A Global Framework for Action

Conjunctive use and managementof groundwater and surface water within existing irrigation commandsthe need for a new focus on an old paradigm

Thematic Paper 2

Groundwater Governance - A Global Framework for Action

Groundwater Governance - A Global Framework for Action (2011-2014) is a joint project supported by the Global Environment Facility (GEF) and implemented by the Food and Agriculture Organisation of the United Nations (FAO), jointly with UNESCO's International Hydrological Programme (UNESCO-IHP), the International Association of Hydrologists (IAH) and the World Bank.

The project is designed to raise awareness of the importance of groundwater resources for many regions of the world, and identify and promote best practices in groundwater governance as a way to achieve the sustainable management of groundwater resources.

The first phase of the project consists of a review of the global situation of groundwater governance and aims to develop of a Global Groundwater Diagnostic that integrates regional and country experiences with prospects for the future. This first phase builds on a series of case studies, thematic papers and five regional consultations.

Twelve thematic papers have thus been prepared to synthesize the current knowledge and experience concerning key economic, policy, institutional, environmental and technical aspects of groundwater management, and address emerging issues and innovative approaches. The 12 thematic papers are listed below and are available on the project website along with a Synthesis Report on Groundwater Governance that compiles the results of the case studies and the thematic papers.

The second phase of the project will develop the main project outcome, a Global Framework for Action consisting of a set of policy and institutional guidelines, recommendations and best practices designed to improve groundwater management at country/local level, and groundwater governance at local, national and transboundary levels.

Thematic PapersNo.1 - Trends in groundwater pollution; trends in loss of groundwater quality and related

aquifers servicesNo.2 - Conjunctive use and management of groundwater and surface waterNo.3 - Urban-rural tensions; opportunities for co-managementNo.4 - Management of recharge / discharge processes and aquifer equilibrium statesNo.5 - Groundwater policy and governanceNo.6 - Legal framework for sustainable groundwater governanceNo.7 - Trends in local groundwater management institutions / user partnershipsNo.8 - Social adoption of groundwater pumping technology and the development of groundwater

cultures: governance at the point of abstractionNo.9 - Macro-economic trends that influence demand for groundwater and related aquifer servicesNo. 10 - Governance of the subsurface and groundwater frontierNo.11 - Political economy of groundwater governanceNo.12 - Groundwater and climate change adaptation

www.groundwatergovernance.org

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GROUNDWATERGOVERNANCE:AGlobalFrameworkforCountryAction

GEFID3726

ThematicPaper2:Conjunctiveuseandmanagementofgroundwaterandsurfacewaterwithinexisting

irrigationcommands:theneedforanewfocusonanoldparadigm

By

W.R.Evans,R.S.EvansandG.F.Holland

SinclairKnightMerz,Australia

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TableofContents

Contents

TableofContents ........................................................................................................................... 2

1. Introduction............................................................................................................................. 5

Part1:Baseline............................................................................................................................... 6

2. Conceptsandmisconceptionsofconjunctiveuse....................................................... 62.1 Systemsthatoccurspontaneouslyandsystemsthatareplanned.......................................... 102.2 Typesofaquifers...................................................................................................................... 112.3 Highlyversuspoorlyconnectedsystems ................................................................................. 12

2.4 Salinitycontrolasadriver ....................................................................................................... 172.5 Technicalandmanagementdifferencesbetweensurfacewaterandgroundwater............... 172.6 Overviewofmajorirrigationsystemsthroughouttheworldwherebothsurfacewaterand

groundwaterareused ......................................................................................................................... 182.7 Lessonslearntaboutgovernance ............................................................................................ 20

Part2:Diagnostic.........................................................................................................................22

3. Examplesofsuccessesandfailuresofconjunctiveuse...........................................223.1 UttarPradesh–INDIA.............................................................................................................. 22

3.2 Mendoza–ARGENTINA ........................................................................................................... 253.3 Queensland–AUSTRALIA ........................................................................................................ 273.4 IndusBasin–PAKISTAN ........................................................................................................... 29

3.5 Otherexamples ....................................................................................................................... 30

4. Scopeforsecuringsocialandenvironmentalbenefitsthroughconjunctiveuseschemes...........................................................................................................................................32

5. Governancetoolsthatpromotetheadoptionofconjunctiveuse........................335.1 Requiredinstitutionalstructuresforeffectiveconjunctiveusemanagement ........................ 355.2 Optimumconjunctivemanagementandwhatismeantbyconjunctiveuseplanning............ 36

Part3:Prospects ..........................................................................................................................37

6. Prospectsforslowingorreversingtrendsthrough‘governance’ .......................376.1 Governanceapproaches .......................................................................................................... 37

6.1.1 Institutionalstrengthening .............................................................................................. 386.1.2 Policyandlegislation ....................................................................................................... 38

6.1.3 Planning ........................................................................................................................... 396.1.4 Marketandpricingapproaches ....................................................................................... 396.1.5 On‐the‐groundimplementation....................................................................................... 39

6.1.6 Knowledgegeneration ..................................................................................................... 406.2 Useoffinancialandmarket‐basedinstrumentstopromoteplannedconjunctiveuse .......... 40

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6.3 Asuggestedsetofconjunctiveuseprinciplesforconsiderationwithinagovernanceapproach 41

7. Conclusions ............................................................................................................................42

8. References ..............................................................................................................................43

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ListofTables

1. Summaryoftypesofaquiferrechargeenhancementstrategies………………………………………………………..8

2. Aquifertypology……………………………………………………………………………………………………………………………….9

3. Typicalcharacteristicsofgroundwaterandsurfacewater………………………………………………………………..15

4. Summaryofdriversforsoleuseofgroundwaterorsurfacewaterresources.....................................17

5. Varyingownershipmodelsanddegreeofmanagementforgroundwaterandsurfacewaterbasedirrigationcommands…………………………………………………………………………………………………………………………32

6. Possiblemanagementapproachestoachieveplannedconjunctiveuseforvaryingmanagementmodelsanddegreeofhydraulicconnectionbetweengroundwaterandsurfacewater.………………….32

ListofFigures

1. Schematiclong‐profileofatypicalalluvialgroundwatersysteminahumidregiondetailingthevariationingroundwater‐surfacewaterconnectivityandsalinisationhazards…………………………………..8

2. Connectivityrelationships:a)gainingconnectedsystem;b)losingconnectedsystem;c)disconnectedsystem;d)fluctuatingconnected/disconnectedsystem……………………………………………………………………12

3. Simplifiedgroundwaterpumpingtimeandimpactrelationship……………………………………………………….13

4. Comparisonofwater‐tabledepthbefore(1984)andafter(1998)recharge,UttarPradesh.MapsoftheLakhaotiBranchCanal,UtterPradesh,India,showingpostmonsoondepthtogroundwaterbeforeand

afterrechargemanagementbegan.Darkblueareasshowwheregroundwaterlevelsareclosetothesurface……………………………………………………………………………………………………………………………………………..20

5. HydrogeologicalprofilealongtheflowdirectionoftheCarrizalaquifersystem……………………………….23

6. Waterbudget,Burdekindistrict,Australia……………………………………………………………………………………..….27

7. Increasingtrendinconjunctiveuse,Punjab,Pakistan……………………………………………………………………....27

ListofBoxes

1. Howtoavoiddoubleaccounting……………………………………………………………............................………....15

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1. Introduction

Conjunctive use of groundwater and surfacewater in an irrigation setting is the process of usingwater from the twodifferent sources for consumptivepurposes. Conjunctiveuse can refer to the

practiceatthefarmlevelofsourcingwaterfrombothawellandanirrigationdeliverycanal,orcanrefertoastrategicapproachattheirrigationcommandlevelwheresurfacewaterandgroundwaterinputsarecentrallymanagedasaninputtoirrigationsystems.Accordingly,conjunctiveusecanbe

characterizedasbeingplanned(where it ispracticedasadirectresultofmanagement intention–generallywith a topdownapproach) comparedwith spontaneoususe (where it occurs at a grassroots level–generallywithabottomupapproach).Thesignificantdifferencebetweenunplanned

and planned conjunctive use, and the approach governancemust take tomaximize the potentialbenefitsfromsuchuse,isexploredwithinthispaper.Wherebothsurfaceandgroundwatersourcesare directly available to the end user, spontaneous conjunctive use generally proliferates, with

individualsopportunisticallyabletomakedecisionsaboutwatersourcesatthefarmscale.

Theplannedconjunctiveuseofgroundwaterandsurfacewaterhasthepotentialtoofferbenefitsinterms of economic and social outcomes through significantly increased water use efficiency. Itsupportsgreater foodandfibreyieldperunitofwateruse,an importantconsiderationwithinthe

internationalpolicyarenagiventhecriticalconcernsforfoodsecuritythatprevail inmanypartsofthe world. At the resource level, groundwater pumping for irrigation used in conjunction withsurfacewaterprovidesbenefitsthatincreasethewatersupplyormitigateundesirablefluctuations

inthesupply(Tsur,1990)andcontrolshallowwater‐tablelevelsandconsequentsoilsalinity.

Theabsenceofplannersandofastrategicagendawithingovernments,tocapitalizeonthepotentialforplannedconjunctiveusetosupporttheseneeds,isgenerallyasignificantimpedimenttomeetingnationaland internationalobjectivesas theypertain to foodand fibresecurity.There isanurgent

need tomaximize productionwithin the context of the sustainablemanagement of groundwaterand surface water. The challenges posed in some ways reflect the evolution in objectives and

management approaches that have been, and remain, common to irrigation developmentthroughouttheworld.

Manyexisting irrigationcommandssourcetheirwatersupply fromboththecaptureofcatchmentrunoffandaquifersystems.Typically,waterhasbeensourced fromeithersurfaceorgroundwater

supplies,with the primary supply supplementedby the alternative source over time.Accordingly,governance settings, infrastructure provisions and water management arrangements haveemphasizedtherequirementsoftheprimarysourceofsupply,inevitablyrequiringthe“retrofitting”

ofmanagementapproachesontoexistingirrigationcommandstoincorporatesupplementarywatersources over time. Optimizing the management and use of such resources, which have beendevelopedseparatelywillinsomesituationsrequiresubstantialinvestmentincapitalinfrastructure

andreformof institutionalstructures.Putsimply,plannedconjunctiveuse isrelativelysimplewithgreenfield (or new development sites), but significantly harder to achieve within existing hydro‐physicalandinstitutional/socialsystems.

Whilst these challenges and the associated benefits of a strategically planned approach are well

understood and the subject of numerous reports on conjunctive use management, the current

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statusofwatermanagementandplanningaroundtheworldsuggeststhatlittlehasbeenachievedinits widespread implementation. This paper explores the reasons underpinning the apparent poor

approachtofullintegrationinthemanagementanduseofbothwatersources,andtheabsenceofmore coordinated planning. It is the authors’ view that there remain significant gaps in watermanagers’ understanding as to what aspects of the contemporary management regime require

overhaultoachieveintegratedmanagementandtheimprovedoutcomesthatcouldbeexpected,ascompared with separatemanagement arrangements. Such lack of understanding is an importantimpediment to the governance, institutional andphysical infrastructure reformswherebyplanned

conjunctive use could improve existing management and regulatory arrangements. Reforms mayalso be impeded by different ‘ownership’ models of groundwater and surface water deliveryinfrastructureandtheassociatedentitlementregime(i.e.privateand/orpublic);asituationthathas

implications for social and institutional behaviour and ultimately the adoption of a conjunctivemanagementapproach.

Thispaper is intendedtoprovide insight into thesebarriers toadoptionandhenceprovideanewfocusonanoldparadigm;afocusintendedtomakeprogresswiththeobjectiveofimprovedwater

management and water use efficiency and so support longer term outcomes in the form ofimprovedfoodsecurityincriticalpartsoftheworld.

Part1:Baseline

2. ConceptsandmisconceptionsofconjunctiveuseIn most climates around the world, precipitation, and consequently peak river discharge, occursduring a particular season of the year, whereas crop irrigation water requirements are at their

greatestduringperiodsof lowrainfallwhenunregulatedstreamflowsaresignificantly lower. Formany irrigation systems, water supply is aligned with crop water requirements through theconstructionandmanagementofdams,whichcapturewaterduringperiodsofhighflow,enabling

regulated releases to meet crop water requirements. However, the construction, operation anddistributionofwater fromdamsare inherently costlyundertakings thathavesocialandecologicalimpactsuponcommunitiesandtheenvironmentinandonwhichtheyarebuilt.Furthermore,dams

and the associated distribution systems are commonly subject to high system losses throughevaporation and leakage, though it is debateablewhether the latter is actually detrimental given

thatitoftencontributessubstantiallytogroundwaterrecharge.

Conversely, under natural recharge regimes, groundwater storage requires no infrastructure, theaquifer serving as the natural distribution system. The point of irrigation, in a groundwater‐fedirrigation command, is commonly opportunistically located close to the groundwater extraction

point, which in turn is integrated into on‐farm irrigation infrastructure. Under a sustainableextractionregime,groundwaterofasuitablequalitycanprovideareliablesourceofwatereitherasasolesupplyofwater,ortosupplementalternativesources.Commonly,thelargestoragetoannual

useratiotypicalofmanyregionalaquifersmeansthatthereliabilityofsupplyfromgroundwaterisless affected by seasonal conditions than are surface water systems, and may indeed providesignificantbufferingagainstdroughts.However,mostintensivelyusedgroundwatersystems(within

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the contextof irrigation) are located in the semi‐aridparts of theworld andare characterizedbyrelativelylowannualrecharge.Thentheratioofannualusetolong‐termannualrechargebecomes

the predominant measure of sustainability for these systems, independent of aquifer storage.Whilst providing a large storage and natural distribution system, aquifers are, generally speaking,unabletocaptureasignificantportionofrunoffarisingfromlargerainfallevents.Aquiferstherefore

donotannuallyharvestwateronascalethatjustifiestheconstructionandoperationofcentralizedwaterdeliverysystemsbasedongroundwateralone.

