looked into in the future
(8) Ground water fluctuations at the periphery of the delta need to be lookedinto
(9) Various stakeholders have difficulty interpreting the results This is a critical
issue that needs to be addressed The target audience should reasonablybe able to assimilate the information relayed to them
42 RecommendationsThe following recommendations are made with regard to the future interactionbetween the Hydrology and Water Resources component and the other ODMPparticipants
(1) While the introductions to the set up and application of the IntegratedHydrologic Model attempted to convey the complexity of the deltahydrology and its computer based representation further effort needs to bemade to present the model and its results in a manner which is fullycomprehensible to the Stakeholders most of whom do not have in depthhydrologic knowledge
(2) It was originally believed that presentation of the model to Stakeholders in acombined forum would allow the interchange of ideas and knowledgeamong the Stakeholders as well as with the Hydrology and Water Resources component The resulting discussion tended to be dominatedby those with technical hydrologic knowledge at the expense of thosewithout The next round of discussions should be on a bilateral basis suchthat the discussions can proceed at a level appropriate for the individualStakeholders and their needs in respect of hydrology and water resources
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(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
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ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
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ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
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Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
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Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
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Hydrology and Water Resources Okavango Delta Management Plan
ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
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bull Surface water levels and flows through the rivers and over the floodedswamp areas and the extent of flooding
bull The moisture content of the soil
bull The ground water levels and flows
bull The overall water balance including inflows outflows and changes insurface and subsurface storage for the delta and selected areas of thedelta
bull Sediment transport along the main channels of the delta showingpatterns of erosion and deposition
The Integrated Hydrologic Model does have practical certain limitations and it isimportant that these are recognised by the stakeholders and management planners
Channel Switching
While the model can predict the impact of cutting and dredging a new channel
through the delta and the impact of closing an existing channel through theencroachment of vegetation it is not able to predict the occurrence of the formation of new channels and the realignment of existing channels which may be initiated by themovement patterns of large mammals and vegetation growth
Certain trends in sedimentation and channel development and decay may bepredicted by the application of sediment transport to the model Work on this areahas just commenced Detailed analyses of selected reaches and areas of the deltamay be carried out through the application of two dimensional morphological modelsThis is beyond the scope of the present component activities
Level of Detail and Accuracy
While the technology exists to simulate the hydrologic behaviour of the delta at a highlevel of detail (previous applications have been made at the level of individualcultivated fields) this is constrained by
bull The resources available to the component do not permit thedevelopment of submodels which could enable the study of a particular area of the delta below the present one square kilometre resolution
bull The available data do not justify high expectations on the level of accuracy with respect to absolute water levels and quantitiesRecommendations have been made for improved data collection andmanagement which when available could justify further modeldevelopment
The key issue at this stage is that the Integrated Hydrologic Model represents theessential hydrologic phenomena in an integrated manner such that it may be appliedwith confidence to the assessment of the impacts of future water resourcesdevelopments on the delta hydrology for the purposes of the management plan
Physical Phenomena
The model simulates physical hydrological phenomena only Studies have revealedin particular the importance of the interdependency of physical and biologicalphenomena for example the movement of large mammals opening new flow pathsthrough the vegetation sedimentation and vegetation in closing existing channels
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Hydrology and Water Resources Okavango Delta Management Plan
bull The data should reflect how the delta may recover in a period of normal inflows after a dry period
The long term inflow in terms of volume per annum from 1933 to date is shown inslide 14 for both Mukwe in Namibia and Mohembo in Botswana Whereas at Mukwethe river is more or less confined to the gauged channel at Mohembo the river has
broadened out with a wide flood plain It is not possible to gauge the flows over theflood plain and Mohembo will not represent the total discharge This is most clearlyevinced in the high flow years 199899 and 200001
An anomaly appears in the data from around 1950 to 1980 where the total inflow atMohembo appears higher than Mukwe As there is no significant inflow to the river between the two gauges this can only be explained by gauging errors The seriesafter 1980 is more consistent with Mukwe showing a higher inflow than Mohembo
The period from 1992 to 1997 represents the sequence of the five lowest inflowyears and is therefore chosen to provide the input data to analyse the impacts under critical conditions for both the existing state and possible future states with water resources developments
The following five year period from 1997 to 2002 represents relatively normalhydrologic conditions in the delta and has been used to assess how the delta mayrecover after a sequence of dry years (see slide 15)
A high inflow period could also be selected eg 1987 to 1992 to assess the impactsunder high inflow conditions It is not planned to analyse this period as
bull The conditions will not be critical to a management planning exercise
bull The number of impacts which have to be assessed in terms of flowsdepths etc will be further increased
Appropriate time series of inputs (inflows precipitation etc) have been prepared and
applied to the existing state of the delta The model results are used as a baselineagainst which future developments are assessed for their impacts The inputs aremodified to represent conditions which may prevail under future conditions
To summarise while the inflows to the delta will be dynamic ranging over two fiveyear periods representing critical dry and normal average hydrologic conditions theexisting and future states will be static This implies that for the duration of the fiveyear model run period the population for instance will not be increasing no newdams or irrigation schemes are built etc
At present the Baseline and Scenario Conditions have been simulated for the criticaldry hydrologic input period from October 1992 to October 1997 Summary results arepresented and discussed in the following sections Slides illustrating the outputs arepresented in Annex 3
233 Presentation of Results
In order to assist the stakeholders assess the outputs and their implications for their particular sectors a common format for the presentation is adopted The resolutionof the model in space is one kilometre and in time four hours In order to limit thesize of the output files the results are output with a temporal resolution of one weekfor surface flows and the unsaturated zone while the slower responding ground water results are output every two months of the five year period
For the purpose of presenting summary data the delta is divided into five zonesaccording to the probability of flooding as assessed from 15 years of satellite images(source J McCarthy Stockholm University) with the Panhandle treated as a fifth
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separate zone (slide 16) The probability delta area and a zone description are givenin the table
Model Area (km 2) 28782 Description
Zone 1 - 01gtFPgt0 19322 rarely flooded
Zone 2 - 05gtFPgt01 3534 occasionally flooded
Zone 3 - 09gtFPgt05 2328 seasonally flooded
Zone 4 - 1gtFPgt09 2152 normally flooded
Zone 5 - Panhandle 1446 Panhandle
(1) Animated sequence of flooding in the delta showing the monthly variation inflooded area and depth (The AVI format file is available from DWA sizearound 110Mb)
(2) Map based on the one kilometre grid showing the minimum depth of water in the delta for the five dry years
(3) Time series showing the variation in the depth of flooding over the five year period The depth is averaged for each of five zones (see table)
(4) Map based on the one kilometre grid showing the minimum level of soilmoisture in the root zone (the zone from which plants draw water) in thedelta over the five dry years
(5) Map based on the one kilometre grid showing the maximum depth toground water in the delta over the five dry years
(6) Summary tables are prepared showing the following
bull Water balance showing inflows outflows and storage changes
bull Baseline conditions and impacts for the surface water soilmoisture and ground water for the entire delta and for each of the five zones
A wide range of outputs of all hydrologic parameters in various formats is possibleand can be tailored to the needs of the individual stakeholders It is possible also toselect different zones to calculate average time series and summary results Theabove selection has been made by the component as samples of what may be usefuland meaningful to the stakeholders and to generate discussion
24 Baseline
Surface Water
The animated depth of flow sequence (slide 17) shows the expansion and contractionof the flooded area and depth as the sequence of flood waves for each of the fiveyears propagates through the Panhandle and spreads out through the delta Slide 18shows the detail for the lower envelope of flooding for the upper delta Each squareis one square kilometre
Time series of the depth of surface water are shown for each of the five zones in slide19 The Panhandle is the first area affected by the flood wave from upstream andbeing relatively confined within a flood plain around 20km wide has the maximumrange from the seasonal wet to dry periods around 06m through the five dry yearsAs the flood wave propagates through the delta the range in water levels declines
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The accumulated impact of the drought years is also felt more as there is a generaldecline in the flood depth
As the summary table (slide 20) shows the area flooded ranges from 1513km 2 to12077km 2 while the depth ranges from 0 to around 5m The average depth in thenormally flooded area ranges from 011m to 092m
SubSurface Water
The distribution of the soil moisture content is shown as a deficit below saturatedlevel as the lower envelope (maximum deficit) for the five year period in slide 21The average deficit ranges from 056m in the rarely flooded area to 012m in thenormally flooded area
The depth to ground water over the delta area is shown for the lower envelope(maximum depth) over the five year period in slide 22 The depth ranges from anaverage of 188m in the rarely flooded area to 037m in the normally flooded area
Water Balance
The overall water balance for the Baseline and Scenarios is shown in slide 23Negative values indicate an inflow to the delta (eg precipitation and river inflow) whilepositive values indicate an outflow (eg evapotranspiration and river outflows) TheTotal should be zero the small value indicates a very minor continuity error Thenegative overland and subsurface storage changes indicate a decline in storage inthese levels
25 Upstream Water Resources Developments
251 Introduction
To date no significant water resources developments have taken place upstream inAngola and Namibia In the past plans have been made for the construction of damsfor irrigation and hydropower Anticipating that these plans may be revived theWERRD project has run a number of scenarios using a modified rainfall-runoff modelof the basin (Pitman model Rhodes University) including a scenario for all planneddams
A number of sources describes potential irrigation in the upstream basin in Angolaand Namibia These have been reviewed and a potential scenario compiled basedon
bull Irrigation demand based on 15000m 3haa with a 25 return flow
bull Irrigated area in Angola 54500ha in Namibia 7500ha
bull Angola grows vegetables in winter (June to October) Namibia growsmaize in summer (December to April)
The corresponding runoff from the upstream basin has been applied under twoscenarios Dams in Angola and Irrigation as inflow to the delta upstream The twopotential developments are kept separate for the purpose of initial appraisal in order that the impact from each can be identified This will assist in minimising the adverseimpacts from these developments
252 Dams in Angola
The impact of the previously planned hydropower dams in Angola on the inflow to the
delta is presented in slide 24 Hydropower development does not consume waterbut stores water in the flood period for release in the dry period This results in a
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redistribution of the natural hydrograph flood flows are reduced while dry seasonflows are increased (The impact appears only to be significant in 1993 and 1996 ndashthis needs further investigation)
The impact of the dams on the surface and subsurface waters of the delta is minimalgiven the limited apparent impact in three out of the five dry years and the fact that
there is no nett water loss in the basin upstream
253 Irrigation
The impact of the potential irrigation scenario on the inflow to the delta is shown inslide 25 The impact is greatest in the dry period when water is withdrawn for therelatively large area of winter crops in Angola The summer withdrawals for irrigationin Namibia are significantly less
Correspondingly the impact on the delta in the flood period is minimal while in thedry period the overland depth of flow is reduced particularly in the Panhandle andnormally flooded areas and the minimum flood extent is reduced by 660km 2 or 40of the present dry period area (slide 26)
26 Abstractions from DeltaWater for largely local domestic use is abstracted from both the surface and groundwaters of the delta The surface water abstractions are based on water rights issuedby DWA (ie the amount which may legitimately be withdrawn ndash actual withdrawals arenot monitored and may be greater or less than allowed) Ground water abstractionsare based on the demands projected from historic information to the present day
In terms of the inflows to the delta (river flows from the basin upstream andprecipitation over the basin the abstractions and corresponding impacts are minimalSurface water abstraction represents 0006 of the inflow and ground water 02In the five dry years analysed the minimum flooded area is reduced by 025Future scenario runs will simulate the impact of abstractions with projected increasedpopulation and rates of consumption to the notional year 2025
27 Climate ChangePotential climate change will have an impact on the delta in respect of inflows fromthe basin upstream and the climate over the delta The WERRD project has run aglobal climate model HadCM3 1 to predict the changed precipitation and temperatureover the basin For the upstream basin the Pitman rainfall-runoff model has beenapplied to predict the modified inflows upstream of the delta (slide 27) The modifiedprecipitation and temperature over the delta have been used as direct inputs to theIntegrated Hydrologic Model (slide 28)
The impact of the climate change scenario is highly significant in both the flood anddry seasons River inflows to the delta are reduced by 38 and precipitation over the delta by 9 Temperature increases by 22ordmC
The corresponding impact on flow depths is shown on the reduced depths the impacton the minimum depths is shown for the Panhandle and normally flooded areas inslide 29 and in each of the five zones through the five year run period in slide 30The reduction in depth averages 003m over the entire delta and the minimumflooded area is almost halved
1 httpwwwmet-officegovukresearchhadleycentremodelsHadCM3html
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28 Management PlanningThe model analyses are carried out to assess the impacts of possible future basinconditions on the delta for the purposes of management planning An iterativeprocess is envisaged with a series of bilateral meetings with the Stakeholders andcommon Workshops in which the inputs and outputs are presented to and discussedwith the stakeholders The outputs can migrate towards a presentation format that isboth meaningful and relevant to the stakeholders
The Hydrology and Water Resources component will only analyse the impacts on thewaters of the delta DWA and its consultants do not have the capability or theresources to analyse the impacts on the wildlife vegetation livestock fisheries or tourists It is up to these respective sectors to assess these impacts based on thechanged delta hydrology
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3 DISCUSSION
31 IntroductionThe following sections record the comments made on the foregoing presentationsand the responses given by the hydrology team (in italics)
32 Database Management(1) What is lithology Remember that as much as you are speaking to experts
you are also speaking to non-experts
The point is well taken A glossary will be prepared to explain technical terms
(2) The presentations are too fast and we need details of the graphs for example
This point is also noted presentations should emphasise important pointsSelected slides from the Workshop are included in Annex 3 and a full report is being prepared of both the Integrated Hydrologic Model and the
preliminary scenario analysis These should be studied by thestakeholders in advance of further (bilateral) discussions
(3) Is there a slide to show locations of critical rainfall and flow stations so thatwe could appreciate all the difficulties encountered We would appreciatemuch if we could have locations of all your data sources
The locations of the existing and proposed gauging stations is available inDWA in GIS format The key source for this and information from other sectors and stakeholders will be the Okavango Delta Information System
implemented in HOORC
33 Integrated Hydrologic Model(1) I like your conceptual model but what is applicable in Europe may not
necessarily be applicable here also
The conceptual model is fundamental to the development of a numerical model The conceptual model is strictly formulated for the Okavango Deltabased on available data and scientific publications on the subject Theconceptual model has no relation to European or other climatic conditions
(2) Your evapotranspiration rates are higher than those from Class A pan whenactually the reverse should be true This should be looked into
Actual rates of evapotranspiration (ET) are not necessarily lower than panevaporation owing to a number of factors including pan correction methodcombined free surface ET and vegetation transpiration in flood plains and actual location in the delta versus the location of pan measurements If new documented field data on ET losses are available the hydrology teamwould be happy compare these to model simulations
(3) Is there any physical evidence of flooding
The assessment of the observed flood extent has been based mainly on ananalysis of satellite images from 1984 to 2000 (J McCarthy StockholmUniversity) and DWA water level observations
(4) How do you parameterize your flow in respect to flow resistance
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The Manning resistance coefficient is used to describe the resistance toflow in the river channels and over the flood plains Values for overland flow are distributed according to three vegetation zones based onvegetation mapping (S Ringrose HOORC) Values in the river channelsare ascribed based on channel vegetation descriptions (Dr CK NaiduDWA) Adjustments are made to give a good match with observed flood extent overall water balance and downstream discharges
(5) Your climate input data comprise rainfall evapotranspiration etc fromMaun and Shakawe To what extent can one use a physically based modelwith such a coarse resolution Could we conclude that this is an empiricalmodel
MIKE SHE is a physically based model which implies that the model parameters have a clear physical interpretation as opposed to lumped conceptual models Data measured in single locations may be used toassign parameter values but the parameters used at the current grid scaleof 1km 2 should be regarded as lsquoefficientrsquo parameters representing the
aggregated responseThe lack of input data on distributed rainfall or any other model input doesnot imply that the MIKE SHE model is empirical Maun and Shakawe arethe only two stations in and adjacent to the delta with reliable data Thedelta is not a conventional catchment area where the runoff from individual subcatchments is essential to arrive at the combined flow in themainstream Overland flows mix the runoff from the subcatchments and evapotranspiration dominates Thus a high resolution of the rainfall data isnot of major importance in a general flow model of the delta Nonethelessrecommendations for improved monitoring include rehabilitation of the eight DCPs which measure rainfall and the installation of an additional eight automatic gauges in the delta
(6) Our confidence on the model cannot be based on your numbers
This particular comment was based on relatively consistent outflows for theBaseline and Scenarios This was owing to the nature of the downstreamboundary condition which has since been improved and now shows avariation
The flow leaving the delta (and the model) has passed through anextremely complex hydrologic system flood propagation flow splits among distributaries spills to vast flood plains and swamps evapotranspirationand infiltration The measurement of the discharge upstream is subject toerrors of at least 10 (say 50m 3 s at the flood peak) Differences between
the model computations and the observations cannot better this(7) What resolution should we have confidence on as it pertains to your
model
Given the complexity of the area and the available data model resultsshould not be interpreted looking at single grid values Interpretation based on delta zones or subsystems is more appropriate Five zones based onflood probability have been applied in the scenario demonstration runs and others may be devised according to stakeholdersrsquo needs The minimumarea should cover several square kilometres
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34 Scenarios(1) You have run the scenarios based on dry period(s) Could you please
revise this You might be missing out on recharge to groundwater as aresult of high floods A single high flood could recharge an aquifer for thenext twenty years for example
It is the intention to run the model for a period of normal flows to see how the delta recovers from a drought As suggested the model will also be runfor high floods (this is also important for sediment transport in the delta)
(2) In taking the dry period as critical you have to consider floods as alsocritical Floods need to be covered as well
The delta is not under stress during high flow periods and the impacts of water resources developments will not be so keenly felt and therefore not critical to management planning See also response to (1) above
(3) People are more worried about the switching of channels Maybe thisaspect needs to come out in your model outputs as well
The introduction of sediment transport to the model (which has just commenced) will give an indication of possible future switches and redistribution of delta flows Switching and realignment of channels has achaotic component (the butterfly effect on global climate is akin to ahippopotamus going walkabout in the delta) and accurate predictions aresimply not possible
(4) Looking at the modelrsquos level of resolution critical management issues willnot be answered
The component has been conceived and ToR written (in 200102) toaddress the broad scale management planning issues (water resources
developments upstream climate change abstractions from the delta reed cutting and dredging) On this basis the model approach has been set outand the model set up and applied Preliminary applications suggest that the main threats to the delta will arise from upstream irrigation and climatechange These are the critical management issues related to hydrology
(5) Channel blockages impacts need to be covered in detail Channel switchingis another fundamental management issue
The model can simulate the impact of channel blockages and channel switching As discussed in (3) above the model cannot predict theseoccurrences
(6) You mentioned that your model could handle sediment transport Do youhave something on sediment transport now
An approach to introducing sediment transport to the model has beendrafted (pending report on the Integrated Hydrologic Model)
(7) You seem not to be representing your conditions
See response to (6) above
35 Presentation of Results(1) You canrsquot have a reduction of flow by 40 and yet have no impact on the
outflow This gives me the confidence of your model
See response to (4) above
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(2) The difference in long-term average discharge between observed andsimulations should not be taken to be insignificant This should becombined with other scenarios to better appreciate its impact
It is important in the preliminary stage to separate the impacts fromindividual water resources developments to obtain a good understanding of
which are critical and which are not A limited number of combinationscenarios may be run at a later stage once these can be defined and agreed by the management planners and stakeholders
(3) It would be good to combine all the scenarios as well
See (2) above
(4) It would be interesting also to look at frequency and duration of flooding
The impact on the duration of flooding can be assessed through the timeseries plots for different zones An estimate can also be made on theimpact of the scenarios on the frequency of flooding
(5) What is the model doing as it pertains to erosion and sedimentation
Sediment transport is being introduced to the model This will enable theassessment of the broad pattern of erosion and deposition through themain river channels along which the bed load is conveyed from the basinupstream
(6) The issue of land use change has to be incorporated into the model
To introduce the impact of land use changes in the basin upstream requiresthe application of a water resources planning model to the upstream basinThis is not within the present scope of ODMP which is relying on theoutputs of basinwide projects such as Sharing Water and WERRD (bothcompleted) and possibly in the future TwinBas (ongoing) If ODMP
partners suggest particular potential land use changes within the deltawhich have an impact on the hydrology these may be simulated using theIntegrated Hydrologic Model
(7) The presentations have mostly been technical I would like to suggest thatwe make handouts available after the workshop so that the participantscould have ample time to go over them and later submit their suggestionscomments and or questions
This document represents a full report on the proceedings Further comments from ODMP partners are welcome that our further work may more closely meet the needs of delta management planning Further discussions will be held with the stakeholders on the ongoing model applications possibly on a bilateral basis to obtain a closer understanding of particular needs and ways to meet these needs
36 Stakeholdersrsquo Responses
Wildlife
(1) We need drying flood plain map to better track movement of wild animals
The drying and wetting of the flood plains was presented as animated sequences in the Workshop for all scenarios with a monthly time step Afiner temporal resolution can be prepared (down to four hours) though the
spatial resolution is limited to one kilometre squares
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(2) We would appreciate information on correlations between the distribution of elephants population and extent of flooding close to the buffalo fence
The HampWR component can provide information on the waters of the deltaIt is up to the individual partners to analyse this information for their ownneeds The HampWR component cannot be expected to carry out all the
analyses for the management planThe integration of information from all ODMP components will be carried out within the Okavango Delta Information System implemented inHOORC (also with support from Danida)
Fisheries
(1) Water quality is very critical as this have impact on fish populationdynamics Sedimentation is also critical as it has a bearing on fishpopulations
Sedimentation is indeed critical to fish populations as fine organic richsediment is washed out from the flood plain into the channels by the flood waters resulting in oxygen depletion
The MIKE SHE integrated hydrologic modelling system has the capability tosimulate water quality This is not within the present scope of ODMPSystematic data (including DO and SOD) do not exist at present on whichto develop such a model Improved monitoring recommendations includethe introduction of systematic sampling and analysis at the key inflow station of Mohembo and monthly in-situ measurements of salinity and pH at around 20 discharge stations throughout the delta
Water Affairs
(1) Is MIKE SHE an instrument or whatMIKE SHE is one of a suite of water and environmental software packagesdeveloped and marketed commercially by DHI Water and EnvironmentThe MIKE SHE package is the most advanced generic (can be applied toany system) hydrologic software available MIKE SHE has a consistent development history over thirty years and has been applied to hundreds of hydrologic systems worldwide
(2) Can the model predict channel shifts
The sediment transport model will predict erosion and deposition leading tochannel aggradation and eventual closure The delta morphology isinherently unstable and chaotic and no model can predict channel abandonment with higher certainty than what is constrained by natural variability (chaos) Nonetheless the impact of major channel shifts can be
predicted as well as possible management measures to mitigate suchshifts
(3) Mr Dikgomo mentioned that Hydrology and Water Resources component isone of the twelve What are the other eleven components
The CTA may best respond to this question though it is suggested that representatives from participating organisations take the trouble to informthemselves of the ODMP structure objectives and outputs before attending such fora
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Land Board
(1) Is it possible for the model to give us depth of water table within at least500 metres from the delta This can help us with land use This will alsohelp us determine how far we can avoid pollution in land allocations
The spatial resolution of the model is one square kilometre The model cangive the various hydrologic parameters such a depth to ground water withinthe general area (within a few square kilometres) This should be quiteadequate for the purpose of broad based management planning
(2) Can the model add value to Tawana land board land use and managementplan (2004-2029)
The Hydrology and Water Resources component is concerned withhydrology and water resources The outputs from the component arehydrologic data and predictions for the delta It is up to the various sectorsand components of the management plan to assess the impact of thesehydrologic parameters for their own purposes The HampWR component can
assist in the interpretation of the hydrologic dataTourism
(1) There are lodges and camps located close to the river channels Can themodel be able to help on the implications of pollution
The model can simulate the pattern of flow in the delta which may give auseful indication of the movement of pollution though not the output whichmay be given by a water quality model (advection dispersion decay etc)
General
(1) This component (Hydrology and Water Resources) is so detached from therest It should relocate to MaunThe component is located in Gaborone as the capital has better infrastructure Progress on the component would be constrained by thelimited infrastructure in Maun
(2) To what extent is your data real time series that it could be relied upon
The data available from the delta at present are poor largely owing todifficulties in access and disturbance of gauging stations by humans and large mammalian wildlife Lack of systematic use of the data to date havealso contributed to neglect Improved monitoring is necessary for management planning and an improved hydrologic model with finer
resolution and greater accuracy Recommendations have been prepared for DWA to improve hydrologic monitoring and it is hoped these can beimplemented in the course of 2005
(3) The presentations are too technical When will ODMP reach out to usSomeone mentioned that communication and or information disseminationis a problem Why cant we find other Batswana who could do the job toconvey the information in an audience screened and targeted way
The hydrology of the delta is complex and requires a complex model for arealistic simulation of the processes The presentations were intended togive all participants an understanding that the model is indeed capable of simulating the key hydrologic phenomena of the delta It is hoped that this
has been achieved though it is recognised that the depth of understanding
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will depend upon the level of the individual participantrsquos hydrologic knowledge
The DWA staff assigned to ODMP will gradually take over presentations insuch fora as part of the process of technology transfer which is anessential part of the component
Lessons have been learnt from this Workshop A second and possibly third Workshop will be planned along with bilateral meetings with the individual Stakeholders hopefully improving the communication to the diverse
participants (see Conclusions)
(4) Communications and networking is lagging behind but its pro-activeness isso crucial The component would simplify information and relay it tocommunity andor stakeholders
The HampWR component looks forward to this component being activatedand to cooperating with the Communications and Networking component in
presenting results of the hydrologic analyses meaningful to all
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4 CONCLUSIONS
41 SummaryProf Francis Sefe from the consultantsrsquo team summarised the Workshop discussionas follows
(1) There were discussions on both spatial and temporal resolutions of themodel which need clarification
(2) It was observed that data quality and availability is a constraint to accuratemodelling of the hydrology of the delta and providing physical evidence toback the model conclusions
(3) In the selection of scenarios it is critical to understand that the individualscenarios are not stand alone
(4) The choice of what constitutes the baseline scenario was discussed It hasto be emphasised that the inclusion of exceptional floods is also importantand hence not only the dry period should be used
(5) The presentation was multifaceted
(6) People could not easily locate any landmark features on the map Thisneed not be Villages could be labelled and even the rivers themselves
(7) Though water quality is not in the scope of the current modelling water quality is very important and this has to be looked into in the future
(8) Ground water fluctuations at the periphery of the delta need to be lookedinto
(9) Various stakeholders have difficulty interpreting the results This is a critical
issue that needs to be addressed The target audience should reasonablybe able to assimilate the information relayed to them
42 RecommendationsThe following recommendations are made with regard to the future interactionbetween the Hydrology and Water Resources component and the other ODMPparticipants
(1) While the introductions to the set up and application of the IntegratedHydrologic Model attempted to convey the complexity of the deltahydrology and its computer based representation further effort needs to bemade to present the model and its results in a manner which is fullycomprehensible to the Stakeholders most of whom do not have in depthhydrologic knowledge
(2) It was originally believed that presentation of the model to Stakeholders in acombined forum would allow the interchange of ideas and knowledgeamong the Stakeholders as well as with the Hydrology and Water Resources component The resulting discussion tended to be dominatedby those with technical hydrologic knowledge at the expense of thosewithout The next round of discussions should be on a bilateral basis suchthat the discussions can proceed at a level appropriate for the individualStakeholders and their needs in respect of hydrology and water resources
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(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
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ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
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ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
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Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
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Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
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ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
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bull The data should reflect how the delta may recover in a period of normal inflows after a dry period
The long term inflow in terms of volume per annum from 1933 to date is shown inslide 14 for both Mukwe in Namibia and Mohembo in Botswana Whereas at Mukwethe river is more or less confined to the gauged channel at Mohembo the river has
broadened out with a wide flood plain It is not possible to gauge the flows over theflood plain and Mohembo will not represent the total discharge This is most clearlyevinced in the high flow years 199899 and 200001
