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DEPARTMENT OF WATER AFFAIRS AND FORESTRY

INTEGRATED WATER RESOURCES MANAGEMENT

GUIDELINES FOR WATER CONSERVATION AND WATER DEMAND MANAGEMENT IN WATER MANAGEMENT AREAS AND IN THE WATER

SERVICES SECTOR, SOUTH AFRICA

VOLUME 3

Implementation of Water Conservation and Water Demand Management Measures within the Water Services

Full Guidelines Version

DANIDA

FUNDING AGENCY

Edition 1

March 2004

TITLE: GUIDELINES FOR WATER CONSERVATION AND WATER DEMAND MANAGEMENT IN WATER MANAGEMENT AREAS AND IN THE WATER SERVICES SECTOR, SOUTH AFRICA Volume 3 – Implementation of Water Conservation and Water Demand Management Measures within the Water Services Sector Full Guidelines Version

FUNDING AGENCY: DANIDA CATEGORY: Guideline PURPOSE: To assist in implementing and sustaining water

conservation and demand management and related efficiency measures in a water services institution.

TARGET GROUPS: Technical and other staff who are responsible for

implementing and sustaining water conservation, demand management and related efficiency measures.

DATE: March 2004 STATUS: Edition 1 ENQUIRIES: Department of Water Affairs and Forestry Private Bag X 313 Pretoria 0001 Republic of South Africa Tel: (012) 336 7500 / +27 12 336 7500 Fax: (012) 323 0321 / +27 12 323 0321 Email: [email protected] Website: www.dwaf.gov.za

TABLE OF CONTENTS

VOLUME 3: WSI IMPLEMENTATION GUIDE MARCH 2004 PAGE i

VOLUME 3

TABLE OF CONTENTS

PREAMBLE ........................................................................................................................ IV

ABBREVIATIONS................................................................................................................VI

GLOSSARY OF TERMS .....................................................................................................VII

CHAPTER 1: WATER RESOURCE MANAGEMENT........................................................... 1

1.1 Water Quality Management – Objectives and Responsibilities .......................... 1 1.2 Water Quality Management – Surface Waters................................................... 1 1.3 Water Quality Management – Groundwaters..................................................... 5 1.4 Removal of Invading Alien Plants...................................................................... 7 1.5 Optimisation of Reservoir Storage................................................................... 12

CHAPTER 2: DISTRIBUTION MANAGEMENT ................................................................. 15

2.1 Flow Measurement.......................................................................................... 15 2.2 Zone Metering and Sectorisation..................................................................... 19 2.3 Water Meter Types, Applications and Selection .............................................. 27 2.4 Leakage Reduction ......................................................................................... 32 2.5 Pressure Management .................................................................................... 41 2.6 Asset Management – Basic Principles............................................................. 47 2.7 Rehabilitation Planning.................................................................................... 49 2.8 Consumer Meter Management........................................................................ 58 2.9 Design and Quality Standards of New Infrastructure – “Leak Free” ................. 60 2.10 Dual Distribution Systems ............................................................................... 62 2.11 Intermittent Supply Rationing .......................................................................... 63

CHAPTER 3: CONSUMER DEMAND MANAGEMENT ..................................................... 68

3.1 Introduction ..................................................................................................... 68 3.2 Water Efficient Appliances and Installations .................................................... 69 3.3 Water Conserving Habits and Practices .......................................................... 76 3.4 Reclamation and Reuse .................................................................................. 76 3.5 Consumer Leak Repairs.................................................................................. 77 3.6 Delivery Point Water Management .................................................................. 81 3.7 Financial Management .................................................................................... 94

CHAPTER 4: RETURN FLOW MANAGEMENT .............................................................. 102

4.1 Minimising Infiltration, Inflow and Exfiltration ................................................. 102 4.2 Wastewater Re-use....................................................................................... 104 4.3 Tariff Management – “Polluter Pays” Principle............................................... 105

CHAPTER 5: SOCIAL AWARENESS AND EDUCATION ............................................... 109

5.1 Introduction ................................................................................................... 109 5.2 Approach to Awareness-Raising ................................................................... 111 5.3 A Communication Campaign......................................................................... 115

CHAPTER 6: MANAGEMENT AND INSTITUTIONAL ASPECTS ................................... 123

6.1 Institutional Strengthening and Capacity Building.......................................... 123 6.2 Human Resources Development................................................................... 129 6.3 Benchmarking and Performance Indicators................................................... 132 6.4 Information Systems...................................................................................... 134 6.5 Consumer Meter Reading ............................................................................. 143 6.6 Drought Management.................................................................................... 145

TABLE OF CONTENTS

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LIST OF ANNEXES

ANNEX 1 COST ESTIMATES AND FINANCIAL APPRAISALS - EXAMPLES

ANNEX 2 FLOW METER TYPES AND SELECTION

ANNEX 3 METHODS OF LOCATING LEAKS IN WATER RETICULATION SYSTEMS

ANNEX 4 SUPPLEMENTARY INFORMATION ON ASSET MANAGEMENT OF FLOW METERS

ANNEX 5 CODES AND STANDARDS APPLICABLE TO DEVELOPMENT OF NEW INFRASTRUCTURE

ANNEX 6 GENERAL METHODOLOGY FOR SETTING WATER SERVICE TARIFFS

ANNEX 7 INNOVATIVE MANAGEMENT APPROACHES

ANNEX 8 INFORMATION MANAGEMENT NEEDS – WATER SUPPLY AND DISTRIBUTION [EXCLUDING FIXED ASSETS]

ANNEX 9 CHARACTERISTICS OF HYDRAULIC MODELLING SOFTWARE PACKAGES

LIST OF FIGURES 1.1 Examples of Aquatic Weeds

1.2 Examples of Woody Species

1.3 Photograph of Sedimentation in a South African River

2.1 Hierarchy of Flow Measurement

2.2 Photograph of Defective Flow Meter

2.3 Photograph of Consumer Meter Testing Using Test Rig

2.4 Photograph of Zone Meter Installation

2.5 Above Ground Zone Boundary Separation

2.6 Implications of Time Delay in Volume of Leakage

2.7 Typical Diurnal Flow Variation

2.8 Flow Monitoring Showing Occurrence of a New Leak

2.9 Photograph of Leak Location Using Listening Stick

2.10 Variation in Pressure at Critical Point, With and Without PRV

2.11 Hydraulic Gradient in Network Between PRV and Critical Point

2.12 PRV with Flow Meter Installation

2.13 The Asset Management Cycle

2.14 Fundamental Law of Decay

3.1 Pressure Compensated Flow Control – Storage Tank with Regulator Box

3.2 Batch Volume Control Device

3.3 Price Elasticity

4.1 Partial Wastewater Re-use System

4.2 Full Wastewater Re-use System

5.1 Achieving Behaviour Change through Awareness and Eductation

6.1 Stages of Capacity Building

TABLE OF CONTENTS

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6.2 Organisational and Community Development

6.3 The Performance Management Process

6.4 Model for Development of Managers

6.5 Information Management – from input to Output LIST OF TABLES 2A Comparison of Open and Closed Reticulation System Management

2B Flow Meter Types

2C Methods of Pressure Control

2D Examples of Scoring System for Mains Rehabilitation

2E Measures to Avoid Pipeline System Leakage

3A Consumer Use Reduction Measures

3B Delivery Point Water Management Methods – Applications and Selection

3C Comparison of Storage Tank / Regulator Box with In-Line Control Valve

3D Advantages and Disadvantages of Batch Volume Control Devices

3E Advantages and Disadvantages of Pre-Payment Meter Systems

3F Advantages and Disadvantages of Shared Connection Batch Volume Control

3G Advantages and Disadvantages of Non Pre-Payment Volume Control

3H Domestic and Small Non Domestic Consumers - Levels of Service and Charging Methods

4A Example of On-Site Re-Use

5A Example of an Awareness Raising Planning Chart

5B Awareness-Raising Budget: Example

6A WSI Capability and Procurement Levels

6B Examples of KPIs Related to WSIs

6C Meter Reading Methods

PREAMBLE

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PREAMBLE

This manual of guidelines on water conservation and water demand management is one of a set of three companion volumes developed for the Department of Water Affairs and Forestry (DWAF) by the DWAF/DANCED (Danish Co-operation for Environment and Development1) Integrated Water Resource Management (IWRM) project.

Volume 1 Water Conservation and Water Demand Management – A Planning Framework at Water Management Area Level

Volume 2 Guidelines for Undertaking a Water Conservation and Water Demand Management Situation Assessment and Development of a Business Plan within the Water Services Sector

Volume 3 Guidelines for Implementing Water Conservation and Water Demand Management Measures within the Water Services Sector

A first draft issue of the guideline manuals was prepared by IZNA, a consortium of South African consultants and other organisations, together with Danish consultants, Carl Bro International, as prime contractors to Danced. These guidelines were first issued in February / March 2002 and were presented at a workshop in DWAF on 24/25th April 2002. They were also utilised, to the extent applicable, in pilot projects undertaken within three water management areas: Crocodile West – Marico, Mvoti – Mzimkulu, and Olifants – Doorn.

As a result of experience with their use in the pilot applications, the guidelines were re-structured into three volumes by the Carl Bro WCDM Adviser in April 2003; significant content revisions were also made at the same time. These second draft versions were reviewed at a workshop in August 2003, attended by local service providers, local authorities and DWAF personnel. Thelani Consulting was then appointed to revise Volume 3 according to the debate and feedback from the workshop. This April 2004 version incorporates those revisions, together with the further edits of the WC/WDM Adviser and of J Boroto, whose specific remit was to check the guidelines for alignment with the WC/WDM strategy documents.

For an understanding of the legislative background, the national policy on water conservation and demand management, and the integrated water resource management approach, the reader is referred to the introductory sections of Volumes 1 and 2 of this series.

For a water service authority or water service provider, the “why” and “what” of water conservation and water demand management is addressed in Volume 2. This Volume 3 is concerned solely with the “how” of implementation of such WC/WDM measures as may be determined by the situation assessment and business plan.

The DWAF model strategy for WC/WDM for Water Services Authorities and for Bulk Water Suppliers (including Water Boards) is set out in Chapter 6 of the national WC/WDM Strategy for the Water Services Sector. This envisages that a range of activities that may need to be undertaken, according to local needs, spread across the four phases of the water utilisation cycle from abstraction through to its return flow back into the natural environment.

1 Danced functions merged with Danida (Danish International Development Agency) part way through the IWRM project implementation

PREAMBLE

VOLUME 3: WSI IMPLEMENTATION GUIDE MARCH 2004 PAGE v

The first four chapters of this document deal with the technical measures that are applicable to these phases as shown on the following figure:

Chapter 5 is devoted to social awareness and education which has an essential crosscutting role to play in any broadly based WC/WDM initiative, as well as featuring prominently within consumer demand management.

Finally, in Chapter 6, guidance is given on related topics that are likely to arise when a WSI introduces water conservation and demand management measures. These include:

� Improvements to data quality and information systems

� Institutional restructuring and strengthening

� Human resource capacity building

Drought management, which is concerned with special measures taken by a WSI under (1), (2) and (3) is also included in Chapter 6.

1 Resource Management

2 Distribution Management

3 Consumer Demand Management

4 Return Flow Management

ABBREVIATIONS

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ABBREVIATIONS

CMA Catchment Management Agency

conn connection (of pipe from water main or sewer to building)

CRC cost rebate charge

DWAF Department of Water Affairs and Forestry

DANCED Danish Cooperation for Environment and Development

EIRR economic internal rate of return

esb equivalent service burst

FIRR financial internal rate of return

GIS geographic information system

ILI infrastructure leakage index

IPM integrated pest (weed) management

IRP integrated resource planning

IWRM integrated water resource management

KAP knowledge, attitudes and practises (survey)

KPI key performance indicator

kl kilolitre (= one cubic metre)

km kilometre

l litre

m metre

NWCDMS national water conservation and demand management strategy

PPRI Plant Protection Research Institute

PRV pressure reducing valve

RBC rising block charge

SABS South African Bureau of Standards

SCADA supervisory control and data acquisition

UARL unavoidable real losses

UAW unaccounted for water

WC water closet

WC water conservation

WDM water demand management

WMA water management area

WSI water services institution

GLOSSARY OF TERMS

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GLOSSARY OF TERMS

Active leakage control

A pro-active monitoring and control regime in which new leaks that occur and which have not been reported are quickly identified, located and then promptly repaired to minimise the loss of water

Acoustic logger Loggers that measures the amplitude of noise that is emitted from the pipeline during a leak. The location of the leak is established from the simultaneous analysis of noise recorded by various loggers as well as their location during survey

Alien plants Plants that have been introduced into an area from outside its boundaries (see also invading plants)

Apparent losses (of water)

Unauthorised consumption and measurement inaccuracies

biocontrol An abbreviation of biological control in which living (biological) organisms are used to control other pest organisms.

Black water The part of wastewater that is produced from toilets

Debt ratio The total money owing from water sales and associated accounts divided by the current month’s water sales and associated charges

Digital map A plan held in digital form in computer software, such as Autocad, and able to be presented either on a screen or printed out as a hard copy in any scale and within any boundaries – usually has ability to present different “layers” of information as needed for clarity or special purposes (see also GIS)

Exfiltration (from sewers)

Wastewater that escapes from the sewer network due to defects in pipes etc. and which pollutes sub-soil and groundwater, where the infrastructure is above the water table

Geographic information system (GIS)

An enhanced digital map in which information pertaining to geographical features or infrastructure components are held in a database linked to the digital map, enabling such information to be manipulated and presented in forms which are helpful to the various users

Grey water Wastewater generated from washing, laundry, food preparation, but excluding toilet wastewater

Hydraulic model (of water reticulation system)

Based on the structural model and using standard hydraulic theory provides a simulation of flows and pressures in the system either at a single point in time or in a dynamic model over a 24 hour period

Infiltration (of groundwater)

Groundwater that enters a sewerage network due to defects in pipes, chambers etc., where the infrastructure is below the water table

Inflow / ingress (of surface water)

Drainage water a from rainfall event, or from connections to springs or groundwater sources such as foundation drains, that enters a sanitary sewerage system which is conveying polluted wastewater to treatment / disposal locations

GLOSSARY OF TERMS

VOLUME 3: WSI IMPLEMENTATION GUIDE MARCH 2004 PAGE viii

Integrated network management

Of a WSI’s supply and distribution infrastructure may be regarded a parallel concept to integrated water resource management and is the process by which all aspects of the serviceability of the assets are subject to monitoring and review using a common information system to enable consumer service levels to be met at minimum cost

Integrated pest management

An approach to the management of invading plants which involves making use of all the available control measures as efficiently and cost-effectively as possible

Invading alien plants A sub-set of alien plant species that have been able to establish themselves outside the sites where they were originally planted

Integrated water resource management

A philosophy, a process and an implementation strategy to achieve equitable access to and sustainable use of water resources by all stakeholders at catchment, regional, national and international levels, while maintaining the characteristics and integrity of water resources at the catchment scale within agreed limits.

Leakage Water that escapes through defects in the infrastructure other than as the result of a deliberate or controllable action over a specified period

Leak noise correlator A two channel electronic microprocessor that measures the time delay in matching the sound frequency spectrum of a leak noise from two different locations on a pipeline, for the purposes of pinpointing the position of a leak

Passive leakage control

A formalised procedure by which the occurrence of new leaks that are reported by the general public or by operations personnel on general duties are repaired promptly to minimise the loss of water

Real losses Also known as physical losses, are escapes of water from the infrastructure due to structural defects in tanks, process losses in treatment, overflows, leakage from trunk mains and in the reticulation network

Supervisory control and data acquisition (SCADA)

Is telemetry combined with a remote control and automation facility which enables an operator, the “supervisor”, to intervene in the operation and change the control set points from the control desk when changed operating circumstances arise

A SCADA system may be wide area and control a whole system or be local on a single site, e.g. a treatment plant or pumping station

A system which provides only for remote control according to fixed set points is strictly speaking not SCADA

Structural model (of a water reticulation network)

A geographic information system that holds data both on the assets themselves and their structural condition and performance

Telemetry Data capture from remote points by cable, optic or radio communication, and their presentation at central monitoring and control locations, it provides for one way flow of information only (see SCADA)

GLOSSARY OF TERMS

VOLUME 3: WSI IMPLEMENTATION GUIDE MARCH 2004 PAGE ix

Waste (of water) Water fed into supply that leaks or is allowed to escape, e.g. from overflows, or that is taken from the distribution network for no useful purpose

Water conservation The minimisation of loss or waste, care and protection of water resources and the efficient and effective use of water (national WC/WDM strategy definition)

Water demand management

The adaptation and implementation of a strategy to influence water demand and usage in order to meet any of the following objectives: economic efficiency, social development, social equity, environmental protection, sustainability of water supply and services, political acceptability (national WC/WDM strategy definition)

Water Services Institution

Is a body that has responsibility in whole or in part for delivery of public water services to the community. WSIs include Water Services Authorities, municipalities, water boards, Water Services Providers, Water Services Committees and Water Services Intermediaries.

Yield (of a water resource)

Is the steady supply of water that could just be maintained through a drought of specified severity. Gross yield is the total available resource. Net yield is the water remaining for supply after any compensation water or residual water has been left and losses have been deducted.

CHAPTER 1

WATER RESOURCE MANAGEMENT


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CHAPTER 1: WATER RESOURCE MANAGEMENT

1.1 Water Quality Management – Objectives and Responsibilities

Water quality management objectives within WC/WDM are inter-related and are concerned with:

� Maintenance of fitness for use

� Minimisation of water requirement

� Minimisation of in-stream water requirement.

At a catchment / water management area level, these can only be established following the application of IWRM principles by the CMA, having regard to the needs of all water users and the requirements of the human and ecological reserve that is being addressed by the Department of Water Affairs and Forestry nationally.

However WSIs are key stakeholders in this process and should make their contribution to setting the water quality objectives by identifying and quantifying the water quality problems that particularly affect them, and by fulfilling their responsibilities for the management of the water resources.

Specific responsibilities of WSIs in implementing groundwater quality management strategies are advocated in DWAF’s Policy and Strategy for Groundwater Quality Management and include:

� Resource monitoring and dissemination of groundwater data

� Preparation of groundwater resource status reports

� Evaluation of applications and issuing of licenses

� Co-operation with the authorities responsible for source-based control to impede the introduction of contaminants into aquifers (with respect to planning)

� Control of groundwater abstraction to provide for sustainable utilisation and to prevent or minimise the migration or intrusion of poor quality groundwater

� Defining source areas and implementing the national well-head protection programme (e.g. when operating a well field)

� Public education and assistance and dissemination of public information.

1.2 Water Quality Management – Surface Waters

1.2.2 Basic Principles / Summary

If the quality of surface water in a catchment is not properly monitored and managed, it may become unsuitable for human consumption and other economic uses using standard treatment processes. Water conservation measures that are taken to avoid deterioration or to improve the quality of surface waters are alternatives to the exploitation of a new resource of good quality water, or to the implementation of more advanced and costly treatment processes, such as membranes or desalination.