Thesespecificcharacteristicsofsurfaceandgroundwaterresourceshaveimportantimplicationsfortheoptimaldesignandoperationof irrigationsystems. However, thebenefitsand limitationsare

rarely fully considered in the optimization of system design. Rather, supply design is normallyfocusedupononesourceofwater,withconjunctiveuseoftencomingasan‘afterthought’.Hence,infrastructureandmanagementresponsesareretrofittedtoexistingarrangements.

‘Conjunctive use’, as formany such technical terms, is the subject of a range of definitions. It is

defined by Foster et al. (2010) as a situation where “both groundwater and surface water aredeveloped (or co‐exist and can be developed) to supply a given ... irrigation canal‐command –although not necessarily using both sources continuously over time nor providing each individual

wateruserfrombothsources”.AlternativelyFAO(1995)describesitasfollows:“Conjunctiveuseofsurface water and groundwater consists of harmoniously combining the use of both sources ofwaterinordertominimizetheundesirablephysical,environmentalandeconomicaleffectsofeach

solutionandtooptimisethewaterdemand/supplybalance”.

Consideringbothof thesedefinitions, theaimofconjunctiveuseandmanagement is tomaximizethe benefits arising from the innate characteristics of surface and groundwater water use;

characteristicsthat,throughplannedintegrationofbothwatersources,providecomplementaryandoptimalproductivityandwateruseefficiencyoutcomes.

At the farm scale, conjunctive use is implemented on a day‐to‐day basis with ‘management’characterized by low‐ or micro‐level decisions incorporating factors such as resource availability,

costsofdeliverytothecrop,tradabilityofunusedallocationandwaterquality. Collectively,thesefactors contribute to minimizing costs, optimizing production and maximizing net profitability.However,attheirrigationcommandlevel,plannedconjunctivewateruseandmanagementaimsfor

higher‐levelobjectives. Plannedconjunctiveuseisexpectedtooptimizeproductivityandequityinthemanagementofsurfacewaterandgroundwater resources (WorldBank2006)andtopromoteeconomic,environmentalandsocialsustainability.

Depending on the relative volumetric mix of the two resources, and on the manner in which

associated irrigation has been historically developed, the nature of conjunctive use at any oneirrigation commandwill be significantly different. For example,management approachesmust bedifferentwhere90percentoftheavailablewaterisfromoneofthetworesources,ascomparedto

thesituationwhereneither resourcesuppliesamajority.Alsosubtly,groundwatercanhave threeseparate roles within a conjunctive management framework: it can be used as an alternativemethodtodistributewateracross irrigationcommands; itcanbeusedasastoragemechanismto

smooth out the supply/demand balance either across seasonal patterns of water availability, oracross decadal variability in climate; or it can be used tomanage shallowwater tables to reduce

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salinizationandwaterlogging.Management (andgovernance)approachesmustbeawareof thesesubtletiesinattributesandplanaccordingly.

Withinthiscontext,Suhaquillo(2004)discussestheuseofaquiferstorageandthepartitioningofits

useintoartificialrechargeversusthealternateuseofgroundwaterandsurfacewaterdependingonseasonally available water. Related to Suhaquillo’s partitioning, an important consideration whenconjunctivelymanaging surfacewater and groundwater is the degree of connection between the

twowater resources–or theoverall resource ‘connectivity’. Conjunctiveuse refers to theway inwhichwaterresourcesaremanaged,whereasa‘connectedsystem’referstoanenvironmentwheresurface water and groundwater are effectively one connected resource. Most conjunctive use

systems use the connectedness of the systems to the advantage of the user; however, naturalconnectedness is not a necessary feature. Engineered intervention can modify the degree ofconnectednesswhereitisdesiredandeconomicallybeneficial.

It is also important to note that, fundamentally, connectivity has nothing to do with conjunctive

management.Oneisaphysicalattributeofthewatersystem;theother isaformofmanagement.However, theyare related in that recognitionof connectivityprovides thecontextand frameworkwithinwhich conjunctivemanagement should be planned and undertaken.When groundwater is

extractedfromaconnectedsystem,itmayinducerechargefromthesurfacewaterbody,reducingthevolumeofavailable surfacewater. Inall circumstances,however, the important considerationformanagementisthetimelagfortheeffectsofuseofoneresourcetobetransmittedtotheother

resource, regardless of how natural or engineered the connectivity. Where time lags are long,specific management challenges are evident and present major impediments. Similarly, whensurfacewaterisdivertedfromaconnectedsystem,itcanreduceaquiferrechargeandthereforethe

availability of suitable quality groundwater for extraction. If surface water and groundwater aremanagedseparately inconnectedsystems,caremustbe taken toavoid ‘doubleaccounting’when

allocatingsurfacewaterandgroundwaterfromtheoneconnectedresource.

Whilst the aquifer provides a natural storage system to source groundwater during periods ofdemand,optimalmanagementmaytakeadvantageofunutilizedstoragecapacitythroughManagedAquiferRecharge(MAR)wherebyrechargeisenhancedfor laterrecovery. Fromaconjunctiveuse

perspective, such amanagement approach enables surplus surface water to be captured (duringhigh‐flowevents)andutilizedat timeswhen thedamor streamflow isdepletedorwhenwater isrequiredforotherpurposes. Groundwaterrechargeenhancementcanbedonevia injectiondown

rechargewells,storageofwaterininfiltrationbasinsorslowingthenaturalflowofsurfacewaterstoinduceadditionalgroundwaterrecharge (Table1).Anexampleof thisapproach is foundontheAlBattinah coastal plain of eastern Oman where highly episodicwadi flood flows are captured by

dams,andtheretainedwaterisencouragedtorechargetheproductivegravelaquiferunderlyingthearea. However, in general, aquifers rarely offer large enough storage capacity for absorbing largevolumesoffloodwaterinashortperiodoftime(FAO,1995).

Theuseofartificialrecharge(orMAR)asamanagementoptioncouplestheattributesoftheaquifer

systemwiththoseofthesurfacewatersystemwithoutrelyinguponthenaturalhydrologicalregimeofthewatercycle. Ineffect, itdecouplestheneedforphysicalconnectionbetweensurfacewaterand groundwater resources through engineering interventions.MAR as an adjunct to conjunctive

managementwould inmostcasesonlybe likelytooccurthroughcoordinatedplanningwhichmay

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range from village‐scale low‐technologywater harvesting approaches, to technically sophisticatedapproaches (as increasingly being adopted in the developedworld). Irrespective of the degree of

technical sophistication, theplanningrequirementsassociatedwithasuccessfulMAR initiativearesuchthatitisunlikelytobeadoptedwherespontaneous‘farmscale’conjunctiveuseprevails.

Table1:Summaryoftypesofaquiferrechargeenhancementstrategies(Fosteretal.2003).

Type GeneralFeatures PreferredApplicationWaterharvesting

Dugshafts/tankstowhichlocalstormrunoffisledundergravityforinfiltration

Fieldsoil/waterconservationthroughterracing/contourploughing/afforestation

Invillagesofrelativelylow‐densitypopulationwithpermeablesubsoil

Widelyapplicablebutespeciallyonslopinglandinupperpartsofcatchments

In‐channelstructures

Check/rubberdamstodetainrunoffwithfirstretainingsedimentandgeneratingclearwater

Rechargedamwithreservoirusedforbedinfiltrationandgeneratingclearwater

Riverbedbafflingtodeflectflowandincreaseinfiltration

Subsurfacecut‐offbyimpermeablemembraneand/orpuddleclayintrenchtoimpoundunderflow

Ingullieswithuncertainrunofffrequencyandhighstreamslope

Uppervalleywithsufficientrunoffandondeepwater‐tableaquifer

Widebraidedriversonpiedmontplain

Onlywidevalleyswiththinalluviumoverlyingimpermeablebedrock

Off‐channeltechniques

Artificialbasins/canalsintowhichstormrunoffisdivertedwithpre‐basinforsedimentremoval

Landspreadingbyfloodingofriparianlandsometimescultivatedwithflood‐tolerantcrops

Onsuperficialalluvialdepositsoflowpermeability

Onpermeablealluvium,alsowithfloodreliefbenefits

Injectionwells

Rechargeboreholesintopermeableaquiferhorizonsusedalternatelyforinjection/pumping

Storage/recoveryofsurpluswaterfrompotabletreatmentplants

At the general level, the benefits attributed to optimizing conjunctive use of surface and

groundwaterhavebeeninvestigatedovermanyyearsthroughtheoreticalmodellingandstudiesofphysicalsystems.Thesebenefitstaketheformof:

• economicgains;• increasesinproductivity;• energysavings;• increasedcapacitytoirrigatevialargerareas;• waterresourceefficiency;and• infrastructureoptimisation.

However, there are few published analyses of the actual socio‐economic benefits that can beattributedto the implementationofconjunctiveusemanagement inspecific irrigationcommands.

This isamajor impediment to furthercommunicatingthepositivemessagesregardingconjunctiveuse.However,anexampleofsuchstudies includesBredehoeftandYoung(1983),whomodelledatwofoldincreaseinnetbenefitarisingfromconjunctivemanagement.AnotheristheAgricultureand

RuralDevelopmentGroup,WorldBank(2006),whichreporteda26percentincreaseinnetfarmerincome, substantial energy savings, increased irrigation and substantial increase in irrigated croparea for Uttar Pradesh, India, as a result of conjunctivemanagement ofmonsoon floodwaters in

combinationwitharegionalgroundwatersystem.

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2.1 SystemsthatoccurspontaneouslyandsystemsthatareplannedThe introductory section of this paper highlights the two fundamentally different approaches to

conjunctive use management, however, there is a continuum in the way that conjunctivemanagement evolves from spontaneous (or incidental/unplanned) conjunctive use at one end, toplannedconjunctivemanagementanduseattheother.

Plannedconjunctivemanagementanduseofsurfacewaterandgroundwaterareusuallypracticed

at the State or regional level and can optimize water allocation with respect to surface wateravailability and distribution, thus reducing evaporative losses in surface water storages andminimizingenergycostsofirrigationintermsofkWhr/ha(Fosteretal.,2010).Plannedconjunctive

managementisbestimplementedatthecommencementofadevelopmentalthoughexperiencehasshownoptimaloutcomesmaybedifficulttoachievewhenattemptsaremadetoredesignandretro‐fittheapproach,oncewaterresourcedevelopmentiswelladvanced.

Where groundwater and surface water are used conjunctively in various parts of the world,

spontaneoususeprevails.FosterandSteenbergen(2011)emphasizethatspontaneousconjunctiveuseof shallowaquifers in irrigation‐canal‐commands is drivenby the capacity for groundwater tobufferthevariabilityofsurfacewateravailabilityenabling:

• greaterwatersupplysecurity;• securingexistingcropsandpermittingnewcroptypestobeestablished;• bettertimingforirrigation,includingextensionofthecroppingseason;• largerwateryieldthanwouldgenerallybepossibleusingonlyonesource;• reducedenvironmentalimpact;and• avoidanceofexcessivesurfacewaterorgroundwaterdepletion.

Fosteretal.(2010)reportthatthemostcommonsituationinwhichspontaneousconjunctiveuseofsurfacewaterandgroundwaterresourcesoccursiswherecanal‐basedirrigationcommandsare:

• inadequatelymaintainedandunabletosustaindesignflowsthroughoutthesystem;• poorlyadministered,allowingunauthorizedorexcessiveoff‐takes;• over‐stretchedwithrespecttosurfacewateravailabilityfordryseasondiversion;and• tiedtorigidcanal‐waterdeliveryschedulesandunabletorespondtocropneeds.

Additionally,spontaneousconjunctiveuseisalsodriventoalargedegreebypoorreliabilityofwater

quality in surfacewater supply cannels.Wellsbecomean insuranceagainst thisunreliability.Poorwaterqualityisacommonfactoratthetailofmostirrigationcanalsystemsandusuallyreflectspoorinfrastructuremaintenance.Thesefactorsleadtoinadequateirrigationservices.Asaconsequence,

the drilling of private waterwells usually proliferates, and a high reliance on groundwater oftenfollows(Fosteretal.,2010).

FosterandSteenbergen(2011)reportspontaneousconjunctivegroundwaterandsurfacewateruseinIndian,Pakistani,MoroccanandArgentineanirrigation‐canalcommandswhichhavelargelyarisen

due to inadequate surface‐water supply to meet irrigation demand. Many other examples fromdevelopedcountriesalsoshowthatitisnotsimplyadevelopingcountryproblem–itisaninherentproblemwherever canal‐based irrigation is practiced andwhere there are challenges in terms of

reliabilityofwatersupplyandquality.

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Insummary,thespontaneousapproachtotheconjunctiveuseofsurfaceandgroundwatersourcesreflectsa’legacyofhistory’.Thefocusforgreen‐fieldirrigationdevelopmentsisprimarilyaccessto

water, rather than theefficientandoptimaluseof thatwater;a consideration thatdoesnotgainattention until competition for water resources intensifies. Advancing beyond the farm‐scalespontaneousaccess toeachwater source toaplannedconjunctivemanagementapproachentails

significanttechnical,economic,institutionalandsocialchallengesthatcanonlybeovercomewithaneffectivegovernancemodel.

2.2 Typesofaquifers

Conjunctive use can be practiced in a large number of combinations of surface water andgroundwaterregimes.Generally,surfacewatersystemshavehighannualflowvolumesandtendtoberegulated,perennial rivers,whereasgroundwatersystemsshowmuchmorevariation.There is,

however, a distinction between those integrated resources systems where conjunctive use hasdevelopedspontaneouslyandthosewhereitisplanned.