An anomaly appears in the data from around 1950 to 1980 where the total inflow atMohembo appears higher than Mukwe As there is no significant inflow to the river between the two gauges this can only be explained by gauging errors The seriesafter 1980 is more consistent with Mukwe showing a higher inflow than Mohembo
The period from 1992 to 1997 represents the sequence of the five lowest inflowyears and is therefore chosen to provide the input data to analyse the impacts under critical conditions for both the existing state and possible future states with water resources developments
The following five year period from 1997 to 2002 represents relatively normalhydrologic conditions in the delta and has been used to assess how the delta mayrecover after a sequence of dry years (see slide 15)
A high inflow period could also be selected eg 1987 to 1992 to assess the impactsunder high inflow conditions It is not planned to analyse this period as
bull The conditions will not be critical to a management planning exercise
bull The number of impacts which have to be assessed in terms of flowsdepths etc will be further increased
Appropriate time series of inputs (inflows precipitation etc) have been prepared and
applied to the existing state of the delta The model results are used as a baselineagainst which future developments are assessed for their impacts The inputs aremodified to represent conditions which may prevail under future conditions
To summarise while the inflows to the delta will be dynamic ranging over two fiveyear periods representing critical dry and normal average hydrologic conditions theexisting and future states will be static This implies that for the duration of the fiveyear model run period the population for instance will not be increasing no newdams or irrigation schemes are built etc
At present the Baseline and Scenario Conditions have been simulated for the criticaldry hydrologic input period from October 1992 to October 1997 Summary results arepresented and discussed in the following sections Slides illustrating the outputs arepresented in Annex 3
233 Presentation of Results
In order to assist the stakeholders assess the outputs and their implications for their particular sectors a common format for the presentation is adopted The resolutionof the model in space is one kilometre and in time four hours In order to limit thesize of the output files the results are output with a temporal resolution of one weekfor surface flows and the unsaturated zone while the slower responding ground water results are output every two months of the five year period
For the purpose of presenting summary data the delta is divided into five zonesaccording to the probability of flooding as assessed from 15 years of satellite images(source J McCarthy Stockholm University) with the Panhandle treated as a fifth
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separate zone (slide 16) The probability delta area and a zone description are givenin the table
Model Area (km 2) 28782 Description
Zone 1 - 01gtFPgt0 19322 rarely flooded
Zone 2 - 05gtFPgt01 3534 occasionally flooded
Zone 3 - 09gtFPgt05 2328 seasonally flooded
Zone 4 - 1gtFPgt09 2152 normally flooded
Zone 5 - Panhandle 1446 Panhandle
(1) Animated sequence of flooding in the delta showing the monthly variation inflooded area and depth (The AVI format file is available from DWA sizearound 110Mb)
(2) Map based on the one kilometre grid showing the minimum depth of water in the delta for the five dry years
(3) Time series showing the variation in the depth of flooding over the five year period The depth is averaged for each of five zones (see table)
(4) Map based on the one kilometre grid showing the minimum level of soilmoisture in the root zone (the zone from which plants draw water) in thedelta over the five dry years
(5) Map based on the one kilometre grid showing the maximum depth toground water in the delta over the five dry years
(6) Summary tables are prepared showing the following
bull Water balance showing inflows outflows and storage changes
bull Baseline conditions and impacts for the surface water soilmoisture and ground water for the entire delta and for each of the five zones
A wide range of outputs of all hydrologic parameters in various formats is possibleand can be tailored to the needs of the individual stakeholders It is possible also toselect different zones to calculate average time series and summary results Theabove selection has been made by the component as samples of what may be usefuland meaningful to the stakeholders and to generate discussion
24 Baseline
Surface Water
The animated depth of flow sequence (slide 17) shows the expansion and contractionof the flooded area and depth as the sequence of flood waves for each of the fiveyears propagates through the Panhandle and spreads out through the delta Slide 18shows the detail for the lower envelope of flooding for the upper delta Each squareis one square kilometre
Time series of the depth of surface water are shown for each of the five zones in slide19 The Panhandle is the first area affected by the flood wave from upstream andbeing relatively confined within a flood plain around 20km wide has the maximumrange from the seasonal wet to dry periods around 06m through the five dry yearsAs the flood wave propagates through the delta the range in water levels declines
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The accumulated impact of the drought years is also felt more as there is a generaldecline in the flood depth
As the summary table (slide 20) shows the area flooded ranges from 1513km 2 to12077km 2 while the depth ranges from 0 to around 5m The average depth in thenormally flooded area ranges from 011m to 092m
SubSurface Water
The distribution of the soil moisture content is shown as a deficit below saturatedlevel as the lower envelope (maximum deficit) for the five year period in slide 21The average deficit ranges from 056m in the rarely flooded area to 012m in thenormally flooded area
The depth to ground water over the delta area is shown for the lower envelope(maximum depth) over the five year period in slide 22 The depth ranges from anaverage of 188m in the rarely flooded area to 037m in the normally flooded area
Water Balance
The overall water balance for the Baseline and Scenarios is shown in slide 23Negative values indicate an inflow to the delta (eg precipitation and river inflow) whilepositive values indicate an outflow (eg evapotranspiration and river outflows) TheTotal should be zero the small value indicates a very minor continuity error Thenegative overland and subsurface storage changes indicate a decline in storage inthese levels
25 Upstream Water Resources Developments
251 Introduction
To date no significant water resources developments have taken place upstream inAngola and Namibia In the past plans have been made for the construction of damsfor irrigation and hydropower Anticipating that these plans may be revived theWERRD project has run a number of scenarios using a modified rainfall-runoff modelof the basin (Pitman model Rhodes University) including a scenario for all planneddams
A number of sources describes potential irrigation in the upstream basin in Angolaand Namibia These have been reviewed and a potential scenario compiled basedon
bull Irrigation demand based on 15000m 3haa with a 25 return flow
bull Irrigated area in Angola 54500ha in Namibia 7500ha
bull Angola grows vegetables in winter (June to October) Namibia growsmaize in summer (December to April)
The corresponding runoff from the upstream basin has been applied under twoscenarios Dams in Angola and Irrigation as inflow to the delta upstream The twopotential developments are kept separate for the purpose of initial appraisal in order that the impact from each can be identified This will assist in minimising the adverseimpacts from these developments
252 Dams in Angola
The impact of the previously planned hydropower dams in Angola on the inflow to the
delta is presented in slide 24 Hydropower development does not consume waterbut stores water in the flood period for release in the dry period This results in a
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redistribution of the natural hydrograph flood flows are reduced while dry seasonflows are increased (The impact appears only to be significant in 1993 and 1996 ndashthis needs further investigation)
The impact of the dams on the surface and subsurface waters of the delta is minimalgiven the limited apparent impact in three out of the five dry years and the fact that
there is no nett water loss in the basin upstream
253 Irrigation
The impact of the potential irrigation scenario on the inflow to the delta is shown inslide 25 The impact is greatest in the dry period when water is withdrawn for therelatively large area of winter crops in Angola The summer withdrawals for irrigationin Namibia are significantly less
Correspondingly the impact on the delta in the flood period is minimal while in thedry period the overland depth of flow is reduced particularly in the Panhandle andnormally flooded areas and the minimum flood extent is reduced by 660km 2 or 40of the present dry period area (slide 26)
26 Abstractions from DeltaWater for largely local domestic use is abstracted from both the surface and groundwaters of the delta The surface water abstractions are based on water rights issuedby DWA (ie the amount which may legitimately be withdrawn ndash actual withdrawals arenot monitored and may be greater or less than allowed) Ground water abstractionsare based on the demands projected from historic information to the present day
In terms of the inflows to the delta (river flows from the basin upstream andprecipitation over the basin the abstractions and corresponding impacts are minimalSurface water abstraction represents 0006 of the inflow and ground water 02In the five dry years analysed the minimum flooded area is reduced by 025Future scenario runs will simulate the impact of abstractions with projected increasedpopulation and rates of consumption to the notional year 2025
27 Climate ChangePotential climate change will have an impact on the delta in respect of inflows fromthe basin upstream and the climate over the delta The WERRD project has run aglobal climate model HadCM3 1 to predict the changed precipitation and temperatureover the basin For the upstream basin the Pitman rainfall-runoff model has beenapplied to predict the modified inflows upstream of the delta (slide 27) The modifiedprecipitation and temperature over the delta have been used as direct inputs to theIntegrated Hydrologic Model (slide 28)
The impact of the climate change scenario is highly significant in both the flood anddry seasons River inflows to the delta are reduced by 38 and precipitation over the delta by 9 Temperature increases by 22ordmC
The corresponding impact on flow depths is shown on the reduced depths the impacton the minimum depths is shown for the Panhandle and normally flooded areas inslide 29 and in each of the five zones through the five year run period in slide 30The reduction in depth averages 003m over the entire delta and the minimumflooded area is almost halved
1 httpwwwmet-officegovukresearchhadleycentremodelsHadCM3html
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28 Management PlanningThe model analyses are carried out to assess the impacts of possible future basinconditions on the delta for the purposes of management planning An iterativeprocess is envisaged with a series of bilateral meetings with the Stakeholders andcommon Workshops in which the inputs and outputs are presented to and discussedwith the stakeholders The outputs can migrate towards a presentation format that isboth meaningful and relevant to the stakeholders
The Hydrology and Water Resources component will only analyse the impacts on thewaters of the delta DWA and its consultants do not have the capability or theresources to analyse the impacts on the wildlife vegetation livestock fisheries or tourists It is up to these respective sectors to assess these impacts based on thechanged delta hydrology
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3 DISCUSSION
31 IntroductionThe following sections record the comments made on the foregoing presentationsand the responses given by the hydrology team (in italics)
32 Database Management(1) What is lithology Remember that as much as you are speaking to experts
you are also speaking to non-experts
The point is well taken A glossary will be prepared to explain technical terms
(2) The presentations are too fast and we need details of the graphs for example
This point is also noted presentations should emphasise important pointsSelected slides from the Workshop are included in Annex 3 and a full report is being prepared of both the Integrated Hydrologic Model and the
preliminary scenario analysis These should be studied by thestakeholders in advance of further (bilateral) discussions
(3) Is there a slide to show locations of critical rainfall and flow stations so thatwe could appreciate all the difficulties encountered We would appreciatemuch if we could have locations of all your data sources
The locations of the existing and proposed gauging stations is available inDWA in GIS format The key source for this and information from other sectors and stakeholders will be the Okavango Delta Information System
implemented in HOORC
33 Integrated Hydrologic Model(1) I like your conceptual model but what is applicable in Europe may not
necessarily be applicable here also
The conceptual model is fundamental to the development of a numerical model The conceptual model is strictly formulated for the Okavango Deltabased on available data and scientific publications on the subject Theconceptual model has no relation to European or other climatic conditions
(2) Your evapotranspiration rates are higher than those from Class A pan whenactually the reverse should be true This should be looked into
Actual rates of evapotranspiration (ET) are not necessarily lower than panevaporation owing to a number of factors including pan correction methodcombined free surface ET and vegetation transpiration in flood plains and actual location in the delta versus the location of pan measurements If new documented field data on ET losses are available the hydrology teamwould be happy compare these to model simulations
(3) Is there any physical evidence of flooding
The assessment of the observed flood extent has been based mainly on ananalysis of satellite images from 1984 to 2000 (J McCarthy StockholmUniversity) and DWA water level observations
(4) How do you parameterize your flow in respect to flow resistance
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The Manning resistance coefficient is used to describe the resistance toflow in the river channels and over the flood plains Values for overland flow are distributed according to three vegetation zones based onvegetation mapping (S Ringrose HOORC) Values in the river channelsare ascribed based on channel vegetation descriptions (Dr CK NaiduDWA) Adjustments are made to give a good match with observed flood extent overall water balance and downstream discharges
(5) Your climate input data comprise rainfall evapotranspiration etc fromMaun and Shakawe To what extent can one use a physically based modelwith such a coarse resolution Could we conclude that this is an empiricalmodel
MIKE SHE is a physically based model which implies that the model parameters have a clear physical interpretation as opposed to lumped conceptual models Data measured in single locations may be used toassign parameter values but the parameters used at the current grid scaleof 1km 2 should be regarded as lsquoefficientrsquo parameters representing the
aggregated responseThe lack of input data on distributed rainfall or any other model input doesnot imply that the MIKE SHE model is empirical Maun and Shakawe arethe only two stations in and adjacent to the delta with reliable data Thedelta is not a conventional catchment area where the runoff from individual subcatchments is essential to arrive at the combined flow in themainstream Overland flows mix the runoff from the subcatchments and evapotranspiration dominates Thus a high resolution of the rainfall data isnot of major importance in a general flow model of the delta Nonethelessrecommendations for improved monitoring include rehabilitation of the eight DCPs which measure rainfall and the installation of an additional eight automatic gauges in the delta
(6) Our confidence on the model cannot be based on your numbers
This particular comment was based on relatively consistent outflows for theBaseline and Scenarios This was owing to the nature of the downstreamboundary condition which has since been improved and now shows avariation
The flow leaving the delta (and the model) has passed through anextremely complex hydrologic system flood propagation flow splits among distributaries spills to vast flood plains and swamps evapotranspirationand infiltration The measurement of the discharge upstream is subject toerrors of at least 10 (say 50m 3 s at the flood peak) Differences between
the model computations and the observations cannot better this(7) What resolution should we have confidence on as it pertains to your
model
Given the complexity of the area and the available data model resultsshould not be interpreted looking at single grid values Interpretation based on delta zones or subsystems is more appropriate Five zones based onflood probability have been applied in the scenario demonstration runs and others may be devised according to stakeholdersrsquo needs The minimumarea should cover several square kilometres
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34 Scenarios(1) You have run the scenarios based on dry period(s) Could you please
revise this You might be missing out on recharge to groundwater as aresult of high floods A single high flood could recharge an aquifer for thenext twenty years for example
It is the intention to run the model for a period of normal flows to see how the delta recovers from a drought As suggested the model will also be runfor high floods (this is also important for sediment transport in the delta)
(2) In taking the dry period as critical you have to consider floods as alsocritical Floods need to be covered as well
The delta is not under stress during high flow periods and the impacts of water resources developments will not be so keenly felt and therefore not critical to management planning See also response to (1) above
(3) People are more worried about the switching of channels Maybe thisaspect needs to come out in your model outputs as well
The introduction of sediment transport to the model (which has just commenced) will give an indication of possible future switches and redistribution of delta flows Switching and realignment of channels has achaotic component (the butterfly effect on global climate is akin to ahippopotamus going walkabout in the delta) and accurate predictions aresimply not possible
(4) Looking at the modelrsquos level of resolution critical management issues willnot be answered
The component has been conceived and ToR written (in 200102) toaddress the broad scale management planning issues (water resources
developments upstream climate change abstractions from the delta reed cutting and dredging) On this basis the model approach has been set outand the model set up and applied Preliminary applications suggest that the main threats to the delta will arise from upstream irrigation and climatechange These are the critical management issues related to hydrology
(5) Channel blockages impacts need to be covered in detail Channel switchingis another fundamental management issue
The model can simulate the impact of channel blockages and channel switching As discussed in (3) above the model cannot predict theseoccurrences
(6) You mentioned that your model could handle sediment transport Do youhave something on sediment transport now
An approach to introducing sediment transport to the model has beendrafted (pending report on the Integrated Hydrologic Model)
(7) You seem not to be representing your conditions
See response to (6) above
35 Presentation of Results(1) You canrsquot have a reduction of flow by 40 and yet have no impact on the
outflow This gives me the confidence of your model
See response to (4) above
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(2) The difference in long-term average discharge between observed andsimulations should not be taken to be insignificant This should becombined with other scenarios to better appreciate its impact
It is important in the preliminary stage to separate the impacts fromindividual water resources developments to obtain a good understanding of
which are critical and which are not A limited number of combinationscenarios may be run at a later stage once these can be defined and agreed by the management planners and stakeholders
(3) It would be good to combine all the scenarios as well
See (2) above
(4) It would be interesting also to look at frequency and duration of flooding
The impact on the duration of flooding can be assessed through the timeseries plots for different zones An estimate can also be made on theimpact of the scenarios on the frequency of flooding
(5) What is the model doing as it pertains to erosion and sedimentation
Sediment transport is being introduced to the model This will enable theassessment of the broad pattern of erosion and deposition through themain river channels along which the bed load is conveyed from the basinupstream
(6) The issue of land use change has to be incorporated into the model
To introduce the impact of land use changes in the basin upstream requiresthe application of a water resources planning model to the upstream basinThis is not within the present scope of ODMP which is relying on theoutputs of basinwide projects such as Sharing Water and WERRD (bothcompleted) and possibly in the future TwinBas (ongoing) If ODMP
partners suggest particular potential land use changes within the deltawhich have an impact on the hydrology these may be simulated using theIntegrated Hydrologic Model
(7) The presentations have mostly been technical I would like to suggest thatwe make handouts available after the workshop so that the participantscould have ample time to go over them and later submit their suggestionscomments and or questions
This document represents a full report on the proceedings Further comments from ODMP partners are welcome that our further work may more closely meet the needs of delta management planning Further discussions will be held with the stakeholders on the ongoing model applications possibly on a bilateral basis to obtain a closer understanding of particular needs and ways to meet these needs
36 Stakeholdersrsquo Responses
Wildlife
(1) We need drying flood plain map to better track movement of wild animals
The drying and wetting of the flood plains was presented as animated sequences in the Workshop for all scenarios with a monthly time step Afiner temporal resolution can be prepared (down to four hours) though the
spatial resolution is limited to one kilometre squares
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(2) We would appreciate information on correlations between the distribution of elephants population and extent of flooding close to the buffalo fence
The HampWR component can provide information on the waters of the deltaIt is up to the individual partners to analyse this information for their ownneeds The HampWR component cannot be expected to carry out all the
analyses for the management planThe integration of information from all ODMP components will be carried out within the Okavango Delta Information System implemented inHOORC (also with support from Danida)
Fisheries
(1) Water quality is very critical as this have impact on fish populationdynamics Sedimentation is also critical as it has a bearing on fishpopulations
Sedimentation is indeed critical to fish populations as fine organic richsediment is washed out from the flood plain into the channels by the flood waters resulting in oxygen depletion
The MIKE SHE integrated hydrologic modelling system has the capability tosimulate water quality This is not within the present scope of ODMPSystematic data (including DO and SOD) do not exist at present on whichto develop such a model Improved monitoring recommendations includethe introduction of systematic sampling and analysis at the key inflow station of Mohembo and monthly in-situ measurements of salinity and pH at around 20 discharge stations throughout the delta
Water Affairs
(1) Is MIKE SHE an instrument or whatMIKE SHE is one of a suite of water and environmental software packagesdeveloped and marketed commercially by DHI Water and EnvironmentThe MIKE SHE package is the most advanced generic (can be applied toany system) hydrologic software available MIKE SHE has a consistent development history over thirty years and has been applied to hundreds of hydrologic systems worldwide
(2) Can the model predict channel shifts
The sediment transport model will predict erosion and deposition leading tochannel aggradation and eventual closure The delta morphology isinherently unstable and chaotic and no model can predict channel abandonment with higher certainty than what is constrained by natural variability (chaos) Nonetheless the impact of major channel shifts can be
predicted as well as possible management measures to mitigate suchshifts
(3) Mr Dikgomo mentioned that Hydrology and Water Resources component isone of the twelve What are the other eleven components
The CTA may best respond to this question though it is suggested that representatives from participating organisations take the trouble to informthemselves of the ODMP structure objectives and outputs before attending such fora
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Land Board
(1) Is it possible for the model to give us depth of water table within at least500 metres from the delta This can help us with land use This will alsohelp us determine how far we can avoid pollution in land allocations
The spatial resolution of the model is one square kilometre The model cangive the various hydrologic parameters such a depth to ground water withinthe general area (within a few square kilometres) This should be quiteadequate for the purpose of broad based management planning
(2) Can the model add value to Tawana land board land use and managementplan (2004-2029)
The Hydrology and Water Resources component is concerned withhydrology and water resources The outputs from the component arehydrologic data and predictions for the delta It is up to the various sectorsand components of the management plan to assess the impact of thesehydrologic parameters for their own purposes The HampWR component can
assist in the interpretation of the hydrologic dataTourism
(1) There are lodges and camps located close to the river channels Can themodel be able to help on the implications of pollution
The model can simulate the pattern of flow in the delta which may give auseful indication of the movement of pollution though not the output whichmay be given by a water quality model (advection dispersion decay etc)
General
(1) This component (Hydrology and Water Resources) is so detached from therest It should relocate to MaunThe component is located in Gaborone as the capital has better infrastructure Progress on the component would be constrained by thelimited infrastructure in Maun
(2) To what extent is your data real time series that it could be relied upon
The data available from the delta at present are poor largely owing todifficulties in access and disturbance of gauging stations by humans and large mammalian wildlife Lack of systematic use of the data to date havealso contributed to neglect Improved monitoring is necessary for management planning and an improved hydrologic model with finer
resolution and greater accuracy Recommendations have been prepared for DWA to improve hydrologic monitoring and it is hoped these can beimplemented in the course of 2005
(3) The presentations are too technical When will ODMP reach out to usSomeone mentioned that communication and or information disseminationis a problem Why cant we find other Batswana who could do the job toconvey the information in an audience screened and targeted way
The hydrology of the delta is complex and requires a complex model for arealistic simulation of the processes The presentations were intended togive all participants an understanding that the model is indeed capable of simulating the key hydrologic phenomena of the delta It is hoped that this
has been achieved though it is recognised that the depth of understanding
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will depend upon the level of the individual participantrsquos hydrologic knowledge
The DWA staff assigned to ODMP will gradually take over presentations insuch fora as part of the process of technology transfer which is anessential part of the component
Lessons have been learnt from this Workshop A second and possibly third Workshop will be planned along with bilateral meetings with the individual Stakeholders hopefully improving the communication to the diverse
participants (see Conclusions)
(4) Communications and networking is lagging behind but its pro-activeness isso crucial The component would simplify information and relay it tocommunity andor stakeholders
The HampWR component looks forward to this component being activatedand to cooperating with the Communications and Networking component in
presenting results of the hydrologic analyses meaningful to all
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4 CONCLUSIONS
41 SummaryProf Francis Sefe from the consultantsrsquo team summarised the Workshop discussionas follows
(1) There were discussions on both spatial and temporal resolutions of themodel which need clarification
(2) It was observed that data quality and availability is a constraint to accuratemodelling of the hydrology of the delta and providing physical evidence toback the model conclusions
(3) In the selection of scenarios it is critical to understand that the individualscenarios are not stand alone
(4) The choice of what constitutes the baseline scenario was discussed It hasto be emphasised that the inclusion of exceptional floods is also importantand hence not only the dry period should be used
(5) The presentation was multifaceted
(6) People could not easily locate any landmark features on the map Thisneed not be Villages could be labelled and even the rivers themselves
(7) Though water quality is not in the scope of the current modelling water quality is very important and this has to be looked into in the future
(8) Ground water fluctuations at the periphery of the delta need to be lookedinto
(9) Various stakeholders have difficulty interpreting the results This is a critical
issue that needs to be addressed The target audience should reasonablybe able to assimilate the information relayed to them
42 RecommendationsThe following recommendations are made with regard to the future interactionbetween the Hydrology and Water Resources component and the other ODMPparticipants
(1) While the introductions to the set up and application of the IntegratedHydrologic Model attempted to convey the complexity of the deltahydrology and its computer based representation further effort needs to bemade to present the model and its results in a manner which is fullycomprehensible to the Stakeholders most of whom do not have in depthhydrologic knowledge
(2) It was originally believed that presentation of the model to Stakeholders in acombined forum would allow the interchange of ideas and knowledgeamong the Stakeholders as well as with the Hydrology and Water Resources component The resulting discussion tended to be dominatedby those with technical hydrologic knowledge at the expense of thosewithout The next round of discussions should be on a bilateral basis suchthat the discussions can proceed at a level appropriate for the individualStakeholders and their needs in respect of hydrology and water resources
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(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
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ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
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ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
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Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
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Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
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ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
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bull The data should reflect how the delta may recover in a period of normal inflows after a dry period
The long term inflow in terms of volume per annum from 1933 to date is shown inslide 14 for both Mukwe in Namibia and Mohembo in Botswana Whereas at Mukwethe river is more or less confined to the gauged channel at Mohembo the river has
broadened out with a wide flood plain It is not possible to gauge the flows over theflood plain and Mohembo will not represent the total discharge This is most clearlyevinced in the high flow years 199899 and 200001
An anomaly appears in the data from around 1950 to 1980 where the total inflow atMohembo appears higher than Mukwe As there is no significant inflow to the river between the two gauges this can only be explained by gauging errors The seriesafter 1980 is more consistent with Mukwe showing a higher inflow than Mohembo
The period from 1992 to 1997 represents the sequence of the five lowest inflowyears and is therefore chosen to provide the input data to analyse the impacts under critical conditions for both the existing state and possible future states with water resources developments
The following five year period from 1997 to 2002 represents relatively normalhydrologic conditions in the delta and has been used to assess how the delta mayrecover after a sequence of dry years (see slide 15)
A high inflow period could also be selected eg 1987 to 1992 to assess the impactsunder high inflow conditions It is not planned to analyse this period as
bull The conditions will not be critical to a management planning exercise
bull The number of impacts which have to be assessed in terms of flowsdepths etc will be further increased
Appropriate time series of inputs (inflows precipitation etc) have been prepared and
applied to the existing state of the delta The model results are used as a baselineagainst which future developments are assessed for their impacts The inputs aremodified to represent conditions which may prevail under future conditions
To summarise while the inflows to the delta will be dynamic ranging over two fiveyear periods representing critical dry and normal average hydrologic conditions theexisting and future states will be static This implies that for the duration of the fiveyear model run period the population for instance will not be increasing no newdams or irrigation schemes are built etc
At present the Baseline and Scenario Conditions have been simulated for the criticaldry hydrologic input period from October 1992 to October 1997 Summary results arepresented and discussed in the following sections Slides illustrating the outputs arepresented in Annex 3
233 Presentation of Results
In order to assist the stakeholders assess the outputs and their implications for their particular sectors a common format for the presentation is adopted The resolutionof the model in space is one kilometre and in time four hours In order to limit thesize of the output files the results are output with a temporal resolution of one weekfor surface flows and the unsaturated zone while the slower responding ground water results are output every two months of the five year period
For the purpose of presenting summary data the delta is divided into five zonesaccording to the probability of flooding as assessed from 15 years of satellite images(source J McCarthy Stockholm University) with the Panhandle treated as a fifth
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separate zone (slide 16) The probability delta area and a zone description are givenin the table
Model Area (km 2) 28782 Description
Zone 1 - 01gtFPgt0 19322 rarely flooded
Zone 2 - 05gtFPgt01 3534 occasionally flooded
Zone 3 - 09gtFPgt05 2328 seasonally flooded
Zone 4 - 1gtFPgt09 2152 normally flooded
Zone 5 - Panhandle 1446 Panhandle
(1) Animated sequence of flooding in the delta showing the monthly variation inflooded area and depth (The AVI format file is available from DWA sizearound 110Mb)
(2) Map based on the one kilometre grid showing the minimum depth of water in the delta for the five dry years
(3) Time series showing the variation in the depth of flooding over the five year period The depth is averaged for each of five zones (see table)
(4) Map based on the one kilometre grid showing the minimum level of soilmoisture in the root zone (the zone from which plants draw water) in thedelta over the five dry years
(5) Map based on the one kilometre grid showing the maximum depth toground water in the delta over the five dry years
(6) Summary tables are prepared showing the following
bull Water balance showing inflows outflows and storage changes
bull Baseline conditions and impacts for the surface water soilmoisture and ground water for the entire delta and for each of the five zones
A wide range of outputs of all hydrologic parameters in various formats is possibleand can be tailored to the needs of the individual stakeholders It is possible also toselect different zones to calculate average time series and summary results Theabove selection has been made by the component as samples of what may be usefuland meaningful to the stakeholders and to generate discussion
24 Baseline
Surface Water
The animated depth of flow sequence (slide 17) shows the expansion and contractionof the flooded area and depth as the sequence of flood waves for each of the fiveyears propagates through the Panhandle and spreads out through the delta Slide 18shows the detail for the lower envelope of flooding for the upper delta Each squareis one square kilometre
Time series of the depth of surface water are shown for each of the five zones in slide19 The Panhandle is the first area affected by the flood wave from upstream andbeing relatively confined within a flood plain around 20km wide has the maximumrange from the seasonal wet to dry periods around 06m through the five dry yearsAs the flood wave propagates through the delta the range in water levels declines
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The accumulated impact of the drought years is also felt more as there is a generaldecline in the flood depth
As the summary table (slide 20) shows the area flooded ranges from 1513km 2 to12077km 2 while the depth ranges from 0 to around 5m The average depth in thenormally flooded area ranges from 011m to 092m