WSIs are key stakeholders in the water resources and need to take an active role

in their management



Effective water quality management requires, in the first instance, an understanding of the causes of poor water quality and its impacts. It is also necessary to be aware of the effect of WDM measures on water quality in order to avoid a situation in which solving one problem creates or exacerbates another problem in a different part of the catchment.

Specific measures to be taken may include the reduction of both point and diffuse source pollutants.

Technical measures may be accompanied by economic measures based on the “polluter pays” principle.

1.2.3 Causes of Poor Water Quality

The development of a water quality management programme requires a good understanding of the causes of water quality problems, which can arise from both natural and anthropological causes at various points in the natural hydrological cycle:

� Precipitation: gases vapours, particulates, salt nuclei

� Surface water: particulates organic matter nitrates, phosphates, biocides

� Spring (and ground water): salts (calcium and magnesium carbonates; chlorides and sulphates), iron and manganese

� Lake water: algae, odours, tastes

� River water: wastewater, soil erosion

� Sea water: salts

The wetter eastern portion of the country generally tends to provide natural water of good quality, whereas the drier interior and western regions tend to produce increasingly saline natural runoff and groundwater. This is accentuated in areas underlain by marine deposits.

Human activities accentuate natural problems and add a whole range of new pollutants to the system. This occurs through:

� Evaporative concentration of salts when water is used for cooling (e.g. power stations, petrochemical and steelworks), in irrigated lands and dams

� Mine de-watering that brings large volumes of saline water to the surface - pyrites oxidised in mining voids provide a large reservoir of sulphate load, which is released by surface water ingress into the underground water

� Rising water tables induced by the irrigation of lands underlain by marine sediments can lead to the decanting of ancient connate saline water into irrigation return flows, such as in the Eastern Cape, where irrigation with Orange River water imported from Garieb Dam via the Orange-Fish tunnel has led to severe salinity problems in the Fish-Sundays river system

� Industrial processes that add inorganic and organic chemicals

� Nutrients from domestic sewage and treated effluent, unless the wastewater treatment plant is specifically designed to remove nutrients - Hartebeespoort Dam is an example of the loss of an otherwise usable resource, users being obliged to consider expensive imported water from the Vaal River



� High organic loads and pathogens from domestic wastewater - a particular problem immediately downstream of informal settlements or where overflows occur from poorly managed or designed sewer systems.

1.2.4 Impact on Water Requirement

Degraded water quality has three important impacts:

� Direct loss of usable resource

� Increased water requirement by users

� Increased in-stream water requirement

High salinity also directly precludes certain uses (such as for the irrigation of some crop types or various industrial applications), thereby effectively reducing the usable water resource.

Increased water requirement

At sub-critical concentrations salinity can increase the water requirement. In the case of irrigation the leaching fraction is increased, thereby necessitating a larger water supply. In cooling water applications the number of cycles of use before wastewater has to be blown down is reduced. This increases the gross water requirement, thereby increasing water demand and the required investment in supply and effluent disposal infrastructure.

Increased in-stream water requirement

The need to maintain a basic reserve for human consumption and to maintain acceptable functioning of the environment has been recognised in the new Water Act. Point and diffuse source effluent pollution levels are often so high as to render the river water unfit for most uses. In such instances fresh water from an uncontaminated source may be required to dilute the water constituents to more acceptable concentrations.

1.2.5 Effect of Reduction in Water Use

Different components of water demand management can have diverse effects on water quality. The likely effects on water quality are discussed below.

Reduction of distribution losses

Any reduction in true water losses should have little effect on the quality or quality of urban effluent return flow. Since much of the interior of the country is semi-arid, it can be expected that little of the leakage water will be returned to the surface drainage system, particularly during dry weather conditions. The overall impact on river quality should therefore be minimal, or beneficial due to the reduced water requirement.

Reduction in consumptive use

The main potential for such a reduction is in the domestic sector, where curtailment of garden watering is achievable. This too should have little impact on effluent water quality.

Reduction in non-consumptive supply

A reduction in non-consumptive supply can be expected to result in an increase in wastewater strength, since the load of pollutant is likely to remain basically the same for the domestic sector.



There is more opportunity for reducing polluting load as well as flows in the industrial sector, if an integrated approach to waste minimisation is adopted. The net impact on surface waters will depend on the design and loadings on the wastewater treatment plant.

Re-Use of Water

A reduction in pollution load will occur if re-use is practised, i.e. substitution of potable water by already used water – the use of grey water on gardens is a good example. Again, depending on the design and loading of the wastewater treatment plant, this might reduce nutrient discharge, due to the removal of phosphate rich detergents.

Industries may need further effluent treatment steps to comply with discharge targets. This will obviously lead to an improvement in water quality, albeit at additional cost. The possibility of some industries deciding to recycle or sell their higher quality treated effluent should be considered, in which case the return flow will disappear entirely. Industries that are compelled to discharge their effluent upstream of the abstraction points will take the necessary steps to ensure effluent treatment, as any pollutants discharged will impact directly on the quality of water abstracted.

1.2.6 Specific WC Measures in Management of Surface Water Quality � Minimise overflow of sewers through the implementation of regular maintenance

programmes

� Improve levels of wastewater effluent treatment – municipal and dedicated industrial plants

� Reduce the nutrient levels in water returned from agricultural run-off (due to over application of fertilizers) and municipal wastewater effluent – will have secondary benefit of limiting growth of alien vegetation

� Control the use of motorised water craft with respect to the discharge of hydro-carbons into the water

� Minimise overflow of combined sewers by ensuring that overflows do not spill until the hydraulic capacity of the sewer system is fully utilised (notwithstanding the nominal forward flow design value that may be significantly lower)

1.2.7 Waste Discharge Charge System

The use of economic instruments to achieve pollution control objectives is complementary to a regulatory regime of enforcement. If charges are set at an appropriate level that reflects the full economic cost of pollution, polluters have the option of continuing to pollute and paying the levy or taking action to minimise polluting. This is consistent with the least cost integrated resource planning approach that is recommended in Volume 2 of these guidelines.

This is generally known internationally as the "Polluter Pays Principle" and has been considered by the Water Research Commission in the South African context. This was followed by a national scale Department of Water Affairs and Forestry study to evaluate the implementation of a Waste Discharge Charge System (WDCS).



References and Suggested Further Reading:

Herold, C E and Rademeyer, J I (2000). Water utilisation in the Vaal River system: The current situation, influences and expected trend. In: Proc. Vaal River 2000 conference, SAICE, Vereeniging.

Herold, C E and Triebel, C (1989). The role of computer models in identifying the PWV blending scheme as the most viable option for ameliorating the effects of salinisation of the Vaal River In: Proc. Fourth South African National Hydrological Symposium, Pretoria.

Herold, C E and van Robbroeck, T P C (1988). Water quality - the fifth dimension in water resources plannin. In: Proc. Eighth Quinquennial Convention of SAICE, Pretoria.

Taviv I, Herold C, Forester S, Roth J & Clement K (1999). A Philosophy and Methodology for implementation of the Polluter Pays Principle WRC Report No. 793/1/99.

Van Duuren FA (1997). Water Purification Works Design Water Research Commission. Report TT92/97.

1.3 Water Quality Management – Groundwaters


The strategies required for groundwater quality management in South Africa are guided by the National Water Act (Act No. 36 of 1998) and the requirements of DWAF. Measures that may be taken fall into one of four types:

1. Resource Directed Measures (Classification, the Reserve, Resource Quality Objectives)

2. Source Directed Measures

3. Well-head Protection Measures

4. Remediation Strategies

Further information is given in the Groundwater Management Guidelines (DWAF / Danced 2002).

1.3.2 Resource Directed Measures

Resource-directed strategies are aimed at understanding the inherent characteristics and current and potential future use of the water resource itself. These are then used to determine the required level of protection. The measures implemented under this strategy are directed at managing such impacts as do inevitably occur in such a manner as to ensure suitability for the beneficial uses of the resource.

The implementation of resource directed measures are outlined by the broad steps listed below. Although these are primarily the responsibility of the CMA, the WSI will be giving effect to the measures by compliance with their licence conditions.

Step 1 Start the determination of resource direct measures.

Step 2 Delineate the resource units.

Step 3 Determine the reference conditions.



Step 4 Determine the present status, importance and vulnerability.

Step 5 Set the management class.

Step 6 Set the reserve and the resource quality objectives.

Step 7 Monitor the strategy.

1.3.3 Source Directed Measures

Source-directed strategies are aimed at minimising, or preventing at source wherever possible, the impact of developments or activities on groundwater quality. Source directed measures have, in the past, been principally targeted at point sources of pollution to surface waters and coastal marine waters.

Implementation of source directed measures should include the following steps:

Step 1 Collect information from source directed measures.

Step 2 Identification of sources.

Step 3 Risk-based ranking of impacting activities.

Step 4 Select sources for intervention or remedial action.

Step 5 Select and apply instrument for source control.

1.3.4 Well-head Protection Measures

Well-head protection measures are aimed at the prevention of contaminants from entering the groundwater supply boreholes by managing activities on the land that contributes water to the boreholes. Generally, these measures include minimum borehole construction standards and the establishment of well-head protection zones. The development of well-head protection plans should involve the following broad steps:

Step 1 Gather information/set up planning committee.

Step 2 Define well-head protection area.

Step 3 Compile a potential contaminant source inventory.

Step 4 Manage sources to prevent contamination.

Step 5 Monitor emergency/contingency/spill response planning.

Step 6 Update the well-head protection plan.

1.3.5 Remediation Measures

Remediation strategies are aimed at rectifying historical groundwater pollution, where practicable, to protect the reserve and ensure fitness for the purpose.

References and Suggested Further Reading

DWAF Policies and Strategies for Groundwater Quality Management. Integrated Strategies to Manage Groundwater Quality in South Africa 1st Edition, 2000

DWAF/Danced IWRM Project. Groundwater Management Guidelines – Chapter 6. Implementation of Existing Groundwater Quality Management Strategies 2002



1.4 Removal of Invading Alien Plants

1.4.1 Basic Principles / Summary Alien plant control involves a sequence of activities aimed at the effective elimination of the invading plant species, or combination of species in a particular area. The timing and nature of these operations are determined largely by the (combination of) species present.

Water (aquatic) weeds invade dams and rivers and impact on water quality as well as quantity. Woody species use more water than the natural vegetation they replace, reducing the quantity of water in rivers and the yields of dams and reservoirs.

A control programme commences with a survey and situation assessment and needs to be planned over a 5 year (say) timescale. After the initial clearance, there are usually follow-up activities required before then progressing to the long term monitoring and maintenance regime that needs to be in place to keep the area free of further invasions.

The programme should be prioritised according to the basic rules of:

� Light before dense

� Work from upstream to downstream

� Target greatest impacts

The specific measures to be implemented are very location dependent due to the wide variance of flora across South Africa. The Working for Water Programme (launched in 1995) and the Plant Protection Research Institute (PPRI) may be referred to for specific guidance. An integrated pest (weed) management approach should be adopted for greatest efficiency and cost-effectiveness, biocontrol alternatives should be considered as well as mechanical control methods. The control programme must also be alert to the opportunities for use of cleared material as a resource that can provide local employment.

The key features of a successful clearance methodology are:

� Work within your means.

� Work systematically

� Be thorough

� Complete the job

1.4.2 Plant Types and Impacts Alien, or exotic, plants are ones that have been introduced into an area from outside its boundaries. In most cases they are plants that have been imported from overseas, mainly for horticulture (garden and street planting) and forestry purposes.

There are many alien plant species in South Africa, but only about 5-10% of these species have been able to establish themselves outside the sites where they have been planted, these are called invasive species or potential invaders. Only about 5-10% of this subset of the alien plant species is able to invade relatively undisturbed natural communities. These are called invading alien plants.

Two primary groups of species can be recognised:

1. Water (aquatic) weeds which invade dams and rivers

2. Woody species ranging from scramblers such as brambles to eucalyptus (gum trees), also including bamboos.



Aquatic weeds have a significant impact on the chemical quality of the water and can increase the prevalence of water-borne diseases. Woody species in group 2 use more water than the natural vegetation they replace, reducing the quantity of water in rivers and the yields of dams and reservoirs.

Figure 1.1: Examples of Aquatic Weeds: Water Hyacinth ( left ) and Red Water Fern (right)

From a control perspective, species may be sub-divided into those that are able to re-grow if cut down (sprouters), and those that cannot re-grow (non-sprouters). Another sub-division is into species that do or do not have long-lived seed banks in the soil. Species which sprout will require herbicides to kill them. Species with long-lived seed banks require more follow-up operations.

Figure 1.2: Example of Woody Species: Perstamarisk

Riverbanks and the adjacent (riparian) areas are particularly open to invasions. Riparian areas are relatively moist, allowing invading plants to take up large amounts of water as well as obstructing watercourses and causing damage to bridges and other infrastructure when washed away by floods.

As well as the impact on water resources, invading alien organisms are regarded as a major threat to our natural environments, to endangered species and to the ecological services, such as water purification, which those environments provide.



1.4.3 Overview of Control Programme

In general, a programme can be divided into a number of stages:

Stage 1: Situation assessment: involves an inventory of the invaded areas and their condition. The Working for Water Programme has created a set of standards for mapping invasions for this kind of inventory; these should be followed to ensure that the information is properly recorded and comparable to information available elsewhere.

Stage 2: Initial planning of the programme: the information from the situation assessment is used, together with information on the resources available to the organisation (e.g. annual budget available, manpower, equipment) to arrive at an overall control plan for a suitable period, say the next 5 years. This plan should incorporate a broad prioritisation based on the factors and principles set out below which will identify the areas to be tackled in each year in an annual plan of operations (APO).

Stage 3 Monthly Schedule of Operations: The framework provided by the APO is used to set up a monthly schedule of operations, assigning responsibilities and control teams and to monitor progress

Stage 4 Execution of initial clearance: according to the schedule of operations with progress assessed at the end of each month and year, corrective measures being taken as necessary if the work is not going according to schedule.

Stage 5 Follow-up: the initial clearing is followed by a series of operations to follow through and control the re-growth that takes place. The number and timing of these operations depends largely on the biological attributes of the invading plant species.

Stage 6 Maintenance to sustain the clearance: involves regular and ongoing inspections on a quarterly to annual basis to ensure that any re-occurrence of invading plants is dealt with before the problem escalates.

1.4.4 Prioritising the Control Programme

Prioritisation is about doing the most important and effective things first and will take place at a number of stages in the planning and execution of a control programme. The general factors and principles described below are primarily for use in the 5-year planning exercise

Light before dense: First priority should go to areas that are only lightly invaded. This maximises the area can be cleared per unit cost and effort. An initial focus on dense areas will allow lightly invaded areas to become denser in the meantime. The impacts of the light invasions on the environment will be much less than those in dense areas, so that rehabilitation will be minimal or not necessary at all.

Work from upstream to downstream: When working on rivers or watercourses, always start with the invasions at the head of those watercourses or their tributaries. If this is not possible, for example if the landowner will not co-operate, then apply pressure to get their compliance. Any clearing of downstream areas simply will make them more vulnerable to invasion by the seeds being washed from upstream uncleared areas. Likewise, there is little point in clearing areas when the adjacent areas are heavily invaded and will not be cleared. Rather concentrate on other areas until these issues have been resolved.

Prioritise the control programme:� Light before dense � Upstream before downstream� Target greatest impact



Go for greatest impacts: Work first on the most sensitive areas and habitats, for example riparian areas and important areas for environmental conservation, and the areas with species that have the greatest impacts. In general:

� Taller plants consume more water than shorter ones

� Evergreen plants consume more water than ones that lose their leaves in winter or during droughts

� Deep-rooted plants such as trees consume more water than shallow rooted ones

This means that invasions by tall evergreen trees, such as Black wattle, should be given priority.

1.4.5 General Guidelines Always try to involve all the affected parties so that concerted action is taken and the efforts can be co-ordinated to achieve maximum effectiveness and efficiency. This is directly in line with the principle that WSIs should work together with other organisations to achieve their overall aims.

The guiding principle of a control operation is to ensure that the available resources are used as cost effectively and efficiently as possible. Ongoing monitoring and assessment is required to ensure that ways of increasing productivity are identified and implemented.

It is beyond the scope of this document to describe a control programme and treatments in detail. There are so many factors that will influence the programme and these differ so widely across the country that it is not possible to deal with all the permutations. For example, programmes in the sub-tropical regions may have to plan for initial clearing and at least two follow-up operations within the annual budget cycle. In the Western Cape a similar set of operations could be done over a period of 3-5 years.

Try to make optimal use of the available control methods, and therefore of resources, by combining and timing them correctly – an approach called Integrated Pest (Weed) Management. For example, different species require different treatments or combinations of treatments. In many ways IPM is the equivalent of IWRM in the field of pest management.

Killing standing trees by ring-barking them, with herbicide where necessary, may be significantly cheaper than cutting them down, let alone removing the cut material. On the other hand there may be markets for the wood and other material for a variety of purposes such as firewood, furniture, mulches, wood chips. The processing of this material can create additional jobs and increase the income of the communities involved thus helping to offset the costs and can be used to create jobs and provide social upliftment. These factors and options have to be evaluated in the local context and cannot be prescribed.

The various methods available for mechanical control are generally well known, but biocontrol is often overlooked. In South Africa the most common form of biological control for invading plants is the use of insects which only feed on specific species or destroy their seeds. In some cases fungal diseases are also successful.

Biocontrol does not produce immediate results but it can result in substantial savings by reducing, or in some cases virtually eliminating, the problem in the medium to long-term.

Adopt an integrated pest (weed) management approach.

Exploit opportunities for resource recovery and job creation



It is best used in areas which will not be controlled for a number of years because of resource or other constraints, thus giving it time to achieve a significant level of control.

Organisations like the Plant Protection Research Institute (PPRI) have specialists who can give general advice on control requirements as well as on specific species. The Working for Water Programme, Rand Water and Umgeni Water, amongst others, have accumulated significant experience in the area of planning and managing alien plant control operations. The WfW programme have a toll free contact number for advice on alien plant control: 0800 005 376. The new handbook by L Henderson (see bibliography) has numerous contact addresses and useful information.

Training may seem expensive but the expenses will be repaid by improving the efficiency of the control operations. Working for Water and the PPRI, amongst others, offer practical training programmes. There is also a legal requirement that the person applying herbicides has to have passed a training course. If they have not, then the employer may be liable for damages that may arise, including impacts on the health of other employees and the public.

1.4.6 General Approach to Execution of Programme

Work within your means: this is particularly important in the early stages where it is very easy to do the initial clearing on a much larger area than you can afford to cover properly in your follow-up operations.

Be systematic: control operations have to be done in a particular sequence and the successful control of some species depends on adhering to the recommended timing of different operations. It is absolutely essential that follow-up operations are completed first before any new areas are worked on.