Planned conjunctive use systems can be developedonmost groundwater regimeswhere there isadequatestorageandwellyieldtoenableefficientutilizationofboththesupplyanddemandsideof

theequation.Theonlydistinction,effectively,isthedegreetowhichtheaquifersystemprovidesasubstantialnaturalconnectivitytothesurfacewatersystem,comparedwiththosewhereconstraints

in hydrological linkages require significant engineering to overcome limitations in connectivity.Where the degree of connectivity between surface water and groundwater is poor or limited,engineered solutions can be used to transfer water from one resource to another. Within such

aquifers,theseinherentconditionsmayrequireMARschemestobeadopted,sometimesonalargescale,subjecttoeconomicviabilityandtoarangeofattributesoftheaquifer/sourcewaterrequiredforfeasibleMAR.Suchplannedandengineeredsolutionsultimatelyaredependentonthe levelof

investmentavailablebyeithergovernmentortheprivatesector,andtheproductivitybenefitsthatcanbeachieved.

Thetypesofaquifersinvolvedinconjunctiveuseregimesthatarespontaneousinnatureareusuallyrestrictedtotypesthatexhibitcertainattributes.Generally,suchsystemsarebroadregionalalluvial

aquifers thathavegoodconnectioneitherwithassociated large riversorwith irrigationcommandareas,bothofwhichhave thepotential toprovidea significantsourceof recharge.Previousworkhasdocumentedthatthepotentialforconjunctiveusevariesconsiderablywiththetypeofaquifer

involved (Foster et al., 2010). These types can be partitioned into four major groupings (

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Table2).

Thistypologywasfurtherrefined(FosterandvanSteenbergen,2011:Figure1)toincludevariationassociatedwithpositionintermsofthelongitudinalprofileofthealluvialsystem;namely,outwash

and peneplain, floodplain and coastal plain. Each of these settings provides a different style ofaquifermaterial,depthtowatertableandsurfacewater‐to‐groundwaterconnectivity.

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Table2:Aquifertypology(afterFosteretal.,2010)

AquiferType ExampleLocationUpstreamhumidoraridoutwashpeneplain

IndianPunjab‐IndusPeneplain,UpperOasesMendoza–ArgentinaYaquiValley,Sonora–Mexico

Humidbutdrought‐pronemiddlealluvialplain

MiddleGangeticPlain–IndiaMiddleChaoPhyraBasin–Thailand

Hyper‐aridmiddlealluvialplain MiddleIndusPlain–PakistanLowerIcaValley–PeruTadla–MoroccoTihama–Yemen

Downstreamalluvialplainordeltawithconfinedgroundwater

GangesDelta–BangladeshLowerOasisMendoza–ArgentinaNileDelta–Egypt

Clearly, therearesomeminimumrequirements thatwillactasa threshold forgroundwater tobeseriouslyconsideredaspartofaconjunctiveusesystem.Theserequirementsrelatetotheaquifer

attributesthatcontrolthesizeoftheresource,therateatwhich itcanyieldgroundwaterandtheeconomic viability of extraction. This means that aquifer size (storage ability), aquifer or basineffectivehydraulicconductivityandthedepthtothewatertable/potentiometricsurfacearecritical.

Sotooiswaterquality.

2.3 HighlyversuspoorlyconnectedsystemsWhengroundwaterandsurfacewaterarehydrologicallyconnected,theinterchangeoftheresource

betweenthesystemsrequiresconsiderationduringthemanagementprocess. Accordingly, it isanaspect thatmustbe consideredwithina conjunctiveuse framework,as it can shape theavailableoptionsandhencedefinetheoptimalapproachtoconjunctivemanagement.

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Figure1:Schematiclong‐profileofatypicalalluvialgroundwatersysteminahumidregiondetailingthevariationingroundwater‐surfacewaterconnectivityandsalinizationhazards(fromFosteretal.,2011)

Connectivity comprises two important components: the degree of connection between the two

resources and the time lag for extraction from one resource to impact upon the other. A highlyconnected resource would be one where the degree of connection is high and the time lag fortransmission of impacts is very fast. A fundamental tenet of connectivity understanding is that,

essentially,allsurfacewaterandgroundwatersystemsareconnectedandthatitisjustamatteroftimeforimpactstobefeltacrosstheconnection.Importantexceptionstothesetruismsarethatofcanal‐dominated irrigationcommands,wherethewatertable isbelowthewater level inthecanal

system or where the water table is shallow and groundwater extraction is capturing losses toevapotranspiration. In such areas rechargemay alsobedominatedby irrigation‐induced rootzonedrainage, and hence vertical unsaturated zone processesmay control the interaction/connectivity

process. In these latter areas, the canal distribution systemsmay provide a significantly reducedcontributiontogroundwaterextraction.

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Alargebodyofresearchandinvestigationhasbeenundertakenontheissueofconnectivityandthiswillnotbedealtwithinanydetailhere.Thesalientissueforconjunctivemanagement,especiallyin

a planned environment, is to understand the nature of connectivity as a factor in resource useoptimization and to ensure that connectivity is understood when considering water resourceaccountinginaconjunctivelymanagedwatersystem.

Figure2providesexamplesofconnectedgainingand losingstreamsandofstreamsthat fluctuate

between these two situations (a, b and d respectively). It also indicates that the head differencebetweentheriverandtheaquiferdetermines thedirectionof flow.Therateof flowbetweentheriver and aquifer will depend on the hydraulic conductivity of the aquifer and the hydraulic

conductanceofthebedoftheriver.Figure2(c)providesanexampleofastreamthatisconnectedto theadjoiningaquifer throughanunsaturated zone; this situation isusually found inaridareas.The interchange ofwater between surfacewater and groundwater is controlled by the hydraulic

conductivityoftheunsaturatedzone(SKM,2011).

Figure2:Connectivityrelationships:a)gainingconnectedsystem;b)losingconnectedsystem;c)disconnectedsystem;d)fluctuatingconnected/disconnectedsystem(modifiedafterWinteretal.,1998)

Thetimingoftheimpactsisveryimportant.Bredehoeft(2011)hasshownthattimingisimportantto

water resources managers whether the impacts from groundwater pumping on a stream occurwithin an irrigation season, or over a longer period. Connectivity will control the timing forgroundwaterrechargeandthetimingofchangesindischargefromgroundwatertothestreamsdue

togroundwaterabstraction.

Figure3showsasimpleexampleoftherelationshipbetweengroundwaterpumpingandthetimingof impacts felt in a connected surface‐water system. In this hypothetical example, the full impacttime(t100)hasnotbeenspecified,butitcanvaryfromveryshort(days)toverylong(manydecades).

Itisimportanttoattempttounderstandorcalculatethelikelyt100timesoimpactscanbeaccountedforwithinintegratedwaterresourceplans.

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Box1. Howtoavoiddoubleaccounting

Aspreviouslydiscussed in thispaper, ‘doubleaccounting’ relates to thedualallocationofa single

parcel of water. It is a common occurrence throughout the world due to the evolution of waterresourcedevelopmentandassociatedregulatoryarrangements,anditmayreflectanabsenceofaproperwaterresourceassessment,poorunderstandingofthewaterbalance,ortheundertakingof

independent resource assessments for surface water and groundwater. Two common situationsoccur.

Firstly, when surface‐water‐based irrigation causes recharge to the groundwater system. Thegroundwaterrechargeisseenasa‘loss’fromasurface‐waterpointofview.Atypicalwaterresource

management response may be to invest in improved sealing canals or constructing pipelines,howeverthismaynotbethemostefficientresponse. Insituationswheregroundwaterrecovery isfinanciallyviable,amoreefficientapproachmaybetoutilizeaquiferstoragecapacityandthediffuse

distributionoftheresourceprovidedbythegroundwatersystem.Ifinsuchsituations,canalleakagehas already been allocated to surface water users, then it should not also be allocated togroundwaterusers.Instead,mechanismssuchastradeshouldbeusedtotransferentitlementsfrom

one user to another, and hence maintain the integrity of the water accounting framework.Furthermore,anydecisiontoreduceleakagethroughcanallining,andhencereducerecharge,wouldrequire revision to the water resource assessment and may require appropriate adjustments to

entitlements,particularlyifsuchrechargehadbeenallocatedtogroundwaterusers.

Secondly, the classical surface water/groundwater interaction situation is where groundwaterdischarges to become base flow. Considered in isolation, thismay be deemed as a “loss” from agroundwatermanagementperspectiveandajustifiablebasisforallowinggroundwaterpumpingto

substantially reduce stream flow. Similarly from a surface‐water management perspective, thesignificance of groundwater discharge in maintaining stream flow during the dry season may bepoorlyrecognized.Therearemanyexamplesintheliterature(forexample,Evans,2007)wherethe

implicationsofnotrecognizingsuch interactionhavecontributedtothedepletionofriversaroundtheworld.Theassessmentoftheinteractionrequiresanintegratedresourceassessment,withthewater balance taking into account all extraction regimes and the consequential impacts on both

groundwaterandsurfacewaterresources.

Eliminating double accounting requires integrating water entitlements with a water balance thatreflects the full hydrological cycle, and hence fully appreciating the amount and timing of theinteraction between groundwater and surfacewater. It is also critical to appreciate the temporal

variabilityof theprocess. In this case, it is important that theconjunctiveplanning time framebelongterm,forexample50years.Short‐termplanningtomeetpoliticalorsocialobjectiveswillnot

achieveeffectiveconjunctivemanagement.Therearesomerelativelyraresituationswherethereiseffectivelyno interactionbetweengroundwaterand surfacewater. In such situations, conjunctivemanagementisrelativelylesscomplicated,butnonethelessimportantintermsofachievingoptimal

watermanagementoutcomes.

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Figure3:Simplifiedgroundwaterpumpingtimeandimpactrelationship

Withinconnectedsystems,groundwaterabstractionwillthereforeinduceaquiferrechargefromthesurfacewaterbodyreducingthevolumeofavailablesurfacewater,althoughasshowninFigure3,

themagnitudeoftheimpactswillbeafunctionoftime,whichinturnwillbedependentuponthepropertiesoftheassociatedhydrology.Similarly,whensurfacewater isdivertedfromaconnectedsystemitcanreduceaquiferrechargeandthereforetheavailabilityofsuitablequalitygroundwater

forextraction.Ifsurfacewaterandgroundwateraremanagedseparatelyinconnectedsystems,caremust be taken to avoid ‘double accounting’ where the same volume of water is potentially

attributedtoboththesurfaceandgroundwaterresource.Theissueofdoubleaccountingisexploredinmoredetail elsewhere in this paper (Box 1), but it isworth notingwithin this section that it isgenerallyreflectedinsituationswherestreamflowleakageisaccountedbothasstreamflowandas

groundwaterrecharge.Similarly,baseflowcanbeaccountedbothasgroundwaterdischargeandasnormalstreamflow.

In cases where the two water resources are highly connected with short time lags, conjunctivemanagementmaybesupportedbyatransparentwater‐accountingframeworkthatcanbereported

on for both surface and groundwater on an annual basis. Itmay provide flexibility in theway inwhichsurfaceandgroundwaterisallocatedonanannualbasis,andcouldfacilitatethedevelopmentof a robust two‐way water‐trading regime between the groundwater and surface water system,

providingthird‐partyimpactsareunderstoodandeffectivelymanaged.

Conjunctive management within an environment where surface and groundwater systems arepoorlyconnectedisunlikelytoprovidesuchadegreeofintegration.Whilstthereareopportunitiesforintegration(suchastheapplicationofMARdiscussedpreviously)andfortakingadvantageofthe

uniqueattributesofgroundwaterandsurfacewater,suchasstorage,distributionandreliability indryperiods (also identifiedearlier), theopportunitiesandbenefits thathavethepotential toarisefrom conjunctive use will be different, reflecting differences in the hydrological environment. In

otherwords,withinpoorlyconnectedsystems,conjunctivemanagementwillbeframedaroundthe

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task of complementary and integrated management of water use, without the need for suchintegrationtoconsiderhydrologicallinkagesofthewatersources.Thisismodified,however,where

engineeredsolutionsenablebetter(anthropogenic)connectionbetweenthetwopartsofthewatersystem.

2.4 Salinitycontrolasadriver

Major benefits and contributing drivers to the establishment of conjunctive use in irrigationcommands are water‐table control and ensuing soil‐salinity management. As has been shownthroughout India and Pakistan, groundwater extraction from unconfined aquifers supports the

managementofsoilsalinitybyprovidinganopportunityforleachingofaccumulatedsalts.Inthesecases, the factors discussed above that drive development of the groundwater system (primarilyhydraulicconductivity)arenotasimportantasthebenefitsofsub‐surfacedrainage.Itisimportant

that governance arrangements clearly acknowledge these benefits, where applicable, and thatplanningalsoconsidersthemanagementofsaltwhereabstractedwatersuppliesareintegratedintothesupplysystem.

2.5 TechnicalandmanagementdifferencesbetweensurfacewaterandgroundwaterThe characteristics of the two primary water sources associated with conjunctive use and

management (i.e. groundwater comparedwith surfacewater)are inherentlydifferent;differencesthatmustbeappreciatedwhenoptimizingtheiruse.AsummaryoftypicalcharacteristicsassociatedwithgroundwaterandsurfacewaterresourcesisprovidedinTable4.

Table4:Typicalcharacteristicsofgroundwaterandsurfacewater

Characteristic Groundwater SurfaceWaterResponsetime Slow QuickTimelag Long ShortSizeofstorage Large SmallSecurityofsupply High LowWaterquality Poor Good*Spatialmanagementscale Diffuse LinearOwnership Private PublicFlexibilityofsupply Veryflexible Notflexible*Whilstsurfacewatersuppliedwithinirrigationareasisgenerallyofahigherqualitythangroundwater,itisworthnotingthat surface water quality often deteriorates toward the downstream end of the distribution system if the irrigationdeliverysystemreceivesdrainage return flows. Thisappliesparticularly inareaswheredrainagesystemsaresubject tosalinegroundwaterinflows.