SubSurface Water
The distribution of the soil moisture content is shown as a deficit below saturatedlevel as the lower envelope (maximum deficit) for the five year period in slide 21The average deficit ranges from 056m in the rarely flooded area to 012m in thenormally flooded area
The depth to ground water over the delta area is shown for the lower envelope(maximum depth) over the five year period in slide 22 The depth ranges from anaverage of 188m in the rarely flooded area to 037m in the normally flooded area
Water Balance
The overall water balance for the Baseline and Scenarios is shown in slide 23Negative values indicate an inflow to the delta (eg precipitation and river inflow) whilepositive values indicate an outflow (eg evapotranspiration and river outflows) TheTotal should be zero the small value indicates a very minor continuity error Thenegative overland and subsurface storage changes indicate a decline in storage inthese levels
25 Upstream Water Resources Developments
251 Introduction
To date no significant water resources developments have taken place upstream inAngola and Namibia In the past plans have been made for the construction of damsfor irrigation and hydropower Anticipating that these plans may be revived theWERRD project has run a number of scenarios using a modified rainfall-runoff modelof the basin (Pitman model Rhodes University) including a scenario for all planneddams
A number of sources describes potential irrigation in the upstream basin in Angolaand Namibia These have been reviewed and a potential scenario compiled basedon
bull Irrigation demand based on 15000m 3haa with a 25 return flow
bull Irrigated area in Angola 54500ha in Namibia 7500ha
bull Angola grows vegetables in winter (June to October) Namibia growsmaize in summer (December to April)
The corresponding runoff from the upstream basin has been applied under twoscenarios Dams in Angola and Irrigation as inflow to the delta upstream The twopotential developments are kept separate for the purpose of initial appraisal in order that the impact from each can be identified This will assist in minimising the adverseimpacts from these developments
252 Dams in Angola
The impact of the previously planned hydropower dams in Angola on the inflow to the
delta is presented in slide 24 Hydropower development does not consume waterbut stores water in the flood period for release in the dry period This results in a
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redistribution of the natural hydrograph flood flows are reduced while dry seasonflows are increased (The impact appears only to be significant in 1993 and 1996 ndashthis needs further investigation)
The impact of the dams on the surface and subsurface waters of the delta is minimalgiven the limited apparent impact in three out of the five dry years and the fact that
there is no nett water loss in the basin upstream
253 Irrigation
The impact of the potential irrigation scenario on the inflow to the delta is shown inslide 25 The impact is greatest in the dry period when water is withdrawn for therelatively large area of winter crops in Angola The summer withdrawals for irrigationin Namibia are significantly less
Correspondingly the impact on the delta in the flood period is minimal while in thedry period the overland depth of flow is reduced particularly in the Panhandle andnormally flooded areas and the minimum flood extent is reduced by 660km 2 or 40of the present dry period area (slide 26)
26 Abstractions from DeltaWater for largely local domestic use is abstracted from both the surface and groundwaters of the delta The surface water abstractions are based on water rights issuedby DWA (ie the amount which may legitimately be withdrawn ndash actual withdrawals arenot monitored and may be greater or less than allowed) Ground water abstractionsare based on the demands projected from historic information to the present day
In terms of the inflows to the delta (river flows from the basin upstream andprecipitation over the basin the abstractions and corresponding impacts are minimalSurface water abstraction represents 0006 of the inflow and ground water 02In the five dry years analysed the minimum flooded area is reduced by 025Future scenario runs will simulate the impact of abstractions with projected increasedpopulation and rates of consumption to the notional year 2025
27 Climate ChangePotential climate change will have an impact on the delta in respect of inflows fromthe basin upstream and the climate over the delta The WERRD project has run aglobal climate model HadCM3 1 to predict the changed precipitation and temperatureover the basin For the upstream basin the Pitman rainfall-runoff model has beenapplied to predict the modified inflows upstream of the delta (slide 27) The modifiedprecipitation and temperature over the delta have been used as direct inputs to theIntegrated Hydrologic Model (slide 28)
The impact of the climate change scenario is highly significant in both the flood anddry seasons River inflows to the delta are reduced by 38 and precipitation over the delta by 9 Temperature increases by 22ordmC
The corresponding impact on flow depths is shown on the reduced depths the impacton the minimum depths is shown for the Panhandle and normally flooded areas inslide 29 and in each of the five zones through the five year run period in slide 30The reduction in depth averages 003m over the entire delta and the minimumflooded area is almost halved
1 httpwwwmet-officegovukresearchhadleycentremodelsHadCM3html
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28 Management PlanningThe model analyses are carried out to assess the impacts of possible future basinconditions on the delta for the purposes of management planning An iterativeprocess is envisaged with a series of bilateral meetings with the Stakeholders andcommon Workshops in which the inputs and outputs are presented to and discussedwith the stakeholders The outputs can migrate towards a presentation format that isboth meaningful and relevant to the stakeholders
The Hydrology and Water Resources component will only analyse the impacts on thewaters of the delta DWA and its consultants do not have the capability or theresources to analyse the impacts on the wildlife vegetation livestock fisheries or tourists It is up to these respective sectors to assess these impacts based on thechanged delta hydrology
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3 DISCUSSION
31 IntroductionThe following sections record the comments made on the foregoing presentationsand the responses given by the hydrology team (in italics)
32 Database Management(1) What is lithology Remember that as much as you are speaking to experts
you are also speaking to non-experts
The point is well taken A glossary will be prepared to explain technical terms
(2) The presentations are too fast and we need details of the graphs for example
This point is also noted presentations should emphasise important pointsSelected slides from the Workshop are included in Annex 3 and a full report is being prepared of both the Integrated Hydrologic Model and the
preliminary scenario analysis These should be studied by thestakeholders in advance of further (bilateral) discussions
(3) Is there a slide to show locations of critical rainfall and flow stations so thatwe could appreciate all the difficulties encountered We would appreciatemuch if we could have locations of all your data sources
The locations of the existing and proposed gauging stations is available inDWA in GIS format The key source for this and information from other sectors and stakeholders will be the Okavango Delta Information System
implemented in HOORC
33 Integrated Hydrologic Model(1) I like your conceptual model but what is applicable in Europe may not
necessarily be applicable here also
The conceptual model is fundamental to the development of a numerical model The conceptual model is strictly formulated for the Okavango Deltabased on available data and scientific publications on the subject Theconceptual model has no relation to European or other climatic conditions
(2) Your evapotranspiration rates are higher than those from Class A pan whenactually the reverse should be true This should be looked into
Actual rates of evapotranspiration (ET) are not necessarily lower than panevaporation owing to a number of factors including pan correction methodcombined free surface ET and vegetation transpiration in flood plains and actual location in the delta versus the location of pan measurements If new documented field data on ET losses are available the hydrology teamwould be happy compare these to model simulations
(3) Is there any physical evidence of flooding
The assessment of the observed flood extent has been based mainly on ananalysis of satellite images from 1984 to 2000 (J McCarthy StockholmUniversity) and DWA water level observations
(4) How do you parameterize your flow in respect to flow resistance
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The Manning resistance coefficient is used to describe the resistance toflow in the river channels and over the flood plains Values for overland flow are distributed according to three vegetation zones based onvegetation mapping (S Ringrose HOORC) Values in the river channelsare ascribed based on channel vegetation descriptions (Dr CK NaiduDWA) Adjustments are made to give a good match with observed flood extent overall water balance and downstream discharges
(5) Your climate input data comprise rainfall evapotranspiration etc fromMaun and Shakawe To what extent can one use a physically based modelwith such a coarse resolution Could we conclude that this is an empiricalmodel
MIKE SHE is a physically based model which implies that the model parameters have a clear physical interpretation as opposed to lumped conceptual models Data measured in single locations may be used toassign parameter values but the parameters used at the current grid scaleof 1km 2 should be regarded as lsquoefficientrsquo parameters representing the
aggregated responseThe lack of input data on distributed rainfall or any other model input doesnot imply that the MIKE SHE model is empirical Maun and Shakawe arethe only two stations in and adjacent to the delta with reliable data Thedelta is not a conventional catchment area where the runoff from individual subcatchments is essential to arrive at the combined flow in themainstream Overland flows mix the runoff from the subcatchments and evapotranspiration dominates Thus a high resolution of the rainfall data isnot of major importance in a general flow model of the delta Nonethelessrecommendations for improved monitoring include rehabilitation of the eight DCPs which measure rainfall and the installation of an additional eight automatic gauges in the delta
(6) Our confidence on the model cannot be based on your numbers
This particular comment was based on relatively consistent outflows for theBaseline and Scenarios This was owing to the nature of the downstreamboundary condition which has since been improved and now shows avariation
The flow leaving the delta (and the model) has passed through anextremely complex hydrologic system flood propagation flow splits among distributaries spills to vast flood plains and swamps evapotranspirationand infiltration The measurement of the discharge upstream is subject toerrors of at least 10 (say 50m 3 s at the flood peak) Differences between
the model computations and the observations cannot better this(7) What resolution should we have confidence on as it pertains to your
model
Given the complexity of the area and the available data model resultsshould not be interpreted looking at single grid values Interpretation based on delta zones or subsystems is more appropriate Five zones based onflood probability have been applied in the scenario demonstration runs and others may be devised according to stakeholdersrsquo needs The minimumarea should cover several square kilometres
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34 Scenarios(1) You have run the scenarios based on dry period(s) Could you please
revise this You might be missing out on recharge to groundwater as aresult of high floods A single high flood could recharge an aquifer for thenext twenty years for example
It is the intention to run the model for a period of normal flows to see how the delta recovers from a drought As suggested the model will also be runfor high floods (this is also important for sediment transport in the delta)
(2) In taking the dry period as critical you have to consider floods as alsocritical Floods need to be covered as well
The delta is not under stress during high flow periods and the impacts of water resources developments will not be so keenly felt and therefore not critical to management planning See also response to (1) above
(3) People are more worried about the switching of channels Maybe thisaspect needs to come out in your model outputs as well
The introduction of sediment transport to the model (which has just commenced) will give an indication of possible future switches and redistribution of delta flows Switching and realignment of channels has achaotic component (the butterfly effect on global climate is akin to ahippopotamus going walkabout in the delta) and accurate predictions aresimply not possible
(4) Looking at the modelrsquos level of resolution critical management issues willnot be answered
The component has been conceived and ToR written (in 200102) toaddress the broad scale management planning issues (water resources
developments upstream climate change abstractions from the delta reed cutting and dredging) On this basis the model approach has been set outand the model set up and applied Preliminary applications suggest that the main threats to the delta will arise from upstream irrigation and climatechange These are the critical management issues related to hydrology
(5) Channel blockages impacts need to be covered in detail Channel switchingis another fundamental management issue
The model can simulate the impact of channel blockages and channel switching As discussed in (3) above the model cannot predict theseoccurrences
(6) You mentioned that your model could handle sediment transport Do youhave something on sediment transport now
An approach to introducing sediment transport to the model has beendrafted (pending report on the Integrated Hydrologic Model)
(7) You seem not to be representing your conditions
See response to (6) above
35 Presentation of Results(1) You canrsquot have a reduction of flow by 40 and yet have no impact on the
outflow This gives me the confidence of your model
See response to (4) above
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(2) The difference in long-term average discharge between observed andsimulations should not be taken to be insignificant This should becombined with other scenarios to better appreciate its impact
It is important in the preliminary stage to separate the impacts fromindividual water resources developments to obtain a good understanding of
which are critical and which are not A limited number of combinationscenarios may be run at a later stage once these can be defined and agreed by the management planners and stakeholders
(3) It would be good to combine all the scenarios as well
See (2) above
(4) It would be interesting also to look at frequency and duration of flooding
The impact on the duration of flooding can be assessed through the timeseries plots for different zones An estimate can also be made on theimpact of the scenarios on the frequency of flooding
(5) What is the model doing as it pertains to erosion and sedimentation
Sediment transport is being introduced to the model This will enable theassessment of the broad pattern of erosion and deposition through themain river channels along which the bed load is conveyed from the basinupstream
(6) The issue of land use change has to be incorporated into the model
To introduce the impact of land use changes in the basin upstream requiresthe application of a water resources planning model to the upstream basinThis is not within the present scope of ODMP which is relying on theoutputs of basinwide projects such as Sharing Water and WERRD (bothcompleted) and possibly in the future TwinBas (ongoing) If ODMP
partners suggest particular potential land use changes within the deltawhich have an impact on the hydrology these may be simulated using theIntegrated Hydrologic Model
(7) The presentations have mostly been technical I would like to suggest thatwe make handouts available after the workshop so that the participantscould have ample time to go over them and later submit their suggestionscomments and or questions
This document represents a full report on the proceedings Further comments from ODMP partners are welcome that our further work may more closely meet the needs of delta management planning Further discussions will be held with the stakeholders on the ongoing model applications possibly on a bilateral basis to obtain a closer understanding of particular needs and ways to meet these needs
36 Stakeholdersrsquo Responses
Wildlife
(1) We need drying flood plain map to better track movement of wild animals
The drying and wetting of the flood plains was presented as animated sequences in the Workshop for all scenarios with a monthly time step Afiner temporal resolution can be prepared (down to four hours) though the
spatial resolution is limited to one kilometre squares
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(2) We would appreciate information on correlations between the distribution of elephants population and extent of flooding close to the buffalo fence
The HampWR component can provide information on the waters of the deltaIt is up to the individual partners to analyse this information for their ownneeds The HampWR component cannot be expected to carry out all the
analyses for the management planThe integration of information from all ODMP components will be carried out within the Okavango Delta Information System implemented inHOORC (also with support from Danida)
Fisheries
(1) Water quality is very critical as this have impact on fish populationdynamics Sedimentation is also critical as it has a bearing on fishpopulations
Sedimentation is indeed critical to fish populations as fine organic richsediment is washed out from the flood plain into the channels by the flood waters resulting in oxygen depletion
The MIKE SHE integrated hydrologic modelling system has the capability tosimulate water quality This is not within the present scope of ODMPSystematic data (including DO and SOD) do not exist at present on whichto develop such a model Improved monitoring recommendations includethe introduction of systematic sampling and analysis at the key inflow station of Mohembo and monthly in-situ measurements of salinity and pH at around 20 discharge stations throughout the delta
Water Affairs
(1) Is MIKE SHE an instrument or whatMIKE SHE is one of a suite of water and environmental software packagesdeveloped and marketed commercially by DHI Water and EnvironmentThe MIKE SHE package is the most advanced generic (can be applied toany system) hydrologic software available MIKE SHE has a consistent development history over thirty years and has been applied to hundreds of hydrologic systems worldwide
(2) Can the model predict channel shifts
The sediment transport model will predict erosion and deposition leading tochannel aggradation and eventual closure The delta morphology isinherently unstable and chaotic and no model can predict channel abandonment with higher certainty than what is constrained by natural variability (chaos) Nonetheless the impact of major channel shifts can be
predicted as well as possible management measures to mitigate suchshifts
(3) Mr Dikgomo mentioned that Hydrology and Water Resources component isone of the twelve What are the other eleven components
The CTA may best respond to this question though it is suggested that representatives from participating organisations take the trouble to informthemselves of the ODMP structure objectives and outputs before attending such fora
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Land Board
(1) Is it possible for the model to give us depth of water table within at least500 metres from the delta This can help us with land use This will alsohelp us determine how far we can avoid pollution in land allocations
The spatial resolution of the model is one square kilometre The model cangive the various hydrologic parameters such a depth to ground water withinthe general area (within a few square kilometres) This should be quiteadequate for the purpose of broad based management planning
(2) Can the model add value to Tawana land board land use and managementplan (2004-2029)
The Hydrology and Water Resources component is concerned withhydrology and water resources The outputs from the component arehydrologic data and predictions for the delta It is up to the various sectorsand components of the management plan to assess the impact of thesehydrologic parameters for their own purposes The HampWR component can
assist in the interpretation of the hydrologic dataTourism
(1) There are lodges and camps located close to the river channels Can themodel be able to help on the implications of pollution
The model can simulate the pattern of flow in the delta which may give auseful indication of the movement of pollution though not the output whichmay be given by a water quality model (advection dispersion decay etc)
General
(1) This component (Hydrology and Water Resources) is so detached from therest It should relocate to MaunThe component is located in Gaborone as the capital has better infrastructure Progress on the component would be constrained by thelimited infrastructure in Maun
(2) To what extent is your data real time series that it could be relied upon
The data available from the delta at present are poor largely owing todifficulties in access and disturbance of gauging stations by humans and large mammalian wildlife Lack of systematic use of the data to date havealso contributed to neglect Improved monitoring is necessary for management planning and an improved hydrologic model with finer
resolution and greater accuracy Recommendations have been prepared for DWA to improve hydrologic monitoring and it is hoped these can beimplemented in the course of 2005
(3) The presentations are too technical When will ODMP reach out to usSomeone mentioned that communication and or information disseminationis a problem Why cant we find other Batswana who could do the job toconvey the information in an audience screened and targeted way
The hydrology of the delta is complex and requires a complex model for arealistic simulation of the processes The presentations were intended togive all participants an understanding that the model is indeed capable of simulating the key hydrologic phenomena of the delta It is hoped that this
has been achieved though it is recognised that the depth of understanding
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will depend upon the level of the individual participantrsquos hydrologic knowledge
The DWA staff assigned to ODMP will gradually take over presentations insuch fora as part of the process of technology transfer which is anessential part of the component
Lessons have been learnt from this Workshop A second and possibly third Workshop will be planned along with bilateral meetings with the individual Stakeholders hopefully improving the communication to the diverse
participants (see Conclusions)
(4) Communications and networking is lagging behind but its pro-activeness isso crucial The component would simplify information and relay it tocommunity andor stakeholders
The HampWR component looks forward to this component being activatedand to cooperating with the Communications and Networking component in
presenting results of the hydrologic analyses meaningful to all
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4 CONCLUSIONS
41 SummaryProf Francis Sefe from the consultantsrsquo team summarised the Workshop discussionas follows
(1) There were discussions on both spatial and temporal resolutions of themodel which need clarification
(2) It was observed that data quality and availability is a constraint to accuratemodelling of the hydrology of the delta and providing physical evidence toback the model conclusions
(3) In the selection of scenarios it is critical to understand that the individualscenarios are not stand alone
(4) The choice of what constitutes the baseline scenario was discussed It hasto be emphasised that the inclusion of exceptional floods is also importantand hence not only the dry period should be used
(5) The presentation was multifaceted
(6) People could not easily locate any landmark features on the map Thisneed not be Villages could be labelled and even the rivers themselves
(7) Though water quality is not in the scope of the current modelling water quality is very important and this has to be looked into in the future
(8) Ground water fluctuations at the periphery of the delta need to be lookedinto
(9) Various stakeholders have difficulty interpreting the results This is a critical
issue that needs to be addressed The target audience should reasonablybe able to assimilate the information relayed to them
42 RecommendationsThe following recommendations are made with regard to the future interactionbetween the Hydrology and Water Resources component and the other ODMPparticipants
(1) While the introductions to the set up and application of the IntegratedHydrologic Model attempted to convey the complexity of the deltahydrology and its computer based representation further effort needs to bemade to present the model and its results in a manner which is fullycomprehensible to the Stakeholders most of whom do not have in depthhydrologic knowledge
(2) It was originally believed that presentation of the model to Stakeholders in acombined forum would allow the interchange of ideas and knowledgeamong the Stakeholders as well as with the Hydrology and Water Resources component The resulting discussion tended to be dominatedby those with technical hydrologic knowledge at the expense of thosewithout The next round of discussions should be on a bilateral basis suchthat the discussions can proceed at a level appropriate for the individualStakeholders and their needs in respect of hydrology and water resources
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(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
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ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
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ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
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Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
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Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
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ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
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separate zone (slide 16) The probability delta area and a zone description are givenin the table
Model Area (km 2) 28782 Description
Zone 1 - 01gtFPgt0 19322 rarely flooded
Zone 2 - 05gtFPgt01 3534 occasionally flooded
Zone 3 - 09gtFPgt05 2328 seasonally flooded
Zone 4 - 1gtFPgt09 2152 normally flooded
Zone 5 - Panhandle 1446 Panhandle
(1) Animated sequence of flooding in the delta showing the monthly variation inflooded area and depth (The AVI format file is available from DWA sizearound 110Mb)
(2) Map based on the one kilometre grid showing the minimum depth of water in the delta for the five dry years
(3) Time series showing the variation in the depth of flooding over the five year period The depth is averaged for each of five zones (see table)
(4) Map based on the one kilometre grid showing the minimum level of soilmoisture in the root zone (the zone from which plants draw water) in thedelta over the five dry years
(5) Map based on the one kilometre grid showing the maximum depth toground water in the delta over the five dry years
(6) Summary tables are prepared showing the following
bull Water balance showing inflows outflows and storage changes
bull Baseline conditions and impacts for the surface water soilmoisture and ground water for the entire delta and for each of the five zones
A wide range of outputs of all hydrologic parameters in various formats is possibleand can be tailored to the needs of the individual stakeholders It is possible also toselect different zones to calculate average time series and summary results Theabove selection has been made by the component as samples of what may be usefuland meaningful to the stakeholders and to generate discussion
24 Baseline
Surface Water
The animated depth of flow sequence (slide 17) shows the expansion and contractionof the flooded area and depth as the sequence of flood waves for each of the fiveyears propagates through the Panhandle and spreads out through the delta Slide 18shows the detail for the lower envelope of flooding for the upper delta Each squareis one square kilometre
Time series of the depth of surface water are shown for each of the five zones in slide19 The Panhandle is the first area affected by the flood wave from upstream andbeing relatively confined within a flood plain around 20km wide has the maximumrange from the seasonal wet to dry periods around 06m through the five dry yearsAs the flood wave propagates through the delta the range in water levels declines
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The accumulated impact of the drought years is also felt more as there is a generaldecline in the flood depth
As the summary table (slide 20) shows the area flooded ranges from 1513km 2 to12077km 2 while the depth ranges from 0 to around 5m The average depth in thenormally flooded area ranges from 011m to 092m
SubSurface Water
The distribution of the soil moisture content is shown as a deficit below saturatedlevel as the lower envelope (maximum deficit) for the five year period in slide 21The average deficit ranges from 056m in the rarely flooded area to 012m in thenormally flooded area
The depth to ground water over the delta area is shown for the lower envelope(maximum depth) over the five year period in slide 22 The depth ranges from anaverage of 188m in the rarely flooded area to 037m in the normally flooded area
Water Balance
The overall water balance for the Baseline and Scenarios is shown in slide 23Negative values indicate an inflow to the delta (eg precipitation and river inflow) whilepositive values indicate an outflow (eg evapotranspiration and river outflows) TheTotal should be zero the small value indicates a very minor continuity error Thenegative overland and subsurface storage changes indicate a decline in storage inthese levels
25 Upstream Water Resources Developments
251 Introduction
To date no significant water resources developments have taken place upstream inAngola and Namibia In the past plans have been made for the construction of damsfor irrigation and hydropower Anticipating that these plans may be revived theWERRD project has run a number of scenarios using a modified rainfall-runoff modelof the basin (Pitman model Rhodes University) including a scenario for all planneddams
A number of sources describes potential irrigation in the upstream basin in Angolaand Namibia These have been reviewed and a potential scenario compiled basedon
bull Irrigation demand based on 15000m 3haa with a 25 return flow
bull Irrigated area in Angola 54500ha in Namibia 7500ha
bull Angola grows vegetables in winter (June to October) Namibia growsmaize in summer (December to April)
The corresponding runoff from the upstream basin has been applied under twoscenarios Dams in Angola and Irrigation as inflow to the delta upstream The twopotential developments are kept separate for the purpose of initial appraisal in order that the impact from each can be identified This will assist in minimising the adverseimpacts from these developments
252 Dams in Angola
The impact of the previously planned hydropower dams in Angola on the inflow to the
delta is presented in slide 24 Hydropower development does not consume waterbut stores water in the flood period for release in the dry period This results in a
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redistribution of the natural hydrograph flood flows are reduced while dry seasonflows are increased (The impact appears only to be significant in 1993 and 1996 ndashthis needs further investigation)
The impact of the dams on the surface and subsurface waters of the delta is minimalgiven the limited apparent impact in three out of the five dry years and the fact that
there is no nett water loss in the basin upstream
253 Irrigation
The impact of the potential irrigation scenario on the inflow to the delta is shown inslide 25 The impact is greatest in the dry period when water is withdrawn for therelatively large area of winter crops in Angola The summer withdrawals for irrigationin Namibia are significantly less
Correspondingly the impact on the delta in the flood period is minimal while in thedry period the overland depth of flow is reduced particularly in the Panhandle andnormally flooded areas and the minimum flood extent is reduced by 660km 2 or 40of the present dry period area (slide 26)
26 Abstractions from DeltaWater for largely local domestic use is abstracted from both the surface and groundwaters of the delta The surface water abstractions are based on water rights issuedby DWA (ie the amount which may legitimately be withdrawn ndash actual withdrawals arenot monitored and may be greater or less than allowed) Ground water abstractionsare based on the demands projected from historic information to the present day
In terms of the inflows to the delta (river flows from the basin upstream andprecipitation over the basin the abstractions and corresponding impacts are minimalSurface water abstraction represents 0006 of the inflow and ground water 02In the five dry years analysed the minimum flooded area is reduced by 025Future scenario runs will simulate the impact of abstractions with projected increasedpopulation and rates of consumption to the notional year 2025
27 Climate ChangePotential climate change will have an impact on the delta in respect of inflows fromthe basin upstream and the climate over the delta The WERRD project has run aglobal climate model HadCM3 1 to predict the changed precipitation and temperatureover the basin For the upstream basin the Pitman rainfall-runoff model has beenapplied to predict the modified inflows upstream of the delta (slide 27) The modifiedprecipitation and temperature over the delta have been used as direct inputs to theIntegrated Hydrologic Model (slide 28)
The impact of the climate change scenario is highly significant in both the flood anddry seasons River inflows to the delta are reduced by 38 and precipitation over the delta by 9 Temperature increases by 22ordmC
The corresponding impact on flow depths is shown on the reduced depths the impacton the minimum depths is shown for the Panhandle and normally flooded areas inslide 29 and in each of the five zones through the five year run period in slide 30The reduction in depth averages 003m over the entire delta and the minimumflooded area is almost halved
1 httpwwwmet-officegovukresearchhadleycentremodelsHadCM3html
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28 Management PlanningThe model analyses are carried out to assess the impacts of possible future basinconditions on the delta for the purposes of management planning An iterativeprocess is envisaged with a series of bilateral meetings with the Stakeholders andcommon Workshops in which the inputs and outputs are presented to and discussedwith the stakeholders The outputs can migrate towards a presentation format that isboth meaningful and relevant to the stakeholders
The Hydrology and Water Resources component will only analyse the impacts on thewaters of the delta DWA and its consultants do not have the capability or theresources to analyse the impacts on the wildlife vegetation livestock fisheries or tourists It is up to these respective sectors to assess these impacts based on thechanged delta hydrology
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3 DISCUSSION
31 IntroductionThe following sections record the comments made on the foregoing presentationsand the responses given by the hydrology team (in italics)
32 Database Management(1) What is lithology Remember that as much as you are speaking to experts
you are also speaking to non-experts
The point is well taken A glossary will be prepared to explain technical terms
(2) The presentations are too fast and we need details of the graphs for example
This point is also noted presentations should emphasise important pointsSelected slides from the Workshop are included in Annex 3 and a full report is being prepared of both the Integrated Hydrologic Model and the
preliminary scenario analysis These should be studied by thestakeholders in advance of further (bilateral) discussions
(3) Is there a slide to show locations of critical rainfall and flow stations so thatwe could appreciate all the difficulties encountered We would appreciatemuch if we could have locations of all your data sources
The locations of the existing and proposed gauging stations is available inDWA in GIS format The key source for this and information from other sectors and stakeholders will be the Okavango Delta Information System
implemented in HOORC
33 Integrated Hydrologic Model(1) I like your conceptual model but what is applicable in Europe may not
necessarily be applicable here also
The conceptual model is fundamental to the development of a numerical model The conceptual model is strictly formulated for the Okavango Deltabased on available data and scientific publications on the subject Theconceptual model has no relation to European or other climatic conditions
(2) Your evapotranspiration rates are higher than those from Class A pan whenactually the reverse should be true This should be looked into
Actual rates of evapotranspiration (ET) are not necessarily lower than panevaporation owing to a number of factors including pan correction methodcombined free surface ET and vegetation transpiration in flood plains and actual location in the delta versus the location of pan measurements If new documented field data on ET losses are available the hydrology teamwould be happy compare these to model simulations
(3) Is there any physical evidence of flooding
The assessment of the observed flood extent has been based mainly on ananalysis of satellite images from 1984 to 2000 (J McCarthy StockholmUniversity) and DWA water level observations
(4) How do you parameterize your flow in respect to flow resistance