Be thorough: deal with all the species in an area at the same time and optimise the operations for the combination of species.

Complete the job: rehabilitate areas that have been cleared by re-establishing indigenous vegetation. This step is often neglected but if it is not done then these areas may be highly susceptible to re-invasion or be the source of other environmental problems such as erosion.

If the people in the organisation have little or no experience in control programmes it is essential to get appropriate advice. This kind of input can be critical in identifying how to apply the principles of integrated IPM in a particular situation.

1.4.7 Sustainability Alien plant control is an expensive activity and will take several years to complete in a particular area. If the work is not carried through to completion, then the money spent to date will be wasted. The importance of this commitment to a long-term plan needs to be clearly understood by those involved in making decisions and in controlling budgets.

A maintenance regime must be established following the initial clearance. Its scheduling may be influenced by fires, floods, overgrazing or reduced competition from indigenous vegetation. Factors that should be considered when planning maintenance programmes include:

Be sure to complete the job by re-establishing indigenous vegetation

Commitment to a medium-long term resource and financial plan is

essential, otherwise the initial investment will be wasted.



� The importance of the catchment in terms of run-off

� The extent of alien invasion

� The species involved

� The water consumption attribute of these invaders

� The level of demand for water.


Bromilow, C (1995). Problem plants of South Africa. Briza Publications CC, Arcadia, Pretoria.

Campbell, P (2000). Wattle Control. 2nd edition. Plant Protection Research Institute Handbook No. 3, Plant Protection Research Institute, Private Bag X6006, Hilton 3245.

Campbell, PL. (2000). Rehabilitation recommendations after alien plant control. Plant Protection Research Institute Handbook No. 11. Agricultural Research Council, Pretoria. Order from Private Bag X6006, Hilton 3245.

Croudace, J (1999). The alien clearing handbook for the Western Cape. Bo-Kloof Fynbos Conservation & Environmental Information Trust, Cape Town.

Henderson, L. (2001). Alien weeds and invasive plants. Plant Protection Research Institute Handbook No 12, Plant Protection Research Institute, Private Bag X134, Pretoria.

Klein, H (1999). Biocontrol agents against alien invasive plants in Fynbos. Handbook No. 10. ARC PPRI, Pretoria.

Holmes, P.M. (2000). Guidelines for indigenous vegetation restoration following invasion by alien plants (eds Sulaiman, A and Le Maitre, DC). Report No ENV-S-C 2000-144, Environmentek, CSIR, Stellenbosch.

Meier, KB, Hughes, GO, Coetzee, JC, Brodie, S and Hine, S (2001). A system for managing Working for Water Operations. Paper presented at the 10th South African National Hydrology Symposium, University of Natal, Pietermaritzburg, 26-28 September 2001.

Standards for Mapping and Capture of Alien Vegetation and Operational Data. Volume 1 (of 3) Mapping Standards, Procedures and Guidelines, Version 3, August 1999. Working for Water Programme, Cape Town.

1.5 Optimisation of Reservoir Storage

1.5.1 Basic Principles / Summary Optimisation of reservoir storage in the context of WC/WDM is concerned with the management of long term storage, e.g. impounding reservoirs and not distribution or service reservoirs. The aim is to:

� Reduce silting to ensure the maximum storage capacity is available through dredging, installation of silt traps and flushing.

� Reduce evaporation or the potential for evaporation to reduce losses through the introduction of transfer of water to storage with potentially lower evaporation rates.

� Implement flexible management, institutional and administrative measures for the transferring of water among alternative users that facilitates the reduction in evaporation and silting.



1.5.2 Siltation The erosion of a catchment that results in sediment particles being transported into lakes and reservoirs is a function of the geology, vegetation and soil cover.

Various factors will determine what proportion of this silt load will be trapped in the reservoir and the amount is generally expressed in terms of the ratio of storage capacity to mean annual run-off.

The depletion of capacity of a reservoir due to sediment accumulation is influenced by:

(a) Total sediment inflow

(b) The “trap efficiency” of the reservoir

(c) The density of the sediment deposits

(a) Can be alleviated, although never eliminated, through interventions such as erosion protection. (b) Is essentially a function of the design of the dam infrastructure but is influenced by operating procedures. (c) Is a function of the nature of the sediment particles and reservoir depth.

Figure 1.3: Photograph of Sedimentation in a South African River

1.5.3 Evaporation The rate of evaporation is affected by the vapour pressures of both the water and the air, which in turn depend on the temperature of the water and air, wind, atmosphere pressure, quality of the water, and the nature and shape of the surface.

To estimate evaporation, it is necessary to determine the inter-relationship of evaporation loss, time of year and recurrence interval, or probability. Expected rainfall must be subtracted from gross evaporation to yield net evaporation from the reservoir surface. Typically this is done on a monthly basis for which evaporation data are known for the geographic location.

The net evaporation rate multiplied by the average reservoir area during that month gives the monthly evaporation quantity. The relationship between surface area and water level / capacity needs to be known as well as that between month and net evaporation. These relationships can be combined to yield a three-dimensional relationship: storage/evaporation-loss/month. It is self-evident that relative evaporation increases in proportion to the surface area / capacity relationship, i.e. evaporative loss is greater from a shallow reservoir than a deep reservoir of the same capacity.

The evaporation loss from an impounding reservoir can only be controlled by the WSI if there are multiple impoundments that are interconnected. It is a matter of operational procedure to maximise the use of the reservoir that has the lowest surface are / capacity relationship, subject to avoidance of spilling.



1.5.4 Procedure

Step 1 Estimate evaporation losses; carry out silt survey and estimate consequential loss of yield.

Step 2 Determine the status of any soil erosion protection programmes and water extraction/transfer permits.

Step 3 Identify any gaps between the current and ideal situation regarding reduction of silt loading and transferring of water to storage that potentially has less evaporation.

Step 4 Identify budget, infrastructure and administrative procedures required to implement corrective measures.

Step 5 Implement and monitor measures.


Barnes D, Bliss PJ, Gould BW & Vallentine HR (1983). Water and Wastewater Engineering Systems. Pitman Press.

Linsley RK & Franzini JB (1979). Water-Resources Engineering. McGraw-Hill.

Frederick KD (1993). Balancing Water Demands with Supplies. World Bank Technical Paper No. 189.

Van Te Chow (1964). Handbook of Applied Hydrology. A Compendium of Water Resources Technology. McGraw-Hill.

CHAPTER 2

DISTRIBUTION MANAGEMENT



CHAPTER 2: DISTRIBUTION MANAGEMENT

2.1 Flow Measurement

2.1.1 Basic Principles / Summary Complete and competent flow measurement from "source to tap" is a pre-requisite of effective demand management as well as for efficient operational management of the water supply infrastructure.

A complete hierarchy of bulk, district, zone and consumer metering is necessary in order to make accurate estimates of the various types of water loss as defined in Volume 2 Figs 3.2 and 3.3. The metering itself must be sufficiently competent to be relied upon in making loss assessments and in developing and undertaking water loss control programmes.

Unless there is already a meter management programme in place, the initiation of WC/WDM measures provides the opportunity to establish a regime of accurate flow monitoring. This commences with a survey and accuracy check, the re-calibration or renewal of defective or obsolete meters, plus the installation of new meters where necessary to complete the hierarchy.

Once the flow metering has been brought up to a satisfactory level of completion and accuracy, a programme of regular calibration of system management meters and replacement of ageing and defective consumer meters should be established.

2.1.2 Flow Measurement Hierarchy

A complete hierarchy of system management flow metering is illustrated in Figure 2.1.

Figure 2.1: Hierarchy of Flow Measurement (consumer meters not shown)

source treatment

plant

supply area 1

zone 2a

zone 2b

zone 2c

Flow meter service

reservoir

service reservoir

waste

A complete hierarchy of competent metering,

from source to consumer, is essential for effective WC/WDM



Flow meters are required at / on:

(a) All raw water abstraction points

(b) Water production from treatment plants

(c) Bulk imports and exports

(d) Feeds into different supply areas or primary districts, such as outlets from service reservoirs

(e) Within the distribution system into sub-districts or zones

(f) On all consumer connections including public standpipes, municipal take-offs such as parks

If active leakage control is to be practised, zone meters as shown in supply area 2 are required.

SABS 0306 (section 4.3.1) uses the following terminology in relation to meter function within a network, in order of decreasing size:

Bulk supply

District

Sub-district (typically 2,000 – 10,000 connections)

Zone (not more than 2,000 connections)

Consumer

In small systems the bulk supply, district and even sub-district may be a single supply area.

It may be noted when referring to literature from other countries, that the term "district meter area" may be equivalent to sub-districts or zones in SABS 0306.

2.1.3 General Approach and Methodology

New meters need to be designed and installed in accordance with sound principles with regard to size and type. Refer section 2.3.

Existing meters need to be checked against the same guidelines and, if there is any doubt as to their accuracy, a calibration check should be undertaken or replacement as appropriate.

Figure 2.2: Photograph of Defective Flow Meter



The meter survey should check for the following faults as applicable:

� Meters which under-record at all flow rates (generally due to age and wear)

� Meters which are oversized and therefore under-record low flows, being outside the manufacturers declared range of accuracy

� Meters which fail to record low flows altogether

� Old meters recording gallons, but being read in litres

� Ultrasonic or magnetic meters which have been incorrectly installed, particularly wiring faults

� Pump running hours used to measure flow

� No meter on fire main by-pass

� Theft of water by meter disablement or use of by-pass

The WSI should maintain a database of information to be held on all meters that includes:

� Manufacturer and model type

� Manufacturer’s serial number

� Size

� Date of installation

A distinction needs to be made between testing of a consumer meter under the Trade Metrology Act, 1973, and the testing of selected representative meters for the purpose of making a general assessment of the quality of the meter stock. Testing under the Act, which is concerned with the contract between the water service provider and its customer, is necessarily a formalised and rigorous procedure. However testing for meter stock appraisal purposes is an exercise which the WSI undertakes internally and can be simplified.

2.1.4 Procedure for Implementation - System Meters

Step 1 Examine system schematic and determine omissions from full hierarchy of system metering.

Step 2 Check information held on meters and identify omissions.

Step 3 Survey existing meters, rectify data omissions and undertake calibration checks.

Step 4 Design, procure and install additional / replacement / refurbished meters.

Step 5 Allocate reference numbers to meters as SABS 0306, create new or update existing meter database.

Calibration checks may require the installation of temporary meters such as insertion or clamp-on types. If it is planned to undertake hydraulic modelling then this check may be done in conjunction with the field testing for model calibration. Otherwise calibration can take the form of drop tests on reservoirs or pump sumps.



2.1.5 Procedure for Implementation - Consumer Meters

Step 1 Obtain consumer meter database and analyse to establish profile of meter stock by age, size, meter type / manufacturer.

Step 2 If database is incomplete, undertake physical survey, at least on representative basis, in order to complete meter stock profiles.

Step 3 Undertake representative meter test programme, either by in situ testing or removing meter for laboratory testing and replacing it with a new meter.

Step 4 Check sizes against recorded use for over or under sizing.

Step 5 From steps 2 – 4, make best estimate of meter accuracy.

Step 6 Devise and implement priority short term meter replacement programme, to include new meters on connections not presently metered.

Step 7 Devise and initiate long term meter management programme (refer section 2.8).

Step 8 Create new or update existing meter database.

If meter installation dates are not known (Step 1), a guide can be the meter manufacturer's serial number, which can give the date of manufacture, from which can be deducted an appropriate allowance for the time in store. Another method is to take the cumulative counter reading and divide by the average recorded consumption.

Physical testing of consumer meters can be undertaken either by replacing the meter and testing the removed meter in the workshop using a purpose made test rig, as illustrated in Figure 2.3, or can be carried out on site by attaching a flow measurement device to the consumer’s tap. The latter method is lower in cost, although less accurate, but has the advantage of providing an opportunity to inspect the consumer’s water fittings.

Figure 2.3: Photograph of Consumer Meter Testing Using Test Rig

2.1.6 Procedure for Maintenance and Sustainability

Step 1 Carry out physical check on bulk supply and primary district meters annually.

Step 2 Calibrate bulk supply and primary district meters every 5 years.

Step 3 Renew consumer meters periodically according to meter management programme.

Step 4 Establish and implement procedures for updating meter databases.



2.2 Zone Metering and Sectorisation

2.2.1 Basic Principles /Summary

The provision of an accurate flow meter on any feed into supply, regardless of the size of the supply area or district, enables the amount of water loss to be estimated, both by mass balance and night flow methods. Sectoring is a process of creating monitored sectors or zones in a network which if fully “open” has multiple paths for water to flow, but if sectored is sub-divided into a number of adjacent but closed cells, or sectors. Multiple paths for water remain within the sectors, but between sectors, flow paths are limited to one or two controlled connections.

Where there is just a single supply main to an area, such as a village or an outer suburb, sectorisation is achieved simply by installing a suitable sized flow meter on the feed main. In larger urbanised areas, sectors are created by closing isolating valves within a given district or sub-district, so that each sector or zone is supplied from one or perhaps two feed mains, on which flow meters can be installed. The terminology differs between references and they may be termed district meter areas (DMAs), or sub-districts, or leakage control zones (LCZs), or sectors. The basic principle of sub-division and monitoring to assist in localising problem areas is the same.

The larger the area supplied from the meter, the more difficult it is (a) to localise leaks and (b) to identify that a new leak, of a magnitude that should be detectable, has occurred. Thus in a fully developed sectorisation scheme, sector sizes should generally be less than 2,000 properties and, ideally, less than 1,000 properties. This has been found from experience to represent a reasonable cost-benefit compromise.

In areas where there is significant variation in ground level, sectorisation goes hand in hand with the establishment of different pressure zones, if these do not already exist. Each pressure or management zone should be equipped with a flow meter wherever water enters or leaves the zone.

The advantages and disadvantages of open and zoned system management alternatives are listed in Table 2A.

Table 2A: Comparison of Open and Closed Reticulation System Management

System

Advantages Disadvantages

Open Maximises use of network hydraulically

Different water sources and quality mixing. Problems of pressure balancing and fluctuations. Poor system information for operation and management purposes. Poor system control. Water can back feed into a reservoir during periods of low demand and skewed hydraulic gradient, thus leading to a possible overflowing of the reservoir.

Dividing the network into metered sectors enables leakage control efforts to be targeted to areas of

highest loss The smaller the size of the sector,

the greater the level of control



Zoned Water source and quality mixing controlled, less consumer complaints. Facilitates pressure management. Facilitates leakage and water loss management. Good system control and ability to localise operating interventions. Good system information usable in general management, rehabilitation planning, etc.

Fire flow restriction (need for emergency procedure). Makes less effective use of overall hydraulic capacity.

2.2.2 Designing a Sectorisation Scheme

The first step is to review the existing pressure regime. If the supply area has significant differences in ground elevation, the network may already be sub-divided into more than one pressure zone, including high elevation zones supplied through booster pumps. If the single supply area or any one of the pressure zones has a variation in ground level exceeding 50 m, say (at the supplied properties and excluding any undeveloped land), then consideration should be given to combining sectorisation with changes in pressure zoning, to minimise the proportion of the network which is above 6 bar.

If an area is fed from more than one service reservoir, the scheme design should achieve separation. This is essential if the reservoirs are not at the same top water level.

The design of a sectorisation scheme is governed by what is practicable with the configuration of the network. Examination of record plans of the network will reveal parts of the network which are fed by a single water main. The network may already be sub-divided into pressure zones, including downstream of pressure reducing valves. In both cases sectorisation is achieved simply by installing a meter.

In many urban areas, however, due to the complex interconnectivity of the reticulation, a sector is created by closing key valves, known as “boundary” valves, to isolate it from the rest of the network, except from the supply main into the sector,

which is fitted with a flow meter. Unless the records of the network are of a high standard of accuracy and a competent hydraulic model has been built (i.e. a validated model, see section 6.4.6), there will be insufficient understanding of the hydraulic conditions within the system to be able to determine zone boundaries without significant risk of disruption to the pressure regime.

A certain amount of trial and error will therefore be necessary.

Figure 2.4: Photograph of Zone Meter Installation

Review and revision of pressure zones should be undertaken at the same

time as sector design



The first requirement of a design is that it maintains a satisfactory supply to consumers. This may mean lower pressures for some consumers, which has the added benefit of reducing leakage and pressure related consumption. A boundary should be designed to cross as few mains as possible. It should follow the “line of least resistance” by using natural geographic and hydraulic boundaries in order to minimise the cost of installation, operation and maintenance. Small mains should be crossed in preference to large ones.

Trunk mains and large distribution mains (greater than 300 mm dia.) should be excluded from the sectorisation. They can be avoided by drawing adjacent sector boundaries parallel to the main and metering the smaller distribution mains where they join the trunk main.

There may be cases where a proliferation of very small sectors may occur due to large numbers of smaller mains leaving the trunk main. The decision must then be made to:

(a) Meter the trunk main, or

(b) Lay a new rider main parallel to the trunk main and reduce the number of take-offs from the trunk main, or

(c) If the areas served are small, exclude them from the sector scheme and use mobile water loss metering or non-metering methods of leakage control.

In some instances the sectorisation design may need to feature:

� The provision more than one metered feed into a sector

� Feeding one sector through another sector (the first sector has flow meters that enable the flow into and out of the sector to be measured and the sector flow pattern is determined by subtraction)

� The necessity to lay short lengths of main in order to create a sector which is hydraulically satisfactory

Due to the additional work involved in such cases, “temporary zoning” may be adopted and, by a process of trial and error, it may be possible to convert some of those to permanent zones.

Where a large proportion of the flow entering a sector passes out again to other parts of the system, the accuracy of estimation of demand in that sector is relatively poor, because changes in inflow and outflow could imply large changes in demand but in fact may be due solely to compounded errors in metering.

Potential problem areas to be aware of include:

� Areas of low pressure

� Maintaining continuity of supply to priority consumers, e.g hospitals

� Maintenance of fire flows

If within a sector there is a service reservoir or water towers, measurement of demand will have to take account of the change in level in the tank. Existing level measuring equipment will have been designed to measure the quantity of water in the reservoir rather than the rate of change of level and it is unlikely to be unsatisfactory for determining demand. Although consideration may be given to upgrading the level measurement equipment, it will only be feasible in the smallest of tanks where there is sufficient discrimination to detect small changes in leakage. In most cases it will be necessary to meter the inlet and outlet of such tanks.



2.2.3 Establishing the Sectorisation Regime

Following the installation of zone meters and laying any short lengths of main that form part of the design, sectorisation is established basically by closing the boundary valves and checking that:

� The boundary valves are drop tight

� The zone is supplied only from the zone meter(s) and there are no inter-zone breaches (“pressure zero” test)

� The pressures within the zone are satisfactory

Each boundary valve must be checked and if there is any doubt about its tightness it should be replaced. It is arguable that it is cheaper in many cases to fit new boundary valves at the outset just to be sure, thus saving wasted time and effort in locating a faulty valve when zone establishment is not achieved. This exercise may reveal that there are valves of both clockwise and anti-clockwise opening in the network. This information needs to be captured and recorded (refer Chapter 6 for further guidance on information systems).