Giventheextentanddiversityof irrigationsystemscoveringavastrangeofphysicalenvironmentsthroughout the world, there are many situations where the characteristics of thesurface/groundwater components of local water resources are represented by the ‘typical’

characteristicspresentedabove.Nonetheless,physicaldifferencesanddifferencesinthehistoryofdevelopment of the two resource types provide both challenges and benefits to conjunctive

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managementanduse.Tomakeprogressonconjunctivemanagement,thespecificcharacteristicsofgroundwaterandsurfacewaterinthetargetregionmustbeassessed.Suchanassessmentincludes

thesocial,economicandenvironmentalaspects(theso‐called‘triplebottomline’)soastoevaluatehow the particular characteristics of the hydrological environment can be integrated to achieveoptimum outcomes. It is almost mandatory in current times to ensure that water resources

management isundertakennotonly inan integratedmanner,butalsocognisantof triple‐bottom‐lineissues.

2.6 Overviewofmajorirrigationsystemsthroughouttheworldwherebothsurfacewaterandgroundwaterareused

Generally,conjunctiveuse,especiallyinthespontaneousform,hasdevelopedonthemajoralluvialplainsandtheirassociatedaquifersoftheworld(asdiscussedabove).Fosteretal. (2010)contendthat the above‐mentioned settings, together with variations of average rainfall and

geomorphological position, control the potential for conjunctive use for irrigated agriculture. Afurtherdriverappearstobewateravailability,ormorepertinently,waterscarcity–thepressureto

findandutilizeotherwatersources increasesaswaterbecomesscarce.Nevertheless, thescaleoftheadoptionofconjunctiveuseisgenerallycontrolledbythescaleofthegroundwatersystem.

Historically, surface water has been the primary source in the majority of such systems, withgroundwater providing an alternative source when surface water availability is low, particularly

duringperiodsofdrought.However,withincreasingdemandforwater,thevalueofgroundwaterisachievinggreaterrecognition,becominginmanyareasanimportantprimarysourceofwatersupplyfor irrigation. The increased value for groundwatermore generally hasbeendrivenby growth in

irrigated areas thatwere traditionally supplied from surfacewater, hence increasing the demandfromthesehistoricsources.

The use of groundwater for irrigation has generally increased worldwide (in some casesexponentially)sincethe1950s.Forinstance,surfacewaterwithdrawalsaccountedfor77percentof

all irrigation in the United Kingdom (UK) in 1950 but, with increasing groundwater development,withdrawalsdeclinedtojust59percentby2005(USGS,2011).Similarpatternsareapparentinthedevelopingworld,althoughsurfacewatercanalcommandsgenerallyremainattheheartofirrigated

agriculturaldistricts,withgroundwaterbeingusedmainlyintimesofsurfacewatershortage.

There are a number of different factors influencing increased groundwater extraction with thedominant drivers being a function of local circumstance. Some of these important drivers arepresented in Table 5. Also included in this table are factors that have contributed to users

maintainingsurfacewaterastheirsolesourceofsupply.

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Table5:Summaryofdriversforsoleuseofgroundwaterorsurfacewaterresources

Driversof

ResourceUse

GroundwaterResource SurfaceWaterResource

Variableclimate Ahighlyvariableclimatewilltypicallyfavourusersofgroundwaterresources,asgroundwatercharacteristicallyprovidesahigherreliabilityofsupplythansurfacewater.

Poorsurfacewaterquality

Poorsurfacewaterquality(oftengeneratedbytheirrigationsystemitself)willfavourgroundwateruse.

Poor

groundwaterquality

Surfacewaterwillremainthedominantresourcewhengroundwaterqualityispoor.

Lackofadequateinfrastructure

Gapsorfailuresininfrastructure(orinitsoperationandmaintenance)thatdeliverssurfacewatertouserswillfavourgroundwateruse.

Depthof

groundwaterresource

Groundwaterresourcesfoundatsignificantdepthsbelowthesurfacewillincursignificantpumpingcostsandhenceoftenfavourtheuseofsurfacewaterresources.

Traditionalfarmingpractices

Usersofmulti‐generationfarmingpracticesthatwereestablishedusingasolewatersupplyarelikelytobereluctanttoincorporateadifferentwatersourceintotheirtraditionalpractices.

Usersofmulti‐generationfarmingpracticesthatwereestablishedusingasolewatersupplyarelikelytobereluctanttoincorporateadifferentwatersourceintotheirtraditionalpractices.

Discoveryofanew

groundwaterresource

Thediscoveryofanewgroundwaterresourcewilldrivegroundwateruse;particularlyinwelldevelopedsystemswheresurfacewaterallocationshavebeencapped.Itisespeciallysoiftherearefewerregulationsongroundwateruse.

Economicvalue

associatedwithproduction

Whereeconomicreturnissignificant,investmentintoobtainingadditionalwaterfromagroundwaterresourceismorelikelytooccur.

Iftheeconomicsintermsoffarmincomearedistortedtowardssurfacewateruse,farmerswillbereluctanttoincuradditionalcosttochangewatersourcesoruse.

Energypricing Subsidizedenergycostsofpumpingcanencouragegroundwateruse

Technologyadvances

Advancessuchasmanagedaquiferrechargemeanthatutilizationofgroundwaterresourcesisoftenmorefeasibleduetoanincreaseinthevolumeofavailablewaterandsecurityofsupply.Alsoadvancesinpumpingtechnologycanencouragegroundwaterusage.

Irrigator Alackofirrigatoreducationandunderstanding Alackofirrigatoreducationand

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educationandunderstanding

ofthebenefitsofconjunctivegroundwaterandsurfacewaterusecaninhibitdeviationfromgroundwatersupplyasasoleresource.

understandingofthebenefitsofconjunctivegroundwaterandsurfacewaterusecaninhibitdeviationfromsurfacewatersupplyasasoleresource.

Institutionalstructures

Unlessthereisagenuinecommitmentatanationalleveltoimplementpoliciesandallocateresourcesthatwillpositivelystimulateachangetowardsconjunctiveuse,surfacewaterorgroundwater(whicheveriscurrentlyfavoured)willremaintheprimarywatersourceforusers.

Unlessthereisagenuinecommitmentatanationalleveltoimplementpoliciesandallocateresourcesthatwillpositivelystimulateachangetowardsconjunctiveuse,surfacewaterorgroundwater(whicheveriscurrentlyfavoured)willremaintheprimarywatersourceforusers.

Shallowwater‐tablemitigation

Largevolumesofirrigationrechargecanleadtoartificiallyhighwater‐tablelevels,whichthreatensurfaceandgroundwaterqualityandtheenvironmentitself.Governmentincentivesthatencouragegroundwateruseasamitigationmeasureultimatelydrivegroundwateruse.

Insurface‐waterirrigationcommands,therecanbedifferencesinwatersecuritybasedonhowclose

the particular farm off‐take is to the primary diversion canal, especially where the deliveryinfrastructureisoperated(orperforms)inaninefficientmanner.Thoseclosetotheprimarysource(termed the ‘head’of the irrigation command)are likely tobenefit from regular supplieswhereas

thoseattheendofthedeliverysystem(the‘tail’)aresubjecttotheefficiencyofthedeliverycanalsandthecomplianceofotherfarmerstoaccessrules.Insomecasesthequalityofthedeliveredwaterwilldeteriorateas thedeliverysystemalsosourcesgroundwaterdischarge from irrigation‐induced

shallow water tables. In such cases, individual wells become an insurance policy against bothdiminishedanduncertainsupplyandpoorwaterquality.

2.7 Lessonslearntaboutgovernance

This paper is essentially about the governance approaches that are required to implementconjunctiveusemanagement in irrigationcommands.Groundwatergovernance isdefinedhereastheprocessbywhichgroundwaterresourcesaremanagedthroughtheapplicationofresponsibility,

participation, information availability, transparency, custom and rule of law. It is the art ofcoordinatingadministrativeactionsanddecision‐makingbetweenandamongdifferentjurisdictionallevels–oneofwhichmaybeglobal(adaptedfromMeganckandSaunier,2007).

Therearedifferentimplicationsforgovernancearrangementsdependingwhetheroneisretrofitting

planned conjunctive use to an existing irrigation command, or whether conjunctive use is beingdeveloped in a ‘greenfields’ situation. These implicationswill be further developed in a followingsection,butit isusefultosummarizethecommonalityofcurrentapproachesandlessonslearntat

thispoint.

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Inbothcases,thefollowingwillberequired:

• institutional strengthening to ensure that integratedwatermanagement occurs, togetherwithexplicitdecisionsaboutsystemmanagementandoperation1;

• commitment to sustainability objectives that target environmental, social and economicoutcomes;

• decisionsaboutfutureinvestmentininfrastructureandcostrecovery;• strong policy and legislative leadership to drive a planned approach, within a compliance

culture;• clear and robust implementation and deliverymechanisms to ensure the central planning

andpolicyapproachcanbetakenthroughtoon‐groundaction;• participatoryinvolvementbythegrass‐rootswaterusersandrelatedstakeholders;and• technicalknowledgeofthesurfacewaterandgroundwatersystemstoenableefficientuse

ofbothresources,aswellascapacitybuildingtoapplythistechnicalknowledge.

However, irrigationcommandswherespontaneousconjunctiveusehasevolvedovertimewillalsorequirea significant investment inplanning toenable integrationofopportunisticpumpingwithintheoptimalconjunctiveuseframework.Thiswillrequire(inadditiontotheabove):

• establishmentofinstitutionsthatprovidecomplementaryplanningandregulatoryfunctions;• modificationofcurrentbehaviour,thatmaybeachievedthrough–

− implementationofacompliancemanagementframework;− potential use of either market instruments or direct incentives to encourage and

effectfarmerchange;and− targeted extension programmes that, through education and demonstrations,

enable farmers to realize the on‐farm benefits to be provided by the plannedapproach.

Because spontaneous conjunctive use has usually evolved over time, policy objectives such as

sustainabilitymaynotbe fullyevidentorunderstood,unless serious resourcedepletion isalreadyplacingphysicalconstraintsonaccess.Regulatedreductionsinaccessmaythereforecreatetensions,highlighting the value in improved understanding by irrigators, and the value in stakeholder

involvementwithintheplanningprocess.

Whereconjunctiveusehasgrownupspontaneouslyaroundapreviouslysurface‐water‐dominatedirrigationcommand,onemightexpectmanagementtobesomewhatcentralizedandrigid.Whereithasgrownaroundastronglygroundwater‐dominantirrigationcommand,managementapproaches

maybe less rigid andmore informal, to thepointwhere there is little regulatory control. Eachoftheseendmemberswillrepresentparticularchallengesinachievingagovernancemodelthatisabletosupportatechnicallyrobustandappropriatelydesignedconjunctivemanagementmodel.

1Institutionally, internationalexperienceisthatsurfacewatermanagementisalmostalwaysseparatedfromgroundwatermanagement,thoughtheymaysharethesame‘head’institutionorgoverningauthority.Itistheauthors’viewthatmajor institutional reform is requiredtobridgethis ‘divide’not just innamebut throughplanningbehavioursandoperationalarrangements.

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Part2:Diagnostic

3. Examplesofsuccessesandfailuresofconjunctiveuse

The following sections describe some examples of irrigation commandswhere conjunctive use of

groundwater and surfacewater resources occur. This chapter draws heavily on thework of GW‐MATE(seeFosteretal.,2010andrelatedreferences)andisbynomeansexhaustive.Examplesareprovidedasawayofdescribingthebreadthoftypesofconjunctiveusesystemscurrentlyoperating

worldwide. It is acknowledged that conjunctive use of groundwater and surface water alreadyoccurs inmostcountrieswhere irrigatedagriculture ispracticed, in thedevelopedanddevelopingworld.Howeveritisalsorecognizedthat,whilstconjunctiveuseisprobablythenormmoresothan

theexception,itsoperationwithinanintegratedwatermanagementframeworkiswhereadoptionissignificantlylacking.

Itisrareforinstitutionsorcommentatorstodocumentthefailuresofconjunctiveusemanagement,thereforethefollowingexamplesfocusentirelyonsuccesses.However,the lackofdocumentation

of failures is in itself amajor impediment to this diagnosis and to the development of improvedmanagementofconjunctiveuseofsurfacewaterandgroundwater.

3.1 UttarPradesh–INDIA

Fosteretal. (2010)havedescribedthesetting forconjunctiveuse in theStateofUttarPradesh inIndia, which is categorized as a humid but drought‐prone middle‐alluvial‐plain hydrogeologicalsetting (

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Table2above).ThealluvialplainsoftheGangesValley(theIndo‐GangeticPlain)inUttarPradeshareunderlain by an extensive aquifer system holding groundwater that represents as much as

70percent of the overall irrigation‐water supply. This is one of the largest groundwater storagereservesintheworld.Itsutilizationasawaterresourcehasprimarilyariseninresponsetoreductionin supply and unreliable operation of the irrigation canal systems. The aquifers are directly

rechargedfrominfiltratingmonsoonrainfallbutalsoindirectlyfromcanalleakageandpoorappliedirrigation efficiency (i.e. excess rates of field application) – a common scenario in suchhydrogeologicalsettings.

Increasing groundwater abstraction has resulted in a declining water table, particularly in high

intensity‘groundwaterexploitationzones’,whereasinotherareas(insomecaseswithin10‐20km),floodirrigationandcanalleakagehavemaintainedshallowwatertables.Thedeclineinwatertablesin some areas is correlated with evidence of irrigation tubewell dewatering, yield reduction and

pump failure, together with hand‐pump failure in rural water‐supply wells. Conversely, threatsarisingfromshallowwatertableselsewhereareevidentinaround20percentofthelandareabeingsubject to shallowor rising groundwater levels,with soilwater‐logging and salinization leading to

croplossesandevenlandabandonment(Fosteretal.,2010).