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The Manning resistance coefficient is used to describe the resistance toflow in the river channels and over the flood plains Values for overland flow are distributed according to three vegetation zones based onvegetation mapping (S Ringrose HOORC) Values in the river channelsare ascribed based on channel vegetation descriptions (Dr CK NaiduDWA) Adjustments are made to give a good match with observed flood extent overall water balance and downstream discharges
(5) Your climate input data comprise rainfall evapotranspiration etc fromMaun and Shakawe To what extent can one use a physically based modelwith such a coarse resolution Could we conclude that this is an empiricalmodel
MIKE SHE is a physically based model which implies that the model parameters have a clear physical interpretation as opposed to lumped conceptual models Data measured in single locations may be used toassign parameter values but the parameters used at the current grid scaleof 1km 2 should be regarded as lsquoefficientrsquo parameters representing the
aggregated responseThe lack of input data on distributed rainfall or any other model input doesnot imply that the MIKE SHE model is empirical Maun and Shakawe arethe only two stations in and adjacent to the delta with reliable data Thedelta is not a conventional catchment area where the runoff from individual subcatchments is essential to arrive at the combined flow in themainstream Overland flows mix the runoff from the subcatchments and evapotranspiration dominates Thus a high resolution of the rainfall data isnot of major importance in a general flow model of the delta Nonethelessrecommendations for improved monitoring include rehabilitation of the eight DCPs which measure rainfall and the installation of an additional eight automatic gauges in the delta
(6) Our confidence on the model cannot be based on your numbers
This particular comment was based on relatively consistent outflows for theBaseline and Scenarios This was owing to the nature of the downstreamboundary condition which has since been improved and now shows avariation
The flow leaving the delta (and the model) has passed through anextremely complex hydrologic system flood propagation flow splits among distributaries spills to vast flood plains and swamps evapotranspirationand infiltration The measurement of the discharge upstream is subject toerrors of at least 10 (say 50m 3 s at the flood peak) Differences between
the model computations and the observations cannot better this(7) What resolution should we have confidence on as it pertains to your
model
Given the complexity of the area and the available data model resultsshould not be interpreted looking at single grid values Interpretation based on delta zones or subsystems is more appropriate Five zones based onflood probability have been applied in the scenario demonstration runs and others may be devised according to stakeholdersrsquo needs The minimumarea should cover several square kilometres
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34 Scenarios(1) You have run the scenarios based on dry period(s) Could you please
revise this You might be missing out on recharge to groundwater as aresult of high floods A single high flood could recharge an aquifer for thenext twenty years for example
It is the intention to run the model for a period of normal flows to see how the delta recovers from a drought As suggested the model will also be runfor high floods (this is also important for sediment transport in the delta)
(2) In taking the dry period as critical you have to consider floods as alsocritical Floods need to be covered as well
The delta is not under stress during high flow periods and the impacts of water resources developments will not be so keenly felt and therefore not critical to management planning See also response to (1) above
(3) People are more worried about the switching of channels Maybe thisaspect needs to come out in your model outputs as well
The introduction of sediment transport to the model (which has just commenced) will give an indication of possible future switches and redistribution of delta flows Switching and realignment of channels has achaotic component (the butterfly effect on global climate is akin to ahippopotamus going walkabout in the delta) and accurate predictions aresimply not possible
(4) Looking at the modelrsquos level of resolution critical management issues willnot be answered
The component has been conceived and ToR written (in 200102) toaddress the broad scale management planning issues (water resources
developments upstream climate change abstractions from the delta reed cutting and dredging) On this basis the model approach has been set outand the model set up and applied Preliminary applications suggest that the main threats to the delta will arise from upstream irrigation and climatechange These are the critical management issues related to hydrology
(5) Channel blockages impacts need to be covered in detail Channel switchingis another fundamental management issue
The model can simulate the impact of channel blockages and channel switching As discussed in (3) above the model cannot predict theseoccurrences
(6) You mentioned that your model could handle sediment transport Do youhave something on sediment transport now
An approach to introducing sediment transport to the model has beendrafted (pending report on the Integrated Hydrologic Model)
(7) You seem not to be representing your conditions
See response to (6) above
35 Presentation of Results(1) You canrsquot have a reduction of flow by 40 and yet have no impact on the
outflow This gives me the confidence of your model
See response to (4) above
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(2) The difference in long-term average discharge between observed andsimulations should not be taken to be insignificant This should becombined with other scenarios to better appreciate its impact
It is important in the preliminary stage to separate the impacts fromindividual water resources developments to obtain a good understanding of
which are critical and which are not A limited number of combinationscenarios may be run at a later stage once these can be defined and agreed by the management planners and stakeholders
(3) It would be good to combine all the scenarios as well
See (2) above
(4) It would be interesting also to look at frequency and duration of flooding
The impact on the duration of flooding can be assessed through the timeseries plots for different zones An estimate can also be made on theimpact of the scenarios on the frequency of flooding
(5) What is the model doing as it pertains to erosion and sedimentation
Sediment transport is being introduced to the model This will enable theassessment of the broad pattern of erosion and deposition through themain river channels along which the bed load is conveyed from the basinupstream
(6) The issue of land use change has to be incorporated into the model
To introduce the impact of land use changes in the basin upstream requiresthe application of a water resources planning model to the upstream basinThis is not within the present scope of ODMP which is relying on theoutputs of basinwide projects such as Sharing Water and WERRD (bothcompleted) and possibly in the future TwinBas (ongoing) If ODMP
partners suggest particular potential land use changes within the deltawhich have an impact on the hydrology these may be simulated using theIntegrated Hydrologic Model
(7) The presentations have mostly been technical I would like to suggest thatwe make handouts available after the workshop so that the participantscould have ample time to go over them and later submit their suggestionscomments and or questions
This document represents a full report on the proceedings Further comments from ODMP partners are welcome that our further work may more closely meet the needs of delta management planning Further discussions will be held with the stakeholders on the ongoing model applications possibly on a bilateral basis to obtain a closer understanding of particular needs and ways to meet these needs
36 Stakeholdersrsquo Responses
Wildlife
(1) We need drying flood plain map to better track movement of wild animals
The drying and wetting of the flood plains was presented as animated sequences in the Workshop for all scenarios with a monthly time step Afiner temporal resolution can be prepared (down to four hours) though the
spatial resolution is limited to one kilometre squares
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(2) We would appreciate information on correlations between the distribution of elephants population and extent of flooding close to the buffalo fence
The HampWR component can provide information on the waters of the deltaIt is up to the individual partners to analyse this information for their ownneeds The HampWR component cannot be expected to carry out all the
analyses for the management planThe integration of information from all ODMP components will be carried out within the Okavango Delta Information System implemented inHOORC (also with support from Danida)
Fisheries
(1) Water quality is very critical as this have impact on fish populationdynamics Sedimentation is also critical as it has a bearing on fishpopulations
Sedimentation is indeed critical to fish populations as fine organic richsediment is washed out from the flood plain into the channels by the flood waters resulting in oxygen depletion
The MIKE SHE integrated hydrologic modelling system has the capability tosimulate water quality This is not within the present scope of ODMPSystematic data (including DO and SOD) do not exist at present on whichto develop such a model Improved monitoring recommendations includethe introduction of systematic sampling and analysis at the key inflow station of Mohembo and monthly in-situ measurements of salinity and pH at around 20 discharge stations throughout the delta
Water Affairs
(1) Is MIKE SHE an instrument or whatMIKE SHE is one of a suite of water and environmental software packagesdeveloped and marketed commercially by DHI Water and EnvironmentThe MIKE SHE package is the most advanced generic (can be applied toany system) hydrologic software available MIKE SHE has a consistent development history over thirty years and has been applied to hundreds of hydrologic systems worldwide
(2) Can the model predict channel shifts
The sediment transport model will predict erosion and deposition leading tochannel aggradation and eventual closure The delta morphology isinherently unstable and chaotic and no model can predict channel abandonment with higher certainty than what is constrained by natural variability (chaos) Nonetheless the impact of major channel shifts can be
predicted as well as possible management measures to mitigate suchshifts
(3) Mr Dikgomo mentioned that Hydrology and Water Resources component isone of the twelve What are the other eleven components
The CTA may best respond to this question though it is suggested that representatives from participating organisations take the trouble to informthemselves of the ODMP structure objectives and outputs before attending such fora
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Land Board
(1) Is it possible for the model to give us depth of water table within at least500 metres from the delta This can help us with land use This will alsohelp us determine how far we can avoid pollution in land allocations
The spatial resolution of the model is one square kilometre The model cangive the various hydrologic parameters such a depth to ground water withinthe general area (within a few square kilometres) This should be quiteadequate for the purpose of broad based management planning
(2) Can the model add value to Tawana land board land use and managementplan (2004-2029)
The Hydrology and Water Resources component is concerned withhydrology and water resources The outputs from the component arehydrologic data and predictions for the delta It is up to the various sectorsand components of the management plan to assess the impact of thesehydrologic parameters for their own purposes The HampWR component can
assist in the interpretation of the hydrologic dataTourism
(1) There are lodges and camps located close to the river channels Can themodel be able to help on the implications of pollution
The model can simulate the pattern of flow in the delta which may give auseful indication of the movement of pollution though not the output whichmay be given by a water quality model (advection dispersion decay etc)
General
(1) This component (Hydrology and Water Resources) is so detached from therest It should relocate to MaunThe component is located in Gaborone as the capital has better infrastructure Progress on the component would be constrained by thelimited infrastructure in Maun
(2) To what extent is your data real time series that it could be relied upon
The data available from the delta at present are poor largely owing todifficulties in access and disturbance of gauging stations by humans and large mammalian wildlife Lack of systematic use of the data to date havealso contributed to neglect Improved monitoring is necessary for management planning and an improved hydrologic model with finer
resolution and greater accuracy Recommendations have been prepared for DWA to improve hydrologic monitoring and it is hoped these can beimplemented in the course of 2005
(3) The presentations are too technical When will ODMP reach out to usSomeone mentioned that communication and or information disseminationis a problem Why cant we find other Batswana who could do the job toconvey the information in an audience screened and targeted way
The hydrology of the delta is complex and requires a complex model for arealistic simulation of the processes The presentations were intended togive all participants an understanding that the model is indeed capable of simulating the key hydrologic phenomena of the delta It is hoped that this
has been achieved though it is recognised that the depth of understanding
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will depend upon the level of the individual participantrsquos hydrologic knowledge
The DWA staff assigned to ODMP will gradually take over presentations insuch fora as part of the process of technology transfer which is anessential part of the component
Lessons have been learnt from this Workshop A second and possibly third Workshop will be planned along with bilateral meetings with the individual Stakeholders hopefully improving the communication to the diverse
participants (see Conclusions)
(4) Communications and networking is lagging behind but its pro-activeness isso crucial The component would simplify information and relay it tocommunity andor stakeholders
The HampWR component looks forward to this component being activatedand to cooperating with the Communications and Networking component in
presenting results of the hydrologic analyses meaningful to all
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4 CONCLUSIONS
41 SummaryProf Francis Sefe from the consultantsrsquo team summarised the Workshop discussionas follows
(1) There were discussions on both spatial and temporal resolutions of themodel which need clarification
(2) It was observed that data quality and availability is a constraint to accuratemodelling of the hydrology of the delta and providing physical evidence toback the model conclusions
(3) In the selection of scenarios it is critical to understand that the individualscenarios are not stand alone
(4) The choice of what constitutes the baseline scenario was discussed It hasto be emphasised that the inclusion of exceptional floods is also importantand hence not only the dry period should be used
(5) The presentation was multifaceted
(6) People could not easily locate any landmark features on the map Thisneed not be Villages could be labelled and even the rivers themselves
(7) Though water quality is not in the scope of the current modelling water quality is very important and this has to be looked into in the future
(8) Ground water fluctuations at the periphery of the delta need to be lookedinto
(9) Various stakeholders have difficulty interpreting the results This is a critical
issue that needs to be addressed The target audience should reasonablybe able to assimilate the information relayed to them
42 RecommendationsThe following recommendations are made with regard to the future interactionbetween the Hydrology and Water Resources component and the other ODMPparticipants
(1) While the introductions to the set up and application of the IntegratedHydrologic Model attempted to convey the complexity of the deltahydrology and its computer based representation further effort needs to bemade to present the model and its results in a manner which is fullycomprehensible to the Stakeholders most of whom do not have in depthhydrologic knowledge
(2) It was originally believed that presentation of the model to Stakeholders in acombined forum would allow the interchange of ideas and knowledgeamong the Stakeholders as well as with the Hydrology and Water Resources component The resulting discussion tended to be dominatedby those with technical hydrologic knowledge at the expense of thosewithout The next round of discussions should be on a bilateral basis suchthat the discussions can proceed at a level appropriate for the individualStakeholders and their needs in respect of hydrology and water resources
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(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
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ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
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ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
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Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
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Hydrology and Water Resources Okavango
Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
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Hydrology and Water Resources Okavango Delta Management Plan
ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
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The accumulated impact of the drought years is also felt more as there is a generaldecline in the flood depth
As the summary table (slide 20) shows the area flooded ranges from 1513km 2 to12077km 2 while the depth ranges from 0 to around 5m The average depth in thenormally flooded area ranges from 011m to 092m
SubSurface Water
The distribution of the soil moisture content is shown as a deficit below saturatedlevel as the lower envelope (maximum deficit) for the five year period in slide 21The average deficit ranges from 056m in the rarely flooded area to 012m in thenormally flooded area
The depth to ground water over the delta area is shown for the lower envelope(maximum depth) over the five year period in slide 22 The depth ranges from anaverage of 188m in the rarely flooded area to 037m in the normally flooded area
Water Balance
The overall water balance for the Baseline and Scenarios is shown in slide 23Negative values indicate an inflow to the delta (eg precipitation and river inflow) whilepositive values indicate an outflow (eg evapotranspiration and river outflows) TheTotal should be zero the small value indicates a very minor continuity error Thenegative overland and subsurface storage changes indicate a decline in storage inthese levels
25 Upstream Water Resources Developments
251 Introduction
To date no significant water resources developments have taken place upstream inAngola and Namibia In the past plans have been made for the construction of damsfor irrigation and hydropower Anticipating that these plans may be revived theWERRD project has run a number of scenarios using a modified rainfall-runoff modelof the basin (Pitman model Rhodes University) including a scenario for all planneddams
A number of sources describes potential irrigation in the upstream basin in Angolaand Namibia These have been reviewed and a potential scenario compiled basedon
bull Irrigation demand based on 15000m 3haa with a 25 return flow
bull Irrigated area in Angola 54500ha in Namibia 7500ha
bull Angola grows vegetables in winter (June to October) Namibia growsmaize in summer (December to April)
The corresponding runoff from the upstream basin has been applied under twoscenarios Dams in Angola and Irrigation as inflow to the delta upstream The twopotential developments are kept separate for the purpose of initial appraisal in order that the impact from each can be identified This will assist in minimising the adverseimpacts from these developments
252 Dams in Angola
The impact of the previously planned hydropower dams in Angola on the inflow to the
delta is presented in slide 24 Hydropower development does not consume waterbut stores water in the flood period for release in the dry period This results in a
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redistribution of the natural hydrograph flood flows are reduced while dry seasonflows are increased (The impact appears only to be significant in 1993 and 1996 ndashthis needs further investigation)
The impact of the dams on the surface and subsurface waters of the delta is minimalgiven the limited apparent impact in three out of the five dry years and the fact that
there is no nett water loss in the basin upstream
253 Irrigation
The impact of the potential irrigation scenario on the inflow to the delta is shown inslide 25 The impact is greatest in the dry period when water is withdrawn for therelatively large area of winter crops in Angola The summer withdrawals for irrigationin Namibia are significantly less
Correspondingly the impact on the delta in the flood period is minimal while in thedry period the overland depth of flow is reduced particularly in the Panhandle andnormally flooded areas and the minimum flood extent is reduced by 660km 2 or 40of the present dry period area (slide 26)
26 Abstractions from DeltaWater for largely local domestic use is abstracted from both the surface and groundwaters of the delta The surface water abstractions are based on water rights issuedby DWA (ie the amount which may legitimately be withdrawn ndash actual withdrawals arenot monitored and may be greater or less than allowed) Ground water abstractionsare based on the demands projected from historic information to the present day
In terms of the inflows to the delta (river flows from the basin upstream andprecipitation over the basin the abstractions and corresponding impacts are minimalSurface water abstraction represents 0006 of the inflow and ground water 02In the five dry years analysed the minimum flooded area is reduced by 025Future scenario runs will simulate the impact of abstractions with projected increasedpopulation and rates of consumption to the notional year 2025
27 Climate ChangePotential climate change will have an impact on the delta in respect of inflows fromthe basin upstream and the climate over the delta The WERRD project has run aglobal climate model HadCM3 1 to predict the changed precipitation and temperatureover the basin For the upstream basin the Pitman rainfall-runoff model has beenapplied to predict the modified inflows upstream of the delta (slide 27) The modifiedprecipitation and temperature over the delta have been used as direct inputs to theIntegrated Hydrologic Model (slide 28)
The impact of the climate change scenario is highly significant in both the flood anddry seasons River inflows to the delta are reduced by 38 and precipitation over the delta by 9 Temperature increases by 22ordmC
The corresponding impact on flow depths is shown on the reduced depths the impacton the minimum depths is shown for the Panhandle and normally flooded areas inslide 29 and in each of the five zones through the five year run period in slide 30The reduction in depth averages 003m over the entire delta and the minimumflooded area is almost halved
1 httpwwwmet-officegovukresearchhadleycentremodelsHadCM3html
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28 Management PlanningThe model analyses are carried out to assess the impacts of possible future basinconditions on the delta for the purposes of management planning An iterativeprocess is envisaged with a series of bilateral meetings with the Stakeholders andcommon Workshops in which the inputs and outputs are presented to and discussedwith the stakeholders The outputs can migrate towards a presentation format that isboth meaningful and relevant to the stakeholders
The Hydrology and Water Resources component will only analyse the impacts on thewaters of the delta DWA and its consultants do not have the capability or theresources to analyse the impacts on the wildlife vegetation livestock fisheries or tourists It is up to these respective sectors to assess these impacts based on thechanged delta hydrology
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3 DISCUSSION
31 IntroductionThe following sections record the comments made on the foregoing presentationsand the responses given by the hydrology team (in italics)
32 Database Management(1) What is lithology Remember that as much as you are speaking to experts
you are also speaking to non-experts
The point is well taken A glossary will be prepared to explain technical terms
(2) The presentations are too fast and we need details of the graphs for example
This point is also noted presentations should emphasise important pointsSelected slides from the Workshop are included in Annex 3 and a full report is being prepared of both the Integrated Hydrologic Model and the
preliminary scenario analysis These should be studied by thestakeholders in advance of further (bilateral) discussions
(3) Is there a slide to show locations of critical rainfall and flow stations so thatwe could appreciate all the difficulties encountered We would appreciatemuch if we could have locations of all your data sources
The locations of the existing and proposed gauging stations is available inDWA in GIS format The key source for this and information from other sectors and stakeholders will be the Okavango Delta Information System
implemented in HOORC
33 Integrated Hydrologic Model(1) I like your conceptual model but what is applicable in Europe may not
necessarily be applicable here also
The conceptual model is fundamental to the development of a numerical model The conceptual model is strictly formulated for the Okavango Deltabased on available data and scientific publications on the subject Theconceptual model has no relation to European or other climatic conditions
(2) Your evapotranspiration rates are higher than those from Class A pan whenactually the reverse should be true This should be looked into
Actual rates of evapotranspiration (ET) are not necessarily lower than panevaporation owing to a number of factors including pan correction methodcombined free surface ET and vegetation transpiration in flood plains and actual location in the delta versus the location of pan measurements If new documented field data on ET losses are available the hydrology teamwould be happy compare these to model simulations
(3) Is there any physical evidence of flooding
The assessment of the observed flood extent has been based mainly on ananalysis of satellite images from 1984 to 2000 (J McCarthy StockholmUniversity) and DWA water level observations
(4) How do you parameterize your flow in respect to flow resistance
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The Manning resistance coefficient is used to describe the resistance toflow in the river channels and over the flood plains Values for overland flow are distributed according to three vegetation zones based onvegetation mapping (S Ringrose HOORC) Values in the river channelsare ascribed based on channel vegetation descriptions (Dr CK NaiduDWA) Adjustments are made to give a good match with observed flood extent overall water balance and downstream discharges
(5) Your climate input data comprise rainfall evapotranspiration etc fromMaun and Shakawe To what extent can one use a physically based modelwith such a coarse resolution Could we conclude that this is an empiricalmodel
MIKE SHE is a physically based model which implies that the model parameters have a clear physical interpretation as opposed to lumped conceptual models Data measured in single locations may be used toassign parameter values but the parameters used at the current grid scaleof 1km 2 should be regarded as lsquoefficientrsquo parameters representing the
aggregated responseThe lack of input data on distributed rainfall or any other model input doesnot imply that the MIKE SHE model is empirical Maun and Shakawe arethe only two stations in and adjacent to the delta with reliable data Thedelta is not a conventional catchment area where the runoff from individual subcatchments is essential to arrive at the combined flow in themainstream Overland flows mix the runoff from the subcatchments and evapotranspiration dominates Thus a high resolution of the rainfall data isnot of major importance in a general flow model of the delta Nonethelessrecommendations for improved monitoring include rehabilitation of the eight DCPs which measure rainfall and the installation of an additional eight automatic gauges in the delta
(6) Our confidence on the model cannot be based on your numbers
This particular comment was based on relatively consistent outflows for theBaseline and Scenarios This was owing to the nature of the downstreamboundary condition which has since been improved and now shows avariation
The flow leaving the delta (and the model) has passed through anextremely complex hydrologic system flood propagation flow splits among distributaries spills to vast flood plains and swamps evapotranspirationand infiltration The measurement of the discharge upstream is subject toerrors of at least 10 (say 50m 3 s at the flood peak) Differences between
the model computations and the observations cannot better this(7) What resolution should we have confidence on as it pertains to your
model
Given the complexity of the area and the available data model resultsshould not be interpreted looking at single grid values Interpretation based on delta zones or subsystems is more appropriate Five zones based onflood probability have been applied in the scenario demonstration runs and others may be devised according to stakeholdersrsquo needs The minimumarea should cover several square kilometres
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34 Scenarios(1) You have run the scenarios based on dry period(s) Could you please
revise this You might be missing out on recharge to groundwater as aresult of high floods A single high flood could recharge an aquifer for thenext twenty years for example
It is the intention to run the model for a period of normal flows to see how the delta recovers from a drought As suggested the model will also be runfor high floods (this is also important for sediment transport in the delta)
(2) In taking the dry period as critical you have to consider floods as alsocritical Floods need to be covered as well
The delta is not under stress during high flow periods and the impacts of water resources developments will not be so keenly felt and therefore not critical to management planning See also response to (1) above
(3) People are more worried about the switching of channels Maybe thisaspect needs to come out in your model outputs as well
The introduction of sediment transport to the model (which has just commenced) will give an indication of possible future switches and redistribution of delta flows Switching and realignment of channels has achaotic component (the butterfly effect on global climate is akin to ahippopotamus going walkabout in the delta) and accurate predictions aresimply not possible
(4) Looking at the modelrsquos level of resolution critical management issues willnot be answered
The component has been conceived and ToR written (in 200102) toaddress the broad scale management planning issues (water resources
developments upstream climate change abstractions from the delta reed cutting and dredging) On this basis the model approach has been set outand the model set up and applied Preliminary applications suggest that the main threats to the delta will arise from upstream irrigation and climatechange These are the critical management issues related to hydrology
(5) Channel blockages impacts need to be covered in detail Channel switchingis another fundamental management issue
The model can simulate the impact of channel blockages and channel switching As discussed in (3) above the model cannot predict theseoccurrences
(6) You mentioned that your model could handle sediment transport Do youhave something on sediment transport now
An approach to introducing sediment transport to the model has beendrafted (pending report on the Integrated Hydrologic Model)
(7) You seem not to be representing your conditions
See response to (6) above
35 Presentation of Results(1) You canrsquot have a reduction of flow by 40 and yet have no impact on the
outflow This gives me the confidence of your model
See response to (4) above
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(2) The difference in long-term average discharge between observed andsimulations should not be taken to be insignificant This should becombined with other scenarios to better appreciate its impact
It is important in the preliminary stage to separate the impacts fromindividual water resources developments to obtain a good understanding of
which are critical and which are not A limited number of combinationscenarios may be run at a later stage once these can be defined and agreed by the management planners and stakeholders
(3) It would be good to combine all the scenarios as well
See (2) above
(4) It would be interesting also to look at frequency and duration of flooding
The impact on the duration of flooding can be assessed through the timeseries plots for different zones An estimate can also be made on theimpact of the scenarios on the frequency of flooding
(5) What is the model doing as it pertains to erosion and sedimentation
Sediment transport is being introduced to the model This will enable theassessment of the broad pattern of erosion and deposition through themain river channels along which the bed load is conveyed from the basinupstream
(6) The issue of land use change has to be incorporated into the model
To introduce the impact of land use changes in the basin upstream requiresthe application of a water resources planning model to the upstream basinThis is not within the present scope of ODMP which is relying on theoutputs of basinwide projects such as Sharing Water and WERRD (bothcompleted) and possibly in the future TwinBas (ongoing) If ODMP
partners suggest particular potential land use changes within the deltawhich have an impact on the hydrology these may be simulated using theIntegrated Hydrologic Model
(7) The presentations have mostly been technical I would like to suggest thatwe make handouts available after the workshop so that the participantscould have ample time to go over them and later submit their suggestionscomments and or questions
This document represents a full report on the proceedings Further comments from ODMP partners are welcome that our further work may more closely meet the needs of delta management planning Further discussions will be held with the stakeholders on the ongoing model applications possibly on a bilateral basis to obtain a closer understanding of particular needs and ways to meet these needs
36 Stakeholdersrsquo Responses
Wildlife
(1) We need drying flood plain map to better track movement of wild animals
The drying and wetting of the flood plains was presented as animated sequences in the Workshop for all scenarios with a monthly time step Afiner temporal resolution can be prepared (down to four hours) though the
spatial resolution is limited to one kilometre squares
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(2) We would appreciate information on correlations between the distribution of elephants population and extent of flooding close to the buffalo fence
The HampWR component can provide information on the waters of the deltaIt is up to the individual partners to analyse this information for their ownneeds The HampWR component cannot be expected to carry out all the
analyses for the management planThe integration of information from all ODMP components will be carried out within the Okavango Delta Information System implemented inHOORC (also with support from Danida)
Fisheries
(1) Water quality is very critical as this have impact on fish populationdynamics Sedimentation is also critical as it has a bearing on fishpopulations
Sedimentation is indeed critical to fish populations as fine organic richsediment is washed out from the flood plain into the channels by the flood waters resulting in oxygen depletion
The MIKE SHE integrated hydrologic modelling system has the capability tosimulate water quality This is not within the present scope of ODMPSystematic data (including DO and SOD) do not exist at present on whichto develop such a model Improved monitoring recommendations includethe introduction of systematic sampling and analysis at the key inflow station of Mohembo and monthly in-situ measurements of salinity and pH at around 20 discharge stations throughout the delta
Water Affairs
(1) Is MIKE SHE an instrument or whatMIKE SHE is one of a suite of water and environmental software packagesdeveloped and marketed commercially by DHI Water and EnvironmentThe MIKE SHE package is the most advanced generic (can be applied toany system) hydrologic software available MIKE SHE has a consistent development history over thirty years and has been applied to hundreds of hydrologic systems worldwide
(2) Can the model predict channel shifts
The sediment transport model will predict erosion and deposition leading tochannel aggradation and eventual closure The delta morphology isinherently unstable and chaotic and no model can predict channel abandonment with higher certainty than what is constrained by natural variability (chaos) Nonetheless the impact of major channel shifts can be
predicted as well as possible management measures to mitigate suchshifts
(3) Mr Dikgomo mentioned that Hydrology and Water Resources component isone of the twelve What are the other eleven components
The CTA may best respond to this question though it is suggested that representatives from participating organisations take the trouble to informthemselves of the ODMP structure objectives and outputs before attending such fora
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Land Board
(1) Is it possible for the model to give us depth of water table within at least500 metres from the delta This can help us with land use This will alsohelp us determine how far we can avoid pollution in land allocations