The “pressure zero” test involves stopping the flow into the zone and with the boundary valves shut the pressures should fall to zero (checked by opening a hydrant). If the system remains pressurised and water continues to flow it means that there is a zone breach, which is due either due to a connection with the adjacent zone that is not shown on the record drawings, or water is passing a faulty boundary valve. Sectorisation is therefore an iterative process, and the speed at which it is achieved depends on:

� Knowledge of the infrastructure

� Accuracy of records

� Good record keeping

� Accessibility of pipelines and valves

� The condition of isolating valves (valves are water-tight in the closed position)

The boundary valves provide the integrity of the zone and should not be opened except in emergency, e.g. large fire demand, or if development requires the reconfiguration of the zone. The boundary valves should therefore be clearly identified, e.g by use of red marker paint or by filling the valve box with polyurethane foam. Unfortunately, not withstanding instructions given in this regard, valves may be tampered with or opened in unauthorised action by operations personnel. If this is likely to be or found to be a problem, one solution is to create an above ground inter-zone connection as shown in Figure 2.5.

It is likely that the establishment of the sectorisation regime will reveal errors

in record plans and valve operation The opportunity to correct and update the asset records should be grasped



Figure 2.5: Above Ground Zone Boundary Separation

2.2.3 Data Capture

Routine monitoring of a district meter falls into three categories:

1. Reading the meter (manually or electronically)

2. Using a data logger

3. Linking the meter to a telemetry system

Meter Reading

In its simplest form, this provides cumulative demand figures only if read manually. Cumulative readings from those meters with a mechanical register are recorded weekly. One or two personnel (depending on safety conditions, and whether or not heavy covers have to be lifted) can read typically 40 meters per day. As a first stage, meter readings are recorded in a notebook, or by means of a portable data capture device (electronic notebook). Later these readings may be transferred to a simple graph or wall chart, or to a data file stored on a computer.

Night flow readings taken for leakage estimation purposes need to be taken every 15 minutes during the hour or more often when flow is at its lowest. The consumer meters of any large non domestic users within the zone also need to be read.

The addition of a simple encoder counter or outreader to the meter greatly enhances meter reading. The outreader can be installed in a small chamber remote from the meter and connected by ducting to an inductive interface fitted to the meter. Meter reading becomes a one-person operation, safety is improved by eliminating the need to lift heavy meter chamber covers, and, in some locations where there are personnel safety concerns, limiting the time in the area.

Other instruments have hybrid registers that combine the proven mechanical register with the latest electronic meter data capture technology. Because the mechanical register works totally independently of the electronics, the meter reading is guaranteed, even if the electronics should fail.

The extremely high integrity of the remote reading is guaranteed using an inductive shaft encoder. Compatibility with existing data transmission systems is ensured by retaining the standard optical pulser interface.

F IR E H Y D R A N T S



The electronic data interface provides additional useful information for management purposes including:

� Actual meter reading

� Momentary flow rate at the time of interrogation

� Maximum flow rate (programmable)

� Minimum flow rate (programmable)

� Volume in reverse flow (independent of reading)

� Meter serial number

� Annual key data value (to synchronise several meter readings at different locations)

� Statistical values (last 12 months).

This register is battery operated but has a long battery life of over 8 years. The collection and manipulation of data from these registers is assisted by hand-held electronic devices (e.g. “Husky” or “Radex”) and readily available software.

This option is favoured by many water undertakings for the ongoing monitoring of management meters.

Data Loggers

There are several ways in which data loggers can be used to enhance the quality and quantity of flow data. The methods employ either ad hoc or continuous data logging.

The use of a data logger on an ad hoc basis allows extra demand information, particularly night demand, to be gained, so that leakage can be distinguished from a temporary increase in demand.

Continuous data logging can be implemented in conjunction with modems and transmission facilities such as land lines or cellular phones as a cost effective telemetry (remote monitoring) system. The greatest advantage of adopting this approach is that the logger retains the data when the transmission system fails. When selecting a particular make of data logger system, emphasis must be placed on the compatibility of the various components of the system. The meters, pick-ups, data loggers, registers and software should be well tried and tested as a complete system as well as incorporating the latest technology.

In areas with high crime and vandalism, the safety of personnel visiting the site for maintenance or data collection is also an issue, especially applicable to zone meters, which may need to be visited at night. The fitment of data loggers and telemetry constitutes a security measure as well improving the efficiency of data collection

For ad hoc use, the following factors influence the number of loggers needed:

� The maximum number of meter sites per district. This includes not only source meters and district boundary meters, but also all the large metered consumers identified as being significant during the initial work.

� The number of districts, which are monitored simultaneously.

� Anticipated or planned frequency of night flow measurement.

� The numbers of staff for monitoring and the size of the area covered.

In continuous mode, one logger per meter site is necessary if on-site interrogation is practised, twice this number if loggers are removed from site for interrogation.



2.2.4 Procedure for Implementation: Step 1 Review pressure regime and decide if pressure zoning is required.

Step 2 Identify possible districts and zones using maps, mains records and site inspection. Undertake preliminary demand analysis.

Step 3 Note low pressure areas, critical consumers, high fire risk premises.

Step 4 Check operability of proposed zone valves, replace if necessary. Alternatively, install above ground inter-zone connection.

Step 5 Isolate zone and monitor pressures, both within zone and beyond as appropriate.

Step 6 Review and repeat as necessary.

Step 7 Analyse demands, decide on sizes and specifications of meters, procure, design and install meter installation.

Step 8 Commission meter and check that zone is tight (zero pressure test).

Step 9 Identify conventional boundary valves with permanent marker system, e.g. red paint, polyurethane foam chamber filling.

Step 10 Mark up record drawings with boundary valves (special symbol) and meter(s).

2.2.5 Procedure for Maintenance and Sustainability – Zone Maintenance

Sector / zone maintenance is concerned with responding to any changes in supply and distribution within the system which may influence the operation of a zone, particularly data interpretation. There may be a consequential need to amend the scheme if changes are significant, such as:

� Changes in zone boundaries

� New supply connections

� Changes in operation

Changes in zone boundaries occur mainly as a result of an extension of the supply area. It will be necessary to re-route the boundaries of affected zones, basically following the relevant parts of the procedure for initial sectorisation. Other components of the system operation, such as record keeping and data interpretation, will also be affected, and appropriate actions are:

� Update mains drawings to show new district boundary and boundary crossings.

� Record new closed boundary valves, or boundary valves which have changed status and are now open.

� Record new meter positions – update meter records for meter type, and number, calibration factor, main diameters, etc.

� Check whether existing meters are affected by new design criteria (e.g. changes in flow range, flow direction). If necessary install a new meter or closed valve.

� Update register of domestic and non domestic connections within zone.

� Allocate new non domestic users according to user category and review numbers of large users who should be data logged. Review significance of non-metered users on zone demand.

� Revise gross and net flow data in the calculations. Add or remove meters and note effect of change of direction of flow in or out of a zone.



� Reappraise zone cost data and demand levels.

There are two implications of new demand connections within a zone:

(a) An increase in the number of properties

(b) An increase in boundary crossings by new mains

Where new supplies are laid across a boundary between adjacent zones, the new main should be metered or valved if there is a supply from an alternative source. If a new main is laid across a boundary which does not join two zones, the boundary is extended to encompass the new area of distribution. Mid-block water mains in dense developing areas should also be carefully investigated. New meters should be installed and appropriate meter records updated.

Flow changes within a zone, or between zones, can significantly affect the interpretation of flow data. These fall into two categories:

Permanent changes

Pressure. The effect of pressure on demand and leakage is well documented. Any permanent change to system pressures should be followed by night demand measurement and a repeat achievement of base levels of leakage.

Pumping. Additional or reduced pumping may affect the range of flow through the zone meter. A pump switching on and off during supply operation may cause a change of direction, e.g. by gravitation. Corresponding changes in flow rate, velocity, and flow direction may require a new meter.

Rezoning. Sudden changes in demand by rezoning, or by changes in population or industry may affect the flow range of the meter and flow direction.

Temporary changes

As with permanent system changes, pressure, flow rate, and flow direction can also be affected in the short term during normal operation of the distribution system. Examples of these changes are:

� Sub-division of the zone by valve closure during leak location (step testing)

� Valving during routine operations such as repairs, cleaning, or renovation

� Temporary changes in demand caused by population fluctuation or cyclic industrial demand patterns

These should be recorded, since awareness of such activities will affect data interpretation.

Sectorisation for leakage control purposes is a compatible activity within a knowledge-based active system management approach. It is recommended that the data needed for establishing sectors and maintaining an active leakage control regime, including records of the leak detection and repairs, should be held together in a zone file for each sector.

Hold all key data on sector characteristics, sectorisation

design and operation, including leakage control

activities, within “zone files”



2.2.6 Procedure for Maintenance and Sustainability – Maintenance of Plant and Equipment

� Routine maintenance and fast repair of any defects to minimise loss of data

� Regular calibration of flow meters to ensure they are maintained within accuracy limits (refer to SABS 0306: 1999 Clause 10.3)

� Regular maintenance of the associated flow logging and data transmission equipment to ensure that adequate monitoring levels are achieved


SABS 0306 (1999) The Management of potable water in distribution systems

2.3 Water Meter Types, Applications and Selection

2.3.1 Basic Principles / Summary There are no universally suitable flow meters for all applications and it is important to choose the one that meets as many of the requirements for a particular installation. Different types of meters have different accuracy curves, i.e. the difference between actual flows and measured values according to the rate of flow between zero and maximum rated capacity of the meter.

Mechanical meters, turbine or velocity, are the most common type of meters in use, both for system management and consumer flow measurement. Electromagnetic and ultrasonic meters are potentially more accurate and cost effective for larger sizes above 300 mm dia, but require specialist skills to ensure correct installation and maintenance if there is to be confidence in the output data.

Differential pressure meters, e.g. venturi, orifice plate, have very poor accuracy at low flows and are generally now regarded as being obsolete.

It is essential that flow meters are correctly sized for the range of flows that will be experienced, otherwise accuracy will suffer and possibly no flow will be registered at all when there is a low flow through the meter. Over-sizing of meters by fitting a meter of the same size as the pipeline in which it is installed is the most common fault in this regard.

Data loggers and telemetry links should be considered to ensure full and efficient data capture and for ease of interrogation and archiving.

2.3.2 Types of Meter

There are two main categories of meters: (i) those that extract energy from the flow, and, (ii) those that add energy to the flow. Type (i) causes a loss of head (pressure drop) through the meter, in proportion to flow. The types of meter generally found in water supply and reticulation systems and their applications are summarised in Table 2B. Further details of meter types and selection are given in Annex 2.



Table 2B: Flow Meter Types

Type Typical Use, Remarks

Positive displacement Small consumer meters. Specification and use controlled by and the Trade Metrology Act 1973 and SABS 1529 (1994).

Accuracy deteriorates with age due to mechanical wear and tear and corrosion - low flows may not be measured at all.

Turbine (velocity), also known as Woltman

Normal choice for zone and small bulk supply meters in range 75 to 300 mm dia. Also large consumers. Up to 100 mm dia covered by Trade Metrology Act.

Subject to mechanical wear and tear, corrosion, poor or no flow measurement. E

xtra

ct e

nerg

y fro

m fl

ow

Differential pressure Venturi, dall tube, orifice plate. Poor accuracy at low flow as much as 25%. Type now obsolete

Electromagnetic 300 mm dia. and above Not uncommon to find wiring faults cause of significant error due to installation by inexperienced personnel

Add

ene

rgy

to fl

ow

Ultrasonic Prone to inaccuracy on treated water mains because they rely upon particulate matter, air bubbles or other entrained elements for their operation. Prone to wiring faults, as electromagnetic type.

2.3.3 Sizing of Meters It is important to fit the correct size of meter so that the range of known or expected flows fall within the acceptable accuracy range of the chosen meter. Care in getting this right will be rewarded with greater accuracy and reliability of the data upon which operational and planning decisions are made. Incorrect sizing will have significant financial consequences, negative to a WSI in the case of an over-sized consumer meter.

The most common fault is to fit a flow meter that is the same size as the pipeline. Unless the pipe has been designed at flow velocities that are above typical design values, it can be expected that, except for small domestic meters, the diameter of the flow meter will be a size or two less than pipeline. A rule of thumb is meter diameter 2/3 of pipe diameter. The consequence of an over-sized meter is under-recording or even failure to record low flows.

Notwithstanding manufacturers’ claims as to low flow accuracy, generally it is desirable to try to maintain low flows above 0.5 m/s and below 3.0 m/s to achieve acceptable accuracy.

If a new meter is to replace an old one, then historical data should be available to assist with the sizing, having due regard to any future increases or decreases in flow at that point in the system.

The most common fault is to fit a meter the same size as the pipe, the result being under measurement at

low flows - normally the meter should be smaller in diameter than the pipe



Selection of a meter for a new installation requires an analysis of the demands downstream of the point of metering, whether this is a bulk meter for a whole supply area or an individual consumer. Further guidance is given in Annex 2.

Procedure: A simplified (generic) procedure for the selection of water meters is as follows:

Step 1 Determine average water demand for the particular installation.

Step 2 Establish peak (maximum) water demand and whether fire flow is to be included.

Step 3 Establish the minimum water demand (usually related to minimum night flows).

Step 4 Compare the flow range determined in steps 1 to 3 with the manufacturer’s specification for various water meters.

Step 5 Determine the energy head loss for the meter corresponding to the maximum flow established in step 2 and establish if it is within the hydraulic requirements of the installation.

Step 6 Consider the purchase and installation cost for the meter selected and other financial considerations.

This is an iterative process that in practice could involve numerous sub-steps within each step. An example of a comprehensive computerised meter sizing system is described by Johnson (2001) and was applied in the case history detailed in Box 2-1.

Box 2-1: Case History of the Implications of Installation of Incorrectly Selected Water Meters

In 1997, a consortium that included Meinecke do Brazil undertook a pilot project for SABESP for the change-out of 354 bulk consumer meters in São Paulo.

Starting with available billing data and the meter database, the consortium selected a total of 354 high-priority meters to be evaluated. Site inspections and data logging followed. With the use of meter sizing software, replacement meters were selected. These were installed. Follow-up logging was undertaken to confirm that the selection and sizing was correct:

Results of pilot study:

• 6 meters were undersized (larger meters were fitted)

• 248 meters were oversized – comprising 70% of all meters (smaller meters were fitted – including 27 combination meters)

• 100 meters were correctly sized (but not necessarily accurate, a few were renewed/recalibrated, most were replaced).

Payback:

• Billed consumption increased by 2,000,865 m³ in the first year

• The average payback on the capital outlay was 2 months

• In 83 cases, the payback was less than 1 month.

Source: Bold (2001)



2.3.4 Factors Affecting Choice of Meters and Installation Design SABS 1529 (1994) and the Trade Metrology Act, 1973 specify the metrological characteristics of mechanical water meters and meters with mechanical measuring elements and electronic indicators. Once these minimum requirements are met, the factors to be considered in selecting and designing system management and zone meters and associated systems are:

• Maintenance. Turbine and other mechanical meters are simpler to maintain and repair and represent familiar technology to all water undertakings. Electro magnetic or ultrasonic types should only be specified if the WSI has competence in electronic instrumentation maintenance or has a reliable outsourced maintenance contract.

• Operational requirements. The installation of a by-pass around the meter installation facilitates maintenance and operations without interruption to supply, but adds to the cost of the installation. Mechanical meters are particularly susceptible to damage through large particles in the water. If there is considered to be a possibility of silt or particles or other deposits in the water, then strainers should be fitted

• Security. In areas with high crime and vandalism, the installation must be designed accordingly with appropriate protective measures. Consideration should also be given to the safety of personnel visiting the site for maintenance or data collection. This is especially applicable to zone meters which may need to be visited at night. The fitment of data loggers and telemetry constitutes a security measure as well improving the efficiency of data collection

• Environment. The physical environment in which the meter is to be operated and maintained has an influence on the choice of equipment. For example the prevalence of lightning at a particular site may require special measures to protect electronic type metering devices and could indicate a preference for a mechanical meter.

2.3.5 Temporary Metering Even with a fully metered system of permanent installations, temporary metering will be necessary if hydraulic modelling is implemented. Calibration of system and major customer meters may also require temporary metering.

Temporary meter types are: ultrasonic clamp-on and insertion meters (electro-magnetic and turbine). Ultrasonic clamp-on types have the advantage of not interfering with the pipe, but may not be sufficiently accurate for the reasons previously given and compounded by the need to know the precise internal bore of the pipes to calibrate the signal. Insertion meters require skilled use in “flow profiling” and the turbine type suffers from significant wear rates.

As with many technologies, there are frequent new product launches and refinements which mean that specifications and equipment are continually subject to change.

2.3.6 Data Loggers and Pulse Units Data loggers have now progressed from innovative to established technology in distribution system management, with relatively inexpensive but robust and reliable data loggers being available to capture data from flow meters and/or pressure sensors. They enable continuous records of flow through meters to be produced without the need for telemetry, although they can be used in conjunction with telemetry (ref section 2.3.7). Leakage management based on district / zone metering relies on night flow data for success in driving leakage down to minimum levels, the provision of data loggers avoids the need for personnel to read meters at night.

The following factors need to be taken into account when considering the specification of different makes and types of logger:



• Memory configurations – for example:

- Logs until memory full

- Barrels (continuous roll-over memory) – i.e. when memory is full, logging continues but the oldest data is overwritten

- When full, the logger time setting changes to the next longest period and the existing data is recalculated into the new period format.

• Memory capacity.

• Logger time intervals, e.g. 30 seconds to 60 minutes.

• Flow sensor types supported, e.g. pulse heads.

• Battery life – long life non-rechargeable batteries have been found to be more satisfactory than rechargeable batteries.

• Logger casing waterproofed to a specified standard, e.g. IP68.

• Need for dual channel loggers, i.e. capable of logging pressure as well as flow.

• Window displays – not all loggers have visual display facilities.

• Method of downloading and software available for storage and analysis of data.

Mechanical meters now generally have a magnetic coupling between the undergear and the reading register. A pulse unit is a device that generates electrical pulses and is fitted between the magnetic drive and the reading register of the meter. The electrical pulses are transmitted to a logger and converted into flow measurement.

Data loggers generally come with proprietary software that manipulates the data and provides graphs and performance indicators that can be used in management reports.

2.3.7 Telemetry

The use of telemetry (remote monitoring) is common practice for monitoring of flows through bulk meters and having these data at a central point such as a treatment plant or water services central control office. Generally these meters are on line continuously and a considerable quantity of data accumulates. Archiving these data must preserve the historic data that is so valuable for use in strategic planning studies and WC/WDM assessments, whilst not taking up unnecessary storage space with temporal operational data.