Protocols for the operation of the distributary canal systemexist, but they have not been strictlyadheredtointhepast,andthishascontributedtoanimbalanceinsurface‐waterdeliverythroughthesystem.

Inthe lightof thechallengesposedbyrisingwatertables insomeareasanddeclines inthewater

resources elsewhere, in the Jaunpur Branch canal‐command area in Central Pradesh a ‘moreplanned conjunctive‐use approach’ is being implemented. The adopted approach uses extensive

datasetsandassociatedanalysistounderstandthehydrogeological,agronomicandsocioeconomicsituation. Strategies include: attempts to reduce leakage throughmaintenance of bank sealing inmajor irrigation canals, enforcing current operational codes, promotion of tubewell use in non‐

commandandhigh‐water‐tableareas,andinvestmentintoresearchandspecialistextensioninsoilsalinitymitigationandsodiclandreclamation.

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Figure4:Comparisonofwater‐tabledepthbefore(1984)andafter(1998)recharge,UttarPradesh(fromIWMI,2002).MapsoftheLakhaotiBranchCanal,UtterPradesh,India,showingpostmonsoondepthtogroundwaterbeforeandafterrechargemanagementbegan.Darkblueareasshowwheregroundwaterlevelsareclosetothesurface.

Theseactivitiesarebeingalignedwiththepursuitofanappropriatemanagementplan,forwhichthe

land surface has been subdivided on the basis of hydrogeologic and agroeconomic criteria into‘micro‐planning and management zones’. For each zone a canal reach (e.g. head, mid or tail) isassigned with an indication of current irrigation canal flow and water‐table level. The irrigation

waterservicesituation,thegroundwaterresourcestatusandthegroundwatermanagementneedsarethenidentified.

This zoning approach allows targeted management actions that range from encouragement ofgroundwateruseintheheadendoftheirrigationsystemswhereshallowgroundwaterlevelsprevail,

focusinguponhighervaluecrops,insomeareas,andonimprovingcanal‐wateravailabilityforthoseat the lower ends of the system. Collectively, thesemechanisms are intended to provide amorebalancedapproachacrossthecanalcommand(andbeyond)andcontributetoasustainablefuture

for agriculture in the region (Fosteret al., 2010). Figure 4 above shows the beneficial changes inwater‐tabledepthforonesuchtargetedarea.

IWMI (2002) describes the situation for thewestern Indo‐Gangetic plain,where, although rainfallrangesbetween650and1000mmannually,only200mmnaturallypercolatethroughsoillayersto

recharge underlying aquifers. In this area, like many others in India, groundwater pumping byfarmersexceedsrecharge(fromrainfalland leakagefromsurfacewaters–canalsandrivers–andapplication excess). Farmers are at themercy ofmonsoon rains, which can fail to provide water

whenandwhereitisneeded.Thehighconcentrationofrainfall,overa3‐monthperiod,meansthemajorityofwater runsoff thealready saturated soil.During thedry season,a lackof canalwatermeansarelianceonpumpingfromgroundwaterstores,whicharenottotallyreplenishedfromthe

previousyear,hencefurtherdepletion(mining)oftheaquifersystem.

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A10‐yearpilotproject(theMadhyaGangaCanalProject)undertakeninthisareahasdemonstrateda low‐cost way of using the excess surface water during monsoon season by conserving and

rejuvenating falling groundwater reserves. Theproject involveddiversionof234m3/sofmonsoonwaters in theRiverGanga to theMadhyaGangaCanal,which feeds both theUpperGangaCanalsystem and the Lakhaoti Branch Canal system. Through systems of unlined (unsealed) earthen

canals,water isdeliveredto farmers for irrigationofwater‐intensivemonsooncropsuchaspaddyriceandsugarcane.Theunlinednatureofthecanalsystemsandinfiltrationofexcessirrigatedwaterfacilitatestherechargeofunderlyingaquifers,inwhichthewatertablewasraisedfromanaverage

12mbgltoanaverage6,5mbgl.Simulationsshowedthat,withoutsuchaconjunctivemanagementapproach,levelswouldhavecontinuedtodeclinetoanaveragedepthof18,5mbgloverthecourseofthestudy.

Theconjunctivemanagementofsurfacewaterandgroundwaterhasprovedproductiveintermsof

theaveragenetincomeincreasingby26percentthroughreductionsinpumpingcostsandimprovedcropping systems. It has demonstrated a more sustainable system through improved croppingpatterns and throughmore reliable and sometimesnew sources ofwater for irrigation andother

uses, suchasdomestic/industrial supplies (e.g.providingwater inpreviouslyexistingdrypockets).Duringthedryseason,drawdownfromgroundwaterpumpingpreventswaterloggingandmaximizesstoragespaceforrechargeduringthefollowingyear’smonsoon.

Unused (often lined)drainagecanalsconstructed in the1950s tocontrolwater loggingand floods

arealsobeingtargetedasameansfordivertingmonsoonwatersacrossIndia,eitherforirrigation,storageandlateruseorforrechargetounderlyingaquifers.Modificationofpreviouslylinedcanalscanaidtheirtransformationintotemporaryreservoirs,where‘checkstructures’atsuitableintervals

slowdownwaterflowandincreasetheaquiferrechargecapacityofthecarrier(Kheparetal.,2000in IWMI, 2002). In combinationwith the use of earthen irrigation canals, the use of old drainage

networks can maximize water use and storage for very low cost compared to building newinfrastructuresuchasdams(Kheparetal.,2000inIWMI,2002).

3.2 Mendoza–ARGENTINAFosterandGarduño(2006)describethesituationintheMendozaAquifersofArgentina,whicharealsohighlydevelopedwithinandoutsideexistingirrigation‐canalcommands.TheMendozaAquifers

are characterized by an upstream arid‐outwash‐peneplain hydrogeological setting (

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Table2above)andareshowndiagrammaticallyinFigure5.TheaquifersarerechargeddirectlyfromtheMendozaandTununyanriversastheyemergefromtheAndeanmountainchainandindirectly

fromirrigationcanalsandirrigatedfields.

The General Department for Irrigation (Departamento General de Irrigacion – DGI) is theautonomous water resource authority responsible for watermanagement in the entire province,down to the primary canals and the delivery of water to Water Users’ Associations (WUAs).

Groundwater abstraction is themain sourceofwater for irrigationoutside the commandofmaincanalsandisusedtosupplementsurfacewaterduringtimesofcriticalplantdemandandinyearsoflowflow.

Figure5:HydrogeologicalprofilealongtheflowdirectionoftheCarrizalaquifersystem(fromFosterandGarduño,2006)

TheDGI’sinitialapproachtogroundwaterresourcemanagementinvolved:

• encouraging irrigation waterwell drilling in areas outside and on the margins of existingirrigation‐canalcommands;and

• permitting waterwell drilling within surface‐water irrigation commands, if existing canalallocationdidnotprovideareliablesupplyattimesoflowriverflowand/ormaximumplantdemand.

Although the strategy was generally a success, problems with high and increasing groundwatersalinity in two areas of intensive groundwater irrigation started to emerge. Salinity distributionduring 2003‐2004 suggested the current groundwater flow, irrigation use and return flow were

significantcontributorstotheseproblems.

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IntheCarrizalValley,theexpansionofhigh‐intensitygroundwateruseforirrigationofexport‐qualityviticultureandfruitproduction,whileefficientduetoapplicationofmodernirrigationpractices,has

put pressure on the groundwater system. Six to seven hundred active production wells werereportedinthevalleyin2006,withconsistentlyelevatedelectricityconsumptionreflectingthehighdependenceonthewellsforagriculturalirrigation.

IntheMontecaseroszone,thesecondproblematicarea,theaquifersystemhasmarkedlayeringinto

sub‐aquiferunitsseparatedbyaquitards.Groundwatersalinityintheshallowestoftheseincreasedsubstantially between the 1970s and 1995, instigating a shift to extraction targeting deeper sub‐aquifers. However, there has been downward migration of saline groundwater, thought to be

related, amongother things, topumping fromsub‐aquifers thewaterwhich ispotentiallyderivedfromoverlying strata, and less so frompoorly constructedand/orhighly corrodedwells providingconduitsforbrackishwater.

When estimated demand exceeded available resources – following continued below‐average

riverbed recharge amidst concerns around fallingwater tables, increasing groundwater salinity insome areas, competition amongst groundwater users and between others dependent ondownstream groundwater discharge –, the Carrizal Valley andMontecaseros zone were declared

groundwateruserestrictionzones(GRZ)in1997and1995,respectively.

GRZshavemorerigorouswaterwell‐drillingcontrolsaimingtoreducecurrent,andpreventfurther,growthofgroundwaterabstraction.Thisiswhilestillallowing:constructionofmoreenergy‐efficient(replacement)wellsandreallocationofgroundwaterresourcestohigh‐valueusesbypurchaseand

sealingofexistingwellswithconstructionofnewwellsatclose‐bylocationswithinthesamezone,even though water trading is not permitted under provincial water law. ‘Sale’ of excess surface

waterisalsopermittedinGRZsbutwiththerelativelyhighcostsofirrigationmodernization,thisisunlikelytobeagreatincentivetoinvestinwater‐savingmeasures.

TheDGI isworking towards a proactive groundwatermanagement and protection programme towidenthebaseofstakeholderparticipationandfostersharedappreciationofproblems.Theinitial

step identified to this endwas to improve scientific understanding of aquifer behaviour. This hasinvolvedsignificant fieldwork (e.g. intensificationofgroundwater levelandsalinitymonitoring) toimproveunderstandingofthehydrogeologicalstructureandirrigationwellabstraction/usepatterns

that will inform numerical modelling. Simulating various scenarios should allow evaluation ofpotentialimpacts,thusprovidinganimprovedbasisforfutureconjunctivewaterusemanagement.

Other land and water management measures to improve water‐use efficiency and minimize thefurthermobilizationofsalinityinstigatedbyDGIinclude:

• delivering surface water by lined canals/pipeline to increase efficiency, and reduceinfiltration touppermost salineaquifer to avoidwater‐table rise and increaseddownwardleakage(Montecaserozone);

• providing additional water, from the surface water supply, to salinity affected areas bydivertingexcessriverflows;

• introducingdripirrigationtechniques;• backfilling or effectively sealing all disused, poorly‐constructed and/or highly corroded

waterwells(particularlytoavoidtransferofbrackishwaterintheMontecaseros);• reducingruralelectricalenergysubsidies;

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• policingandreducingillegalpumping;• increasingriverbedrechargethroughworksintheMendozariverbed;and• providingcanalwatertogroundwater‐onlyareas.

Thesemeasureshavehadvarying impactson thewaterbalanceof theCarrizalAquifer,whichare

yettobefullyrealized.Someremainingchallengesincludethefollowing:

• Groundwaterrightshavebeengranted inperpetuityandthere isnomechanismtoreduceentitlementstosupportmoreefficientuseofwater.

• Thereisanabsenceoflegalpowersandmarketmechanismsthatwouldenablethetransferofsurfacewaterentitlementstoareaswithoutaccessrights.

• Surface water and groundwater have differential cost structures that apply to users, asgroundwater users fully finance the associated infrastructure whereas surface waterinfrastructurehasbeeneitherwhollyorpartlysubsidizedbytheState.

• Localwater‐usergroupshavebeenfocuseduponsurfacewaterissues,andtherehasbeenareluctance to engage in groundwater management issues, which would requirereorganizationtobetterreflectthedistributionofusers2.

Notwithstanding the above, the Carrizal Valley strategy appeared to be succeeding according to

post‐2007 monitoring data that suggest partial water‐table recovery and groundwater salinityreduction.

3.3 Queensland–AUSTRALIA

Hafi (2002) highlighted the importance of taking amultiple‐water‐resource‐system perspective inaddressing issuesofconjunctiveuseofgroundwaterandsurfacewater intheBurdekindeltaarea,Queensland,Australia(Figure6).Withinthissystem,thereissignificantinteractionbetweensurface

water and groundwater resources, and hence complementary policies have been formulated forsurfacewaterandgroundwatermanagement.

The Burdekin delta is a major sugar production district in Australia and overlies a shallowgroundwater aquifer, which is hydrogeologically linked to environmentally sensitive wetlands,

waterways,estuariesandtotheGreatBarrierReef.Inadditiontoirrigationsupply,theaquiferalsosupplies potablewater for three towns in the delta. The Burdekin River Delta aquifer consists of

sedimentarydeposits,upto100mbelowthesurface.An important featureof thedeltaaquifer isthat the sediments are not continuous laterally even over short distances. Discontinuity inimperviousclay layersexposestheaquifer to infiltrationofwater fromthesurfaceandasaresult

theaquifer isgenerallyconsideredunconfined. In termsof thehydrogeological settingsdefined in

2Overcoming this issue is exacerbatedby the absenceof a revenuebase and the politicizationof the user

groupstowardsmaintainingsubsidizedsurface‐watersupplies.

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Table2above,theBurdekinfallsintothedownstreamalluvialdeltacategory.

Inthedelta,surfacewaterispumpedfromtheBurdekinRiveranddivertedintocanalstodelivertorechargepitsandchannel‐intrusionareasandtoirrigationfarms(Figure6).Thechannelsystemalso

deliverswatertonaturalwaterways,gulliesandlagoons.Theaquiferandtheextensivecanal,gullyand lagoon system are collectively used as low‐cost storage of diverted water and to capture asignificantportionofthearea’srainfallrunoff.Whenthewaterdivertedfromtheriveristooturbid

to be used in recharge pits or in excess of recharge capacities, it is made available as asupplementary irrigation supply. In normal years, rainfall recharge from outcrop areas anddischarges from flooded rivers are sufficient to recharge the aquifer. However, after several

successiveyearsofdrought,theaquiferhasbeendepletedtonearsealevelmainlyduetopumpingforirrigationandcontinuousdischargetothesea.