The spatial resolution of the model is one square kilometre The model cangive the various hydrologic parameters such a depth to ground water withinthe general area (within a few square kilometres) This should be quiteadequate for the purpose of broad based management planning
(2) Can the model add value to Tawana land board land use and managementplan (2004-2029)
The Hydrology and Water Resources component is concerned withhydrology and water resources The outputs from the component arehydrologic data and predictions for the delta It is up to the various sectorsand components of the management plan to assess the impact of thesehydrologic parameters for their own purposes The HampWR component can
assist in the interpretation of the hydrologic dataTourism
(1) There are lodges and camps located close to the river channels Can themodel be able to help on the implications of pollution
The model can simulate the pattern of flow in the delta which may give auseful indication of the movement of pollution though not the output whichmay be given by a water quality model (advection dispersion decay etc)
General
(1) This component (Hydrology and Water Resources) is so detached from therest It should relocate to MaunThe component is located in Gaborone as the capital has better infrastructure Progress on the component would be constrained by thelimited infrastructure in Maun
(2) To what extent is your data real time series that it could be relied upon
The data available from the delta at present are poor largely owing todifficulties in access and disturbance of gauging stations by humans and large mammalian wildlife Lack of systematic use of the data to date havealso contributed to neglect Improved monitoring is necessary for management planning and an improved hydrologic model with finer
resolution and greater accuracy Recommendations have been prepared for DWA to improve hydrologic monitoring and it is hoped these can beimplemented in the course of 2005
(3) The presentations are too technical When will ODMP reach out to usSomeone mentioned that communication and or information disseminationis a problem Why cant we find other Batswana who could do the job toconvey the information in an audience screened and targeted way
The hydrology of the delta is complex and requires a complex model for arealistic simulation of the processes The presentations were intended togive all participants an understanding that the model is indeed capable of simulating the key hydrologic phenomena of the delta It is hoped that this
has been achieved though it is recognised that the depth of understanding
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will depend upon the level of the individual participantrsquos hydrologic knowledge
The DWA staff assigned to ODMP will gradually take over presentations insuch fora as part of the process of technology transfer which is anessential part of the component
Lessons have been learnt from this Workshop A second and possibly third Workshop will be planned along with bilateral meetings with the individual Stakeholders hopefully improving the communication to the diverse
participants (see Conclusions)
(4) Communications and networking is lagging behind but its pro-activeness isso crucial The component would simplify information and relay it tocommunity andor stakeholders
The HampWR component looks forward to this component being activatedand to cooperating with the Communications and Networking component in
presenting results of the hydrologic analyses meaningful to all
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4 CONCLUSIONS
41 SummaryProf Francis Sefe from the consultantsrsquo team summarised the Workshop discussionas follows
(1) There were discussions on both spatial and temporal resolutions of themodel which need clarification
(2) It was observed that data quality and availability is a constraint to accuratemodelling of the hydrology of the delta and providing physical evidence toback the model conclusions
(3) In the selection of scenarios it is critical to understand that the individualscenarios are not stand alone
(4) The choice of what constitutes the baseline scenario was discussed It hasto be emphasised that the inclusion of exceptional floods is also importantand hence not only the dry period should be used
(5) The presentation was multifaceted
(6) People could not easily locate any landmark features on the map Thisneed not be Villages could be labelled and even the rivers themselves
(7) Though water quality is not in the scope of the current modelling water quality is very important and this has to be looked into in the future
(8) Ground water fluctuations at the periphery of the delta need to be lookedinto
(9) Various stakeholders have difficulty interpreting the results This is a critical
issue that needs to be addressed The target audience should reasonablybe able to assimilate the information relayed to them
42 RecommendationsThe following recommendations are made with regard to the future interactionbetween the Hydrology and Water Resources component and the other ODMPparticipants
(1) While the introductions to the set up and application of the IntegratedHydrologic Model attempted to convey the complexity of the deltahydrology and its computer based representation further effort needs to bemade to present the model and its results in a manner which is fullycomprehensible to the Stakeholders most of whom do not have in depthhydrologic knowledge
(2) It was originally believed that presentation of the model to Stakeholders in acombined forum would allow the interchange of ideas and knowledgeamong the Stakeholders as well as with the Hydrology and Water Resources component The resulting discussion tended to be dominatedby those with technical hydrologic knowledge at the expense of thosewithout The next round of discussions should be on a bilateral basis suchthat the discussions can proceed at a level appropriate for the individualStakeholders and their needs in respect of hydrology and water resources
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(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
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ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
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ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
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Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
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Hydrology and Water Resources Okavango
Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
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Hydrology and Water Resources Okavango Delta Management Plan
ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
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redistribution of the natural hydrograph flood flows are reduced while dry seasonflows are increased (The impact appears only to be significant in 1993 and 1996 ndashthis needs further investigation)
The impact of the dams on the surface and subsurface waters of the delta is minimalgiven the limited apparent impact in three out of the five dry years and the fact that
there is no nett water loss in the basin upstream
253 Irrigation
The impact of the potential irrigation scenario on the inflow to the delta is shown inslide 25 The impact is greatest in the dry period when water is withdrawn for therelatively large area of winter crops in Angola The summer withdrawals for irrigationin Namibia are significantly less
Correspondingly the impact on the delta in the flood period is minimal while in thedry period the overland depth of flow is reduced particularly in the Panhandle andnormally flooded areas and the minimum flood extent is reduced by 660km 2 or 40of the present dry period area (slide 26)
26 Abstractions from DeltaWater for largely local domestic use is abstracted from both the surface and groundwaters of the delta The surface water abstractions are based on water rights issuedby DWA (ie the amount which may legitimately be withdrawn ndash actual withdrawals arenot monitored and may be greater or less than allowed) Ground water abstractionsare based on the demands projected from historic information to the present day
In terms of the inflows to the delta (river flows from the basin upstream andprecipitation over the basin the abstractions and corresponding impacts are minimalSurface water abstraction represents 0006 of the inflow and ground water 02In the five dry years analysed the minimum flooded area is reduced by 025Future scenario runs will simulate the impact of abstractions with projected increasedpopulation and rates of consumption to the notional year 2025
27 Climate ChangePotential climate change will have an impact on the delta in respect of inflows fromthe basin upstream and the climate over the delta The WERRD project has run aglobal climate model HadCM3 1 to predict the changed precipitation and temperatureover the basin For the upstream basin the Pitman rainfall-runoff model has beenapplied to predict the modified inflows upstream of the delta (slide 27) The modifiedprecipitation and temperature over the delta have been used as direct inputs to theIntegrated Hydrologic Model (slide 28)
The impact of the climate change scenario is highly significant in both the flood anddry seasons River inflows to the delta are reduced by 38 and precipitation over the delta by 9 Temperature increases by 22ordmC
The corresponding impact on flow depths is shown on the reduced depths the impacton the minimum depths is shown for the Panhandle and normally flooded areas inslide 29 and in each of the five zones through the five year run period in slide 30The reduction in depth averages 003m over the entire delta and the minimumflooded area is almost halved
1 httpwwwmet-officegovukresearchhadleycentremodelsHadCM3html
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28 Management PlanningThe model analyses are carried out to assess the impacts of possible future basinconditions on the delta for the purposes of management planning An iterativeprocess is envisaged with a series of bilateral meetings with the Stakeholders andcommon Workshops in which the inputs and outputs are presented to and discussedwith the stakeholders The outputs can migrate towards a presentation format that isboth meaningful and relevant to the stakeholders
The Hydrology and Water Resources component will only analyse the impacts on thewaters of the delta DWA and its consultants do not have the capability or theresources to analyse the impacts on the wildlife vegetation livestock fisheries or tourists It is up to these respective sectors to assess these impacts based on thechanged delta hydrology
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3 DISCUSSION
31 IntroductionThe following sections record the comments made on the foregoing presentationsand the responses given by the hydrology team (in italics)
32 Database Management(1) What is lithology Remember that as much as you are speaking to experts
you are also speaking to non-experts
The point is well taken A glossary will be prepared to explain technical terms
(2) The presentations are too fast and we need details of the graphs for example
This point is also noted presentations should emphasise important pointsSelected slides from the Workshop are included in Annex 3 and a full report is being prepared of both the Integrated Hydrologic Model and the
preliminary scenario analysis These should be studied by thestakeholders in advance of further (bilateral) discussions
(3) Is there a slide to show locations of critical rainfall and flow stations so thatwe could appreciate all the difficulties encountered We would appreciatemuch if we could have locations of all your data sources
The locations of the existing and proposed gauging stations is available inDWA in GIS format The key source for this and information from other sectors and stakeholders will be the Okavango Delta Information System
implemented in HOORC
33 Integrated Hydrologic Model(1) I like your conceptual model but what is applicable in Europe may not
necessarily be applicable here also
The conceptual model is fundamental to the development of a numerical model The conceptual model is strictly formulated for the Okavango Deltabased on available data and scientific publications on the subject Theconceptual model has no relation to European or other climatic conditions
(2) Your evapotranspiration rates are higher than those from Class A pan whenactually the reverse should be true This should be looked into
Actual rates of evapotranspiration (ET) are not necessarily lower than panevaporation owing to a number of factors including pan correction methodcombined free surface ET and vegetation transpiration in flood plains and actual location in the delta versus the location of pan measurements If new documented field data on ET losses are available the hydrology teamwould be happy compare these to model simulations
(3) Is there any physical evidence of flooding
The assessment of the observed flood extent has been based mainly on ananalysis of satellite images from 1984 to 2000 (J McCarthy StockholmUniversity) and DWA water level observations
(4) How do you parameterize your flow in respect to flow resistance
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The Manning resistance coefficient is used to describe the resistance toflow in the river channels and over the flood plains Values for overland flow are distributed according to three vegetation zones based onvegetation mapping (S Ringrose HOORC) Values in the river channelsare ascribed based on channel vegetation descriptions (Dr CK NaiduDWA) Adjustments are made to give a good match with observed flood extent overall water balance and downstream discharges
(5) Your climate input data comprise rainfall evapotranspiration etc fromMaun and Shakawe To what extent can one use a physically based modelwith such a coarse resolution Could we conclude that this is an empiricalmodel
MIKE SHE is a physically based model which implies that the model parameters have a clear physical interpretation as opposed to lumped conceptual models Data measured in single locations may be used toassign parameter values but the parameters used at the current grid scaleof 1km 2 should be regarded as lsquoefficientrsquo parameters representing the
aggregated responseThe lack of input data on distributed rainfall or any other model input doesnot imply that the MIKE SHE model is empirical Maun and Shakawe arethe only two stations in and adjacent to the delta with reliable data Thedelta is not a conventional catchment area where the runoff from individual subcatchments is essential to arrive at the combined flow in themainstream Overland flows mix the runoff from the subcatchments and evapotranspiration dominates Thus a high resolution of the rainfall data isnot of major importance in a general flow model of the delta Nonethelessrecommendations for improved monitoring include rehabilitation of the eight DCPs which measure rainfall and the installation of an additional eight automatic gauges in the delta
(6) Our confidence on the model cannot be based on your numbers
This particular comment was based on relatively consistent outflows for theBaseline and Scenarios This was owing to the nature of the downstreamboundary condition which has since been improved and now shows avariation
The flow leaving the delta (and the model) has passed through anextremely complex hydrologic system flood propagation flow splits among distributaries spills to vast flood plains and swamps evapotranspirationand infiltration The measurement of the discharge upstream is subject toerrors of at least 10 (say 50m 3 s at the flood peak) Differences between
the model computations and the observations cannot better this(7) What resolution should we have confidence on as it pertains to your
model
Given the complexity of the area and the available data model resultsshould not be interpreted looking at single grid values Interpretation based on delta zones or subsystems is more appropriate Five zones based onflood probability have been applied in the scenario demonstration runs and others may be devised according to stakeholdersrsquo needs The minimumarea should cover several square kilometres
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34 Scenarios(1) You have run the scenarios based on dry period(s) Could you please
revise this You might be missing out on recharge to groundwater as aresult of high floods A single high flood could recharge an aquifer for thenext twenty years for example
It is the intention to run the model for a period of normal flows to see how the delta recovers from a drought As suggested the model will also be runfor high floods (this is also important for sediment transport in the delta)
(2) In taking the dry period as critical you have to consider floods as alsocritical Floods need to be covered as well
The delta is not under stress during high flow periods and the impacts of water resources developments will not be so keenly felt and therefore not critical to management planning See also response to (1) above
(3) People are more worried about the switching of channels Maybe thisaspect needs to come out in your model outputs as well
The introduction of sediment transport to the model (which has just commenced) will give an indication of possible future switches and redistribution of delta flows Switching and realignment of channels has achaotic component (the butterfly effect on global climate is akin to ahippopotamus going walkabout in the delta) and accurate predictions aresimply not possible
(4) Looking at the modelrsquos level of resolution critical management issues willnot be answered
The component has been conceived and ToR written (in 200102) toaddress the broad scale management planning issues (water resources
developments upstream climate change abstractions from the delta reed cutting and dredging) On this basis the model approach has been set outand the model set up and applied Preliminary applications suggest that the main threats to the delta will arise from upstream irrigation and climatechange These are the critical management issues related to hydrology
(5) Channel blockages impacts need to be covered in detail Channel switchingis another fundamental management issue
The model can simulate the impact of channel blockages and channel switching As discussed in (3) above the model cannot predict theseoccurrences
(6) You mentioned that your model could handle sediment transport Do youhave something on sediment transport now
An approach to introducing sediment transport to the model has beendrafted (pending report on the Integrated Hydrologic Model)
(7) You seem not to be representing your conditions
See response to (6) above
35 Presentation of Results(1) You canrsquot have a reduction of flow by 40 and yet have no impact on the
outflow This gives me the confidence of your model
See response to (4) above
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(2) The difference in long-term average discharge between observed andsimulations should not be taken to be insignificant This should becombined with other scenarios to better appreciate its impact
It is important in the preliminary stage to separate the impacts fromindividual water resources developments to obtain a good understanding of
which are critical and which are not A limited number of combinationscenarios may be run at a later stage once these can be defined and agreed by the management planners and stakeholders
(3) It would be good to combine all the scenarios as well
See (2) above
(4) It would be interesting also to look at frequency and duration of flooding
The impact on the duration of flooding can be assessed through the timeseries plots for different zones An estimate can also be made on theimpact of the scenarios on the frequency of flooding
(5) What is the model doing as it pertains to erosion and sedimentation
Sediment transport is being introduced to the model This will enable theassessment of the broad pattern of erosion and deposition through themain river channels along which the bed load is conveyed from the basinupstream
(6) The issue of land use change has to be incorporated into the model
To introduce the impact of land use changes in the basin upstream requiresthe application of a water resources planning model to the upstream basinThis is not within the present scope of ODMP which is relying on theoutputs of basinwide projects such as Sharing Water and WERRD (bothcompleted) and possibly in the future TwinBas (ongoing) If ODMP
partners suggest particular potential land use changes within the deltawhich have an impact on the hydrology these may be simulated using theIntegrated Hydrologic Model
(7) The presentations have mostly been technical I would like to suggest thatwe make handouts available after the workshop so that the participantscould have ample time to go over them and later submit their suggestionscomments and or questions
This document represents a full report on the proceedings Further comments from ODMP partners are welcome that our further work may more closely meet the needs of delta management planning Further discussions will be held with the stakeholders on the ongoing model applications possibly on a bilateral basis to obtain a closer understanding of particular needs and ways to meet these needs
36 Stakeholdersrsquo Responses
Wildlife
(1) We need drying flood plain map to better track movement of wild animals
The drying and wetting of the flood plains was presented as animated sequences in the Workshop for all scenarios with a monthly time step Afiner temporal resolution can be prepared (down to four hours) though the
spatial resolution is limited to one kilometre squares
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(2) We would appreciate information on correlations between the distribution of elephants population and extent of flooding close to the buffalo fence
The HampWR component can provide information on the waters of the deltaIt is up to the individual partners to analyse this information for their ownneeds The HampWR component cannot be expected to carry out all the
analyses for the management planThe integration of information from all ODMP components will be carried out within the Okavango Delta Information System implemented inHOORC (also with support from Danida)
Fisheries
(1) Water quality is very critical as this have impact on fish populationdynamics Sedimentation is also critical as it has a bearing on fishpopulations
Sedimentation is indeed critical to fish populations as fine organic richsediment is washed out from the flood plain into the channels by the flood waters resulting in oxygen depletion
The MIKE SHE integrated hydrologic modelling system has the capability tosimulate water quality This is not within the present scope of ODMPSystematic data (including DO and SOD) do not exist at present on whichto develop such a model Improved monitoring recommendations includethe introduction of systematic sampling and analysis at the key inflow station of Mohembo and monthly in-situ measurements of salinity and pH at around 20 discharge stations throughout the delta
Water Affairs
(1) Is MIKE SHE an instrument or whatMIKE SHE is one of a suite of water and environmental software packagesdeveloped and marketed commercially by DHI Water and EnvironmentThe MIKE SHE package is the most advanced generic (can be applied toany system) hydrologic software available MIKE SHE has a consistent development history over thirty years and has been applied to hundreds of hydrologic systems worldwide
(2) Can the model predict channel shifts
The sediment transport model will predict erosion and deposition leading tochannel aggradation and eventual closure The delta morphology isinherently unstable and chaotic and no model can predict channel abandonment with higher certainty than what is constrained by natural variability (chaos) Nonetheless the impact of major channel shifts can be
predicted as well as possible management measures to mitigate suchshifts
(3) Mr Dikgomo mentioned that Hydrology and Water Resources component isone of the twelve What are the other eleven components
The CTA may best respond to this question though it is suggested that representatives from participating organisations take the trouble to informthemselves of the ODMP structure objectives and outputs before attending such fora
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Land Board
(1) Is it possible for the model to give us depth of water table within at least500 metres from the delta This can help us with land use This will alsohelp us determine how far we can avoid pollution in land allocations
The spatial resolution of the model is one square kilometre The model cangive the various hydrologic parameters such a depth to ground water withinthe general area (within a few square kilometres) This should be quiteadequate for the purpose of broad based management planning
(2) Can the model add value to Tawana land board land use and managementplan (2004-2029)
The Hydrology and Water Resources component is concerned withhydrology and water resources The outputs from the component arehydrologic data and predictions for the delta It is up to the various sectorsand components of the management plan to assess the impact of thesehydrologic parameters for their own purposes The HampWR component can
assist in the interpretation of the hydrologic dataTourism
(1) There are lodges and camps located close to the river channels Can themodel be able to help on the implications of pollution
The model can simulate the pattern of flow in the delta which may give auseful indication of the movement of pollution though not the output whichmay be given by a water quality model (advection dispersion decay etc)
General
(1) This component (Hydrology and Water Resources) is so detached from therest It should relocate to MaunThe component is located in Gaborone as the capital has better infrastructure Progress on the component would be constrained by thelimited infrastructure in Maun
(2) To what extent is your data real time series that it could be relied upon
The data available from the delta at present are poor largely owing todifficulties in access and disturbance of gauging stations by humans and large mammalian wildlife Lack of systematic use of the data to date havealso contributed to neglect Improved monitoring is necessary for management planning and an improved hydrologic model with finer
resolution and greater accuracy Recommendations have been prepared for DWA to improve hydrologic monitoring and it is hoped these can beimplemented in the course of 2005
(3) The presentations are too technical When will ODMP reach out to usSomeone mentioned that communication and or information disseminationis a problem Why cant we find other Batswana who could do the job toconvey the information in an audience screened and targeted way
The hydrology of the delta is complex and requires a complex model for arealistic simulation of the processes The presentations were intended togive all participants an understanding that the model is indeed capable of simulating the key hydrologic phenomena of the delta It is hoped that this
has been achieved though it is recognised that the depth of understanding
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will depend upon the level of the individual participantrsquos hydrologic knowledge
The DWA staff assigned to ODMP will gradually take over presentations insuch fora as part of the process of technology transfer which is anessential part of the component
Lessons have been learnt from this Workshop A second and possibly third Workshop will be planned along with bilateral meetings with the individual Stakeholders hopefully improving the communication to the diverse
participants (see Conclusions)
(4) Communications and networking is lagging behind but its pro-activeness isso crucial The component would simplify information and relay it tocommunity andor stakeholders
The HampWR component looks forward to this component being activatedand to cooperating with the Communications and Networking component in
presenting results of the hydrologic analyses meaningful to all
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4 CONCLUSIONS
41 SummaryProf Francis Sefe from the consultantsrsquo team summarised the Workshop discussionas follows
(1) There were discussions on both spatial and temporal resolutions of themodel which need clarification
(2) It was observed that data quality and availability is a constraint to accuratemodelling of the hydrology of the delta and providing physical evidence toback the model conclusions
(3) In the selection of scenarios it is critical to understand that the individualscenarios are not stand alone
(4) The choice of what constitutes the baseline scenario was discussed It hasto be emphasised that the inclusion of exceptional floods is also importantand hence not only the dry period should be used
(5) The presentation was multifaceted
(6) People could not easily locate any landmark features on the map Thisneed not be Villages could be labelled and even the rivers themselves
(7) Though water quality is not in the scope of the current modelling water quality is very important and this has to be looked into in the future
(8) Ground water fluctuations at the periphery of the delta need to be lookedinto
(9) Various stakeholders have difficulty interpreting the results This is a critical
issue that needs to be addressed The target audience should reasonablybe able to assimilate the information relayed to them
42 RecommendationsThe following recommendations are made with regard to the future interactionbetween the Hydrology and Water Resources component and the other ODMPparticipants
(1) While the introductions to the set up and application of the IntegratedHydrologic Model attempted to convey the complexity of the deltahydrology and its computer based representation further effort needs to bemade to present the model and its results in a manner which is fullycomprehensible to the Stakeholders most of whom do not have in depthhydrologic knowledge
(2) It was originally believed that presentation of the model to Stakeholders in acombined forum would allow the interchange of ideas and knowledgeamong the Stakeholders as well as with the Hydrology and Water Resources component The resulting discussion tended to be dominatedby those with technical hydrologic knowledge at the expense of thosewithout The next round of discussions should be on a bilateral basis suchthat the discussions can proceed at a level appropriate for the individualStakeholders and their needs in respect of hydrology and water resources
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(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
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ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
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ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
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Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
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Hydrology and Water Resources Okavango
Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
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ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
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28 Management PlanningThe model analyses are carried out to assess the impacts of possible future basinconditions on the delta for the purposes of management planning An iterativeprocess is envisaged with a series of bilateral meetings with the Stakeholders andcommon Workshops in which the inputs and outputs are presented to and discussedwith the stakeholders The outputs can migrate towards a presentation format that isboth meaningful and relevant to the stakeholders
The Hydrology and Water Resources component will only analyse the impacts on thewaters of the delta DWA and its consultants do not have the capability or theresources to analyse the impacts on the wildlife vegetation livestock fisheries or tourists It is up to these respective sectors to assess these impacts based on thechanged delta hydrology
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3 DISCUSSION
31 IntroductionThe following sections record the comments made on the foregoing presentationsand the responses given by the hydrology team (in italics)
32 Database Management(1) What is lithology Remember that as much as you are speaking to experts
you are also speaking to non-experts
The point is well taken A glossary will be prepared to explain technical terms
(2) The presentations are too fast and we need details of the graphs for example
This point is also noted presentations should emphasise important pointsSelected slides from the Workshop are included in Annex 3 and a full report is being prepared of both the Integrated Hydrologic Model and the
preliminary scenario analysis These should be studied by thestakeholders in advance of further (bilateral) discussions
(3) Is there a slide to show locations of critical rainfall and flow stations so thatwe could appreciate all the difficulties encountered We would appreciatemuch if we could have locations of all your data sources
The locations of the existing and proposed gauging stations is available inDWA in GIS format The key source for this and information from other sectors and stakeholders will be the Okavango Delta Information System
implemented in HOORC
33 Integrated Hydrologic Model(1) I like your conceptual model but what is applicable in Europe may not
necessarily be applicable here also
The conceptual model is fundamental to the development of a numerical model The conceptual model is strictly formulated for the Okavango Deltabased on available data and scientific publications on the subject Theconceptual model has no relation to European or other climatic conditions
(2) Your evapotranspiration rates are higher than those from Class A pan whenactually the reverse should be true This should be looked into
Actual rates of evapotranspiration (ET) are not necessarily lower than panevaporation owing to a number of factors including pan correction methodcombined free surface ET and vegetation transpiration in flood plains and actual location in the delta versus the location of pan measurements If new documented field data on ET losses are available the hydrology teamwould be happy compare these to model simulations
(3) Is there any physical evidence of flooding
The assessment of the observed flood extent has been based mainly on ananalysis of satellite images from 1984 to 2000 (J McCarthy StockholmUniversity) and DWA water level observations
(4) How do you parameterize your flow in respect to flow resistance
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The Manning resistance coefficient is used to describe the resistance toflow in the river channels and over the flood plains Values for overland flow are distributed according to three vegetation zones based onvegetation mapping (S Ringrose HOORC) Values in the river channelsare ascribed based on channel vegetation descriptions (Dr CK NaiduDWA) Adjustments are made to give a good match with observed flood extent overall water balance and downstream discharges
(5) Your climate input data comprise rainfall evapotranspiration etc fromMaun and Shakawe To what extent can one use a physically based modelwith such a coarse resolution Could we conclude that this is an empiricalmodel
MIKE SHE is a physically based model which implies that the model parameters have a clear physical interpretation as opposed to lumped conceptual models Data measured in single locations may be used toassign parameter values but the parameters used at the current grid scaleof 1km 2 should be regarded as lsquoefficientrsquo parameters representing the
aggregated responseThe lack of input data on distributed rainfall or any other model input doesnot imply that the MIKE SHE model is empirical Maun and Shakawe arethe only two stations in and adjacent to the delta with reliable data Thedelta is not a conventional catchment area where the runoff from individual subcatchments is essential to arrive at the combined flow in themainstream Overland flows mix the runoff from the subcatchments and evapotranspiration dominates Thus a high resolution of the rainfall data isnot of major importance in a general flow model of the delta Nonethelessrecommendations for improved monitoring include rehabilitation of the eight DCPs which measure rainfall and the installation of an additional eight automatic gauges in the delta
(6) Our confidence on the model cannot be based on your numbers
This particular comment was based on relatively consistent outflows for theBaseline and Scenarios This was owing to the nature of the downstreamboundary condition which has since been improved and now shows avariation
The flow leaving the delta (and the model) has passed through anextremely complex hydrologic system flood propagation flow splits among distributaries spills to vast flood plains and swamps evapotranspirationand infiltration The measurement of the discharge upstream is subject toerrors of at least 10 (say 50m 3 s at the flood peak) Differences between
the model computations and the observations cannot better this(7) What resolution should we have confidence on as it pertains to your
model
Given the complexity of the area and the available data model resultsshould not be interpreted looking at single grid values Interpretation based on delta zones or subsystems is more appropriate Five zones based onflood probability have been applied in the scenario demonstration runs and others may be devised according to stakeholdersrsquo needs The minimumarea should cover several square kilometres
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34 Scenarios(1) You have run the scenarios based on dry period(s) Could you please
revise this You might be missing out on recharge to groundwater as aresult of high floods A single high flood could recharge an aquifer for thenext twenty years for example
It is the intention to run the model for a period of normal flows to see how the delta recovers from a drought As suggested the model will also be runfor high floods (this is also important for sediment transport in the delta)
(2) In taking the dry period as critical you have to consider floods as alsocritical Floods need to be covered as well
The delta is not under stress during high flow periods and the impacts of water resources developments will not be so keenly felt and therefore not critical to management planning See also response to (1) above
(3) People are more worried about the switching of channels Maybe thisaspect needs to come out in your model outputs as well
The introduction of sediment transport to the model (which has just commenced) will give an indication of possible future switches and redistribution of delta flows Switching and realignment of channels has achaotic component (the butterfly effect on global climate is akin to ahippopotamus going walkabout in the delta) and accurate predictions aresimply not possible