Extending an existing telemetry system to monitor new district / zone meters may appear to be a logical progression, but would multiply the data to be captured and stored and could incur high costs in communication charges. The preferred option in many applications is not to have continuous flow monitoring and data transfer. If telemetry is used in conjunction with a data logger, it is adequate to download the data for interrogation once per day, say. Once interrogated for leakage control purposes there is no need to store and archive all of the logged flow data, which can be limited to total day, maximum and minimum (night) flows.

References and Suggested Further Reading Johnson EH (1995). Field evaluation of large in-line flow meters. Water SA Vol. 21 No. 2, pp 131-138.

Johnson EH (1999). In-situ calibration of large water meters. Water SA Vol. 25 No. 2, pp 123-135.

Bold BE (2001). Applying the Latest Technology to Improve Water Supply Systems. African Water Conference, Midrand.



British Standards Institution BS6700 (1987). Design, Installation, Testing and Maintenance of Services Supplying Water for Domestic Use Within Buildings and their Curtilages.

British Standards Institution BS7405 (1991). Selection and Application of Flow Meters for the Measurement of Fluid Flow in Closed Conduits.

Booyens JD (2000). Spitsvloei in Munisipale Waterverspreidingnetwerke. M.Eng in Civ. Eng. Rand Afrikaans Univ. Johnson EH (2001). Optimal water meter selection system. Water SA, Vol. 27, No. 4.

Miller RW (1989). Flow Measurement Handbook. McGraw-Hill.

South African Standard Specification SABS 0252-1 (1994). Code of Practice Part 1: Water Supply Installations for Buildings.

South African Standard Specification SABS 1529-1 (1994). Water meters for cold potable water, Part 1: Metrological characteristics of mechanical water meters of nominal bore not exceeding 100 mm.

2.4 Leakage Reduction

2.4.1 Basic Principles / Summary There are various factors that cause water leakage from potable water supply and delivery systems and these can be summarised as follows (SABS 0306: 1999):

� Appropriateness of original design, specification of materials and construction workmanship – if the infrastructure is built to a high standard, leakage should be negligible

� Pressure - the higher the pressure, the higher the flow rate from a given defect

� Soil type - soils such as clays are subject to movement as the moisture of the soil varies, potentially causing fractures in pipes and fittings; corrosive soils can also cause failure of metallic pipe materials and fittings

� Corrosion potential of the pipe and soil systems together

� Climate - variations in temperature, rainfall, humidity all have an effect on the structural and chemical characteristics of the infrastructure

� Traffic - vibrations induced by vehicles can cause defects

� WSI resources - adequate skilled human resources as well as financial resources for active management of water loss reduction

There is often a failure to appreciate that time is fundamental to the practice of leakage control, whether “passive” or “active”. When a leak occurs, its discovery and repair may be a matter of hours only in the case of a major burst that causes loss of supply and/or flood damage. But other leaks may run for many months or years before discovery. Even quite small leaks can lose very considerable quantities of water if they run for many years. Consequently the objective of leakage control is: to minimise the time between a new leak occurring and its repair. This is illustrated in Fig 17 in SABS 0306, and is reproduced as Fig. 2.6.

The objective of leakage control is to minimise the time between a new leak occurring and its repair



Figure 2.6: Implications of Time Delay on Volume of Leakage (SAB0306-1999)

In a reticulation system new leaks are occurring all the time, at a rate dependent on the factors previously mentioned. This phenomenon is known as the “natural rate of leak propagation” and when considered in conjunction with the time factor, this means that a water loss control programme must comprise two stages:

Stage 1 Reducing losses to a practicable/economic level

Stage 2 Maintaining losses at the above levels permanently

There are many examples of good results from one-off campaigns as (1). Unfortunately a significant number of initiatives fail to be sustained as in (2).

Leakage control can be applied to the following main group of assets:

� Service reservoirs and water retaining structures.

� Large dedicated supply pipelines with few or no off-takes (bulk).

� Water distribution networks (reticulation).

In all cases, the activity comprises the three stages of:

1. Estimating the amount of loss

2. Locating the source(s) of loss

3. Stopping the loss by repair or operational control.

The time between (2) and (3) is a measure of the effectiveness of the control methodology and procedures adopted.

In existing water distribution networks, the basic methods of leakage control employed comprise:

� Passive leakage control: a formalised procedure for receiving reports of leaks from the general public and WSI’s own personnel that ensures that all reported leaks are repaired quickly

� Active leakage control: a pro-active monitoring and control regime in which new leaks that occur and which have not been reported are quickly identified, located and then promptly repaired to minimise the loss of water

� Pressure management: the reduction of excessive pressures in the network to levels that are nevertheless adequate for consumers, typically 20 to 30 m pressure



� Rehabilitation of the network: renewal of water mains and services that are beyond economic repair, i.e. that in a given area are prone to repeated bursts and incur high costs in maintenance and repair

“Active leakage control” is an ongoing operational activity and must not be seen as a one-off or occasional campaign initiative. An initial effort to establish the active leakage control regime and to bring leakage down to target levels, is followed by a maintenance regime that keeps leakage at the these lower levels. The financial and economic justification for this approach within integrated resource planning is outlined in Volume 2 of these guidelines.

Pressure management does not involve the location and repair of leaks; it simply reduces the amount of water lost through a given leak. It may have spin-off benefit in reducing the frequency of bursts in parts of the network that are in poor structural condition.

Rehabilitation of a water distribution network is not normally justified financially on leakage reduction grounds alone, except in very severe localised instances. An integrated approach to rehabilitation that addresses general structural / pipe life, failure rates (burst frequency), hydraulic performance and also water quality issues, if applicable, is recommended.

Finally consideration must be given to the installation of new infrastructure, particularly underground water mains and services, to quality standards that do not lead to a recurrence of the leakage problems that the WSI may be facing with its existing infrastructure. Technically there is no reason why a “leak free” system cannot be devised and implemented, if that aspiration is given equal priority and importance in design and installation to that of hydraulic capacity. This is a matter for the purchaser to ensure is given the necessary prominence in drawing up terms of reference for consultants, in contract works specifications, and in site quality control procedures.

2.4.2 Service Reservoirs and Other Water Retaining Structures Details of the methodology for determining the amount of leakage are given in Volume 2, section 3.2.3. Ideally the drop test should be repeated at several water levels in the tank and a graph plotted showing the relationship between leakage and water depth. Any discontinuity in the profile of the graph is indicative of a significant leak at an intermediate level.

Overflow or spillage from reservoirs can be detected by either visual inspection or specifically constructed weirs that are calibrated in conjunction with the reservoir level measuring equipment.

Location of defects involves physical inspection for cracks, potential leakage paths around built in pipework, dye testing, monitoring of floor under drains, in conjunction with interpretation of drop test results.

2.4.3 Large Supply Pipelines

Details of the methodology for determining the amount of leakage are given in Volume 2, section 3.2.5.

Whatever technique is used to determine leakage over a section of pipeline, it still remains to be located. Various methods can be employed such as: walking the main to look for signs of water, changes in the colour of vegetation; sounding valves and fittings for leakage noise; use of chemicals as tracers, etc. Specialist acoustic apparatus is also available for detecting leaks in trunk mains, which typically have a low noise level.



2.4.4 Passive Leakage Control This method makes no attempt to search for leaks but only to repair those leaks, which are visible and reported, or those found as a result of complaints of low pressure, or of no water, or of noises in the internal system.

The effectiveness of passive leakage control is entirely dependent on:

(a) The awareness of the public about leakage and their willingness to report visible leaks

(b) The mechanisms and procedures established by the water undertaking to receive and act on such reports, essentially in relation to the time taken between the burst being reported and its repair

A water undertaking that claims to practise passive leakage control should have appropriate records and should be monitoring the activity. In simple terms, this just comprises a report logging system that allocates an incident number, which is then linked to the repair “job”. The measure of performance is the average time between report (whether internal or from consumer/third party) and repair.

The establishment of a “toll free” number for the reporting of all water leaks and poor pressure problems will encourage consumers to report the incidents timeously. This must be followed by an awareness and education campaign, which advises consumers on how to report leaks, and why they should do so in the first place.

There are two pre-conditions of establishing a passive leakage control regime, which involves the co-operation and participation of the community. Firstly, the WSI must ensure that any leak repairs known to be outstanding are carried out. Secondly, it must ensure that there are adequate lines of communication and responsibilities within its organisation, so that the public sees that reporting leaks and other defects does lead to prompt and effective action. This means that the awareness campaign should start with informing WSI personnel who are not directly involved in responding to leak reports, but who interface with the community in other ways. Included in this category, certainly, are meter readers, who ideally should be part of the communication network.

Procedure:

Step 1 Review existing procedures, responsibilities, lines of communication, documentation used to receive, process and act on leak reports (make flow chart).

Step 2 Estimate approximate average time between a leak report and its repair, the numbers of repairs per year, the total volume of water lost due to time lag and the cost to the WSI of inefficiency in dealing with reported leaks. Include an allowance for visible / known leaks which are not reported by the public because of lack of awareness or their lack of confidence that the WSI will act on the report.

Step 3 Decide on target response time and estimate the water and financial savings.

Step 4 Develop new procedures, lines of communication, job responsibilities, documentation (make flow chart) and create awareness amongst all WSI staff within water services, and all other WSI personnel who have regular contact with consumers, including meter readers.

The WSI must establish effective mechanisms and procedures which

will enable it to respond effectively to leak reports (and be seen by the

community to do so)



Step 5 Start implementation using new procedures, internally, using meter readers as surrogate for public reports and ensure that all visible leaks are repaired, amend procedures if necessary.

Step 6 Launch public awareness campaign and implement passive leakage control programme in full.

2.4.5 Active Leakage Control - Types

In active leakage control (ALC) the objective is to identify, locate and repair leaks which are not reported. When moving from passive control to active control, there is firstly the need to catch up on the backlog of non-reported leaks and then to establish a maintenance regime that will prevent a return to the status quo and suppress the “natural rate of leak propagation”.

The location of leaks under ALC falls into three types:

1. Routine

2. Intelligent search

3. Sectorisation and metering of zones

The routine method involves leak detection, generally by acoustic methods, across the whole network in sequence. Typically this might have a one or two year cycle. No distinction is made between one part of the network and another.

Intelligent search is a natural progression from routine in which leak location is targeted with greater frequency in areas that are known to be more troublesome, effectively where there is a higher natural rate of leak propagation.

The fundamental weakness of both of these methods is that the leak detection teams do not have a target to work to. In intelligent search the effort is more focused and should therefore be more productive in terms of water saved per Rand cost of resources deployed, but is inevitably less efficient and effective than monitored zones.

By sectorisation and zone metering, the areas of highest leakage can be identified and estimates of the amount of leakage in each zone made. The leak detection team have therefore a target to work to and need not search the whole area once the necessary number/severity of leaks have been found. The smaller the zone the easier it is to be able to identify from continuous flow monitoring that a new leak has occurred.

2.4.6 Sectorisation and Monitored Zones

There are two district stages in ALC using monitored zones:

1. Sectorisation, or zone installation. As described in section 2.2, this comprises the design of the zone and its meter(s), the installation of the meter(s) with data loggers and the checking/addition of boundary valves (trial valving). In the absence of data loggers, it is possible to read water meters manually at night, and write down the values of the meter readings at set intervals, typically every 10 or 15 minutes. Meter reading will require a team of field workers, and the accuracy of the results will depend on their honesty and some incentive or positive motivation to carry out the meter reading correctly. The work required to install a zone should not be under-estimated.

2. After successful installation the zone is then established. This commences with the interpretation of the logger data from the meter and setting of initial targets, i.e. what is a reasonable minimum night (or total daily) flow and how many leaks are we looking for?



Leaks are then detected and repaired and the achievement both in terms of total volume and reduction in specific loss computed, which comprises the “first pass”.

When there is very high leakage, total daily flow is an adequate indicator due to the relative proportions of consumer use and leakage. When leakage is lower, it is more difficult to distinguish between leakage and normal variations in consumption within the total daily flow, but it can be “seen” more clearly by examining the night flow readings, as shown in Figure 2.7.

m³/h

0

400

800

1200

1600

2000

Mon,12/6/,12 h Tue,13/6/,0 h12 h 15 h 18 h 21 h 0 h 3 h 6 h 9 h

Time period: 2000/06/12 11:25:00 AM - 2000/06/13 10:15:00 AM Mean interval: 2 minutes

INLE

T

ED-2/INLET/1427

Figure 2.7: Typical Diurnal Flow Variation Showing Leakage

In Figure 2.7, for simplicity, leakage is shown as a constant. In reality, leakage is pressure dependent and is lower during the day when consumer use draws the pressure down, and higher at night when consumer use is low. This phenomenon is use to advantage in the operation of a pressure reduction regime, as described in section 2.5. Success in some zones may come early on, but in others the results may be disappointing despite considerable time and effort being deployed in several passes. In older areas, which have mains that are “fragile”, initial repairs reduce the total demand, resulting in an increase in pressure that merely triggers new leaks. If this is repetitious then a very relaxed target for the zone may have to be accepted and/or it is scheduled for rehabilitation.

In the case of leaks detected on the consumer’s side of the stop cock, special actions are required as described in section 3.5.

It is emphasised that once initial zone establishment is achieved, zones must be continuously monitored and prompt action taken to locate and repair any new leaks identified, such as the example shown in Figure 2.7. This zone maintenance requires a lower level of activity than zone establishment, but is nevertheless additional to the situation pre-project and will require some organisational change and additional resources, paid for out of the ongoing savings being made, with a net financial benefit to the authority (Refer Volume 2 of guidelines for planning approach).

Minimum Nightflow 720m3/hour

Leakage550 m3/hr



Figure 2.8: Monitoring of Zone Flow Showing New Leak Occurring

2.4.7 Locating Leaks in Reticulation Networks “Finding the needles in the haystacks”

Several methods are available and, in each location, different methods / makes of equipment will prove to be more successful. Often this comes down to the personal preference / aptitude of the personnel concerned. The engineer in charge of the leakage control effort should, however, keep an open mind.

Leak location methods include:

� Step testing – involves further narrowing the area of search within a leakage control zone, by progressive valve closure to a pre-determined plan, at night, and monitoring the flow trace for “steps”

� Direct sounding of fittings – using a listening stick or stethoscope

� Ground microphone (geophone) – indirect sounding on road and footpath surfaces

� Leak-noise correlation – direct sounding at two points on a water main and interpolation of sound of leak using special apparatus (leak-noise correlator)

� Acoustic loggers – an alternative to step testing that deploys a number of acoustic sensors over an area

� Hydrogen injection

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All but step testing and hydrogen injection rely on the fact a leak under pressure emits a sound that can be heard. If there is widespread general leakage in a zone then there will be a considerable volume of noise and the high frequency sound of leaks from small defects may mask lower frequency but larger leaks.

Figure 2.9: Photograph of Leak Location using Listening Stick

It is recommended that a first pass of visual inspection and direct sounding of fittings is undertaken, and these leaks repaired, before proceeding with step testing and the more advanced acoustic methods. This is especially applicable if the WSI intends to outsource acoustic logging or leak noise correlation.

Further details of each of these methods are given in Annex 3.

2.4.8 How Many Leaks? Reference is made to section 5.4 of Volume 2 of these guidelines for the basis of determining leakage targets. Exactly the same basis is used for an individual sector as it is for a whole supply area. When implementing active leakage control, the question that is naturally asked is “how many leaks are there?” To this question there is not a simple answer since one cannot know the proportion of leaks of different sizes, although generally there are likely to be many more small leaks on service connections and fittings than mains leaks.

To help with the planning and implementation of ALC, the concept of the “equivalent service burst” (esb) was derived (Lambert 1994). Thus if one esb is 30 m³/d and the zone target represents a saving of 150 m³/d, then the leakage team has a target of 5 esbs. In theory, therefore, the team continues to search until 5 esbs are found and repaired. This may take more than one pass, or, if fortunate, one large leak may be found and the search stops.

The value of one esb as proposed in Managing Leakage (UK Water Industry, 1994) is 32 m³/d at 50 m pressure, however experience has shown that in some systems, smaller leaks can be found and for the purpose of estimating the cost of ALC (repairs) it may be prudent to adopt a lower value.



Box 2-2: Case History: Tlhabane Water Loss Management Project The main objective of the Tlhabane Water Loss Management Pilot Programme was to improve and manage the water losses occurring in the distribution network.

The two-year project commenced in August 1998 and was implemented in five phases based on the draft SABS 0306 (1999) and described briefly as follows:

⇒ Develop a plan for the Water Loss Management programme

⇒ Select, order, purchase and install meters, valves and a monitoring system

⇒ Implement water loss and leak detection procedures

⇒ Analyse results

⇒ Undertake a water audit/balance.

The project included several skills transfer and training workshops for RCC’s officials.

The project involved the establishment of three water management districts within the water distribution network providing potable water to some 45 000 residents of the suburb.

The method(s) adopted for the water loss control in Tlhabane was based on the philosophy of “to measure is to know”. Empirical measurements taken during this water loss programme included:

• Diurnal flow patterns

• Listening/sounding surveys

• Night usage/wastage surveys

• Meter reading surveys

• In-situ meter testing.

Some of the findings and observations of this investigation included:

• The existing 250 mm diameter management water meter supplying the lower reservoir was under-reading by 29%.

• The empirical measurement of minimum night flows, domestic night usage/wastage, institutional night usage/wastage and commercial/ industrial night usage/wastage indicates that 11% (or nearly 86 000 m³/ annum) is leakage from the distribution network, 14% is attributable to legitimate night usage (some 112 000 m³/annum) and the remaining 75% (or just over 595 000 m³ per annum) is wastage/leakage within properties together with possible unauthorised usage. This net minimum night flow represented approximately 28% of the water suplied to Tlhabane (some 0,68 million of the 2,4 million m³/annum).

• Leak detection surveys identified over 140 leaks of which approximately 8% were in the distribution system and the remainder within properties. All leaks identified in the distribution system were repaired.

• Various unmetered connections or metered connections that did not appear on the RCC billing system were identified which were the cause of a loss of revenue to the Council.

• Comparison of the Council’s billing database with a field survey of approximately 44% of the residential properties highlighted some anomalies in the billing database.

• In situ and off-site testing of a small sample of domestic meters indicated that generally the meters complied with the accuracy requirements of SABS 1529. However, the results clearly identified wastage/leakage within properties.



2.5 Pressure Management

2.5.1 Basic Principles

The term "pressure management" is taken to mean the design and operation of the network so that adequate pressures are available to meet consumer service levels at all points in the network and under all demand conditions, whilst also minimising stress on the network by avoiding excessive pressures and fluctuations.

The amount (flow) of water from a pressurised pipe system, in line with basic hydraulic theory, is dependent on the size of the opening and its shape, and the pressure in the system at the point of discharge. This principle applies to a leak in a pipe in just the same way as a consumer's tap.