A numericalmodelwas used to identify optimal strategies to conjunctivelymanage groundwaterand surface water resources to maximize their economic value. The model provided solutions

relatingtotheoptimalgroundwaterpumpinglevelsrequiredtomanagethegroundwaterresource,suchthatthewatertabledoesnotrisetolevelsthatmightcausewaterlogginginsomeareas,anddoesnotfalltoalevelthatwouldpermitseawaterintrusion.Thisdecisionsupporttoolhasproved

tobeinvaluabletowatermanagersintheBurdekinRiverDelta.Itprovidesinformationonoptimalpumping quotas and the allocation of surface water resources. It further provides a basis forsustainableresourceallocation,enablingdecisionsontheimmediateuseofsuppliestomeetshort‐

termdemand,anddecisionssupportingaquiferrechargeforstorageandfutureuse.

Figure6Waterbudget,Burdekindistrict,Australia(fromMcMahon,2002)

ThemajorconjunctiveuseregionsintheBurdekindeltaaremanagedthroughaseparateactofthe

Queenslandparliament.TwoseparateWaterBoardswerecreatedcoveringdifferentregions,whicharecontrolledbyaboardcomprisinglargelylocalwaterusers.Theboardhassubstantialpowersintheday‐to‐dayoperationofthescheme.Thesuccessoftheschemeischaracterizedbystrongand

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clear local ‘ownership’, combinedwith significant technical support provided by government, andhasthebenefitofahydrogeologicallyfavourableregionofhigh‐transmissivityaquifers.

3.4 IndusBasin–PAKISTANPakistan’s major groundwater resource is located in the irrigated areas of the Indus Basin. Thehydrogeological setting can be classified as hyper‐arid middle alluvial plain (

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Table2).AgricultureisthesinglelargestsectorofPakistan’seconomy.Duetoaridconditionsinmostpartsofthecountry,thecontributionofdirectrainfall tothetotalcropwaterrequirements is less

than15percent.Thehugegapbetweenwateravailabilityanddemandisbridgedviaexploitationofgroundwaterresources.

Figure8:Increasingtrendinconjunctiveuse,Punjab,Pakistan(takenfromQureshietal,2004)

Mostgroundwaterexploitation inPakistanoccursviaconjunctiveusewithsurfacewater. Irrigatedagricultureusingonlygroundwaterislimitedmainlytothreesituations:

• inareasnotsuppliedbycanalcommands;• insmallsystemsoutsidetheIndusBasin;and• atthetailendofcanalcommandsthathavelostaccesstosurfacewaterthroughinequitable

distributionofcanalwatersupplies.

ThemostproductiveareasoftheIndusBasincommonlyincorporateconjunctiveuseofcanalwaterandhightomediumqualitygroundwater.Conjunctiveuseofgroundwaterandsurfacewaterallows

farmers to cope with the unreliable surface‐water supplies and to achieve more secure andpredictable yields. However, there are adverse impacts of conjunctive use where poor‐quality

groundwater is used adding large amounts of salt in the root zone, and hence causing additionalsalinizationproblemstothosearising fromshallowwater tables. Insomeareas, thesalinityof thegroundwater resource is such that there is full reliance upon canal deliveries to sustain irrigated

agriculture. Even in areaswhere groundwater is deemed tobeusable, thebrackishnatureof theresource commonly requires mixing with surface water prior to application to crops. HoweverQureshietal.(2004)notedthatfarmersarenotfullyawareoftheratiosrequiredwhenmixingthe

twowatertypesandhencenegativeconsequencesof irrigatingwithhighsalinitywaterhavebeenobserved.

The ratio of surface water and groundwater conjunctive use in irrigated agriculture identified inresearch undertaken by Murray‐Rust and Vander Velde (1994) averaged 2:5 throughout the

distributary canal command, resulting in anaverage irrigation‐water electrical conductivity (EC)of

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1400 µS/cm. This value exceeds the current international standard that sets the upper limit for‘good’qualityirrigationwateratEC700µS/cm.Tobringthataveragewater‐qualityconditiondown

to1000µS/cm(stillhigherthanthemaximumvaluerecommendedbyinternationalstandards),anaveragecanal‐tubewellwaterconjunctiveuseratioof3:4wouldberequired.Assumingnochangeinthetotalvolumeofirrigationwaterusedinthecommandarea,thismeansthatthevolumeofcanal

waterwouldhavetobeincreasedbymorethan50percentandthevolumeofpumpedgroundwaterreducedbymorethan20percentofcurrentvolumes.

In addition to the technical issues, institutional challenges are also significant. Murray‐Rust andVanderVelde(1994)highlightthat,tohaltthedecliningtrendinsustainabilityofPakistan’sirrigated

agriculture, “Pakistan’s public agencies and supporting research institutions must begin sheddingthis ‘historical baggage’, reorganize internally and establish functional, working linkageswith oneanother”.

3.5 OtherexamplesSahuquillo(2005)discussesanumberofexamplesunderthethemeofalternateuseofgroundwaterandsurfacewaterforirrigationinamoregeneraldiscussionofconjunctiveuse.Theseexamplesare

from the Mediterranean Basins of Spain and the Central valley of California, United States ofAmerica(USA).

In theSpanishbasinexamples, Sahuquillo (2005) reportson theevolutionof conjunctiveuseas a

process associated with the expanding irrigation industry during wet years via surface waterdiversions. As groundwater resources were identified through the region, more and moregroundwater abstraction was incorporated into the system. In response to an expansion in the

irrigatedarea,moreintenseuseofsurfacewaterduringwetyearsincreased,leadingtosubstantialincreasesinoveralluse.Theseexamplesdemonstrateabottom‐upapproachthatwasproposedandimplementedbytheirrigators,whichhavenowbeenincorporatedintolegallysanctionedschemes.

Sahuquillo(2005)discussesinmoredetailthestatusoftheMijaresBasin,nearValencia,Spain.The

basin is characterized by large surfacewater reservoirs situated over a karstic limestone aquifer,with resulting high leakage rates to groundwater. In addition, the Mijares River also leaks andrechargesthelocalalluvialwater‐tableaquifer.Surfacewaterorgroundwater isusedasthewater

sourcedependingonwateravailability,bothinstreamandinstorage.Thebeneficialaspectoftherelationshipbetweensurfacewaterandaquiferisthat,whenevermoresurfacewaterisavailable–which is hence used by irrigators –, recharge rates to the groundwater system are higher. This

provides a natural counter‐cyclical process, where the groundwater resource is recharged duringperiodsoflowgroundwaterdemand.

Bredehoeft(2011)providessomeexamplesofconjunctiveuseoperationinthewesternUSAaspartofamoregeneraldiscussionofconjunctiveuse.Theexampleshighlightthesituationwheresurface

waterwasgenerallyfirstdevelopedandusedtoitsmaximumtoundertakeirrigation–usuallyfullydeveloped by the early 1900s. Bredehoeft points out that a large number of these river valleyscontained alluvial deposits whose groundwater systems were well connected to the rivers. As

surface water was fully appropriated, and as knowledge of the groundwater systems grew,

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groundwaterbecamethenewwatersource,anddevelopmentfollowedinagenerallyunregulatedfashion. Institutionstomanageabstractionhaveevolvedovertime.Theyhave,however,generally

favouredpriorrightsinwaterandrequiredthenewerwaterusers,thatis,thegroundwaterusers,toprovide‘new’watertooffsettheirpumpingimpacts.Considerationofopportunitiestosolvethesechallengesdoesnotappeartohaveexploredconjunctiveresourcemanagement.

Pulido‐Velazquez et al. (2004) and, to a certain extent, Sahuquillo (2005) discuss an interesting

adjunct to the idea of conjunctive use. Both sets of authors provide examples of conjunctive useoccurrences, where the surface water resource is used to artificially recharge the groundwaterresource. Pulido‐Velazquez et al. (2004) discuss the situation in Southern California, though

associatedwithwatersupplyprojects formetropolitanareasratherthan irrigation,andSahuquillodiscussesexamplesassociatedwithtreatedwastewaternearTelAviv, Israel,andBarcelona,Spain.Whilstnotdirectlyrelevanttoirrigationsupplies,theydodemonstrateafurthertypeofconjunctive

managementthatcouldbeimplementedelsewhere,presumablysubjecttocost.

These examples highlight a common history and common challenges. In nearly all cases whereconjunctiveuseisbeingpracticed(eitherspontaneouslyorinaplannedmanner),surfacewaterwasthedominanthistoricalwatersource.Either throughexpansion, technologyuplift,newknowledge

ordeterioratingwateraccess/qualitythereweremovestowardsincorporatinggroundwaterintothewater management system. This was done either within a regulatory environment (with varyingdegrees of compliance) or spontaneously by individuals. The development of bothwater sources

brings into juxtaposition the inherentdifferencebetweensurfacewaterandgroundwater.Surfacewater ispredominantlyaState‐ownedormanaged“good”that inmostcases isheavilysubsidizedvia direct infrastructure spending, as a part of national agricultural or food security policy.

Groundwater,ontheotherhand, is rarelyState‐ownedandmanagedanddoesnotusuallyattractthesamelevelofsubsidy. Inotherwords,themanagementofgroundwaterandsurfacewaterare

commonly underpinned by different philosophies, differences that arguably are a significantimpedimenttoprogressingconjunctivemanagement.

ThemainimpedimentstoplannedconjunctiveuseidentifiedbyFosteretal.(2010),assummarizedfromtheirworkonexamininganumberofglobalexamplesofconjunctiveuse,are:

• theoftendisconnectedresponsibilities forwatermanagementbetweensurfacewaterandgroundwaterdepartmentsatvariouslevelsofgovernment,whichusuallyresultsinafailuretounderstandtheintegrativebenefitsofholisticresourcemanagement;

• thelackofinformationregardingconjunctiveusemanagementthatcanbeusedtoinfluenceandeducatebothpoliticiansandthegeneralpublicaboutconjunctiveusebenefits;and

• an inadequate knowledge of the degree to which privately‐driven groundwater use ispracticedinirrigationcommands,itsbenefitsanditsrisks.

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4. Scopeforsecuringsocialandenvironmentalbenefitsthroughconjunctiveuseschemes

It is often instructive to consider where a particular approach has succeeded compared with

exampleswheresub‐optimaloutcomeshavebeenapparent.Inordertogainsuchinsight,acommonunderstandingastowhatsuccessmeanswithinthecontextofconjunctivemanagementisrequired.

Thethreadofthispaper,basedonothers’work(primarilythatofFosterandothers)isthatplannedconjunctiveusemanagement shouldbea clearobjectivewhereverboth surfaceandgroundwater

resources are available. As alluded to earlier, whilst there are few examples that demonstrateeffective implementationofplannedconjunctiveusemanagement,spontaneousconjunctiveuseiscommon. The apparent widespread evidence of this spontaneous conjunctive use suggests that

substantial financial benefits are being realized by irrigators, otherwise the practice would notprevail.

Twoend‐membersofapossiblecontinuumbetweensuccessfulattemptstoretrofitconjunctiveusemanagement (which by its very nature must be planned) and areas where it is not possible to

retrofitareproposedasUtterPradeshinIndiaandtheSouthPlatteValleyinColorado,USA,eachofwhichisdiscussedbelow.

In Utter Pradesh, a planned approach was implemented at the regional scale aimed at effectingchangestothewatersupply/demandbalancebyconsideringthenatureofthecompletewatercycle

for the area and how this behaved spatially and temporally. A series of actions were thenundertaken tooptimize theexisting infrastructure soas toenablea largeramountofwater tobeaccessed in a more efficient manner. It seems there was little in the way of State‐sponsored

investment and no apparent changes to management and/or regulation levels. However, localownershipwasfocusedonincreasingthetotalwateravailability.Thebenefitsoftheseactionshavebeenwidelyreported.

Conversely, within the South Platte River Valley of Colorado, the focus upon conjunctive

managementhasbeentoapplyexistingregulationsaroundwaterrightsingroundwaterabstractionand use, rather than considering appropriate reforms that may assist in delivering broader andlonger‐term water management outcomes. As Bredehoeft said (as reported above): “Effective

conjunctivemanagement can probably only be accomplished by an approach that integrates thegroundwater and surface water into a single institutional framework; they must be managed

togethertobeefficient.Currentinstitutionsbaseduponthepresentapplicationoftherulesofpriorappropriationmake conjunctivemanagement not practical.” This is because the existing surface‐water rights are strongly maintained and enforced by the relevant water authorities and,

consequently,groundwaterisnotabletobeusedinanunencumberedconjunctive‐usesense.

If these two high‐level summaries reflect the broader experience related to conjunctive usemanagementthenthekeytosuccessfulimplementationiscomplexandprobablyreliantonamixofinstitutional,social,technicalandeconomicfactorsthatvaryatthelocaltosovereignlevel.

Thesocial,technicalandeconomicfactorsrequireconsiderationwithinthelocalcontext,astheyare

critical to developing the optimummanagement arrangements. However, the optimum approach

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mayprovetobepurelytheoretical, if implementationis inhibitedbyexistinginstitutionalorpolicystructures.Thisspecificallyappliestothelegal‘ownership’ofwaterrights,theabilityoflocalbodies

or water user associations to make day‐to‐day decisions and the ability to undertake effectiveplanningforconjunctiveuse.