(4) Looking at the modelrsquos level of resolution critical management issues willnot be answered
The component has been conceived and ToR written (in 200102) toaddress the broad scale management planning issues (water resources
developments upstream climate change abstractions from the delta reed cutting and dredging) On this basis the model approach has been set outand the model set up and applied Preliminary applications suggest that the main threats to the delta will arise from upstream irrigation and climatechange These are the critical management issues related to hydrology
(5) Channel blockages impacts need to be covered in detail Channel switchingis another fundamental management issue
The model can simulate the impact of channel blockages and channel switching As discussed in (3) above the model cannot predict theseoccurrences
(6) You mentioned that your model could handle sediment transport Do youhave something on sediment transport now
An approach to introducing sediment transport to the model has beendrafted (pending report on the Integrated Hydrologic Model)
(7) You seem not to be representing your conditions
See response to (6) above
35 Presentation of Results(1) You canrsquot have a reduction of flow by 40 and yet have no impact on the
outflow This gives me the confidence of your model
See response to (4) above
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(2) The difference in long-term average discharge between observed andsimulations should not be taken to be insignificant This should becombined with other scenarios to better appreciate its impact
It is important in the preliminary stage to separate the impacts fromindividual water resources developments to obtain a good understanding of
which are critical and which are not A limited number of combinationscenarios may be run at a later stage once these can be defined and agreed by the management planners and stakeholders
(3) It would be good to combine all the scenarios as well
See (2) above
(4) It would be interesting also to look at frequency and duration of flooding
The impact on the duration of flooding can be assessed through the timeseries plots for different zones An estimate can also be made on theimpact of the scenarios on the frequency of flooding
(5) What is the model doing as it pertains to erosion and sedimentation
Sediment transport is being introduced to the model This will enable theassessment of the broad pattern of erosion and deposition through themain river channels along which the bed load is conveyed from the basinupstream
(6) The issue of land use change has to be incorporated into the model
To introduce the impact of land use changes in the basin upstream requiresthe application of a water resources planning model to the upstream basinThis is not within the present scope of ODMP which is relying on theoutputs of basinwide projects such as Sharing Water and WERRD (bothcompleted) and possibly in the future TwinBas (ongoing) If ODMP
partners suggest particular potential land use changes within the deltawhich have an impact on the hydrology these may be simulated using theIntegrated Hydrologic Model
(7) The presentations have mostly been technical I would like to suggest thatwe make handouts available after the workshop so that the participantscould have ample time to go over them and later submit their suggestionscomments and or questions
This document represents a full report on the proceedings Further comments from ODMP partners are welcome that our further work may more closely meet the needs of delta management planning Further discussions will be held with the stakeholders on the ongoing model applications possibly on a bilateral basis to obtain a closer understanding of particular needs and ways to meet these needs
36 Stakeholdersrsquo Responses
Wildlife
(1) We need drying flood plain map to better track movement of wild animals
The drying and wetting of the flood plains was presented as animated sequences in the Workshop for all scenarios with a monthly time step Afiner temporal resolution can be prepared (down to four hours) though the
spatial resolution is limited to one kilometre squares
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(2) We would appreciate information on correlations between the distribution of elephants population and extent of flooding close to the buffalo fence
The HampWR component can provide information on the waters of the deltaIt is up to the individual partners to analyse this information for their ownneeds The HampWR component cannot be expected to carry out all the
analyses for the management planThe integration of information from all ODMP components will be carried out within the Okavango Delta Information System implemented inHOORC (also with support from Danida)
Fisheries
(1) Water quality is very critical as this have impact on fish populationdynamics Sedimentation is also critical as it has a bearing on fishpopulations
Sedimentation is indeed critical to fish populations as fine organic richsediment is washed out from the flood plain into the channels by the flood waters resulting in oxygen depletion
The MIKE SHE integrated hydrologic modelling system has the capability tosimulate water quality This is not within the present scope of ODMPSystematic data (including DO and SOD) do not exist at present on whichto develop such a model Improved monitoring recommendations includethe introduction of systematic sampling and analysis at the key inflow station of Mohembo and monthly in-situ measurements of salinity and pH at around 20 discharge stations throughout the delta
Water Affairs
(1) Is MIKE SHE an instrument or whatMIKE SHE is one of a suite of water and environmental software packagesdeveloped and marketed commercially by DHI Water and EnvironmentThe MIKE SHE package is the most advanced generic (can be applied toany system) hydrologic software available MIKE SHE has a consistent development history over thirty years and has been applied to hundreds of hydrologic systems worldwide
(2) Can the model predict channel shifts
The sediment transport model will predict erosion and deposition leading tochannel aggradation and eventual closure The delta morphology isinherently unstable and chaotic and no model can predict channel abandonment with higher certainty than what is constrained by natural variability (chaos) Nonetheless the impact of major channel shifts can be
predicted as well as possible management measures to mitigate suchshifts
(3) Mr Dikgomo mentioned that Hydrology and Water Resources component isone of the twelve What are the other eleven components
The CTA may best respond to this question though it is suggested that representatives from participating organisations take the trouble to informthemselves of the ODMP structure objectives and outputs before attending such fora
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Land Board
(1) Is it possible for the model to give us depth of water table within at least500 metres from the delta This can help us with land use This will alsohelp us determine how far we can avoid pollution in land allocations
The spatial resolution of the model is one square kilometre The model cangive the various hydrologic parameters such a depth to ground water withinthe general area (within a few square kilometres) This should be quiteadequate for the purpose of broad based management planning
(2) Can the model add value to Tawana land board land use and managementplan (2004-2029)
The Hydrology and Water Resources component is concerned withhydrology and water resources The outputs from the component arehydrologic data and predictions for the delta It is up to the various sectorsand components of the management plan to assess the impact of thesehydrologic parameters for their own purposes The HampWR component can
assist in the interpretation of the hydrologic dataTourism
(1) There are lodges and camps located close to the river channels Can themodel be able to help on the implications of pollution
The model can simulate the pattern of flow in the delta which may give auseful indication of the movement of pollution though not the output whichmay be given by a water quality model (advection dispersion decay etc)
General
(1) This component (Hydrology and Water Resources) is so detached from therest It should relocate to MaunThe component is located in Gaborone as the capital has better infrastructure Progress on the component would be constrained by thelimited infrastructure in Maun
(2) To what extent is your data real time series that it could be relied upon
The data available from the delta at present are poor largely owing todifficulties in access and disturbance of gauging stations by humans and large mammalian wildlife Lack of systematic use of the data to date havealso contributed to neglect Improved monitoring is necessary for management planning and an improved hydrologic model with finer
resolution and greater accuracy Recommendations have been prepared for DWA to improve hydrologic monitoring and it is hoped these can beimplemented in the course of 2005
(3) The presentations are too technical When will ODMP reach out to usSomeone mentioned that communication and or information disseminationis a problem Why cant we find other Batswana who could do the job toconvey the information in an audience screened and targeted way
The hydrology of the delta is complex and requires a complex model for arealistic simulation of the processes The presentations were intended togive all participants an understanding that the model is indeed capable of simulating the key hydrologic phenomena of the delta It is hoped that this
has been achieved though it is recognised that the depth of understanding
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will depend upon the level of the individual participantrsquos hydrologic knowledge
The DWA staff assigned to ODMP will gradually take over presentations insuch fora as part of the process of technology transfer which is anessential part of the component
Lessons have been learnt from this Workshop A second and possibly third Workshop will be planned along with bilateral meetings with the individual Stakeholders hopefully improving the communication to the diverse
participants (see Conclusions)
(4) Communications and networking is lagging behind but its pro-activeness isso crucial The component would simplify information and relay it tocommunity andor stakeholders
The HampWR component looks forward to this component being activatedand to cooperating with the Communications and Networking component in
presenting results of the hydrologic analyses meaningful to all
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4 CONCLUSIONS
41 SummaryProf Francis Sefe from the consultantsrsquo team summarised the Workshop discussionas follows
(1) There were discussions on both spatial and temporal resolutions of themodel which need clarification
(2) It was observed that data quality and availability is a constraint to accuratemodelling of the hydrology of the delta and providing physical evidence toback the model conclusions
(3) In the selection of scenarios it is critical to understand that the individualscenarios are not stand alone
(4) The choice of what constitutes the baseline scenario was discussed It hasto be emphasised that the inclusion of exceptional floods is also importantand hence not only the dry period should be used
(5) The presentation was multifaceted
(6) People could not easily locate any landmark features on the map Thisneed not be Villages could be labelled and even the rivers themselves
(7) Though water quality is not in the scope of the current modelling water quality is very important and this has to be looked into in the future
(8) Ground water fluctuations at the periphery of the delta need to be lookedinto
(9) Various stakeholders have difficulty interpreting the results This is a critical
issue that needs to be addressed The target audience should reasonablybe able to assimilate the information relayed to them
42 RecommendationsThe following recommendations are made with regard to the future interactionbetween the Hydrology and Water Resources component and the other ODMPparticipants
(1) While the introductions to the set up and application of the IntegratedHydrologic Model attempted to convey the complexity of the deltahydrology and its computer based representation further effort needs to bemade to present the model and its results in a manner which is fullycomprehensible to the Stakeholders most of whom do not have in depthhydrologic knowledge
(2) It was originally believed that presentation of the model to Stakeholders in acombined forum would allow the interchange of ideas and knowledgeamong the Stakeholders as well as with the Hydrology and Water Resources component The resulting discussion tended to be dominatedby those with technical hydrologic knowledge at the expense of thosewithout The next round of discussions should be on a bilateral basis suchthat the discussions can proceed at a level appropriate for the individualStakeholders and their needs in respect of hydrology and water resources
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(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
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ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
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ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
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Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
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Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
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ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
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3 DISCUSSION
31 IntroductionThe following sections record the comments made on the foregoing presentationsand the responses given by the hydrology team (in italics)
32 Database Management(1) What is lithology Remember that as much as you are speaking to experts
you are also speaking to non-experts
The point is well taken A glossary will be prepared to explain technical terms
(2) The presentations are too fast and we need details of the graphs for example
This point is also noted presentations should emphasise important pointsSelected slides from the Workshop are included in Annex 3 and a full report is being prepared of both the Integrated Hydrologic Model and the
preliminary scenario analysis These should be studied by thestakeholders in advance of further (bilateral) discussions
(3) Is there a slide to show locations of critical rainfall and flow stations so thatwe could appreciate all the difficulties encountered We would appreciatemuch if we could have locations of all your data sources
The locations of the existing and proposed gauging stations is available inDWA in GIS format The key source for this and information from other sectors and stakeholders will be the Okavango Delta Information System
implemented in HOORC
33 Integrated Hydrologic Model(1) I like your conceptual model but what is applicable in Europe may not
necessarily be applicable here also
The conceptual model is fundamental to the development of a numerical model The conceptual model is strictly formulated for the Okavango Deltabased on available data and scientific publications on the subject Theconceptual model has no relation to European or other climatic conditions
(2) Your evapotranspiration rates are higher than those from Class A pan whenactually the reverse should be true This should be looked into
Actual rates of evapotranspiration (ET) are not necessarily lower than panevaporation owing to a number of factors including pan correction methodcombined free surface ET and vegetation transpiration in flood plains and actual location in the delta versus the location of pan measurements If new documented field data on ET losses are available the hydrology teamwould be happy compare these to model simulations
(3) Is there any physical evidence of flooding
The assessment of the observed flood extent has been based mainly on ananalysis of satellite images from 1984 to 2000 (J McCarthy StockholmUniversity) and DWA water level observations
(4) How do you parameterize your flow in respect to flow resistance
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The Manning resistance coefficient is used to describe the resistance toflow in the river channels and over the flood plains Values for overland flow are distributed according to three vegetation zones based onvegetation mapping (S Ringrose HOORC) Values in the river channelsare ascribed based on channel vegetation descriptions (Dr CK NaiduDWA) Adjustments are made to give a good match with observed flood extent overall water balance and downstream discharges
(5) Your climate input data comprise rainfall evapotranspiration etc fromMaun and Shakawe To what extent can one use a physically based modelwith such a coarse resolution Could we conclude that this is an empiricalmodel
MIKE SHE is a physically based model which implies that the model parameters have a clear physical interpretation as opposed to lumped conceptual models Data measured in single locations may be used toassign parameter values but the parameters used at the current grid scaleof 1km 2 should be regarded as lsquoefficientrsquo parameters representing the
aggregated responseThe lack of input data on distributed rainfall or any other model input doesnot imply that the MIKE SHE model is empirical Maun and Shakawe arethe only two stations in and adjacent to the delta with reliable data Thedelta is not a conventional catchment area where the runoff from individual subcatchments is essential to arrive at the combined flow in themainstream Overland flows mix the runoff from the subcatchments and evapotranspiration dominates Thus a high resolution of the rainfall data isnot of major importance in a general flow model of the delta Nonethelessrecommendations for improved monitoring include rehabilitation of the eight DCPs which measure rainfall and the installation of an additional eight automatic gauges in the delta
(6) Our confidence on the model cannot be based on your numbers
This particular comment was based on relatively consistent outflows for theBaseline and Scenarios This was owing to the nature of the downstreamboundary condition which has since been improved and now shows avariation
The flow leaving the delta (and the model) has passed through anextremely complex hydrologic system flood propagation flow splits among distributaries spills to vast flood plains and swamps evapotranspirationand infiltration The measurement of the discharge upstream is subject toerrors of at least 10 (say 50m 3 s at the flood peak) Differences between
the model computations and the observations cannot better this(7) What resolution should we have confidence on as it pertains to your
model
Given the complexity of the area and the available data model resultsshould not be interpreted looking at single grid values Interpretation based on delta zones or subsystems is more appropriate Five zones based onflood probability have been applied in the scenario demonstration runs and others may be devised according to stakeholdersrsquo needs The minimumarea should cover several square kilometres
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34 Scenarios(1) You have run the scenarios based on dry period(s) Could you please
revise this You might be missing out on recharge to groundwater as aresult of high floods A single high flood could recharge an aquifer for thenext twenty years for example
It is the intention to run the model for a period of normal flows to see how the delta recovers from a drought As suggested the model will also be runfor high floods (this is also important for sediment transport in the delta)
(2) In taking the dry period as critical you have to consider floods as alsocritical Floods need to be covered as well
The delta is not under stress during high flow periods and the impacts of water resources developments will not be so keenly felt and therefore not critical to management planning See also response to (1) above
(3) People are more worried about the switching of channels Maybe thisaspect needs to come out in your model outputs as well
The introduction of sediment transport to the model (which has just commenced) will give an indication of possible future switches and redistribution of delta flows Switching and realignment of channels has achaotic component (the butterfly effect on global climate is akin to ahippopotamus going walkabout in the delta) and accurate predictions aresimply not possible
(4) Looking at the modelrsquos level of resolution critical management issues willnot be answered
The component has been conceived and ToR written (in 200102) toaddress the broad scale management planning issues (water resources
developments upstream climate change abstractions from the delta reed cutting and dredging) On this basis the model approach has been set outand the model set up and applied Preliminary applications suggest that the main threats to the delta will arise from upstream irrigation and climatechange These are the critical management issues related to hydrology
(5) Channel blockages impacts need to be covered in detail Channel switchingis another fundamental management issue
The model can simulate the impact of channel blockages and channel switching As discussed in (3) above the model cannot predict theseoccurrences
(6) You mentioned that your model could handle sediment transport Do youhave something on sediment transport now
An approach to introducing sediment transport to the model has beendrafted (pending report on the Integrated Hydrologic Model)
(7) You seem not to be representing your conditions
See response to (6) above
35 Presentation of Results(1) You canrsquot have a reduction of flow by 40 and yet have no impact on the
outflow This gives me the confidence of your model
See response to (4) above
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(2) The difference in long-term average discharge between observed andsimulations should not be taken to be insignificant This should becombined with other scenarios to better appreciate its impact
It is important in the preliminary stage to separate the impacts fromindividual water resources developments to obtain a good understanding of
which are critical and which are not A limited number of combinationscenarios may be run at a later stage once these can be defined and agreed by the management planners and stakeholders
(3) It would be good to combine all the scenarios as well
See (2) above
(4) It would be interesting also to look at frequency and duration of flooding
The impact on the duration of flooding can be assessed through the timeseries plots for different zones An estimate can also be made on theimpact of the scenarios on the frequency of flooding
(5) What is the model doing as it pertains to erosion and sedimentation
Sediment transport is being introduced to the model This will enable theassessment of the broad pattern of erosion and deposition through themain river channels along which the bed load is conveyed from the basinupstream
(6) The issue of land use change has to be incorporated into the model
To introduce the impact of land use changes in the basin upstream requiresthe application of a water resources planning model to the upstream basinThis is not within the present scope of ODMP which is relying on theoutputs of basinwide projects such as Sharing Water and WERRD (bothcompleted) and possibly in the future TwinBas (ongoing) If ODMP
partners suggest particular potential land use changes within the deltawhich have an impact on the hydrology these may be simulated using theIntegrated Hydrologic Model
(7) The presentations have mostly been technical I would like to suggest thatwe make handouts available after the workshop so that the participantscould have ample time to go over them and later submit their suggestionscomments and or questions
This document represents a full report on the proceedings Further comments from ODMP partners are welcome that our further work may more closely meet the needs of delta management planning Further discussions will be held with the stakeholders on the ongoing model applications possibly on a bilateral basis to obtain a closer understanding of particular needs and ways to meet these needs
36 Stakeholdersrsquo Responses
Wildlife
(1) We need drying flood plain map to better track movement of wild animals
The drying and wetting of the flood plains was presented as animated sequences in the Workshop for all scenarios with a monthly time step Afiner temporal resolution can be prepared (down to four hours) though the
spatial resolution is limited to one kilometre squares
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(2) We would appreciate information on correlations between the distribution of elephants population and extent of flooding close to the buffalo fence
The HampWR component can provide information on the waters of the deltaIt is up to the individual partners to analyse this information for their ownneeds The HampWR component cannot be expected to carry out all the
analyses for the management planThe integration of information from all ODMP components will be carried out within the Okavango Delta Information System implemented inHOORC (also with support from Danida)
Fisheries
(1) Water quality is very critical as this have impact on fish populationdynamics Sedimentation is also critical as it has a bearing on fishpopulations
Sedimentation is indeed critical to fish populations as fine organic richsediment is washed out from the flood plain into the channels by the flood waters resulting in oxygen depletion
The MIKE SHE integrated hydrologic modelling system has the capability tosimulate water quality This is not within the present scope of ODMPSystematic data (including DO and SOD) do not exist at present on whichto develop such a model Improved monitoring recommendations includethe introduction of systematic sampling and analysis at the key inflow station of Mohembo and monthly in-situ measurements of salinity and pH at around 20 discharge stations throughout the delta
Water Affairs
(1) Is MIKE SHE an instrument or whatMIKE SHE is one of a suite of water and environmental software packagesdeveloped and marketed commercially by DHI Water and EnvironmentThe MIKE SHE package is the most advanced generic (can be applied toany system) hydrologic software available MIKE SHE has a consistent development history over thirty years and has been applied to hundreds of hydrologic systems worldwide
(2) Can the model predict channel shifts
The sediment transport model will predict erosion and deposition leading tochannel aggradation and eventual closure The delta morphology isinherently unstable and chaotic and no model can predict channel abandonment with higher certainty than what is constrained by natural variability (chaos) Nonetheless the impact of major channel shifts can be
predicted as well as possible management measures to mitigate suchshifts
(3) Mr Dikgomo mentioned that Hydrology and Water Resources component isone of the twelve What are the other eleven components
The CTA may best respond to this question though it is suggested that representatives from participating organisations take the trouble to informthemselves of the ODMP structure objectives and outputs before attending such fora
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Land Board
(1) Is it possible for the model to give us depth of water table within at least500 metres from the delta This can help us with land use This will alsohelp us determine how far we can avoid pollution in land allocations
The spatial resolution of the model is one square kilometre The model cangive the various hydrologic parameters such a depth to ground water withinthe general area (within a few square kilometres) This should be quiteadequate for the purpose of broad based management planning
(2) Can the model add value to Tawana land board land use and managementplan (2004-2029)
The Hydrology and Water Resources component is concerned withhydrology and water resources The outputs from the component arehydrologic data and predictions for the delta It is up to the various sectorsand components of the management plan to assess the impact of thesehydrologic parameters for their own purposes The HampWR component can
assist in the interpretation of the hydrologic dataTourism
(1) There are lodges and camps located close to the river channels Can themodel be able to help on the implications of pollution
The model can simulate the pattern of flow in the delta which may give auseful indication of the movement of pollution though not the output whichmay be given by a water quality model (advection dispersion decay etc)
General
(1) This component (Hydrology and Water Resources) is so detached from therest It should relocate to MaunThe component is located in Gaborone as the capital has better infrastructure Progress on the component would be constrained by thelimited infrastructure in Maun
(2) To what extent is your data real time series that it could be relied upon
The data available from the delta at present are poor largely owing todifficulties in access and disturbance of gauging stations by humans and large mammalian wildlife Lack of systematic use of the data to date havealso contributed to neglect Improved monitoring is necessary for management planning and an improved hydrologic model with finer
resolution and greater accuracy Recommendations have been prepared for DWA to improve hydrologic monitoring and it is hoped these can beimplemented in the course of 2005
(3) The presentations are too technical When will ODMP reach out to usSomeone mentioned that communication and or information disseminationis a problem Why cant we find other Batswana who could do the job toconvey the information in an audience screened and targeted way
The hydrology of the delta is complex and requires a complex model for arealistic simulation of the processes The presentations were intended togive all participants an understanding that the model is indeed capable of simulating the key hydrologic phenomena of the delta It is hoped that this
has been achieved though it is recognised that the depth of understanding
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will depend upon the level of the individual participantrsquos hydrologic knowledge
The DWA staff assigned to ODMP will gradually take over presentations insuch fora as part of the process of technology transfer which is anessential part of the component
Lessons have been learnt from this Workshop A second and possibly third Workshop will be planned along with bilateral meetings with the individual Stakeholders hopefully improving the communication to the diverse
participants (see Conclusions)
(4) Communications and networking is lagging behind but its pro-activeness isso crucial The component would simplify information and relay it tocommunity andor stakeholders
The HampWR component looks forward to this component being activatedand to cooperating with the Communications and Networking component in
presenting results of the hydrologic analyses meaningful to all
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4 CONCLUSIONS
41 SummaryProf Francis Sefe from the consultantsrsquo team summarised the Workshop discussionas follows
(1) There were discussions on both spatial and temporal resolutions of themodel which need clarification
(2) It was observed that data quality and availability is a constraint to accuratemodelling of the hydrology of the delta and providing physical evidence toback the model conclusions
(3) In the selection of scenarios it is critical to understand that the individualscenarios are not stand alone
(4) The choice of what constitutes the baseline scenario was discussed It hasto be emphasised that the inclusion of exceptional floods is also importantand hence not only the dry period should be used
(5) The presentation was multifaceted
(6) People could not easily locate any landmark features on the map Thisneed not be Villages could be labelled and even the rivers themselves
(7) Though water quality is not in the scope of the current modelling water quality is very important and this has to be looked into in the future
(8) Ground water fluctuations at the periphery of the delta need to be lookedinto
(9) Various stakeholders have difficulty interpreting the results This is a critical
issue that needs to be addressed The target audience should reasonablybe able to assimilate the information relayed to them
42 RecommendationsThe following recommendations are made with regard to the future interactionbetween the Hydrology and Water Resources component and the other ODMPparticipants
(1) While the introductions to the set up and application of the IntegratedHydrologic Model attempted to convey the complexity of the deltahydrology and its computer based representation further effort needs to bemade to present the model and its results in a manner which is fullycomprehensible to the Stakeholders most of whom do not have in depthhydrologic knowledge
(2) It was originally believed that presentation of the model to Stakeholders in acombined forum would allow the interchange of ideas and knowledgeamong the Stakeholders as well as with the Hydrology and Water Resources component The resulting discussion tended to be dominatedby those with technical hydrologic knowledge at the expense of thosewithout The next round of discussions should be on a bilateral basis suchthat the discussions can proceed at a level appropriate for the individualStakeholders and their needs in respect of hydrology and water resources
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(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
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ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
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ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
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Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
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Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
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ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
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The Manning resistance coefficient is used to describe the resistance toflow in the river channels and over the flood plains Values for overland flow are distributed according to three vegetation zones based onvegetation mapping (S Ringrose HOORC) Values in the river channelsare ascribed based on channel vegetation descriptions (Dr CK NaiduDWA) Adjustments are made to give a good match with observed flood extent overall water balance and downstream discharges
(5) Your climate input data comprise rainfall evapotranspiration etc fromMaun and Shakawe To what extent can one use a physically based modelwith such a coarse resolution Could we conclude that this is an empiricalmodel
MIKE SHE is a physically based model which implies that the model parameters have a clear physical interpretation as opposed to lumped conceptual models Data measured in single locations may be used toassign parameter values but the parameters used at the current grid scaleof 1km 2 should be regarded as lsquoefficientrsquo parameters representing the
aggregated responseThe lack of input data on distributed rainfall or any other model input doesnot imply that the MIKE SHE model is empirical Maun and Shakawe arethe only two stations in and adjacent to the delta with reliable data Thedelta is not a conventional catchment area where the runoff from individual subcatchments is essential to arrive at the combined flow in themainstream Overland flows mix the runoff from the subcatchments and evapotranspiration dominates Thus a high resolution of the rainfall data isnot of major importance in a general flow model of the delta Nonethelessrecommendations for improved monitoring include rehabilitation of the eight DCPs which measure rainfall and the installation of an additional eight automatic gauges in the delta
(6) Our confidence on the model cannot be based on your numbers
This particular comment was based on relatively consistent outflows for theBaseline and Scenarios This was owing to the nature of the downstreamboundary condition which has since been improved and now shows avariation
The flow leaving the delta (and the model) has passed through anextremely complex hydrologic system flood propagation flow splits among distributaries spills to vast flood plains and swamps evapotranspirationand infiltration The measurement of the discharge upstream is subject toerrors of at least 10 (say 50m 3 s at the flood peak) Differences between
the model computations and the observations cannot better this(7) What resolution should we have confidence on as it pertains to your
model
Given the complexity of the area and the available data model resultsshould not be interpreted looking at single grid values Interpretation based on delta zones or subsystems is more appropriate Five zones based onflood probability have been applied in the scenario demonstration runs and others may be devised according to stakeholdersrsquo needs The minimumarea should cover several square kilometres
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34 Scenarios(1) You have run the scenarios based on dry period(s) Could you please
revise this You might be missing out on recharge to groundwater as aresult of high floods A single high flood could recharge an aquifer for thenext twenty years for example
It is the intention to run the model for a period of normal flows to see how the delta recovers from a drought As suggested the model will also be runfor high floods (this is also important for sediment transport in the delta)
(2) In taking the dry period as critical you have to consider floods as alsocritical Floods need to be covered as well
The delta is not under stress during high flow periods and the impacts of water resources developments will not be so keenly felt and therefore not critical to management planning See also response to (1) above
(3) People are more worried about the switching of channels Maybe thisaspect needs to come out in your model outputs as well
The introduction of sediment transport to the model (which has just commenced) will give an indication of possible future switches and redistribution of delta flows Switching and realignment of channels has achaotic component (the butterfly effect on global climate is akin to ahippopotamus going walkabout in the delta) and accurate predictions aresimply not possible