A reduction of operating pressure within the distribution system will reduce the volume of leakage water lost in a given time from a given sized hole or crack. A saving may also be realised, especially in older networks of cast iron, by reducing the frequency of burst occurrences. A reduction of operating pressure will also reduce waste and pressure related consumption e.g. the flow from an open tap or garden sprinklers, as well as reducing customer leakage.

The amount of leakage reduction can be estimated from Table 5B of Volume 2 of the guidelines. In Figure 5.1 of Volume 2, an example of the relationship between the frequency of mains bursts and system pressure is given.

The total water saved divides into 3 components:

� Leakage in the WSI's mains and service connections

� Leakage in the consumers' systems

� Reduced pressure dependent consumption

Ideally these should be estimated separately.

The objective of pressure management is to develop a pressure regime within the distribution network that is as close as possible to the ideal of providing just the declared minimum at all times and no more. The factors which act as a constraint to the ideal are (a) topography, (b) friction losses within the network, and (c) fluctuations in consumer demand.

In new systems the design should be carefully undertaken to achieve an optimal pressure profile using hydraulic modelling methods. Wherever possible pressures should not exceed 50 m and the average pressure across the system should be significantly lower. Sufficient capacity should be provided in the mains so that the diurnal fluctuation does not exceed +/- 5 m. Careful zoning configuration and location of service reservoirs should minimise the need for pressure reducing valves (PRVs), but may not eliminate them altogether in areas of undulating topography. This exercise should be undertaken concurrently with sectorisation as described in section 2.2.

Where the topography of the supply area varies significantly, the system may already be sub-divided into basic pressure zones. Normally, however, pressure within these primary zones will still vary to a considerable extent. Pressure management as envisaged within this guideline may be seen as an extension of that principle by separating off areas that, due to their elevation, are operating at much higher pressures than are necessary for basic service provision.

Excessive water pressure (head) can also be used to advantage by the installation of a small hydro-electric power plant which converts it to electricity.



This can benefit rural communities by providing a valuable supplementary supply, even though the amount of electrical energy may not be sufficient to power an entire village.

2.5.2 Methods of Pressure Control

The several methods of pressure control are summarised in Table 2C.

Table 2C: Methods of Pressure Control

Method Advantages Disadvantages

Break pressure tanks, service reservoirs

No special maintenance regime required

Likely to be costly unless designed in as part of a general system improvement scheme

Pump control Simple and cheap Limited application

Valving, zoning Simple and cheap Limited application

Pressure reducing valves

Versatile, relatively inexpensive, need not restrict flow rates

Prone to incorrect siting or sizing if not adequately designed

Limited life device and regular maintenance required

The simplest form of pressure reducing device is a break pressure tank, indeed service reservoirs within a large supply network fulfil that function as well as providing basic storage. An example would be where a municipality's take off from a water board trunk main is via a service reservoir whose top water level is much lower than the pressure in the trunk main. If there is insufficient storage within the distribution network then its provision can provide the opportunity to reconfigure the network in such a way as to improve the pressure regime.

Pump control applies where the network is fed from a booster pump, generally, but not necessarily, without a header tank. Applicable to either multiple or variable speed pumps the method involves linking the pump start / speed to a pressure monitor on the pump delivery which is set so that pressure at the highest point in the network is kept to no more than the minimum needed, as far as practicable.

Valving or zoning applies where there are several service reservoirs at different levels. By changing the zone boundaries it may be possible to reduce average pressures.

An in-line pressure reducing valve performs a similar role to a break pressure tank, but the downstream static head is not reduced to atmospheric at the device location.



In-line devices are:

Throttle Simply by partially closing a valve, pressures will reduce downstream,

but the amount of pressure reduction is wholly dependent on the flow through the throttle. If set such that sufficient pressure is maintained to supply consumers during peak hour demand, at night the pressure reduction will be much less. This is the opposite of what would be the feature of an ideal design.

Fixed Outlet PRV

This comprises a throttle whose aperture is continuously adjusted so as to maintain a fixed pressure downstream of the valve. Whereas there is a fixed outlet pressure at the valve, the pressures within the zone will vary according to demand and distance from the PRV. In the case of a large zone, or one which has higher than average pipe losses within the zone, the valve setting to attain sufficient pressure for peak hour demand at the critical point in the network will be significantly higher than desirable for low demand periods.

Dual Outlet PRV

Sometimes known as "two point" PRV in which the outlet pressure is time based. The pressure setting between 06.00 to 22.00, say, would be the same as for the fixed outlet valve, but a lower setting from 22.00 to 06.00 would still attain the minimum pressure at the critical point. The average pressure in the network over 24 hours is therefore less than is the case with the fixed outlet PRV.

Dual Outlet Flow Regulated

Instead of operating on a timer, the PRV is linked to a flow meter and the high or low setting is determined by the flow through the valve. Thus whilst generally the higher pressure would apply during the day and the lower at night, the unit can respond to any flow variation regardless of time of day, ‘toggling’ between pressures as the flow in the system rises and falls. Therefore the average pressure will generally be less than with the standard dual outlet type. This type of control also ensures that, in the case of a fire demand during a period of low pressure, the pressure setting will revert to the higher level.

Flow Modulated PRV

In this type the PRV is also linked to a flow meter and continuously adjusts its outgoing pressure according to demand. It is therefore possible to achieve a near constant minimum pressure at the critical point in the network and to achieve the lowest possible average pressure in the network downstream of the valve.

The differences between fixed outlet and flow modulated PRVs on pressure at the critical point (minimum pressure) within the downstream reticulation and the hydraulic gradients from the PRV are illustrated in Figures 2.10 and 2.11 respectively. The critical point on the network is normally at the highest ground elevation, although it can be elsewhere depending on the distribution of demand, e.g. if a major user is situated at an extremity of the network.



Figure 2.10 is representative of a network which is under a reasonable degree of hydraulic stress, since there is significant variation in pressure at the critical point, i.e an increase in demand will pull down the hydraulic gradient. In that case the sophistication of flow modulated or dual outlet pressure PRVs offer potentially greater water savings to justify the higher costs of installation and maintenance and in frequency of breakdown, compared with the simpler fixed outlet type. If the network is under low stress, i.e has significant spare hydraulic capacity, the diurnal variation in pressure is small and dual outlet pressure or flow modulated PRVs are not justified.

Within gravity fed parts of the network, a pressure reduced area must be hydraulically isolated from adjacent areas and it is often convenient to combine this with a district meter area, with the pressure reducing device being physically adjacent to the meter within a common structure, as shown in Figure 2.12. Whereas the principle of district metering for active leakage control necessitates the creation of relatively small supply areas, pressure reduced areas can be as large as the topography and system configuration permits, indeed the larger the area the more cost-effective the PRV installation becomes. Where applicable, a single pressure reducing device can serve more than one district meter area (although in that case care must be taken in positioning the PRV and district meters to avoid meter accuracy problems).

It is not advisable to feed a pressure reduced area from more than one pressure reducing device, since this will introduce an inherent hydraulic instability.

The implementation of a pressure reduction scheme is likely to limit the capacity of a distribution system to deliver water to customers. The impact on commercial customers, particularly those with fire fighting sprinkler systems, high rise buildings and the fire services, needs to be taken into account. Even domestic and other customers who are not affected in any material way, may perceive a difference and some customer complaints may result, even if advance notice has been given. The existence of combination boilers, kidney dialysis machines and other pressure-sensitive appliances should also be appreciated.

Figure 2.10: Variation in Pressure at Critical Point, With and Without PRV

Figure 2.11: Hydraulic Gradient in Network between PRV and Critical Point

Only specify a more costly variable outlet pressure PRV if

there is sufficient diurnal pressure variation to justify the

additional costs and maintenance commitment.



2.5.3 Methodology for PRV Implementation

The following depends upon having reasonably competent records of the mains and sufficient contours / spot heights to be able to interpolate to within one metre. Ideally pressure management schemes should be designed using validated hydraulic models (refer section 6.4.6), but in their absence the following procedure is used:

Step 1 Determine minimum level of service pressure to be adopted, e.g. 15 m in the water main for low rise residential developments, 25 m in urban centres

Step 2 Estimate static pressures in system at key nodes and extremities by reference to top water level of the service reservoir or water tower and draw zero flow pressure contours.

Step 3 Examine the configuration of network and, where pressures are excessive, look for parts that can readily be fed through a single supply link by closure of as few adjacent area boundary valves as possible. None of these vales should represent a primary feed into an adjacent area.

Step 4 Check if break pressure tank solution is possible, especially if there is insufficient distribution storage.

Step 5 Locate likely critical point or points in the pressure reduced area from topography and distance from the potential PRV location

Step 6 Estimate peak hour demands in the network and calculate pressures at the PRV location and at the critical point with pressure reduced zone isolated.

Step 7 Assuming this confirms potential of the site, discuss proposals with fire officer and agree on any operational procedures, design features.

Step 8 Design and install flow meter (that may also be used for active leakage control).

Step 9 Advise consumers of possible changes to pressures in their system, both inside the pressure reduced area and in adjacent areas.

Step 10 Identify critical consumers, e.g. kidney dialysis patients, and ensure that they are aware and that they have emergency contact details.

Step 11 Advise water services admin office to expect consumer reports of pressure problems and ensure that these are properly recorded for possible follow up.

Step 12 With flow meter installed, close boundary valves and measure pressures upstream and downstream of the meter and at critical point(s), ideally using electronic data loggers for 24 hours, but visual observations from standard hydrant pressure gauges otherwise.

Step 13 At night, close inlet valve to zone and check for zero pressure. If not then there is zone breach that must be found and rectified before proceeding to next step.

Step 14 Optional: use line valve to throttle pressure at night to achieve minimum pressure at critical point(s) and confirm the pressure drop across the valve.

Step 15 If there are no problems, decide on type of valve to be specified and procure.

Step 16 Design PRV (and meter if applicable) installation, build chamber, install and commission valve (and telemetry if applicable). Reduce pressures in steps over a period of weeks.

Step 17 Monitor PRV performance closely for first few weeks.



Step 18 Establish maintenance regime and maintenance contract with valve supplier or other competent service provider

Step 19 Appreciate the benefits!

PRVs should be fitted downstream of the flow meter and on a by-pass so that it can be taken out of line if a fault occurs, as shown in Figure 2.12. If necessary, the pressure reduction can be maintained approximately by valve throttling as a temporary expedient.

Figure 2.12: PRV with Flow Meter Installation

The sizing of the PRV is important and reasonably reliable flow estimation as well as pressure ranges must be provided to suppliers when obtaining quotations.

Telemetry adds to the cost but is strongly recommended if a flow control PRV is adopted.

2.5.4 Methodology for PRV Maintenance and Sustainability

PRVs are definitely not ‘fit and forget’ items. They are akin to short life pumps, requiring regular maintenance and renewal every 5 – 10 years. Telemetry is therefore of benefit since it enables a 10 minute check to be made on the valve on, say, a weekly basis, to ensure that it is operating as intended.

Items which require regular checks, and, if necessary, corresponding alterations in PRV settings are:

� Status of boundary valves.

� Extensions at margins of PRV area e.g. additional properties/roads/streets at elevations near design setting.

� Additions/changes to consumption profile within defined area; e.g. new housing site or changing industrial consumption.

� Regular checks on PRV inlet/outlet settings to confirm profile against design settings.

� Status of valves within the PRV area.

Yearly maintenance of a PRV should include cleaning of filters in the small bore pipework to the pilot valve. If the water contains sediment, whether from the treatment plant or from deposits inside the pipelines, then more frequent maintenance may prove to be necessary. If there is any doubt as to the capacity of the WSI to undertake PRV maintenance, a maintenance contract should be established with the original supplier or other suitable specialist service provider. With a PSTN type telemetry link they can monitor valve performance remotely.

The technical and financial benefits of pressure reduction are

considerable, but pressure reducing valves are hard working devices and regular performance monitoring and

maintenance is essential

flow meter PRV

10 x dia. 5 x dia. 10 x dia.



2.5.5 Risk Factors / Confidence

Risk factors:

� Investigation and design short cuts leading to incorrect choice of PRV

� Zone boundary breaches

� Reduced pressure acceptability to consumers used to higher pressures

� Ditto fire service

� Lack of maintenance

Overall confidence factor: High

2.5.6 Pitfalls and Constraints

Pressure management requires highly specialised intervention and it may not be appropriate in water pressures are generally low and the hydraulic gradient is flat. Pressure management also leads to the reduction of supply pressure at the property boundaries, and in steep topography, the supply pressure at the point of use may be too low for domestic geysers and appliances to function.

PRVs that are too large will be unstable at low flows, and PRVs that are too small will impair service delivery.

Failure of the PRV in the fully open or partially open position renders the downstream pressure equal to the upstream pressure. This could have serious implications, especially for private plumbing installations, and the infrastructure.

Cavitation of the PRV close to the shut position could result in the destruction of the PRV and induce a water hammer into the infrastructure.

References and Suggested Further Reading Stewart Scott (2000). Thlabane Water Loss Management Project Final Report for Rand Water.

DVGW Technical Information Bulletin (Germany) (1984). Regulations for Water Mains.

Lambert A (1994). Accounting for Losses: The Bursts and Background Concept, Journal CIWEM (UK), April. Managing Leakage (1994). UK Water Industry Water Research Centre (UK).

SABS 0306 (1999). The management of potable water in distribution systems.

McKenzie R (1999). Development of a Standardised Approach to Evaluate Bursts and Background Losses in Water Distribution Systems in South Africa, SAWRC, June.

Lambert A (2000). A Realistic Basis for International Comparison of Real Losses from Public Water Supply Systems, Journal CIWEM (UK), June.

2.6 Asset Management – Basic Principles

The provision of a water service to consumers requires the necessary physical infrastructure assets to abstract, treat, store, convey and deliver water to consumers, and the appropriate deployment of operational resources. Assets that are in good physical condition will require less operational attendance and will perform better than those in poor physical condition.



In the context of WC/WDM: distribution management, asset management is primarily concerned with the structural condition of the infrastructure and the amount of leakage there from, and the competence of the flow metering, especially the large stock of consumer meters. There are five key principles:

1. Focus on aligning assets with the service delivery requirements of the community;

2. Develop a consistent framework for evaluating assets;

3. Establish clear accountability for asset management decisions;

4. Integrate asset management with executive management decision making and link asset management with the budgetary process;

5. Evaluate assets in terms of need to meet community requirements.

Once these principles are understood and followed, the application of asset management can be undertaken with clarity, consistency and with simple common sense.

Essentially asset management consists of the following activities:

� Identification of need

� Initial provision and subsequent upgrade

� Operation and maintenance

� Disposal and/or removal

Identification of need requires that sufficient reasonably reliable information on the extent, condition and performance of assets is available for informed analysis.

The concept of an asset management cycle as shown in Figure 2.13 can be used to illustrate the framework for commercial effectiveness structured around basic asset management fundamentals.

Figure 2.13: The Asset Management Cycle

Asset Management Cycle

Goals

Processes Outcomes

Business Plan Service Strategy

Needs Analysis

Asset Assessment

Performance Assessment

Asset Strategy

OperatingPlan

MaintenancePlan

DisposalPlan

Replacement andAcquisition Plan

Forw

ard

Targ

et a

nd B

udge

t Req

uire

men

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Asse

t Per

form

ance



The age of infrastructure such as pipelines can act as a proxy variable for determining the approximate value of water lost due to leakage, however great caution should be observed since there are many examples of networks where the quality of installation during a particular era was poorer than the preceding era. Reasons for this can include quality of original materials from a particular supplier, local ground conditions, quality of workmanship and supervision of works at the time of installation. For example there is evidence to suggest that current rate of infrastructure development in RDP areas is putting the quality of work at risk (refer Section 2.9 of these guidelines). It is also the case that within any given age band there will be a variation and therefore age alone should not be the sole criterion for deciding to spend money on rehabilitation (refer Section 2.7).

Nevertheless in a large network it is helpful to try to develop a linkage between the age distribution of pipelines and the cost of leakage, through the application of the Fundamental Law of Decay. This is illustrated in Figure 2.14, in which the age distribution of a pipeline system is converted to a weighted Law of Decay S-curve relating to the annual cost of water leakage from the system.

The curve was derived from pipe age data and year 2000 costs to illustrate the effect that the deterioration of infrastructure can have on leakage costs if maintenance and refurbishment of the piping system is neglected.

Figure 2.14: Fundamental Law of Decay

References and Suggested Further Reading:

University of Melbourne (1996). Project Management Practices 4 – Asset Management of Infrastructure. Engineering Education Australia (Pty) Ltd.

Speigel MR (1972). Schaum’s outline of theory and problems of statistics in SI units. McGraw-Hill.

2.7 Rehabilitation Planning

2.7.1 Terminology

The term rehabilitation in its widest sense is generally defined as:

"All measures that involve changing the condition, design or specification of a network in order to rectify performance deficiencies within the network "

Rehabilitation includes measures to reinforce the hydraulic capacity of the network to deal with increases in demand from the areas that are already served, but not extensions to the network or associated reinforcement to meet demand in new areas.

Rehabilitation of a network can take several forms:

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� Replacement of mains, in which the old main or service connection is either abandoned or destroyed and is replaced by a new pipe.

� Renovation in which the existing main is retained and continues to perform a structural function

� Reinforcement in which the hydraulic capacity of the network is increased, either by providing a new main or mains, or by renewing an existing main in a larger size

Techniques for rehabilitation that are designed to minimise disruption to the public by on-line replacement or relining to minimise the amount of open trench works are commonly termed trenchless technology or no-dig. In reality, however, there is still a significant amount of excavation required, at access points and for service connections.

A water main is a length of pipe between valves or junctions and is the minimum length to which a particular type of rehabilitation would apply.

The term interruption to supply is used in this section to mean the short term absence of water to a consumer or group of consumers arising from the occurrence of a defect in the water network that is subsequently repaired, such as a burst or plant breakdown. This is distinct from an absence of water due to an excess of demand over supply, necessitating rationing in some form.

2.7.2 Integrated Approach to Network Rehabilitation

Performance deficiencies in a water distribution network that affect the consumer may relate to the quantity supplied, the pressure at which it is supplied, and the continuity of service as applicable. Some of these also affect the WSI's cost of operations in terms of paying for water production that is not put to beneficial use, repairing bursts, having to flush mains to remove products of corrosion, etc.

Compensation to consumers as a result of a failure to meet expected standards of service may also apply in certain circumstances.

Rehabilitation may be undertaken for reasons of:

� Water quality (old iron mains, lead)

� Structural performance (high burst frequency and leakage losses)

� Hydraulic performance (poor pressures / excessive head losses in mains)

For the purposes of WC/WDM, rehabilitation would focus on the structural condition of the infrastructure that is at the root cause of excessive physical water loss. However a single strand approach is not the most cost effective in the long run. For example it may be decided to replace a defective high leaking water main, but the question then arises as to the size of the replacement pipe. In a single strand approach the replacement would be the same size, but adopting an integrated approach would see the main correctly sized for future demands.