It is clear that there needs to be economic incentives to justify the adoption of conjunctive usemanagementatboth(oreitherof)thesovereignorindividual level, independentofwhetherthere

arestrongmarketdriversoperating.Asdiscussedbrieflyinprevioussectionsofthispaper,itappearsthateconomicgainismade–whereithasbeenassessedandreported–asaresultoftheadoptionofconjunctiveusemanagement.Thishasusuallybeenatthefarm‐gatelevelintheformofreduced

costsandincreasedincome,howevereconomicreturnsmayalsobeachievedatthesovereignlevelthroughmore efficient use of the available water resource, lower subsidies to achieve the sameproductionandincreasedlevelsofproductionleadingtomoreregionaldevelopmentopportunities

frompost‐farmgatemultipliers.Furtherworktodemonstratethesovereign‐leveleconomicgainsisprobably warranted as part of a programme to encourage governments to commit to theinstitutionalandpolicyreformsnecessarytoachieveadoptionofplannedconjunctivemanagement

atanirrigation‐commandscale.Foreffectivemanagement,regulatoryarrangementsarerequiredtoinclude access entitlements and powers to place restrictions on the timing and volume of waterabstraction.

Anumberofresearchershaveassessedandconfirmedthegainstobemadefromconjunctiveuse

management (for instance, see Shah et al., 2006).Where economic gains have been assessed ininvestigationsand research studies, all showpositive results. This knowledgehasbecomeamajorpieceofevidenceusedtopromotetheimplementationofconjunctivemanagementinrecentyears.

However, theextentof the analysis of socio‐economicbenefits at the irrigation‐command level islimitedandmainlyheldinunpublishedreports.Itisraretoseedetailedanalysesofthebenefitsand

costsofconjunctiveuse;ratherthedatashowstheincrementaleconomicbenefitswhenconjunctiveusemanagement isretrofittedtounplannedirrigationcommands. Inparticular, it israretoseeananalysisofbenefitandcostassociatedwithplannedconjunctivemanagement,andevenrarertosee

adiscussionofthepolicyandinstitutionalapproachessupportingplannedconjunctiveuse.Veryfewresearchers or commentators provide detail on what policies need to be put in place. It is theauthors’viewthatthisisamajorimpedimenttothe‘socialisation’oftheissueacrossgovernments.

5. GovernancetoolsthatpromotetheadoptionofconjunctiveuseA rangeofmanagementmodelsexistacrossnumerous irrigationdevelopmentsaround theworld.Most surface‐water‐based delivery infrastructure tends to be in public ownership, while most

groundwater relate infrastructure is farm‐based and hence tends to be privately owned. Thedifferent ownership arrangements between groundwater and surface water tend to correlatestronglywiththedegreeofcommitmentfromgovernmentstowardsmanagementoftheresource.

ThissituationisdepictedinTable6.

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Table6:Varyingownershipmodelsanddegreeofmanagementforgroundwaterandsurfacewaterbasedirrigationcommands.

PublicOwnershipof

Infrastructure(Government/State‐

Owned)

PartPublicand

PartPrivateOwnershipof

Infrastructure

PrivateOwnership

ofInfrastructure

HighlyManaged Common–usuallysurfacewaterbased

Common Rare

LightlyManaged Notcommon Verycommon NotcommonDegreeofmanagement

NoManagement Rare Common Common–usuallygroundwaterbased

EvidenceofthedifferentialattributespresentedwithinTable6isapparentwhenconsideringspecificexamplesaroundtheworld,withsuchdifferencesbeingpotentially‘cultural’innature.Forexample,in most parts of India, private ownership of groundwater wells prevails, and there is minimal

groundwatermanagement,withsomenotableexceptions(IWMI,2006).Howeverincircumstanceswhere there is communal ownershipof groundwaterwells, a strongermanagement framework islikely,albeitstillverylocallybased.

Well‐plannedconjunctiveuseistheoreticallyeasiertoachievewithpublicownership.Conversely,in

a private‐ownership model, stronger regulations and/or sanctions, or appropriate marketmechanisms are normally required to support a transition to effective conjunctive management.However the objective should always be tailored towards providingwell‐planned conjunctive use

models irrespective of the public/private ownership model, and whether there are centrally‐regulatedormarket‐drivenenvironments.

One obvious market mechanism that should be considered within a planned conjunctivemanagementregimeiswatertrading,whichrequiresawaterallocationframeworkthatsets limits

onentitlements to sustainable levelsof take.When theallocation frameworkhas fully committedthese entitlements, a trading regime– either explicitly or implicitly implemented – is an effectivemethod to allow for redistribution of water in response to market forces. In a fully‐integrated

conjunctivemanagementmodel, such trading regimesmay enable groundwater to surfacewatertrade (andviceversa),withassociated rulesnecessarilybeinghighly cognisantof theamountandtimingofthehydraulicinteractionandotherattributesofthedifferententitlements.

Table 7 provides a simple outline of the types of management approaches and of attempts to

classify thembasedon thedegreeofconnectionbetweensurfacewaterandgroundwaterandonthedegreeofregulationofwaterresourcesbytheState.Thetableacknowledgesthecontinuumin(effective)regulationofthewaterresourceandsetsoutbroadapproaches.

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Table7:Possiblemanagementapproachestoachieveplannedconjunctiveuseforvaryingmanagementmodelsanddegreeofhydraulicconnectionbetweengroundwaterandsurfacewater.

DegreeofConnection HighlyRegulated LightlyRegulated FreeMarketHighlyconnected Relativelysimple

managementrulesGeneralmanagementrulesnecessary

Lowlevelofmanagementmayberequired–potentialforoptimalresourceuse

Moderatelyconnected Specificmanagementrulesrequired

Specificmanagementrulesrequired

Specificmanagementrulesrequired

Nopracticalconnection Needforintegratedmanagementismoreimportant

Moreinvolvedmanagementnecessary

Complexmanagementrequired–someregulationnecessary

5.1 Requiredinstitutionalstructuresforeffectiveconjunctiveusemanagement

Conjunctiveusemanagementisnotconstrainedmostlybyalackoftechnicalunderstanding(thoughthis isan importantconstraint),butratherby ineffectiveand incompatible institutionalstructures,with separate management arrangements, almost always established and operated by different

institutions. As well, water resources at the sovereign level are often managed by a dedicatedagency, whilst irrigation commands are often managed by agricultural agencies or dedicatedirrigation‐command authorities. Overall water resource policymay be set at a jurisdictional scale

withtheirrigationsectorrequiredtooperateundertheauthorityofaregulatoryagency.Thisresultsinacomplexmosaicofplanninganddecisionpathwaysthatarenoteasilyovercomeinthepursuitofaplannedconjunctivemanagementmodel.

Foster and Steenbergen (2011) acknowledge that: “In many alluvial systems, the authority and

capacity forwater‐resourcesmanagementaremainly retained in surface‐water‐orientedagencies,because of the historical relationship with the development of irrigated agriculture (fromimpounded reservoirsor river intakesandmajor irrigationcanals). Thishas led to little interest in

complementary and conjunctive groundwater management. Some significant reform of thissituation is essential – such as strengthening the groundwater‐resource management functionand/or creating an overarching and authoritative ‘apex’ agency’’. Similarly Shah et al. (2006)

recognizethat:“Waterresourcesaretypicallymanagedbyirrigationdepartmentsandgroundwaterdepartments.Thereisrarelyanycoordinationbetweenthese...”.

Foster et al. (2010) also emphasize that: “The promotion of improved conjunctive use andmanagement of groundwater and surface water resources will often require significant

strengthening(orsomereform)oftheinstitutionalarrangementsforwaterresourceadministration,enhanced coordination among the usually split irrigation, surface water and groundwater

management agencies, and gradual institutional reform learning from carefully monitored pilotprojects. Water organizations and agencies often tend to ‘mirror’ historical water‐supplydevelopmentrealitiesandtendtoperpetuatethestatusquoandfinditdifficulttograspconjunctive

useopportunities.Thereisoftenconsiderablerigidity,andinitialresistancetochange.”Addtothisahigher‐levelneedtoalignwaterresourcesandagriculturalstrategy,atboththesovereignandsub‐regionalirrigation‐commandlevel,andtheenormityofthetaskbecomesapparent.

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Bredehoeft (2011) emphasizes that effectivemanagementof conjunctiveuse “requires integratedinstitutions that can plan and sustain the management of the system for long periods”. This is

becauseittypically“takesmorethanadecadeforsignificantchangesingroundwaterpumping...tohave their full impacton the river” (as seen in theUSAcasehestudied).Bredehoeftalso stressesthat, in much of the USA, the water management legal system based on prior appropriation

fundamentally works against conjunctive management: “Effective conjunctive management canprobablyonlybeaccomplishedbyanapproachthat integratesthegroundwaterandsurfacewaterinto a single institutional framework; they must be managed together to be efficient. Current

institutionsbaseduponthepresentapplicationoftherulesofpriorappropriationmakeconjunctivemanagementnotpractical.”Conjunctiveusemanagementwillrequiremajororganizationalchangein water agencies. Furthermore reformed institutions need structures that can operate at the

multiplescaleswithwhichgroundwater,especially,requires.

Arecentreport for theWorldBank(Garduñoetal.,2011)discussedthat“Thepromotionofmoreplanned and integrated conjunctive use has to overcome significant socio‐economic impedimentsthrough institutional reforms, public investments, and practical measures, including: (a)the

introduction of a new overarching government agency for water resources, because existingagencies tended to rigidly follow historical sectoral boundaries and thus tend to perpetuateseparation rather than the integrationneeded for conjunctiveuse; (b)gradual institutional reform

learning fromcarefullymonitoredpilotprojects;and (c)a long‐termcampaign toeducate farmersthrough water user associations on the benefits of conjunctive use of both canal water andgroundwater, crop diversification, and land micro‐management according to prevailing

hydrogeologic conditions.” These commentators reflect a view that institutional strengthening isprobably the most important challenge to conjunctive use management, especially in already

developed irrigation systems where a more optimized management approach needs to beretrofitted.

5.2 Optimumconjunctivemanagementandwhatismeantbyconjunctiveuseplanning

Importantfactorstobeconsideredintheplanningprocesstooptimizetheuseofgroundwaterandsurface water are the fundamental differences between the two water sources in terms of:availability; cost, both capital and operating; and energy requirements (and hence CO2 impacts).

These three factors need to be considered individually and collectively to develop awell‐plannedconjunctive‐use irrigation system. Of these, the different availability (as a volume) and timingbetweengroundwaterandsurfacewaterisalreadyrecognizedandpositivelyutilizedinoptimisation

planning.

Costdifferences–asusuallyseenbyfarmers–betweengroundwaterandsurfacewaterareakeyfactortobeconsidered,withsubsidiescommonforelectricitysupplies(see,forexample,Shahetal.,2006) impacting upon farmers behaviours (i.e. choices between surface and groundwater) and

henceleadingtooutcomesthatarenotconsistentwithwaterplanningobjectives.Inaddition,thenetenvironmentaloutcomesresultingfromamanagementstrategyarenotyetconsideredinmostplanning frameworks, such as the CO2 impact of different options. Many authors (for example

Piludo‐Velazquezetal.,2006)haveproducedeconomicoptimizationapproaches.Thesetendtorely

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on assuming that there is a water‐trading regime in place that allows or encourages theredistributionoftotalwaterresourcestothegreatesteconomicgood. Inpracticesurfacewaterto

groundwater (and vice versa) trading regimes rarely operate across irrigation‐command areasworldwide.However,suchatradingapproachshouldbeencouragedaspartofeffectiveconjunctivemanagement,notingthattherearelikelytobesignificantchallengesinestablishingrulesthattake

into account the different nature of the resources. All the above factorsmust ultimately aim toproducethemaximumcropyieldpercubicmeterofwaterused.

Part3:Prospects

6. Prospectsforslowingorreversingtrendsthrough‘governance’Thebroadertopictowhichthispapercontributesisrelatedtogroundwatergovernance.However,

within the context of conjunctive usemanagement, it is important to considerwater governanceglobally, that is,governance forbothsurfacewaterandgroundwater.Goodgovernanceprinciplesassociatedwithgroundwateralonestillapply,buttheymustbemadetofitabroadergovernance

paradigm–so‐calledIntegratedWaterResourceManagement(IWRM).

General water governance principles cover a number of main areas – authority, accountability,transparency,stakeholderparticipationandinstitutional integration.Authorityrelatestothepolicyand statutory powers vested in the government or delegated to an agency to administer and

regulateonbehalfofthegovernment.Theassociated‘authority’becomesthedecision‐makerwhomustbeheldaccountableforoperationalizingpolicyandlegislative instruments.Suchanauthoritymustbeaccountableforitsdecisions,withappropriatemechanismsinplace,supportiveofnatural

justicebyenablingappealsagainstdecisionstobeindependentlyreviewed.As a third element, transparency is required to demystify the decision‐making process, support

stakeholder confidence in the management process and provide the grounds for any appeal.Participation is required toensure that there is ownershipof theprocessby all stakeholders; thisgoesalongwaytoachievingplannedoutcomes.Finally,integration(bothinstitutionalandtechnical)

is required toensure thatall aspectsofwater tenureare subject toa singlebasicwater resourceregime.Waterisasingleresourceandshouldbemanagedaccordingly.

6.1 GovernanceapproachesIt is clear that optimum water‐resource use will be significantly advanced through plannedmanagement of conjunctive use in irrigation commandsworldwide. There are a number of areas

where the governance model is crucial to the adoption of this planned management approach.However, it is useful to note that there is no single governance model that can be applieduniversally; rather elements of different approaches may need to be chosen depending on the

specificcircumstancesforeachcase.

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Effectivegovernancearrangementstounderpinaconjunctivemanagementstrategyaredeemedtobe the most significant challenge. Danton and Marr (2007) in a discussion of the governance

arrangements associated with the Uttar Pradesh conjunctive use example, make the point that“multi‐facetedgovernancearrangementsarenecessary for successfulmanagementof smallholdersurfacewaterirrigationsystems.Inmanagingconjunctiveuse...thesearrangementsbecomemore

complex.... The greater complexity in management arises from the need for coordinatedmanagementofthetworesourcesthroughgreaterparticipationandnetworkingofstakeholdersateach stageofwaterallocation,useandmanagement.” Further, Livingston (2005;as referenced in

DantonandMarr,2007)subdivideswatergovernancemodels forwatersupplysystems into threetypes:bureaucracy,communityandmarket.Governanceapproachesmayfavouronemodel,butwillultimatelyincludeelementsofallthree.