(4) Looking at the modelrsquos level of resolution critical management issues willnot be answered
The component has been conceived and ToR written (in 200102) toaddress the broad scale management planning issues (water resources
developments upstream climate change abstractions from the delta reed cutting and dredging) On this basis the model approach has been set outand the model set up and applied Preliminary applications suggest that the main threats to the delta will arise from upstream irrigation and climatechange These are the critical management issues related to hydrology
(5) Channel blockages impacts need to be covered in detail Channel switchingis another fundamental management issue
The model can simulate the impact of channel blockages and channel switching As discussed in (3) above the model cannot predict theseoccurrences
(6) You mentioned that your model could handle sediment transport Do youhave something on sediment transport now
An approach to introducing sediment transport to the model has beendrafted (pending report on the Integrated Hydrologic Model)
(7) You seem not to be representing your conditions
See response to (6) above
35 Presentation of Results(1) You canrsquot have a reduction of flow by 40 and yet have no impact on the
outflow This gives me the confidence of your model
See response to (4) above
Hydrology and Water Resources Workshop No 1 page 16
882019 ODMP Stakeholder Workshop Report hydrological model
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Hydrology and Water Resources Okavango Delta Management Plan
(2) The difference in long-term average discharge between observed andsimulations should not be taken to be insignificant This should becombined with other scenarios to better appreciate its impact
It is important in the preliminary stage to separate the impacts fromindividual water resources developments to obtain a good understanding of
which are critical and which are not A limited number of combinationscenarios may be run at a later stage once these can be defined and agreed by the management planners and stakeholders
(3) It would be good to combine all the scenarios as well
See (2) above
(4) It would be interesting also to look at frequency and duration of flooding
The impact on the duration of flooding can be assessed through the timeseries plots for different zones An estimate can also be made on theimpact of the scenarios on the frequency of flooding
(5) What is the model doing as it pertains to erosion and sedimentation
Sediment transport is being introduced to the model This will enable theassessment of the broad pattern of erosion and deposition through themain river channels along which the bed load is conveyed from the basinupstream
(6) The issue of land use change has to be incorporated into the model
To introduce the impact of land use changes in the basin upstream requiresthe application of a water resources planning model to the upstream basinThis is not within the present scope of ODMP which is relying on theoutputs of basinwide projects such as Sharing Water and WERRD (bothcompleted) and possibly in the future TwinBas (ongoing) If ODMP
partners suggest particular potential land use changes within the deltawhich have an impact on the hydrology these may be simulated using theIntegrated Hydrologic Model
(7) The presentations have mostly been technical I would like to suggest thatwe make handouts available after the workshop so that the participantscould have ample time to go over them and later submit their suggestionscomments and or questions
This document represents a full report on the proceedings Further comments from ODMP partners are welcome that our further work may more closely meet the needs of delta management planning Further discussions will be held with the stakeholders on the ongoing model applications possibly on a bilateral basis to obtain a closer understanding of particular needs and ways to meet these needs
36 Stakeholdersrsquo Responses
Wildlife
(1) We need drying flood plain map to better track movement of wild animals
The drying and wetting of the flood plains was presented as animated sequences in the Workshop for all scenarios with a monthly time step Afiner temporal resolution can be prepared (down to four hours) though the
spatial resolution is limited to one kilometre squares
Hydrology and Water Resources Workshop No 1 page 17
882019 ODMP Stakeholder Workshop Report hydrological model
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Hydrology and Water Resources Okavango Delta Management Plan
(2) We would appreciate information on correlations between the distribution of elephants population and extent of flooding close to the buffalo fence
The HampWR component can provide information on the waters of the deltaIt is up to the individual partners to analyse this information for their ownneeds The HampWR component cannot be expected to carry out all the
analyses for the management planThe integration of information from all ODMP components will be carried out within the Okavango Delta Information System implemented inHOORC (also with support from Danida)
Fisheries
(1) Water quality is very critical as this have impact on fish populationdynamics Sedimentation is also critical as it has a bearing on fishpopulations
Sedimentation is indeed critical to fish populations as fine organic richsediment is washed out from the flood plain into the channels by the flood waters resulting in oxygen depletion
The MIKE SHE integrated hydrologic modelling system has the capability tosimulate water quality This is not within the present scope of ODMPSystematic data (including DO and SOD) do not exist at present on whichto develop such a model Improved monitoring recommendations includethe introduction of systematic sampling and analysis at the key inflow station of Mohembo and monthly in-situ measurements of salinity and pH at around 20 discharge stations throughout the delta
Water Affairs
(1) Is MIKE SHE an instrument or whatMIKE SHE is one of a suite of water and environmental software packagesdeveloped and marketed commercially by DHI Water and EnvironmentThe MIKE SHE package is the most advanced generic (can be applied toany system) hydrologic software available MIKE SHE has a consistent development history over thirty years and has been applied to hundreds of hydrologic systems worldwide
(2) Can the model predict channel shifts
The sediment transport model will predict erosion and deposition leading tochannel aggradation and eventual closure The delta morphology isinherently unstable and chaotic and no model can predict channel abandonment with higher certainty than what is constrained by natural variability (chaos) Nonetheless the impact of major channel shifts can be
predicted as well as possible management measures to mitigate suchshifts
(3) Mr Dikgomo mentioned that Hydrology and Water Resources component isone of the twelve What are the other eleven components
The CTA may best respond to this question though it is suggested that representatives from participating organisations take the trouble to informthemselves of the ODMP structure objectives and outputs before attending such fora
Hydrology and Water Resources Workshop No 1 page 18
882019 ODMP Stakeholder Workshop Report hydrological model
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Hydrology and Water Resources Okavango Delta Management Plan
Land Board
(1) Is it possible for the model to give us depth of water table within at least500 metres from the delta This can help us with land use This will alsohelp us determine how far we can avoid pollution in land allocations
The spatial resolution of the model is one square kilometre The model cangive the various hydrologic parameters such a depth to ground water withinthe general area (within a few square kilometres) This should be quiteadequate for the purpose of broad based management planning
(2) Can the model add value to Tawana land board land use and managementplan (2004-2029)
The Hydrology and Water Resources component is concerned withhydrology and water resources The outputs from the component arehydrologic data and predictions for the delta It is up to the various sectorsand components of the management plan to assess the impact of thesehydrologic parameters for their own purposes The HampWR component can
assist in the interpretation of the hydrologic dataTourism
(1) There are lodges and camps located close to the river channels Can themodel be able to help on the implications of pollution
The model can simulate the pattern of flow in the delta which may give auseful indication of the movement of pollution though not the output whichmay be given by a water quality model (advection dispersion decay etc)
General
(1) This component (Hydrology and Water Resources) is so detached from therest It should relocate to MaunThe component is located in Gaborone as the capital has better infrastructure Progress on the component would be constrained by thelimited infrastructure in Maun
(2) To what extent is your data real time series that it could be relied upon
The data available from the delta at present are poor largely owing todifficulties in access and disturbance of gauging stations by humans and large mammalian wildlife Lack of systematic use of the data to date havealso contributed to neglect Improved monitoring is necessary for management planning and an improved hydrologic model with finer
resolution and greater accuracy Recommendations have been prepared for DWA to improve hydrologic monitoring and it is hoped these can beimplemented in the course of 2005
(3) The presentations are too technical When will ODMP reach out to usSomeone mentioned that communication and or information disseminationis a problem Why cant we find other Batswana who could do the job toconvey the information in an audience screened and targeted way
The hydrology of the delta is complex and requires a complex model for arealistic simulation of the processes The presentations were intended togive all participants an understanding that the model is indeed capable of simulating the key hydrologic phenomena of the delta It is hoped that this
has been achieved though it is recognised that the depth of understanding
Hydrology and Water Resources Workshop No 1 page 19
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Hydrology and Water Resources Okavango Delta Management Plan
will depend upon the level of the individual participantrsquos hydrologic knowledge
The DWA staff assigned to ODMP will gradually take over presentations insuch fora as part of the process of technology transfer which is anessential part of the component
Lessons have been learnt from this Workshop A second and possibly third Workshop will be planned along with bilateral meetings with the individual Stakeholders hopefully improving the communication to the diverse
participants (see Conclusions)
(4) Communications and networking is lagging behind but its pro-activeness isso crucial The component would simplify information and relay it tocommunity andor stakeholders
The HampWR component looks forward to this component being activatedand to cooperating with the Communications and Networking component in
presenting results of the hydrologic analyses meaningful to all
Hydrology and Water Resources Workshop No 1 page 20
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Hydrology and Water Resources Okavango Delta Management Plan
4 CONCLUSIONS
41 SummaryProf Francis Sefe from the consultantsrsquo team summarised the Workshop discussionas follows
(1) There were discussions on both spatial and temporal resolutions of themodel which need clarification
(2) It was observed that data quality and availability is a constraint to accuratemodelling of the hydrology of the delta and providing physical evidence toback the model conclusions
(3) In the selection of scenarios it is critical to understand that the individualscenarios are not stand alone
(4) The choice of what constitutes the baseline scenario was discussed It hasto be emphasised that the inclusion of exceptional floods is also importantand hence not only the dry period should be used
(5) The presentation was multifaceted
(6) People could not easily locate any landmark features on the map Thisneed not be Villages could be labelled and even the rivers themselves
(7) Though water quality is not in the scope of the current modelling water quality is very important and this has to be looked into in the future
(8) Ground water fluctuations at the periphery of the delta need to be lookedinto
(9) Various stakeholders have difficulty interpreting the results This is a critical
issue that needs to be addressed The target audience should reasonablybe able to assimilate the information relayed to them
42 RecommendationsThe following recommendations are made with regard to the future interactionbetween the Hydrology and Water Resources component and the other ODMPparticipants
(1) While the introductions to the set up and application of the IntegratedHydrologic Model attempted to convey the complexity of the deltahydrology and its computer based representation further effort needs to bemade to present the model and its results in a manner which is fullycomprehensible to the Stakeholders most of whom do not have in depthhydrologic knowledge
(2) It was originally believed that presentation of the model to Stakeholders in acombined forum would allow the interchange of ideas and knowledgeamong the Stakeholders as well as with the Hydrology and Water Resources component The resulting discussion tended to be dominatedby those with technical hydrologic knowledge at the expense of thosewithout The next round of discussions should be on a bilateral basis suchthat the discussions can proceed at a level appropriate for the individualStakeholders and their needs in respect of hydrology and water resources
Hydrology and Water Resources Workshop No 1 page 21
882019 ODMP Stakeholder Workshop Report hydrological model
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Hydrology and Water Resources Okavango Delta Management Plan
(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
Hydrology and Water Resources Workshop No 1 page 22
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Hydrology and Water Resources Okavango Delta Management Plan
ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
Hydrology and Water Resources Workshop No 1 page 23
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Hydrology and Water Resources Okavango
ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
Hydrology and Water Resources Workshop No 1
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Hydrology and Water Resources Okavango
Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
Hydrology and Water Resources Workshop No 1
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Hydrology and Water Resources Okavango
Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
Hydrology and Water Resources Workshop No 1
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Hydrology and Water Resources Okavango Delta Management Plan
ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
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Hydrology and Water Resources Okavango Delta Management Plan
34 Scenarios(1) You have run the scenarios based on dry period(s) Could you please
revise this You might be missing out on recharge to groundwater as aresult of high floods A single high flood could recharge an aquifer for thenext twenty years for example
It is the intention to run the model for a period of normal flows to see how the delta recovers from a drought As suggested the model will also be runfor high floods (this is also important for sediment transport in the delta)
(2) In taking the dry period as critical you have to consider floods as alsocritical Floods need to be covered as well
The delta is not under stress during high flow periods and the impacts of water resources developments will not be so keenly felt and therefore not critical to management planning See also response to (1) above
(3) People are more worried about the switching of channels Maybe thisaspect needs to come out in your model outputs as well
The introduction of sediment transport to the model (which has just commenced) will give an indication of possible future switches and redistribution of delta flows Switching and realignment of channels has achaotic component (the butterfly effect on global climate is akin to ahippopotamus going walkabout in the delta) and accurate predictions aresimply not possible
(4) Looking at the modelrsquos level of resolution critical management issues willnot be answered
The component has been conceived and ToR written (in 200102) toaddress the broad scale management planning issues (water resources
developments upstream climate change abstractions from the delta reed cutting and dredging) On this basis the model approach has been set outand the model set up and applied Preliminary applications suggest that the main threats to the delta will arise from upstream irrigation and climatechange These are the critical management issues related to hydrology
(5) Channel blockages impacts need to be covered in detail Channel switchingis another fundamental management issue
The model can simulate the impact of channel blockages and channel switching As discussed in (3) above the model cannot predict theseoccurrences
(6) You mentioned that your model could handle sediment transport Do youhave something on sediment transport now
An approach to introducing sediment transport to the model has beendrafted (pending report on the Integrated Hydrologic Model)
(7) You seem not to be representing your conditions
See response to (6) above
35 Presentation of Results(1) You canrsquot have a reduction of flow by 40 and yet have no impact on the
outflow This gives me the confidence of your model
See response to (4) above
Hydrology and Water Resources Workshop No 1 page 16
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 1929
Hydrology and Water Resources Okavango Delta Management Plan
(2) The difference in long-term average discharge between observed andsimulations should not be taken to be insignificant This should becombined with other scenarios to better appreciate its impact
It is important in the preliminary stage to separate the impacts fromindividual water resources developments to obtain a good understanding of
which are critical and which are not A limited number of combinationscenarios may be run at a later stage once these can be defined and agreed by the management planners and stakeholders
(3) It would be good to combine all the scenarios as well
See (2) above
(4) It would be interesting also to look at frequency and duration of flooding
The impact on the duration of flooding can be assessed through the timeseries plots for different zones An estimate can also be made on theimpact of the scenarios on the frequency of flooding
(5) What is the model doing as it pertains to erosion and sedimentation
Sediment transport is being introduced to the model This will enable theassessment of the broad pattern of erosion and deposition through themain river channels along which the bed load is conveyed from the basinupstream
(6) The issue of land use change has to be incorporated into the model
To introduce the impact of land use changes in the basin upstream requiresthe application of a water resources planning model to the upstream basinThis is not within the present scope of ODMP which is relying on theoutputs of basinwide projects such as Sharing Water and WERRD (bothcompleted) and possibly in the future TwinBas (ongoing) If ODMP
partners suggest particular potential land use changes within the deltawhich have an impact on the hydrology these may be simulated using theIntegrated Hydrologic Model
(7) The presentations have mostly been technical I would like to suggest thatwe make handouts available after the workshop so that the participantscould have ample time to go over them and later submit their suggestionscomments and or questions
This document represents a full report on the proceedings Further comments from ODMP partners are welcome that our further work may more closely meet the needs of delta management planning Further discussions will be held with the stakeholders on the ongoing model applications possibly on a bilateral basis to obtain a closer understanding of particular needs and ways to meet these needs
36 Stakeholdersrsquo Responses
Wildlife
(1) We need drying flood plain map to better track movement of wild animals
The drying and wetting of the flood plains was presented as animated sequences in the Workshop for all scenarios with a monthly time step Afiner temporal resolution can be prepared (down to four hours) though the
spatial resolution is limited to one kilometre squares
Hydrology and Water Resources Workshop No 1 page 17
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2029
Hydrology and Water Resources Okavango Delta Management Plan
(2) We would appreciate information on correlations between the distribution of elephants population and extent of flooding close to the buffalo fence
The HampWR component can provide information on the waters of the deltaIt is up to the individual partners to analyse this information for their ownneeds The HampWR component cannot be expected to carry out all the
analyses for the management planThe integration of information from all ODMP components will be carried out within the Okavango Delta Information System implemented inHOORC (also with support from Danida)
Fisheries
(1) Water quality is very critical as this have impact on fish populationdynamics Sedimentation is also critical as it has a bearing on fishpopulations
Sedimentation is indeed critical to fish populations as fine organic richsediment is washed out from the flood plain into the channels by the flood waters resulting in oxygen depletion
The MIKE SHE integrated hydrologic modelling system has the capability tosimulate water quality This is not within the present scope of ODMPSystematic data (including DO and SOD) do not exist at present on whichto develop such a model Improved monitoring recommendations includethe introduction of systematic sampling and analysis at the key inflow station of Mohembo and monthly in-situ measurements of salinity and pH at around 20 discharge stations throughout the delta
Water Affairs
(1) Is MIKE SHE an instrument or whatMIKE SHE is one of a suite of water and environmental software packagesdeveloped and marketed commercially by DHI Water and EnvironmentThe MIKE SHE package is the most advanced generic (can be applied toany system) hydrologic software available MIKE SHE has a consistent development history over thirty years and has been applied to hundreds of hydrologic systems worldwide
(2) Can the model predict channel shifts
The sediment transport model will predict erosion and deposition leading tochannel aggradation and eventual closure The delta morphology isinherently unstable and chaotic and no model can predict channel abandonment with higher certainty than what is constrained by natural variability (chaos) Nonetheless the impact of major channel shifts can be
predicted as well as possible management measures to mitigate suchshifts
(3) Mr Dikgomo mentioned that Hydrology and Water Resources component isone of the twelve What are the other eleven components
The CTA may best respond to this question though it is suggested that representatives from participating organisations take the trouble to informthemselves of the ODMP structure objectives and outputs before attending such fora
Hydrology and Water Resources Workshop No 1 page 18
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2129
Hydrology and Water Resources Okavango Delta Management Plan
Land Board
(1) Is it possible for the model to give us depth of water table within at least500 metres from the delta This can help us with land use This will alsohelp us determine how far we can avoid pollution in land allocations
The spatial resolution of the model is one square kilometre The model cangive the various hydrologic parameters such a depth to ground water withinthe general area (within a few square kilometres) This should be quiteadequate for the purpose of broad based management planning
(2) Can the model add value to Tawana land board land use and managementplan (2004-2029)
The Hydrology and Water Resources component is concerned withhydrology and water resources The outputs from the component arehydrologic data and predictions for the delta It is up to the various sectorsand components of the management plan to assess the impact of thesehydrologic parameters for their own purposes The HampWR component can
assist in the interpretation of the hydrologic dataTourism
(1) There are lodges and camps located close to the river channels Can themodel be able to help on the implications of pollution
The model can simulate the pattern of flow in the delta which may give auseful indication of the movement of pollution though not the output whichmay be given by a water quality model (advection dispersion decay etc)
General
(1) This component (Hydrology and Water Resources) is so detached from therest It should relocate to MaunThe component is located in Gaborone as the capital has better infrastructure Progress on the component would be constrained by thelimited infrastructure in Maun
(2) To what extent is your data real time series that it could be relied upon
The data available from the delta at present are poor largely owing todifficulties in access and disturbance of gauging stations by humans and large mammalian wildlife Lack of systematic use of the data to date havealso contributed to neglect Improved monitoring is necessary for management planning and an improved hydrologic model with finer
resolution and greater accuracy Recommendations have been prepared for DWA to improve hydrologic monitoring and it is hoped these can beimplemented in the course of 2005
(3) The presentations are too technical When will ODMP reach out to usSomeone mentioned that communication and or information disseminationis a problem Why cant we find other Batswana who could do the job toconvey the information in an audience screened and targeted way
The hydrology of the delta is complex and requires a complex model for arealistic simulation of the processes The presentations were intended togive all participants an understanding that the model is indeed capable of simulating the key hydrologic phenomena of the delta It is hoped that this
has been achieved though it is recognised that the depth of understanding
Hydrology and Water Resources Workshop No 1 page 19
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2229
Hydrology and Water Resources Okavango Delta Management Plan
will depend upon the level of the individual participantrsquos hydrologic knowledge
The DWA staff assigned to ODMP will gradually take over presentations insuch fora as part of the process of technology transfer which is anessential part of the component
Lessons have been learnt from this Workshop A second and possibly third Workshop will be planned along with bilateral meetings with the individual Stakeholders hopefully improving the communication to the diverse
participants (see Conclusions)
(4) Communications and networking is lagging behind but its pro-activeness isso crucial The component would simplify information and relay it tocommunity andor stakeholders
The HampWR component looks forward to this component being activatedand to cooperating with the Communications and Networking component in
presenting results of the hydrologic analyses meaningful to all
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4 CONCLUSIONS
41 SummaryProf Francis Sefe from the consultantsrsquo team summarised the Workshop discussionas follows
(1) There were discussions on both spatial and temporal resolutions of themodel which need clarification
(2) It was observed that data quality and availability is a constraint to accuratemodelling of the hydrology of the delta and providing physical evidence toback the model conclusions
(3) In the selection of scenarios it is critical to understand that the individualscenarios are not stand alone
(4) The choice of what constitutes the baseline scenario was discussed It hasto be emphasised that the inclusion of exceptional floods is also importantand hence not only the dry period should be used
(5) The presentation was multifaceted
(6) People could not easily locate any landmark features on the map Thisneed not be Villages could be labelled and even the rivers themselves
(7) Though water quality is not in the scope of the current modelling water quality is very important and this has to be looked into in the future
(8) Ground water fluctuations at the periphery of the delta need to be lookedinto
(9) Various stakeholders have difficulty interpreting the results This is a critical
issue that needs to be addressed The target audience should reasonablybe able to assimilate the information relayed to them
42 RecommendationsThe following recommendations are made with regard to the future interactionbetween the Hydrology and Water Resources component and the other ODMPparticipants
(1) While the introductions to the set up and application of the IntegratedHydrologic Model attempted to convey the complexity of the deltahydrology and its computer based representation further effort needs to bemade to present the model and its results in a manner which is fullycomprehensible to the Stakeholders most of whom do not have in depthhydrologic knowledge
(2) It was originally believed that presentation of the model to Stakeholders in acombined forum would allow the interchange of ideas and knowledgeamong the Stakeholders as well as with the Hydrology and Water Resources component The resulting discussion tended to be dominatedby those with technical hydrologic knowledge at the expense of thosewithout The next round of discussions should be on a bilateral basis suchthat the discussions can proceed at a level appropriate for the individualStakeholders and their needs in respect of hydrology and water resources
Hydrology and Water Resources Workshop No 1 page 21
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Hydrology and Water Resources Okavango Delta Management Plan
(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
Hydrology and Water Resources Workshop No 1 page 22
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ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
Hydrology and Water Resources Workshop No 1 page 23
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ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
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Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
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Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
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Hydrology and Water Resources Okavango Delta Management Plan
ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
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Hydrology and Water Resources Okavango Delta Management Plan
(2) The difference in long-term average discharge between observed andsimulations should not be taken to be insignificant This should becombined with other scenarios to better appreciate its impact
It is important in the preliminary stage to separate the impacts fromindividual water resources developments to obtain a good understanding of
which are critical and which are not A limited number of combinationscenarios may be run at a later stage once these can be defined and agreed by the management planners and stakeholders
(3) It would be good to combine all the scenarios as well
See (2) above
(4) It would be interesting also to look at frequency and duration of flooding
The impact on the duration of flooding can be assessed through the timeseries plots for different zones An estimate can also be made on theimpact of the scenarios on the frequency of flooding
(5) What is the model doing as it pertains to erosion and sedimentation
Sediment transport is being introduced to the model This will enable theassessment of the broad pattern of erosion and deposition through themain river channels along which the bed load is conveyed from the basinupstream
(6) The issue of land use change has to be incorporated into the model
To introduce the impact of land use changes in the basin upstream requiresthe application of a water resources planning model to the upstream basinThis is not within the present scope of ODMP which is relying on theoutputs of basinwide projects such as Sharing Water and WERRD (bothcompleted) and possibly in the future TwinBas (ongoing) If ODMP
partners suggest particular potential land use changes within the deltawhich have an impact on the hydrology these may be simulated using theIntegrated Hydrologic Model
(7) The presentations have mostly been technical I would like to suggest thatwe make handouts available after the workshop so that the participantscould have ample time to go over them and later submit their suggestionscomments and or questions
This document represents a full report on the proceedings Further comments from ODMP partners are welcome that our further work may more closely meet the needs of delta management planning Further discussions will be held with the stakeholders on the ongoing model applications possibly on a bilateral basis to obtain a closer understanding of particular needs and ways to meet these needs
36 Stakeholdersrsquo Responses
Wildlife
(1) We need drying flood plain map to better track movement of wild animals
The drying and wetting of the flood plains was presented as animated sequences in the Workshop for all scenarios with a monthly time step Afiner temporal resolution can be prepared (down to four hours) though the
spatial resolution is limited to one kilometre squares
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(2) We would appreciate information on correlations between the distribution of elephants population and extent of flooding close to the buffalo fence
The HampWR component can provide information on the waters of the deltaIt is up to the individual partners to analyse this information for their ownneeds The HampWR component cannot be expected to carry out all the
analyses for the management planThe integration of information from all ODMP components will be carried out within the Okavango Delta Information System implemented inHOORC (also with support from Danida)
Fisheries
(1) Water quality is very critical as this have impact on fish populationdynamics Sedimentation is also critical as it has a bearing on fishpopulations
Sedimentation is indeed critical to fish populations as fine organic richsediment is washed out from the flood plain into the channels by the flood waters resulting in oxygen depletion
The MIKE SHE integrated hydrologic modelling system has the capability tosimulate water quality This is not within the present scope of ODMPSystematic data (including DO and SOD) do not exist at present on whichto develop such a model Improved monitoring recommendations includethe introduction of systematic sampling and analysis at the key inflow station of Mohembo and monthly in-situ measurements of salinity and pH at around 20 discharge stations throughout the delta
Water Affairs
(1) Is MIKE SHE an instrument or whatMIKE SHE is one of a suite of water and environmental software packagesdeveloped and marketed commercially by DHI Water and EnvironmentThe MIKE SHE package is the most advanced generic (can be applied toany system) hydrologic software available MIKE SHE has a consistent development history over thirty years and has been applied to hundreds of hydrologic systems worldwide
(2) Can the model predict channel shifts
The sediment transport model will predict erosion and deposition leading tochannel aggradation and eventual closure The delta morphology isinherently unstable and chaotic and no model can predict channel abandonment with higher certainty than what is constrained by natural variability (chaos) Nonetheless the impact of major channel shifts can be
predicted as well as possible management measures to mitigate suchshifts
(3) Mr Dikgomo mentioned that Hydrology and Water Resources component isone of the twelve What are the other eleven components
The CTA may best respond to this question though it is suggested that representatives from participating organisations take the trouble to informthemselves of the ODMP structure objectives and outputs before attending such fora
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Land Board
(1) Is it possible for the model to give us depth of water table within at least500 metres from the delta This can help us with land use This will alsohelp us determine how far we can avoid pollution in land allocations
The spatial resolution of the model is one square kilometre The model cangive the various hydrologic parameters such a depth to ground water withinthe general area (within a few square kilometres) This should be quiteadequate for the purpose of broad based management planning
(2) Can the model add value to Tawana land board land use and managementplan (2004-2029)
The Hydrology and Water Resources component is concerned withhydrology and water resources The outputs from the component arehydrologic data and predictions for the delta It is up to the various sectorsand components of the management plan to assess the impact of thesehydrologic parameters for their own purposes The HampWR component can
assist in the interpretation of the hydrologic dataTourism
(1) There are lodges and camps located close to the river channels Can themodel be able to help on the implications of pollution
The model can simulate the pattern of flow in the delta which may give auseful indication of the movement of pollution though not the output whichmay be given by a water quality model (advection dispersion decay etc)
General
(1) This component (Hydrology and Water Resources) is so detached from therest It should relocate to MaunThe component is located in Gaborone as the capital has better infrastructure Progress on the component would be constrained by thelimited infrastructure in Maun
(2) To what extent is your data real time series that it could be relied upon
The data available from the delta at present are poor largely owing todifficulties in access and disturbance of gauging stations by humans and large mammalian wildlife Lack of systematic use of the data to date havealso contributed to neglect Improved monitoring is necessary for management planning and an improved hydrologic model with finer
resolution and greater accuracy Recommendations have been prepared for DWA to improve hydrologic monitoring and it is hoped these can beimplemented in the course of 2005
(3) The presentations are too technical When will ODMP reach out to usSomeone mentioned that communication and or information disseminationis a problem Why cant we find other Batswana who could do the job toconvey the information in an audience screened and targeted way