2.7.3 Network Serviceability and Performance Requirements

The objective of an integrated rehabilitation plan is to attain a configuration and condition that, with competent operation and maintenance, the WSI can provide consumers with water that meets statutory standards of quality, at sufficient but not excessive pressure, and on a continuous 24 hour per day 365 day per year basis.

An integrated approach to the rehabilitation of reticulation

is recommended, in which the several types of deficiency are addressed concurrently



From the WSI's perspective, the cost of operation and maintenance to achieve satisfactory consumer quality standards should not be excessive.

Water Quality

Whilst for the most part, water quality is dependent on the raw water source and the form of treatment of the raw water, compliance with the standards also requires that the passage of water through the network does not cause an otherwise compliant water to become non-compliant because of the internal condition of the pipes and fittings. For example iron mains and lead service connections.

Pressure and Flow

The minimum pressure in the water main when consumers are drawing water at the maximum hourly rate of demand will normally be stated in the bylaws under general conditions of supply, e.g. 150 kPa (15 m head). When pressure drops below the minimum target level this can represent a trigger level for rehabilitation, but when providing new or rehabilitated mains a higher design pressure would normally be set, e.g. 250 kPa (25 m head), as a design safety margin. Fire flow provision also needs to be considered but under that condition it is only necessary to ensure that negative pressures in the mains do not occur. Maximum pressure should ideally not exceed 500 kPa (50 m) since problems with plumbing fittings can occur and burst rates are likely to increase exponentially.

Interruptions to Supply / Mains Failures

Typical average mains failure rates for a system (Twort) are:

Trunk mains:

"good" condition 0.015 -0.020 per km per year

"below average" 0.06 - 0.07 per km per year

Distribution mains:

“low” 0.10 – 0.15 per km per year

“average” 0.20 – 0.35 per km per year

“high” 0.40 – 0.55 per km per year

In a recent survey of 27 water undertakings in Europe (AWWRF, 1998):

10 undertakings had "low" failure rates <0.2 per km per year

7 had "moderate" failure rates 0.2 - 0.4 per km per year

9 had "high/very high" failure rate 0.4 - >1.0 per km per year

Failure rates also vary according to pipe material and age (and it is not necessarily the case in a given system that the oldest mains exhibit the highest failure rate).

The above statistics relate to the whole network but when individual mains or zones are considered, much higher failure rates expressed per unit of length will be found. Whilst the impact of bursts on the consumer is partly a function of the efficiency of response by the water undertaking, typical trigger levels for rehabilitation of mains that are deemed to encompass both consumer service and economic factors are (CIWEM 1996):



- 3 times per year per 1000 population in urban areas*

- 4 times per year per 1 km of pipeline in rural areas

*equivalent to around 0.5 per km per year

Service Pipe Defects

Individually, these are dealt with as and when they arise as part of normal operations, but considered as a group within a DMA where there has been a history of past failures, the likelihood of an ongoing significant commitment to service repair works may be expected. Average defects rates collated from a number of sources have been reported (Twort) as:

Communication pipes and stop taps 1 – 2 per 100 services per year

Supply pipes and internal plumbing c 2 per 100 services per year

Valves and Stop Taps

Valves and stop taps are essential appurtenances that if, in poor condition, absent in key locations or inaccessible, make normal operational activities more difficult, and therefore costly, and will aggravate the effect on consumers and third parties of burst incidents.

Leakage

Ideally, a water distribution network would not leak. Except for water taken for operational purposes and fire fighting, all water produced would be delivered to consumers. In practice, however, there are no leak free systems, although it is perfectly possible using good quality modern materials and high standards of design and installation, to provide new mains and services that are virtually 100% watertight on completion.

Due to many factors, water networks do develop leaks and the numbers inevitably increase over time if no action is taken. But providing prompt repairs are made to bursts that cause loss of supply or cause damage to persons or property, the system can be said to remain "serviceable". Mains may be regarded as unserviceable on leakage grounds if there are security of supply or hydraulic capacity problems and if, due to the condition of the mains, the leakage cannot be practically or economically reduced.

Many leaks are found on service connections and since they are generally of smaller flow than a most mains leaks, they are less likely to show on the surface and likely to run for much longer before discovery and repair. They will also be greater in number than mains leaks. Service pipe leakage can therefore represent a greater proportion of total losses than mains leakage and in a rehabilitation programme service pipe renewal should be evaluated accordingly.

Financial and Economic Factors

In a system that is in need of rehabilitation, excessive operating costs for the WSI go hand in hand with poor serviceability in relation to consumer needs. Parts of a network that are in poor condition will incur higher than average costs with regard to:

- Numbers of reported bursts to be repaired

- Frequency of intervention and numbers of unreported bursts to be repaired to maintain leakage at target levels under active leakage control

- Frequency of mains flushing to remove loose particle corrosion products



Social factors that come into the economic appraisal include reliability of supply expected by existing and potential industrial consumers, third party damage resulting from burst events, and disruption to commercial activities in urban centres. The point at which a particular main becomes unserviceable due to its high cost of maintenance is a matter for economic appraisal, but many such mains will probably also be classified as unserviceable on grounds of consumer service quality.

2.7.4 Integrated Approach Methodology

If an integrated approach is to be adopted, it is recommended that generally rehabilitation is prioritised and undertaken on a zonal basis, dealing with all of the known deficiencies in a zone within the one contract. An integrated design for the rehabilitation works in a zone would deal with all serviceability issues concurrently in the most cost-effective manner.

Where there are unlined iron mains, if not now but in the future they will give rise to water quality problems. Relining will deal with the water quality problem, but in an integrated approach their continued deterioration would be assessed and a decision made on whether just to reline or whether to renew, according to structural condition. Relining of course stops any further internal corrosion, but not external corrosion.

Structurally sound mains can therefore be non-structurally relined, providing that there is sufficient hydraulic capacity. Structurally defective mains can either be replaced by pipe insertion or by pipe bursting to increase hydraulic capacity if required, as an alternative to conventional open cut construction. In considering hydraulic capacity, it should be remembered that reducing leakage demand will effectively release capacity for consumption.

In town centre zones, rehabilitation by zone also provides an opportunity to rationalise the configuration of the network - often the historical development of the network has left a legacy of duplication of mains and unnecessary redundancy.

Prioritisation by Zone

To prioritise rehabilitation works by zone, the following physical and performance characteristics should be evaluated, to the extent that data are available:

� Mains properties - proportion of old unlined cast iron mains (% of total length)

� Connections - lead services (% of total connections)

� Structural performance (per km of main)

� Leakage performance (per connection)

� Water quality - unlined iron mains, dirty water complaints, sample data (per 100 customers), lead services

� Hydraulic performance – length of mains or numbers of consumers having less than the minimum pressure stated in the bylaws at peak demand (per km or per 100 connections)

� Other factors - critical consumers, sensitive mains, development planning

For each category, a simple ranking order procedure is quite satisfactory, e.g for 10 zones, from 10 for the highest to 1 for the least in need of rehabilitation.

Having established the ranking order for each condition and performance category these are then used to derive a composite or weighted zone prioritisation rating. The weightings will be a matter for the WSI to determine according to its priorities.



Some of the categories overlap since a particular condition can have more than one effect. Weightings can be used to reflect this.

Rehabilitation of Mains

Within a zone, in the detailed design stage, available condition, performance and strategic importance information on individual mains or groups of mains would be examined for:

- Burst frequency

- Leakage (from step testing)

- Physical condition

- Soil corrosivity (in relation to metallic mains and fittings)

- Head loss

- Age

- Importance

Each parameter can be given a score and weighting in a similar manner to the procedure for prioritising zones. A possible format and provisional condition and performance rankings based on a 0 to 5 score for each parameter is outlined in Table 2D, but as with the prioritisation by zone, the scorings and weightings will be determined by the WSI according to local priorities and issues.

Table 2D: Example of Scoring System for Mains Rehabilitation

Parameter Scoring Range Weigh-ting

Burst frequency 0 = < 0.05/km.yr 5 = >2/km.yr 2

Leakage 0 = <UARL 5 = >5* 2

Physical condition

0 = excellent 5 = very poor 3

Soil corrosivity 0 = non aggressive soil or not relevant (plastic main, non-ferrous fittings) 5 = highly aggressive soil

1

Head loss 0 = <1 m/km 5 = >20 m/km 1

Age 0 = < 20 years 5 = >80 years 1

Importance 0 = not critical or sensitive and without development impact 5 = both critical and sensitive and with development impact

1

* UARL – Unavoidable Real Losses litres/connection.day – see Volume 2 guidelines Section 5.4.2

In respect of physical condition gradings, a 0 score would represent a main that is in best "as new" condition, designed and installed under a competent quality control regime. New mains laid with only minimal building control inspection may well not achieve a 0 score. At the other end of the range, a cast iron main with a physical condition score of 5 would be one which, from test sample analysis, had a predicted remaining life of less than 5 years.

Where the available information relates to a part of a zone comprising a group of mains, e.g. interpolation between pipe samples or step test results, the rating would be applied equally to the whole group.



The resultant rating would then be used to determine whether an individual main should be replaced. For example using the above suggested scoring and weighting values a rating of 15 should provide a trigger point, since one would suppose that a main in “very poor” condition (5 x 3 = 15) should be replaced, regardless of any other factors. It may be visualised that the trigger value may vary according to the cost of rehabilitation, since cost benefit needs to be demonstrated.

Having determined which mains are to be replaced on (mainly) structural grounds, the hydraulic regime of the zone would be examined, a validated hydraulic model of the existing system being a valuable, some would argue essential, tool in this regard. As a baseline case, the result of adopting structural and non-structural liners where appropriate would first be evaluated. The hydraulic design would then be optimised by selective size for size pipe replacement or up-sizing as required to meet the level of service and fire flow design criteria.

Trunk mains can be considered on the same principle as distribution mains, but in all cases the importance score would be 5.

Rehabilitation of Services - Structural and Hydraulic Considerations

The factors that determine the need for replacement of service pipes and connections are similar to those applicable to mains, except that it is impracticable to assess the condition of individual services. As far as structural and hydraulic performance is concerned they can be grouped on a street by street basis. Historic failure rates, the condition of ferrules and stop taps and leakage rates would all be considered in determining the need for rehabilitation.

Rehabilitation of Services – Water Quality (Lead)

The present maximum permitted level in South Africa under SABS 241 is 100 µg/l with a recommended maximum 50 µg/l. Therefore replacement of lead services for water quality reasons may only be required in a minority of cases. [In Europe the permitted lead concentration was reduced in a 1998 directive from 50 to 10 µg/l (at the consumer’s tap) and this is giving rise to the implementation of both chemical dosing to reduce plumbosolvency, where the water characteristics are suited, and lead service replacement programmes.]

Operational Considerations

As well as determining the rehabilitation for individual mains, the opportunity should be taken to deal with any operational problems and to rationalise the configuration of the network. Examples would include:

- The replacement of defective key valves that would not otherwise be renewed as part of the mains relining or replacement

- Any additional valves required to minimise numbers of consumers affected by shut-offs

- Elimination of unnecessary parallel mains, ensuring that redundant mains are sealed off and all services transferred



Box 2-4: Case Study Waterford (Ireland) 2000/1

The implementation of a water conservation and network management project for the Corporation of Waterford (pop 45,000), identified a number of cast iron mains totalling 6.5 km in length that had very poor structural, leakage and hydraulic performance. These were allocated a high priority for selective rehabilitation in a first phase works contract, in advance of a planned DMA rehabilitation programme. The mains were generally very old and in and around the commercial centre of the city and a "no-dig" solution using a PE all welded pipe and services system was designed, with a combination of slip lining and pipe bursting according to the hydraulic requirements determined from hydraulic model.

A contractor was appointed who had considerable rehabilitation works experience in the UK, but their Irish division was unused to this kind of work. A very experienced contracts supervisor was assigned to ensure that many of the novel (in Ireland) procedures were followed and quality standards met. This included consumer care procedures and a "street in a week" completion (including permanent reinstatement) planning methodology. The rigorous PE joint testing regime in the specification was followed and all jointing operatives had to possess a current certificate of competence in use of the apparatus.

Waterford Corporation personnel were trained in the use of PE pipes and fittings to enable them to make new connections and repairs resulting from third party damage. The Corporation also purchased and now uses impact mole apparatus to make "no-dig" service connections in PE.

On completion of the work, the Corporation reported a reduction in water into supply of nearly 2,000 m3/d, corresponding to a specific saving of 12.8 m3/hr per km of main for the 6.5 km. The selected mains were in several DMAs where average specific losses were in the range 4 - 6 m3/km.hr. The associated low pressure and dirty water problems, which the project was also designed to address, were also rectified.

The Corporation, not unused to complaints from the public about street works, were pleasantly surprised that an article in the local newspaper complimented them on the efficiency with which these essential works were carried out and the care that had been taken to minimise disruption to the community.

The hydraulic design of a rehabilitated network follows standard design criteria, with leakage demand being separately modelled. In an urban area leakage losses in poor condition zones can easily be of the order of 5xUARL or more, whereas a system in near new condition should not exceed 1xUARL, exclusive of consumer leakage.

2.7.5 Procedure for Implementation - Integrated Approach The following depends upon having reasonably competent records of the mains, including pipe materials and approximate year laid (can be roughly estimated if not recorded by reference to age of development), and burst locations. It assumes that the network is or will be sub-divided into management districts or zones.

Ideally rehabilitation schemes should be designed using validated hydraulic models, but as these are not yet common practice in SA, the following procedure is used:

Step 1 Collate all data on burst locations and consumer complaints if available and prepare incident maps (in GIS if available).

Step 2 Collate physical evidence of system condition that can be location referenced, e.g. pieces of failed pipe, services, corroded valves, photographs.

Step 3 Establish pressure contours within system by reference to topographical maps, service reservoir levels, field pressure tests.



Step 4 Review customer profile in zones - key and critical.

Step 5 Identify "sensitive" mains.

Step 6 Establish development potential each zone.

Step 7 Use ranking system to prioritise by zone.

Step 8 Develop unit costs for rehabilitation elements, estimate approximate works in each zone and develop phased programme.

Step 9 For first phase priority zone carry out field investigations - pipe sampling and laboratory testing, soil tests, pressure monitoring.

Step 10 Review results of active leakage control - frequency of intervention, step tests, etc. to confirm "fragile" mains.

Step 11 Estimate future demands, including potential leakage reduction, and assess pressure changes, identify mains under hydraulic stress.

Step 12 Use scoring method to prioritise mains.

Step 13 Decide on relining / renewal policy for any iron mains.

Step 14 Determine hydraulic reinforcement required - use poor condition mains that are going to be replaced on structural grounds for this reinforcement, wherever possible.

Step 15 Finalise integrated design and estimate costs.

Step 16 Make the business case!

Step 17 Appoint a competent contractor for the works and employ adequate supervision - one inspector / clerk of works for every two gangs plus Resident Engineer.

Step 18 Keep good records of the work which will invariably differ from the design and on completion ensure that the previous mains records and any asset databases are amended.

Step 19 Finally: Make absolutely sure that all old mains are disconnected.

2.7.6 Procedure for Implementation - Focused Approach ( leakage considerations

only) The following methodology is applicable to a single zone:

Step 1 As integrated methodology 1.

Step 2 Collate physical evidence of system condition that can be location referenced, e.g. pieces of failed pipe, services, corroded valves, photographs.

Step 3 Review results of active leakage control - frequency of intervention, step tests, etc. to confirm "fragile" and high leakage mains. If necessary repeat and sub-divide step tests.

Step 4 Understand pressure regime and assess benefit of pressure reduction, if appropriate.

Step 5 Decide on criteria for replacement of individual mains (abbreviated version of integrated approach).

Step 6 Apply criteria and identify mains to be replaced

Step 7 To the extent practicable, review hydraulic regime within the zone and decide if slightly smaller mains may be acceptable in some cases, permitting use of slip-lining technology, or if size for size or up-sizing is needed.



Step 8 Also examine opportunities for system rationalisation without incurring significant additional cost.

Step 9 Finalise design and estimate cost, to include replacement of all services, stop taps and consumer meters unless these are relatively new.

Step 10 Appoint a competent contractor for the works and employ adequate supervision - one inspector / clerk of works for every two gangs plus Resident Engineer.

Step 11 Keep good records of the work which will invariably differ from the design and on completion ensure that the previous mains records and any asset databases are amended.

Step 12 Finally: Make absolutely sure that all old mains are disconnected.

2.7.7 Methodology for Maintenance and Sustainability

No special measures other than good asset management practice

2.7.8 Risk Factors / Confidence Risk factors:

• Poor workmanship, inadequate supervision

Overall confidence factor: High

References and Suggested Further Reading Decision Criteria to Prioritise Replacement and Rehabilitation of Mains and Appurtenances, LNEC, Lisbon, for AWWRF, 1998

Monograph on Best Practice: Rehabilitation of Water Mains, CIWEM, 1996

2.8 Consumer Meter Management

Consumer meters may require replacement for several reasons:

(a) They are worn and provide inaccurate / misleading readings, especially at low flows – not necessarily immediately apparent

(b) They do not work at all – immediately apparent unless property is not occupied

(c) They are not correctly sized, typically over –sized, and are therefore inaccurate, more likely to under-record rather than over-record

The rate of deterioration of the consumer meter stock depends on the quality of the original meter - design and materials of manufacture - and the characteristics of the water, in terms of corrosion potential and the erosion / seizing up of mechanisms due to particulate matter in the water.

The establishment of a consumer meter management programme consists of three stages:

1. Devising a consumer meter management programme through an evaluation of the existing meter stock and the establishment of criteria for meter replacement based on accuracy requirements

2. Accelerated initiation of the programme to catch up with the backlog of past neglect

3. Ongoing meter replacement to maintain the meter stock within the required accuracy levels.



The appraisal of existing meter stock is described in section 2.1.5. The results of this analysis, including representative meter testing, are then used to develop both the immediate replacement and longer term meter management programme. This should ideally be done on a financial payback basis. Whilst a simplistic programme could be devised based on age, e.g. no meters greater than 10 years old (implying replacement of 10% of the meter stock annually), this ignores the fact that the cost of replacement of a meter on a small commercial property, say, with half of the overall average consumption per connection, will take twice as long to recover through the additional revenue generated than a meter on average consumption (approx., subject to tariff structure). Therefore an “intelligent” meter management programme would have larger revenue earning meters being replaced, or at least checked, at greater frequency than the meters in the lowest band of users. An example of such a programme might therefore be:

top 10% check / replace as necessary every 5 years

next 30% every 8 years

next 30% every 10 years

lowest 30% every 12 years

The above profile assumes that replacement meters being installed are to the correct size and that the meter types / manufacturers have been carefully selected for maximum accuracy and reliability. Within the scope of the initial priority replacement programme, as well as meter age, the replacement of meters of a type that appear to have poor reliability and existing meters on major consumers that appear to be over-sized should be included.