Garduño and Foster (2010) listed a number of challenges when considering the governance of

conjunctive usemanagement. They reported that: “Serious impediments have to be overcome torealizesuchwaterresourcemanagementpolicies.Theyareprimarilyinstitutionalincharacter,giventhat the structure of provincial government organizations often simplymirrors current water‐use

realitiesandtendstoperpetuatethestatusquo,ratherthanofferingaplatformforthepromotionofconjunctivemanagement.”

In summary, the governance model needs to address four areas of endeavour: legislative,organisational,capacityandsocio‐political.Inmanycountries,theorganizationalaspectmayrequire

themostsignificantchangestobemade.

6.1.1 InstitutionalstrengtheningInstitutionsthatmanagewater,atboththenationalandregionalscale,needtobestrengthenedto

removeimpediments.ThisrequirestheadoptionofframeworksthatpromoteIWRMwheresurfacewater and groundwater functionsoperate collectively towards a single overarchingobjective, andthefunctionofwaterandagricultureministriesarealsoalignedforthispurpose.Institutionsneedto

beclearonwhooperatesandmanagesirrigationcommands;arrangementsthatmaybeinclusiveofeitherthepublicorprivatesphere,oracombinationofboth.

The resolution of chain of command issues across various levels of government also needs to bereviewed.Thatis,eachlevelofgovernmentmustunderstanditsroleinimplementingnationalwater

resource policy and be effective in enacting that role. Counter‐activities at any level must beconfrontedandremediesprovided.Institutionsneedtohaveastrongcomplianceculturetoensurethatoutcomesareachieved.

6.1.2 PolicyandlegislationInmany instances, there isaneed tounderstandand reviewthecurrentapproaches toallocatingrights in water, and the form and attributes of those rights. In many situations, policies and

regulationsmaybepoorly formulatedandhencenotoperatingefficiently toachievethe intendedoutcomes.Effectivewaterallocationplanningisparamount.Suchplanningneedstobesupportedbystrongnationalpolicyandtooccurwithinaframeworkthatensuressustainable levelsoftakeand

42

use of the resource. This requires significant technical input, especially within the context of theneedtoassesstheavailableconsumptivepool.

Conjunctiveusemanagementreliesonwaterpoliciesandregulationsthatareefficientatpromoting

movementofaccessbetweenthetworesourceswhenrequiredandappropriate.Legalandmarketpowersandmechanismsmustbealignedtoachievethisgoal.

6.1.3 Planning

Byitsverynature,plannedconjunctiveuserequiresastrongmanagementplatform.Thereisaneedto clearly define objectives, outcomes, activities and performance measurement and compliancearrangements.Suchplansshouldbebasedaroundwaterallocationmechanismsandhaveregardto

thetechnicalunderstandingofthetotalconsumptivewateravailable.

Implementationplanning requiresdefinitionof investment requirementsanddecisionsaboutwhowillmakethose investments,andwhowillultimatelypay. Ideally,planningshould incorporatethetriple‐bottom‐linenotionsofachievingenvironmental,economicandsocialobjectives.

Conjunctive use management also requires consideration of land use policy changes so that

groundwaterprotectionoutcomescanbeachieved.Thisisnotausualsetofpolicydecisionsinmostdevelopinganddevelopedcountriesandmaynotonlyrequireconsiderableinput,butalsopoliticalsupport.

6.1.4 MarketandpricingapproachesSurface water and groundwater always have differential cost structures that apply to users. In

centralized government systems, these cost structures may be heavily subsidized as a result of

related policy decisions (for instance, those for food and energy) and there may be unwanted

outcomes as a result; usually, these relate to poor water use efficiency outcomes. In general,

groundwaterusersfullyfinancetheirassociatedinfrastructurewhereassurfacewaterinfrastructure

hasbeeneitherwhollyorpartlysubsidizedbytheState.Thedifferentownershipmodelscontribute

todifferential cost impacts for irrigators, leading todecisions thatare inconsistentwithoptimized

planningobjectives.Conjunctivemanagementneedstounderstandandremovetheseimpediments.

State‐sponsoredgroundwaterdevelopmentisanareawhereinvestmentmayberequired.

Therearealsobedifferencesineconomicapproachesatthemacroandmicroscale,andanyactivity

toenhancethewatermarketneedstoacknowledgethetwodifferentscalesofbenefits.Thisisalso

truewhereeconomicincentivesareimplemented.

6.1.5 On­the­groundimplementationPlanned conjunctive use management will benefit strongly from, and possibly require, strong

ownershipbytheirrigatedfarmingsector.Thiscanbeachievedbybuildingstronglocalwateruser

43

groups through targeted education and enabling actions. In the past, communities have been

focuseduponsingleissues(eithersurfacewaterorgroundwater)andtherehasbeenareluctanceto

engage inmanagement issues associated with the other side of the resource picture that would

require reorganization to better reflect the distribution of users. Overcoming this issue is

exacerbatedbyanumberoffactorsincludingtheabsenceofarevenuebaseforcostrecoveryand

thepoliticizationof theuser groups towardsmaintaining subsidized surfacewater supplies. There

needs to be a participatory culture of education, demonstration and capacity building between

governmentsandtheirrigationfarmingcommunityanditskeystakeholders.

6.1.6 KnowledgegenerationTo facilitate conjunctive use management, knowledge is required in two key areas – technical

understandingofthespatialandtemporaldistributionofthetotalconsumptiveavailablewaterand

supportforplanningthroughthecapabilitytoprovidefutureimpactscenarios.Thelatterisgenerally

in the form of a complex numerical model of aquifer‐river basin performance. Conjunctive use

management also requires the establishment or improvement ofmonitoring programmes so that

thequantityandqualityimpactsoftheuseofsurfacewaterongroundwaterandviceversacanbe

demonstrated,andsothatthebeneficial impactsofwatermanagementactionscanbeseenbyall

stakeholders.

6.2 Useoffinancialandmarket­basedinstrumentstopromoteplannedconjunctiveuse

Financialandmarket‐basedinstruments(FMBI)arearangeoffinancialandeconomicmeasuresthatcan be used to encourage specific actions and trends. In the context ofwater resource planning,FMBIcanconsistindirectfinancialincentives(e.g.taxationreduction,subsidiestolowerelectricity

prices) or disincentives (e.g. taxation increases) or alternatively indirect tradeoffs or offsets (e.g.pollutionreductionschemes)andtheintroductionofwatertrading.

Some countries have favoured a regulatory approach to bring about various water resourceoutcomes, while other countries have tended to favour economic instruments, in the belief that

clearfinancialsignalsareastronglevertoactivepolicyobjectives.Inthecaseofconjunctiveuse,theauthorsareoftheviewthatinmanycountriessubsidiesthatdistortthetruecostofwaterdelivery(surface water and groundwater) bias irrigator behaviours and hence retard the potential for

plannedconjunctiveusetocontributetooptimalwateruseoutcomes.

Conversely other FMBI (i.e. those not aligned with subsidies) can be a very powerful tool toencouragetheadoptionofoptimalconjunctiveuse.Therangeofoptionstendstobeverylocation‐and culture‐specific. Nonetheless schemes that provide both financial incentives (e.g. through

taxationdecreases),whenadefinedminimumvolumeofwater isusedconjunctively,and indirecteconomicoffsets(e.g.forsalinitycontrol)areconsideredthemosteffective.Theseshouldgenerally

beusedto‘kickstart’plannedconjunctiveuseandshouldnotbeseenaspermanentmeasures.

44

Theintroductionofclearlydefinedwaterrights,theapplicationofwelldefinedcaps(i.e.maximumlimitsofuseofgroundwaterandsurfacewater)andtheintroductionofawatertradingregimecan

operatetostronglyfacilitatemoreefficienttotalwateruse.Surface‐watertradingregimescurrentlyoperate in many countries, however groundwater‐trading regimes are not so common. Surfacewater to groundwater (and vice versa) trading regimes are rare. Nonetheless water trading can

representastrongmarketinstrumenttoencourageconjunctiveuse,ifitismanagedappropriately.Thereare,however,fewexamples intheworldwherethishasoccurred.This isespeciallyanissuewhere market mechanisms are not designed to account for environmental impacts (e.g. salinity

effects).

FMBIsarenotreadilyrecognizablewheregovernmentsexercisecentralizedcontrolasopposedtoamarket‐basedapproach.However,insuchcentralizedgovernanceapproaches,positivebenefit‐costoutcomesthroughsimilarinitiativesasFMBIscanstillbeachievedintermsofmeasuresof‘national

good’,thatis,nationalgrossproductionfromirrigatedagriculture,povertyalleviation,etc.Theissuehere isaboutapplying themostappropriate rewardandcompliancesignals to thewater/irrigatedagriculturesector.

Thisdiscussionalso indicates thatwatermanagementpolicy– and its role inplanned conjunctive

use– ispartofa largerpolicypositionbygovernments that involvesnational foodpolicy,povertyalleviation, economic growth, sustainability, climate change and energy considerations. Goodgovernanceismorelikelytoensueoncetheimpactonnationalwaterusepolicyofpolicydecisions

(includingsubsidies)intheserelatedareasisconsidered.

6.3 Asuggestedsetofconjunctiveuseprinciplesforconsiderationwithinagovernanceapproach

The following is a suggested set of principles for the implementation of conjunctive usemanagementwithin existing irrigation commands,where infrastructure and historical governancearrangementsareinplace:

• Planning should be undertakenwith full and detailed knowledge of the characteristics ofboththesurfacewaterandgroundwatersystems,ofexistingsystemoperationsandofthedemandsofthecroppingsystems.

• Goals should be established that are intended to optimize the water supply/demandbalance,irrespectiveofexistinginstitutional,governanceandregulatorymodels.

• Revised institutional arrangements underpinning thenew conjunctivemanagementmodelmustbesupportedwithastrongpolicyandlegislativebase.

• Thecombinedsurfacewater/groundwatersystemandtheiruseshouldbemanagedsoastooptimize net economic, social and environmental benefits, taking into account nationalenergy, foodsecurity,populationandpoverty reduction, sustainabilityandclimatechangepoliciesandprograms.

• Stakeholderparticipationshouldbeencouraged.Fromanoperationalpointofview,somekeyguidelinesto implementingconjunctivemanagementinclude:

• atechnicallyrobustunderstandingofstream‐catchment‐aquiferinteractions;

45

• a water balance that is inclusive of connectivity between the surface and groundwatersystems;

• technicalassessmenttechniquescommensuratewiththeunderstandingofthehydrologicalsystemandwithexplicitrecognitionastothelimitationstothevalidityandapplicabilityofinformation;

• a strategic monitoring programme for the catchment, including the alignment ofgroundwaterandsurfacewatermonitoring3.

In summary, conjunctive use planning is the structured water‐planning process whereby thedifferent characteristics (technical, economic, social and institutional) of groundwater and surface

water are compared andweighed against each other so that the optimum use of the twowatersources is achieved. The fact that this rarely occurs throughout the world is testament to theentrenchedwaterinstitutionalstructuresandtheverypoorunderstandingoffundamentaltechnical

processes.

7. Conclusionsa) Thereisarangeofsettingswithinwhichconjunctiveusemanagementcanoccur,andthere

do not appear to be any situation where conjunctive use management should not be

practiced.

b) Planned conjunctive use management is far better than spontaneous conjunctive use in

terms of deriving a better set of outcomes from the point of view of the resource, of

nationalgoodandeconomicreturn.

c) Most development has already occurred and no new ‘greenfield’ irrigation developments

are likelyata significant scale, thusmost implementationofconjunctiveusemanagement

willbebyretrofittingmanagementarrangementstoalreadyexistingsystems.

d) There are major economic and social reasons to encourage planned conjunctive use, an

opportunitytheworldcannotaffordtocontinueignoring.

e) Povertyreductioninirrigationareasiscloselylinkedtowatersupplyefficiencyandhenceto

conjunctiveusemanagement.

f) Institutional,economic,socialandtechnicalchallengeswillneedtobeaddressed,probably

inthatorder,atthesovereignscale.

g) The regulatory settings for water management for different sovereign States will be the

most important setting for management approaches. Any institutional strengthening will

needtobesupportedbystrongpolicyandpossiblelegislativechanges.

h) Conjunctiveusemanagementwillbelinkedtosovereignpoliciesrelatedtoenergy,climate

changeadaptionandtofoodsecurityandhenceabroadergovernmentalapproachwillneed

tooccur.

3 Monitoring regimes should recognize the differences between assessment monitoring and management

monitoring. Management monitoring refers to the monitoring of management rules and processes whilstassessmentmonitoringreferstomonitoringofthetechnicalorscientificaspectsofstream‐aquiferinteractions

(Fullagar,2004).

46

i) An importantpartofplannedconjunctiveuse is the identificationof the true total costof

waterresourcesandtheseparatecosttoindividualusers(forexample,electricitysubsidies

areverycommon),whichcangreatlydiffer.

j) The degree of connectivity of surface water and groundwater is an important technical

consideration,butnotonethatwillgreatlyinfluencewhetherconjunctiveusemanagement

issuccessful.

k) Institutional strengthening around groundwatermanagement and a fully integratedwater

agencywillbeamajorchallengeinmostareas.

l) A minimum standard for conjunctive use management is the presence of some form of

institutionalarrangementrelatedtogroundwatermanagement,whichaddressesissuessuch

assustainabilityviasomeformofregulation.

m) Publiceducationandsupporting technicalassessments isan importantpartofconjunctive

usemanagement.

n) Approachesthatgeneratethegreatestdegreeofflexibilityinwatermanagementaretobe

encouraged.

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