The hydrology of the delta is complex and requires a complex model for arealistic simulation of the processes The presentations were intended togive all participants an understanding that the model is indeed capable of simulating the key hydrologic phenomena of the delta It is hoped that this
has been achieved though it is recognised that the depth of understanding
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will depend upon the level of the individual participantrsquos hydrologic knowledge
The DWA staff assigned to ODMP will gradually take over presentations insuch fora as part of the process of technology transfer which is anessential part of the component
Lessons have been learnt from this Workshop A second and possibly third Workshop will be planned along with bilateral meetings with the individual Stakeholders hopefully improving the communication to the diverse
participants (see Conclusions)
(4) Communications and networking is lagging behind but its pro-activeness isso crucial The component would simplify information and relay it tocommunity andor stakeholders
The HampWR component looks forward to this component being activatedand to cooperating with the Communications and Networking component in
presenting results of the hydrologic analyses meaningful to all
Hydrology and Water Resources Workshop No 1 page 20
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4 CONCLUSIONS
41 SummaryProf Francis Sefe from the consultantsrsquo team summarised the Workshop discussionas follows
(1) There were discussions on both spatial and temporal resolutions of themodel which need clarification
(2) It was observed that data quality and availability is a constraint to accuratemodelling of the hydrology of the delta and providing physical evidence toback the model conclusions
(3) In the selection of scenarios it is critical to understand that the individualscenarios are not stand alone
(4) The choice of what constitutes the baseline scenario was discussed It hasto be emphasised that the inclusion of exceptional floods is also importantand hence not only the dry period should be used
(5) The presentation was multifaceted
(6) People could not easily locate any landmark features on the map Thisneed not be Villages could be labelled and even the rivers themselves
(7) Though water quality is not in the scope of the current modelling water quality is very important and this has to be looked into in the future
(8) Ground water fluctuations at the periphery of the delta need to be lookedinto
(9) Various stakeholders have difficulty interpreting the results This is a critical
issue that needs to be addressed The target audience should reasonablybe able to assimilate the information relayed to them
42 RecommendationsThe following recommendations are made with regard to the future interactionbetween the Hydrology and Water Resources component and the other ODMPparticipants
(1) While the introductions to the set up and application of the IntegratedHydrologic Model attempted to convey the complexity of the deltahydrology and its computer based representation further effort needs to bemade to present the model and its results in a manner which is fullycomprehensible to the Stakeholders most of whom do not have in depthhydrologic knowledge
(2) It was originally believed that presentation of the model to Stakeholders in acombined forum would allow the interchange of ideas and knowledgeamong the Stakeholders as well as with the Hydrology and Water Resources component The resulting discussion tended to be dominatedby those with technical hydrologic knowledge at the expense of thosewithout The next round of discussions should be on a bilateral basis suchthat the discussions can proceed at a level appropriate for the individualStakeholders and their needs in respect of hydrology and water resources
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Hydrology and Water Resources Okavango Delta Management Plan
(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
Hydrology and Water Resources Workshop No 1 page 22
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ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
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ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
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Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
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Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
Hydrology and Water Resources Workshop No 1
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Hydrology and Water Resources Okavango Delta Management Plan
ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2029
Hydrology and Water Resources Okavango Delta Management Plan
(2) We would appreciate information on correlations between the distribution of elephants population and extent of flooding close to the buffalo fence
The HampWR component can provide information on the waters of the deltaIt is up to the individual partners to analyse this information for their ownneeds The HampWR component cannot be expected to carry out all the
analyses for the management planThe integration of information from all ODMP components will be carried out within the Okavango Delta Information System implemented inHOORC (also with support from Danida)
Fisheries
(1) Water quality is very critical as this have impact on fish populationdynamics Sedimentation is also critical as it has a bearing on fishpopulations
Sedimentation is indeed critical to fish populations as fine organic richsediment is washed out from the flood plain into the channels by the flood waters resulting in oxygen depletion
The MIKE SHE integrated hydrologic modelling system has the capability tosimulate water quality This is not within the present scope of ODMPSystematic data (including DO and SOD) do not exist at present on whichto develop such a model Improved monitoring recommendations includethe introduction of systematic sampling and analysis at the key inflow station of Mohembo and monthly in-situ measurements of salinity and pH at around 20 discharge stations throughout the delta
Water Affairs
(1) Is MIKE SHE an instrument or whatMIKE SHE is one of a suite of water and environmental software packagesdeveloped and marketed commercially by DHI Water and EnvironmentThe MIKE SHE package is the most advanced generic (can be applied toany system) hydrologic software available MIKE SHE has a consistent development history over thirty years and has been applied to hundreds of hydrologic systems worldwide
(2) Can the model predict channel shifts
The sediment transport model will predict erosion and deposition leading tochannel aggradation and eventual closure The delta morphology isinherently unstable and chaotic and no model can predict channel abandonment with higher certainty than what is constrained by natural variability (chaos) Nonetheless the impact of major channel shifts can be
predicted as well as possible management measures to mitigate suchshifts
(3) Mr Dikgomo mentioned that Hydrology and Water Resources component isone of the twelve What are the other eleven components
The CTA may best respond to this question though it is suggested that representatives from participating organisations take the trouble to informthemselves of the ODMP structure objectives and outputs before attending such fora
Hydrology and Water Resources Workshop No 1 page 18
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2129
Hydrology and Water Resources Okavango Delta Management Plan
Land Board
(1) Is it possible for the model to give us depth of water table within at least500 metres from the delta This can help us with land use This will alsohelp us determine how far we can avoid pollution in land allocations
The spatial resolution of the model is one square kilometre The model cangive the various hydrologic parameters such a depth to ground water withinthe general area (within a few square kilometres) This should be quiteadequate for the purpose of broad based management planning
(2) Can the model add value to Tawana land board land use and managementplan (2004-2029)
The Hydrology and Water Resources component is concerned withhydrology and water resources The outputs from the component arehydrologic data and predictions for the delta It is up to the various sectorsand components of the management plan to assess the impact of thesehydrologic parameters for their own purposes The HampWR component can
assist in the interpretation of the hydrologic dataTourism
(1) There are lodges and camps located close to the river channels Can themodel be able to help on the implications of pollution
The model can simulate the pattern of flow in the delta which may give auseful indication of the movement of pollution though not the output whichmay be given by a water quality model (advection dispersion decay etc)
General
(1) This component (Hydrology and Water Resources) is so detached from therest It should relocate to MaunThe component is located in Gaborone as the capital has better infrastructure Progress on the component would be constrained by thelimited infrastructure in Maun
(2) To what extent is your data real time series that it could be relied upon
The data available from the delta at present are poor largely owing todifficulties in access and disturbance of gauging stations by humans and large mammalian wildlife Lack of systematic use of the data to date havealso contributed to neglect Improved monitoring is necessary for management planning and an improved hydrologic model with finer
resolution and greater accuracy Recommendations have been prepared for DWA to improve hydrologic monitoring and it is hoped these can beimplemented in the course of 2005
(3) The presentations are too technical When will ODMP reach out to usSomeone mentioned that communication and or information disseminationis a problem Why cant we find other Batswana who could do the job toconvey the information in an audience screened and targeted way
The hydrology of the delta is complex and requires a complex model for arealistic simulation of the processes The presentations were intended togive all participants an understanding that the model is indeed capable of simulating the key hydrologic phenomena of the delta It is hoped that this
has been achieved though it is recognised that the depth of understanding
Hydrology and Water Resources Workshop No 1 page 19
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2229
Hydrology and Water Resources Okavango Delta Management Plan
will depend upon the level of the individual participantrsquos hydrologic knowledge
The DWA staff assigned to ODMP will gradually take over presentations insuch fora as part of the process of technology transfer which is anessential part of the component
Lessons have been learnt from this Workshop A second and possibly third Workshop will be planned along with bilateral meetings with the individual Stakeholders hopefully improving the communication to the diverse
participants (see Conclusions)
(4) Communications and networking is lagging behind but its pro-activeness isso crucial The component would simplify information and relay it tocommunity andor stakeholders
The HampWR component looks forward to this component being activatedand to cooperating with the Communications and Networking component in
presenting results of the hydrologic analyses meaningful to all
Hydrology and Water Resources Workshop No 1 page 20
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2329
Hydrology and Water Resources Okavango Delta Management Plan
4 CONCLUSIONS
41 SummaryProf Francis Sefe from the consultantsrsquo team summarised the Workshop discussionas follows
(1) There were discussions on both spatial and temporal resolutions of themodel which need clarification
(2) It was observed that data quality and availability is a constraint to accuratemodelling of the hydrology of the delta and providing physical evidence toback the model conclusions
(3) In the selection of scenarios it is critical to understand that the individualscenarios are not stand alone
(4) The choice of what constitutes the baseline scenario was discussed It hasto be emphasised that the inclusion of exceptional floods is also importantand hence not only the dry period should be used
(5) The presentation was multifaceted
(6) People could not easily locate any landmark features on the map Thisneed not be Villages could be labelled and even the rivers themselves
(7) Though water quality is not in the scope of the current modelling water quality is very important and this has to be looked into in the future
(8) Ground water fluctuations at the periphery of the delta need to be lookedinto
(9) Various stakeholders have difficulty interpreting the results This is a critical
issue that needs to be addressed The target audience should reasonablybe able to assimilate the information relayed to them
42 RecommendationsThe following recommendations are made with regard to the future interactionbetween the Hydrology and Water Resources component and the other ODMPparticipants
(1) While the introductions to the set up and application of the IntegratedHydrologic Model attempted to convey the complexity of the deltahydrology and its computer based representation further effort needs to bemade to present the model and its results in a manner which is fullycomprehensible to the Stakeholders most of whom do not have in depthhydrologic knowledge
(2) It was originally believed that presentation of the model to Stakeholders in acombined forum would allow the interchange of ideas and knowledgeamong the Stakeholders as well as with the Hydrology and Water Resources component The resulting discussion tended to be dominatedby those with technical hydrologic knowledge at the expense of thosewithout The next round of discussions should be on a bilateral basis suchthat the discussions can proceed at a level appropriate for the individualStakeholders and their needs in respect of hydrology and water resources
Hydrology and Water Resources Workshop No 1 page 21
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2429
Hydrology and Water Resources Okavango Delta Management Plan
(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
Hydrology and Water Resources Workshop No 1 page 22
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2529
Hydrology and Water Resources Okavango Delta Management Plan
ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
Hydrology and Water Resources Workshop No 1 page 23
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2629
Hydrology and Water Resources Okavango
ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2729
Hydrology and Water Resources Okavango
Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2829
Hydrology and Water Resources Okavango
Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2929
Hydrology and Water Resources Okavango Delta Management Plan
ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2129
Hydrology and Water Resources Okavango Delta Management Plan
Land Board
(1) Is it possible for the model to give us depth of water table within at least500 metres from the delta This can help us with land use This will alsohelp us determine how far we can avoid pollution in land allocations
The spatial resolution of the model is one square kilometre The model cangive the various hydrologic parameters such a depth to ground water withinthe general area (within a few square kilometres) This should be quiteadequate for the purpose of broad based management planning
(2) Can the model add value to Tawana land board land use and managementplan (2004-2029)
The Hydrology and Water Resources component is concerned withhydrology and water resources The outputs from the component arehydrologic data and predictions for the delta It is up to the various sectorsand components of the management plan to assess the impact of thesehydrologic parameters for their own purposes The HampWR component can
assist in the interpretation of the hydrologic dataTourism
(1) There are lodges and camps located close to the river channels Can themodel be able to help on the implications of pollution
The model can simulate the pattern of flow in the delta which may give auseful indication of the movement of pollution though not the output whichmay be given by a water quality model (advection dispersion decay etc)
General
(1) This component (Hydrology and Water Resources) is so detached from therest It should relocate to MaunThe component is located in Gaborone as the capital has better infrastructure Progress on the component would be constrained by thelimited infrastructure in Maun
(2) To what extent is your data real time series that it could be relied upon
The data available from the delta at present are poor largely owing todifficulties in access and disturbance of gauging stations by humans and large mammalian wildlife Lack of systematic use of the data to date havealso contributed to neglect Improved monitoring is necessary for management planning and an improved hydrologic model with finer
resolution and greater accuracy Recommendations have been prepared for DWA to improve hydrologic monitoring and it is hoped these can beimplemented in the course of 2005
(3) The presentations are too technical When will ODMP reach out to usSomeone mentioned that communication and or information disseminationis a problem Why cant we find other Batswana who could do the job toconvey the information in an audience screened and targeted way
The hydrology of the delta is complex and requires a complex model for arealistic simulation of the processes The presentations were intended togive all participants an understanding that the model is indeed capable of simulating the key hydrologic phenomena of the delta It is hoped that this
has been achieved though it is recognised that the depth of understanding
Hydrology and Water Resources Workshop No 1 page 19
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2229
Hydrology and Water Resources Okavango Delta Management Plan
will depend upon the level of the individual participantrsquos hydrologic knowledge
The DWA staff assigned to ODMP will gradually take over presentations insuch fora as part of the process of technology transfer which is anessential part of the component
Lessons have been learnt from this Workshop A second and possibly third Workshop will be planned along with bilateral meetings with the individual Stakeholders hopefully improving the communication to the diverse
participants (see Conclusions)
(4) Communications and networking is lagging behind but its pro-activeness isso crucial The component would simplify information and relay it tocommunity andor stakeholders
The HampWR component looks forward to this component being activatedand to cooperating with the Communications and Networking component in
presenting results of the hydrologic analyses meaningful to all
Hydrology and Water Resources Workshop No 1 page 20
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2329
Hydrology and Water Resources Okavango Delta Management Plan
4 CONCLUSIONS
41 SummaryProf Francis Sefe from the consultantsrsquo team summarised the Workshop discussionas follows
(1) There were discussions on both spatial and temporal resolutions of themodel which need clarification
(2) It was observed that data quality and availability is a constraint to accuratemodelling of the hydrology of the delta and providing physical evidence toback the model conclusions
(3) In the selection of scenarios it is critical to understand that the individualscenarios are not stand alone
(4) The choice of what constitutes the baseline scenario was discussed It hasto be emphasised that the inclusion of exceptional floods is also importantand hence not only the dry period should be used
(5) The presentation was multifaceted
(6) People could not easily locate any landmark features on the map Thisneed not be Villages could be labelled and even the rivers themselves
(7) Though water quality is not in the scope of the current modelling water quality is very important and this has to be looked into in the future
(8) Ground water fluctuations at the periphery of the delta need to be lookedinto
(9) Various stakeholders have difficulty interpreting the results This is a critical
issue that needs to be addressed The target audience should reasonablybe able to assimilate the information relayed to them
42 RecommendationsThe following recommendations are made with regard to the future interactionbetween the Hydrology and Water Resources component and the other ODMPparticipants
(1) While the introductions to the set up and application of the IntegratedHydrologic Model attempted to convey the complexity of the deltahydrology and its computer based representation further effort needs to bemade to present the model and its results in a manner which is fullycomprehensible to the Stakeholders most of whom do not have in depthhydrologic knowledge
(2) It was originally believed that presentation of the model to Stakeholders in acombined forum would allow the interchange of ideas and knowledgeamong the Stakeholders as well as with the Hydrology and Water Resources component The resulting discussion tended to be dominatedby those with technical hydrologic knowledge at the expense of thosewithout The next round of discussions should be on a bilateral basis suchthat the discussions can proceed at a level appropriate for the individualStakeholders and their needs in respect of hydrology and water resources
Hydrology and Water Resources Workshop No 1 page 21
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2429
Hydrology and Water Resources Okavango Delta Management Plan
(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
Hydrology and Water Resources Workshop No 1 page 22
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2529
Hydrology and Water Resources Okavango Delta Management Plan
ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
Hydrology and Water Resources Workshop No 1 page 23
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2629
Hydrology and Water Resources Okavango
ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2729
Hydrology and Water Resources Okavango
Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2829
Hydrology and Water Resources Okavango
Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2929
Hydrology and Water Resources Okavango Delta Management Plan
ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2229
Hydrology and Water Resources Okavango Delta Management Plan
will depend upon the level of the individual participantrsquos hydrologic knowledge
The DWA staff assigned to ODMP will gradually take over presentations insuch fora as part of the process of technology transfer which is anessential part of the component
Lessons have been learnt from this Workshop A second and possibly third Workshop will be planned along with bilateral meetings with the individual Stakeholders hopefully improving the communication to the diverse
participants (see Conclusions)
(4) Communications and networking is lagging behind but its pro-activeness isso crucial The component would simplify information and relay it tocommunity andor stakeholders
The HampWR component looks forward to this component being activatedand to cooperating with the Communications and Networking component in
presenting results of the hydrologic analyses meaningful to all
Hydrology and Water Resources Workshop No 1 page 20
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2329
Hydrology and Water Resources Okavango Delta Management Plan
4 CONCLUSIONS
41 SummaryProf Francis Sefe from the consultantsrsquo team summarised the Workshop discussionas follows
(1) There were discussions on both spatial and temporal resolutions of themodel which need clarification
(2) It was observed that data quality and availability is a constraint to accuratemodelling of the hydrology of the delta and providing physical evidence toback the model conclusions
(3) In the selection of scenarios it is critical to understand that the individualscenarios are not stand alone
(4) The choice of what constitutes the baseline scenario was discussed It hasto be emphasised that the inclusion of exceptional floods is also importantand hence not only the dry period should be used
(5) The presentation was multifaceted
(6) People could not easily locate any landmark features on the map Thisneed not be Villages could be labelled and even the rivers themselves
(7) Though water quality is not in the scope of the current modelling water quality is very important and this has to be looked into in the future
(8) Ground water fluctuations at the periphery of the delta need to be lookedinto
(9) Various stakeholders have difficulty interpreting the results This is a critical
issue that needs to be addressed The target audience should reasonablybe able to assimilate the information relayed to them
42 RecommendationsThe following recommendations are made with regard to the future interactionbetween the Hydrology and Water Resources component and the other ODMPparticipants
(1) While the introductions to the set up and application of the IntegratedHydrologic Model attempted to convey the complexity of the deltahydrology and its computer based representation further effort needs to bemade to present the model and its results in a manner which is fullycomprehensible to the Stakeholders most of whom do not have in depthhydrologic knowledge
(2) It was originally believed that presentation of the model to Stakeholders in acombined forum would allow the interchange of ideas and knowledgeamong the Stakeholders as well as with the Hydrology and Water Resources component The resulting discussion tended to be dominatedby those with technical hydrologic knowledge at the expense of thosewithout The next round of discussions should be on a bilateral basis suchthat the discussions can proceed at a level appropriate for the individualStakeholders and their needs in respect of hydrology and water resources
Hydrology and Water Resources Workshop No 1 page 21
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2429
Hydrology and Water Resources Okavango Delta Management Plan
(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
Hydrology and Water Resources Workshop No 1 page 22
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2529
Hydrology and Water Resources Okavango Delta Management Plan
ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
Hydrology and Water Resources Workshop No 1 page 23
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2629
Hydrology and Water Resources Okavango
ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2729
Hydrology and Water Resources Okavango
Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2829
Hydrology and Water Resources Okavango
Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2929
Hydrology and Water Resources Okavango Delta Management Plan
ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2329
Hydrology and Water Resources Okavango Delta Management Plan
4 CONCLUSIONS
41 SummaryProf Francis Sefe from the consultantsrsquo team summarised the Workshop discussionas follows
(1) There were discussions on both spatial and temporal resolutions of themodel which need clarification
(2) It was observed that data quality and availability is a constraint to accuratemodelling of the hydrology of the delta and providing physical evidence toback the model conclusions
(3) In the selection of scenarios it is critical to understand that the individualscenarios are not stand alone
(4) The choice of what constitutes the baseline scenario was discussed It hasto be emphasised that the inclusion of exceptional floods is also importantand hence not only the dry period should be used
(5) The presentation was multifaceted
(6) People could not easily locate any landmark features on the map Thisneed not be Villages could be labelled and even the rivers themselves
(7) Though water quality is not in the scope of the current modelling water quality is very important and this has to be looked into in the future
(8) Ground water fluctuations at the periphery of the delta need to be lookedinto
(9) Various stakeholders have difficulty interpreting the results This is a critical
issue that needs to be addressed The target audience should reasonablybe able to assimilate the information relayed to them
42 RecommendationsThe following recommendations are made with regard to the future interactionbetween the Hydrology and Water Resources component and the other ODMPparticipants
(1) While the introductions to the set up and application of the IntegratedHydrologic Model attempted to convey the complexity of the deltahydrology and its computer based representation further effort needs to bemade to present the model and its results in a manner which is fullycomprehensible to the Stakeholders most of whom do not have in depthhydrologic knowledge
(2) It was originally believed that presentation of the model to Stakeholders in acombined forum would allow the interchange of ideas and knowledgeamong the Stakeholders as well as with the Hydrology and Water Resources component The resulting discussion tended to be dominatedby those with technical hydrologic knowledge at the expense of thosewithout The next round of discussions should be on a bilateral basis suchthat the discussions can proceed at a level appropriate for the individualStakeholders and their needs in respect of hydrology and water resources
Hydrology and Water Resources Workshop No 1 page 21
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2429
Hydrology and Water Resources Okavango Delta Management Plan
(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
Hydrology and Water Resources Workshop No 1 page 22
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2529
Hydrology and Water Resources Okavango Delta Management Plan
ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
Hydrology and Water Resources Workshop No 1 page 23
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2629
Hydrology and Water Resources Okavango
ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2729
Hydrology and Water Resources Okavango
Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2829
Hydrology and Water Resources Okavango
Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2929
Hydrology and Water Resources Okavango Delta Management Plan
ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2429
Hydrology and Water Resources Okavango Delta Management Plan
(3) Each ODMP component should identify a suitable person to act as a focalpoint for liaison with the Hydrology and Water Resources component Thisperson would attend all future meetings and Workshops aimed atintegrating hydrology into ODMP thereby providing continuity to theprocess
(4) The Data Management component of ODMP implemented in HOORC iscrucial to integrating and interpreting information among the partners Amember of the Data Management component should also be involved indiscussions to demonstrate how this can be realised in practice
Hydrology and Water Resources Workshop No 1 page 22
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2529
Hydrology and Water Resources Okavango Delta Management Plan
ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
Hydrology and Water Resources Workshop No 1 page 23
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2629
Hydrology and Water Resources Okavango
ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2729
Hydrology and Water Resources Okavango
Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2829
Hydrology and Water Resources Okavango
Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2929
Hydrology and Water Resources Okavango Delta Management Plan
ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2529
Hydrology and Water Resources Okavango Delta Management Plan
ANNEX 1
PRESENTATION OF HYDROLOGY AND WATER RESOURCESCOMPONENT TO ODMP STAKEHOLDERS
11 th February 2005
Time Presentation Presenter
900 to 920 Background and Implementation Ontlogetse Dikgomo
920 to 950 Improved Hydrologic Monitoring Ontlogetse Dikgomo
950 to 1010 Introduction to Integrated Hydrologic Model Alasdair Macdonald
1010 to 1030 Coffee break
1030 to 1100 Data Management Kobamelo Dikgola
1100 to 1140 Integrated Hydrologic Model Torsten Jacobsen
1140 to 1210 Introduction to Scenarios Alasdair Macdonald
1210 to 1240 Upstream Water Resources Developments Ontlogetse Dikgomo
1240 to 1340 Lunch
1340 to 1410 Surface and Ground Water Abstractions Benjamin Mafa1410 to 1430 Climate Change Ditiro Moalafhi
1430 to 1445 Tea break
1445 to 1500 Discussion on Scenarios and Presentation of Results - Wildlife
1500 to 1515 Discussion on Scenarios and Presentation of Results - Vegetation
1515 to 1530 Discussion on Scenarios and Presentation of Results - Agriculture
1530 to 1545 Discussion on Scenarios and Presentation of Results ndash Fisheries
1545 to 1600 Discussion on Scenarios and Presentation of Results ndash Tourism
1600 to 1630 Discussion on Scenarios and Presentation of Results - General
1630 to 1700 Summary and Concluding Remarks Francis Sefe
Hydrology and Water Resources Workshop No 1 page 23
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2629
Hydrology and Water Resources Okavango
ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2729
Hydrology and Water Resources Okavango
Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2829
Hydrology and Water Resources Okavango
Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2929
Hydrology and Water Resources Okavango Delta Management Plan
ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2629
Hydrology and Water Resources Okavango
ANNEX 2
WORKSHOP PARTICIPANTS
Name Surname Organisation Address Telephone E-mail
Eliot Taylor ODMP-CTA POBox 35 Maun 6801035 Eliottayloriucnorg
Sekgowa Motsumi ODMP POBox 35 Maun 6801237
Hannelore Bendsen HOORC PBag 285 Maun 6861833 hbendsenorcubbw
Felicity Rabolo Department of Tourism
POBox 439Maun
6860492 frabolohotmailcom
Shimane Mongati Tawana LandBoard
POBox 134Maun
6860292 mongatiyahoocouk
Jonathan Diedricks DANIDA POBox 11439Hatfield PretoriaRSA
+271244309350 jondieumdk
Tapson Bombo DWA PBag 02 Maun 6860452 tbombogovbw
Clifford Libalamwe DWA PBag 02 Maun 6860452
Uziruapi Hange DWA PBag 02 Maun 6860452
Saleshando Tsheko DWA PBag 02 Maun 6860452
Banyatsang Dinyando DWA PBag 02 Maun 6860452
Kago Salepito DWA PBag 02 Maun 6860452
Cecilia Molosi DWA PBag 02 Maun 6860452
Ntshwarang Matsuntsube DWA PBag 02 Maun 6860452
Kelemogile Moncho DWA PBag 02 Maun 6860452
Kebuseditswe Shimwe DWA PBag 02 Maun 6860452
Babinang Majatsie DWA PBag 02 Maun 6860452
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2729
Hydrology and Water Resources Okavango
Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2829
Hydrology and Water Resources Okavango
Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2929
Hydrology and Water Resources Okavango Delta Management Plan
ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2729
Hydrology and Water Resources Okavango
Name Surname Organisation Address Telephone E-mail
Keletso Kgosana DWA PBag 02 Maun 6860452
Karaere Tjiparoro DWA PBag 02 Maun 6860452
Chandrasekar Kurugundla DWA PBag 02 Maun 6860452
Amogelang Tebape DWA PBag 02 Maun 6860452
Ompoetse Chere DWA PBag 02 Maun 6860452
Goitebetswe Pharatlhatlhe DWA PBag 02 Maun 6860452
Olebeng Balapi DWA POBox 131Gumare
6874029 obalapigovbw
Bonatla Tsholofelo KCS-ERP PBag BO 50Maun
6862352 coordinatorkcsorgbw
Khawulani Ale Bachobeli DWNP-Research
POBox 11 Maun 6860275 lekkerkosehotmailcom
Margaret Joan McFarlane ODMPBosele POBox 66 Maun 6862349 mcfdynabytebw
Maxwell Kebuelemang MZCDT POBox 21637Maun
6800010
Geoffrey Manja MZCDT POBox 21637Maun
6800010
Constance Masalila ODMPHOORC PBag 285 Maun 6861833 cmasalilaorcubbw
Piotr Wolski HOORC PBag 285 Maun 6861833 pwolskiorcubbw
Benjamin Mafa DWA PBag 0029Gaborone
3952241 bmafagovbw
Kobamelo Dikgola DWA PBag 0029Gaborone
3952241 kdikgolagovbw
Ditiro Moalafhi DWA PBag 0029Gaborone
3952241 dmoalafhigovbw
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2829
Hydrology and Water Resources Okavango
Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2929
Hydrology and Water Resources Okavango Delta Management Plan
ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2829
Hydrology and Water Resources Okavango
Name Surname Organisation Address Telephone E-mail
Alasdair Macdonald DWA PBag 0029Gaborone
3952241 amacdonaldgovbw
Ontlogetse Dikgomo DWA PBag 0029
Gaborone
3952241 odikgomogovbw
Mompoloki Pitlagano DWNP POBox 11 Maun 6860275
Letty Regonamanye NWDC PBag 001 Maun 6861729 lettieshotmailcom
Thethela Bokhutlo Fisheries POBox 70 Maun 6860262 tbokzoneyahoocom
Dominic Mazvimavi HOORC PBag 285 Maun 6861833 dmazvimaviorcubbw
Francis Sefe EHES POBox 20502Gaborone
3952652 ehesbotsnetbw
Pete Hancock BirdlifeBotswana
POBox 20463Maun
6862481 peteinfobw
Hans Enggrob DHI Agern Alle 52970 HorsholmDENMARK
+4545169127 hgedhidk
Nathalie Barbancho ConservationInternational
PBag 132 Maun 6860017 nbarbanchoconservationorg
Nlisi Chillie Mothusi ConservationInternational
PBag 132 Maun 6860017 nmothusiconservationorg
Kesefilwe Thomologo OkavangoConservationTrust
POBox 5Seronga
6876851 octinfobw
Nthakeng Ramotswetla TribalAdministration
POBox 25 Maun 6862238
Hydrology and Water Resources Workshop No 1
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2929
Hydrology and Water Resources Okavango Delta Management Plan
ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
882019 ODMP Stakeholder Workshop Report hydrological model
httpslidepdfcomreaderfullodmp-stakeholder-workshop-report-hydrological-model 2929
Hydrology and Water Resources Okavango Delta Management Plan
ANNEX 3
SELECTED PRESENTATION SLIDES
1 Key Flow Processes in Delta
2 Key Features of MIKE SHE Software Package
3 Evapotranspiration Mechanism
4 Distributed Vegetation Parameters
5 Vegetation Density from Remote Sensing
6 Extent of Surface Water and Rate of Evapotranspiration
7 Characteristics of Surface Water Flows
8 River Channel ndash Flood Plain Coupling
9 Two Dimensional Flood Pattern
10 Ground Water Dynamics
11 Soil Types in Unsaturated Zone
12 Unsaturated Zone and Ground Water
13 Saturated Zone
14 Upstream Inflows (70 years)
15 Upstream Inflows (1992 to 2002)
16 Delta Zones
17 Baseline Overland Flow
18 Baseline Overland Flow (detail)
19 Baseline Depth Time Series
20 Flooded Areas
21 Baseline Soil Moisture
22 Baseline Ground Water Depth
23 Water Balance
24 Dams in Angola ndash Inflows
25 Irrigation Upstream ndash Inflows
26 Irrigation Upstream ndash Impact on Depth of Overland Flow
27 Climate Change ndash Inflows
28 Climate Change ndash Temperature and Precipitation
29 Climate Change ndash Impact on Depth of Overland Flow
30 Climate Change ndash Impact on Depth of Overland Flow ndash Time Series
CLICK HERE TO VIEW SLIDES
(then click Full Screen Slide Show button in bottom right hand corner)
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