It should go without saying that any meter that is obviously defective, i.e is registering no flow to premises that are occupied, should be replaced. But it is not uncommon for just this most basic of procedures to be neglected. In some cases the omission is only revealed when scrutiny of meter readings reveals “write in” figures that represent someone’s estimate, perhaps based on historic consumption. This may be acceptable for one or at the most two meter readings while the meter is awaiting replacement, but not more.

Another method of meter management, which can be used in conjunction with maximum age criteria, is monitoring of the measured flows over several years. By interrogation of computer databases, progressive reduction or sudden step changes in consumption may be identified. There may of course be reasons for this, other than meter fault, and this method does require the results to be reviewed by knowledgeable personnel.

Further details of topics relevant to meter management are provided in Annex 4.

References and Suggested Further Reading American Water Works Association. Water Meters – Selection, Installation, Testing and Maintenance. AWWA Manual M6.

Adopt an intelligent consumer meter management programme which

recognises that the highest earning meters should be checked and/or

replaced more frequently than those which bring in less income

The reading of meters is a vital activity over which quality control must be

exercised. “Write–in” figures used when a meter

is faulty or cannot be accessed are acceptable only for one or two

readings



2.9 Design and Quality Standards of New Infrastructure – “Leak Free”

This section is not intended as a guide to the design and installation of new infrastructure, which would form a complete guideline in itself, e.g. the “Red Book”. There are also numerous standards and codes of practice applicable. Annex 5 lists some of the guidelines and legal requirements associated with the development of water infrastructure.

Given the very significant levels of leakage that are often found in existing systems, the focus of this section is on the achievement of quality standards in new systems that are inherently “leak free” when new and that experience only a slow rate of degradation.

Adverse comparisons may be made between buried pipelines for water services and those conveying other liquids, the consequences of leakage from which are more serious in environmental and financial terms. Levels of leakage commonly experienced in water reticulation systems would be totally unacceptable in oil or gas pipelines, for example, yet the basic pipe materials, fittings, jointing systems are no different.

Water undertakings in other countries do have what amounts to leak free pipeline systems. For example, in Singapore, the highest quality of materials, in combination, together with a rigorous installation quality control regime, have achieved leakage levels below ILI 1.0 for the system as a whole. In Madrid, much of the system in the city centre is laid in service ducts where any leakage at all is visible and can be repaired. Of course these performance levels come at a cost, but the crucial lesson to be learned is that “leak free” systems are a reality to which one may aspire.

After construction of any water main infrastructure, the standard Hydraulic Pipe Test as specified in SABS 1200 L-1983 must be carried out and the permissible leakage tares determined by Section 7.3.3 of SABS 1200 L should not be exceeded. The test results are normally archived with the contract documentation. There is a tendency for water mains installed in-house by local authorities not to be tested for pressure and leakage, but this is unsatisfactory. The requirement for pressure testing of any infrastructure, irrespective of who carries out the work, is paramount. The test results should be filed with the record drawings for reference.

A pro-forma checklist should also be designed by the WSI, and should capture the following key information:

� Municipality details

� Reason for construction of infrastructure

� Installed by (Name) and certificate/registration number

� Date of installation

� Cross reference drawing number

� Material used

� Length of mains

� Test Pressure

� Test Duration

� Leakage volume over test period

� Permissible leakage volume as per SABS 1200 L

� WSI Inspector present during testing (Name)

� Handover date

� Signatures of plumber, inspector and WSI



Table 2E summarises the measures that need to be taken to ensure leak free longevity in new systems. A cross cutting theme applicable to all items is the need for construction and installation to be in accordance with the designer’s intentions through close adherence to procurement specifications and construction workmanship requirements.

Table 2E: Measures to Avoid Pipeline System Leakage

Cause of Leak Preventative Measures Corrosion of metallic pipe body

Ensure adequate ground investigation to determine corrosivity of soils, both chemical and bacteriological, and presence of stray currents. Ensure pipe material or lining in contact with the water is completely corrosion resistant – indicators include pH, dissolved oxygen, chloride, conductivity, Ryznar Index. Use non metallic pipe. Provide protective linings and coatings. Provide cathodic protection.

Corrosion of joints and fittings

As above for ground and water characteristics and specification of corrosion resistant materials. Avoid galvanic corrosion opportunities. Adopt fully welded system, steel or polyethylene.

Failure of pipe body or joints due to stress / stress corrosion or ground movement

Ensure uniform pipe bedding support and surround appropriate to type of pipe – rigid or flexible material; avoid temporary point supports such as bricks and large stones within the bedding material. Provide movement joints at interfaces with structures. “Snake” polyethylene service connections. Ensure careful delivery, storage and handling to avoid damage before laying pipe in trench.

It will be appreciated that achievement of these worthy goals may well incur a cost that is greater than that represented by the cheapest construction price offered. The WSI must consider whether it wishes to base its procurement decisions on initial or lifetime cost of ownership. The WSI that is serious about WC/WDM should establish a culture of zero tolerance to poor quality design and construction that simply leads to an unnecessary repetition of their existing leaking systems in the new systems that they procure.

New infrastructure, if designed, specified and installed in full accordance with SABS 1200 should be leak-free. An essential ingredient in achieving the leak free goal is the quality of both the construction workforce and the site supervision, coupled with a formalised quality assurance system. A leak free system will be achieved in an underground (buried) pipe system only if the labour force has the necessary skill to achieve the required standard of workmanship and there is sufficient knowledgeable and diligent supervision in attendance, aided by effective QA procedures, to ensure that it happens. The expensive components of high quality, such as pipes and valves, are produced in factories under rigorous quality controlled conditions. Only by continuing this quality culture in the installation phase will the objective of a leak free system be realised.

There is no technical barrier to virtually leak free new water infrastructure

WSIs should have a “zero tolerance” stance to leaks in new infrastructure and

should insist on qualified technical supervision and rigorous quality control

regimes



References and Suggested Further Reading American Water Works Association. Water Meters – Selection, Installation, Testing and Maintenance. AWWA Manual M6.

American Water Works Association (1964). Steel Pipeline Design.

Peabody AW (1970). Control of Pipeline Corrosion. National Association of Corrosion Engineer.

SABS 1200 (1983). Standard Specification for Civil Engineering Construction

American Water Works Association (1986). Introduction to Water Distribution Principles and Practices of Water Supply Operations.

De Wit PWC & Hamersma SA (1996). Production and Operations Management. A practical approach. International Thomson Publishing (Southern Africa) (Pty) Ltd.

Department of Planning, Provincial Affairs and Housing (1991). Guidelines for the provision of engineering services and amenities in residential township development (Red Book). Prepared by the Division of Building Technology, CSIR.

2.10 Dual Distribution Systems

A dual distribution system supplies two grades of water through two separate pipe networks in the same service area, one being potable and the other non-potable. Non-potable water may derive from natural raw water sources that have not been treated to drinking water standards. Of interest in water conservation are dual systems that utilise treated effluent from wastewater treatment plants, either directly or indirectly from surface waters that have received wastewater effluent. The non-potable water is generally used for irrigation / garden water, but also may have applications in industry. Whilst not suitable for direct human consumption, non-potable water in such systems should be microbiologically and chemically safe for skin contact, garden irrigation of vegetables eaten raw and salad crops.

Dual distribution systems can reduce the demand for potable quality water by some 25 to 50%.

The principle of increased agricultural irrigation to leach surplus salts from the root zone of crops is applicable. As the salt load is carried mainly by the garden water system, it is distributed over the entire supply area, rather than discharged into the water source.

The reticulation costs of a dual system are approximately 160% that of a single system and not double as would be expected, this is because of the reduction in treatment costs.

Mass balances and cost comparisons have indicated that re-use in dual systems entail smaller desalination streams, less salts to be removed, better water utilisation indices and probably better economics than to reclaim effluents for direct potable re-use.

The use of dual systems becomes more attractive when the treatment of raw water for potable use is very expensive such as:

� Where sea or brackish water (with high Total Dissolved Solids TDS concentrations) is the closest available water source;

� Where intensive indirect re-use of water may cause high TDS concentrations in the source (as with the Vaal River Barrage); and

� Where the high increment cost of developing new fresh water sources may dictate consideration of reclamation and direct re-use of treated sewage effluents.



Box 2-5: Garies Local Authority

Garies Local Authority is situated within the Benede Oranje Catchment Area on the West Coast of South Africa and has a population of approximately 1500 people. The area has an average monthly rainfall of 14 mm and during the summer months, the average temperature is 32°C. The average daily water consumption is 275 m³ (2000) and expected to be 347 m³/d in 2005.

Boreholes can deliver approximately 300 m³ per day of potable water and 219 m³ per day of salt water.

In 2000, nearly 95% of the 325 households were connected to the sewerage reticulation system. A dual water distribution system is utilised to provide salt water for use with the waterborne sewage system and potable water for human consumption.

Operating and maintenance costs are included in the fixed tariff for the salt water supply. The Council introduced a double-billing system that separates current water accounts and previous debts as well as a potable water disconnection policy to encourage payment of water accounts. The salt water system is not included in the disconnection regulations which prevents any health risks from the lack of flushing water. Monthly charges for full waterborne sanitation systems is R34 (2000).

A surface dam has been constructed to replenish the groundwater resource through infiltration.

References and Suggested Further Reading: Botha J (1998). Dual water supply – a viable option. Water Sewage & Effluent (December).

Botha J & Pretorius WA (1998). Die uitvoerbaarheid van dubbelwater-voorsieningstelsels. Water Research Commission Report KUV 113/98.

Garies Local Authority (2000). Integrated Water Services Development Plan: Starter Requirements : Focus on Demand Management. DWAF and Octagonal Development CC.

2.11 Intermittent Supply Rationing

2.11.1 Application

This distribution management tool may need to be considered in cases where the water demand is in excess of the water available at source or from a particular water distribution reservoir. It can also be considered in areas where the water demand needs to be reduced to cut operational costs. The method simply involves closing the inlet isolating valve(s) to the selected area of the network for a predetermined period. For large areas, this valve is usually a distribution reservoir outlet valve.

Intermittent supply rationing is most suitable in areas where total water wastage from the distribution system is high. Total wastage comprises wastage from the distribution system, i.e leakage, consumer leakage and other forms of waste.

It is easiest to apply in areas where no water point flow control devices have been installed to deliver a fixed maximum amount of water to individual customers. If such flow control devices are not adjusted, customers with these devices fitted will be further rationed unjustly.



2.11.2 Regulatory and Consumer Service Considerations

The draft regulations relating to compulsory national standards, issued in terms of section 9(1) of the Water Services Act 1997, state that no customer is to be without a water supply for more than seven full days in any year (see regulation 3(b)(iii)). To maintain minimum standards, WSIs must ensure that at least one complete flow no-flow cycle takes place every 24 hours rather than, say, every 48 hours. Thus, a cycle comprising a flow period of 16 hours followed by a no-flow period of 32 hours is not permitted in terms of the regulations whilst a flow period of 8 hours followed by a no-flow period of 16 hours is permitted, provided all the other requirements of a basic water supply service are met.

As the flow period per day decreases, the peak water demand from the system will rise, and the pressures in the system will fall, until customers at or near the system’s critical pressure point will not have access to water for a part of the flow period. It is therefore essential that the flow period is long enough to allow customers access to water for the full flow period and that the minimum flow of water from shared access points is not less than 10 litres per minute (see regulation 3(b)(i) relating to compulsory national standards).

Whilst intermittent supply rationing is introduced to control the water demand in a distribution system, or an isolatable part thereof, it still generally allows customers with unregulated household connections to access an amount of water in excess of any free basic amount. If this excess amount is such that the WSI needs to recover the cost, it is recommended that payment be based on a graded flat rate system which makes use of bulk water meters to calculate the total revenue to be raised. For more detailed recommendations on introducing a graded flat rate payment system see section 5.3 of “Prepayment water meters and management systems: a booklet for local authorities and community institutions” Department of Water Affairs and Forestry (DWAF) April 2001. Where a household already has a meter and there is evidence that the discharge of air through the meter is causing it to over register, the customer should be asked to pay the graded rate or the metered consumption, whichever is less.

2.11.3 Methodology and Procedure

Before intermittent supply distribution management is introduced it is important for the WSI to clarify its aims and to have a reasonable understanding of both its customers and the distribution system. For example are there any non domestic customers who need an uninterrupted 24 hour supply? What is the total inflow to the system each hour over a 24 hour period? This allows the WSI to calculate the maximum water saving possible from shutting off the supply over different time periods.

Further analysis of the system and, in particular, of the minimum night flow, will help the WSI to estimate what percentage of the maximum savings are likely to be transferred to water usage at another period, after intermittent supplies have been introduced. For example a high minimum night flow, with low explainable normal night use, indicates high combined losses from pipe leaks, pipework fittings and customer fittings. This minimum night flow demand, which is wastage, will not be transferred, if intermittent supply rationing is introduced. Low minimum night lows indicate low wastage and means that customers may transfer water usage to other times.

If it appears that intermittent supply rationing on its own is not going to reduce the demand sufficiently, a WSI can consider combining this management tool with other methods of reducing the demand, such as placing restrictions on the use of hoses.

After clarifying its aims and estimating the number of hours per 24 hours that the water needs to be shut off, the WSI needs to discuss the implementation strategy with its customers. Care needs to be taken to check if there are any customers that will be more than inconvenienced by the proposals.



The hours of shut off also need to be discussed. In areas with shared standpipes, customers often take the opportunity to encourage as much water collection outside school hours as is practical. For example water demand may be remarkably constant from 6am through to 8pm, but when told that the WSI is planning to supply water for 7 hours each day from 8am to 3pm, they may recommend that Monday to Friday during school terms the hours be changed to 3 hours in the morning from 5am to 8am and 4 hours in the afternoon 3pm to 7pm.

Customers are also likely to ask about longer term plans. It is important that WSIs answer such queries honestly and thoughtfully, so that they do not make promises they cannot keep. This means having a good understanding of all the other water demand management and cost recovery techniques, so that they know what types of systems and actions are likely to be appropriate for any future upgrading that is to be implemented: refurbishment, pressure management, equity valve or in tank flow regulators used in conjunction with yard or roof-mounted tank, conventional metering, conventional metering combined with an electronic maximum daily quantity regulator, prepayment meters with or without a maximum daily quantity regulator. Customers should not be left with the impression that intermittent supply rationing is only a short term interim measure until all individual households connections are fitted with conventional water meters, if in fact such a solution would be inappropriate and therefore is unlikely to be implemented.

For customers with individual household connections the introduction of intermittent supply rationing may mean having to learn how to store water hygienically. The provision of appropriate education in this respect is also required in terms of draft regulation 3(a) relating to compulsory national standards.

After these essential preliminary steps have been taken the WSI will be ready to implement the intermittent supply rationing as follows:

Step 1 Shut the selected isolating valve(s) at the agreed time. As the valve gets close to the fully closed position, close it more slowly to prevent dangerous water hammer upstream of the valve. There will only be more than one valve to close in instances where there is more than one valve feeding the system to be controlled.

Step 2 Re-open the selected valve(s) to refill the pipelines at the agreed time.

Step 3 Ensure the pipelines are refilled slowly, so that they are not damaged by water hammer as the refilling process ends.

Step 4 Especially in the early days, the system should be monitored to ensure that no unintended outcomes have occurred: e.g. excessive queues at shared standpipes or customers near the critical pressure points being deprived of water for additional periods because of an excessive peak demand.

Step 5 Monitoring is also necessary to check that the WSI’s objectives have been met.

Step 6 Lastly, the quality of the water towards the end of the distribution system needs to be checked occasionally to ensure that no poor quality water is being sucked into the pipelines whilst they are not under pressure.

WSIs need not allow these water hammer and water quality warnings to discourage them unduly from using intermittent supply rationing. It has been used successfully for several years on a number of remote community-operated schemes in Northern Province.



2.11.4 Advantages and Disadvantages

Advantages

Once customers agree to its introduction, intermittent supply rationing can implemented at very short notice at minimum cost.

In areas where the water wastage is high, the demand for water can often be halved by intermittent supply rationing.

Disadvantages

The supply of water intermittently allows air to enter the pipelines and accumulate during the period feed water is shut off. After reconnecting, ideally all the accumulated should leave through air release valves within the pipe network, however, this is often not the case, and instead some of the air passes through consumer water meters. If this occurs, the flow of air through the meter causes it to over register and the customer is over-charged for water taken.

There is no fire protection water available during the period the water is switched off.

2.11.5 Examples

Northern Province

A number of remote communities in Northern Province have had stand alone reticulated schemes operated by the communities themselves (see Department of Water Affairs and Forestry (DWAF) 1997, pp 33 & 34). All these schemes, which supplied water to customers through a limited number of shared standpipes, were operated on an intermittent supply basis, with water being available fairly regularly in the morning, and again later in the afternoon and evening, for a total of up to 12 hours per day. The reasons these communities operated their schemes on an intermittent supply basis varied from scheme to scheme but was always for one or a combination of these three reasons:

1. Operating the scheme in this manner reduced running costs by curtailing demand and water losses.

2. The water source or pumping equipment could not deliver the total un-rationed demand. Water was therefore only made available when there was water in the distribution reservoir. This manner of operation helped to ensure that all customers had equal access to the limited water delivered by the system.

3. Organising pump operators to operate the pumping equipment on a semi-continuous basis, including overnight, to ensure that the full un-rationed demand could be met proved more difficult than organising the limited set hours for water availability.

Odi Retail, North West Province

Since the introduction of the free basic water policy in July 2001, many of the larger municipalities have indicated that they can afford, in the medium term at least, to supply all households with 6 kilolitres of water per month free. However, many poor urban families within these municipalities, with unregulated un-metered house connections, are using up to 20 and 25 kilolitres per month and paying a low flat rate for this water rather than paying on a consumption basis (Hemson 2001). This is threatening the financial viability of the free basic amount of water policy in these larger municipalities.



In many instances, intermittent supply rationing could be used to reduce the free water delivered to around the 6 kilolitres level. This was done in one of Odi Retail’s peri-urban supply areas by shutting off of the supply to the villages for 36 hours out of every 48 hours. This was undertaken after an extensive cost recovery and awareness campaign and with the co-operation of the community.

CHAPTER 3

CONSUMER DEMAND MANAGEMENT



CHAPTER 3: CONSUMER DEMAND MANAGEMENT

3.1 Introduction

This chapter of the guideline focuses on household water use, but the technical measures described are equally applicable to employee water use in commercial and industrial establishments, in washrooms and toilets.

Of the four phases of the water utilisation cycle that the structure of this guideline document follows, consumer demand management is the phase where social awareness and education programmes have the greatest role to play. The “technical” measures that are dealt with in this chapter must be accompanied by and be integrated with a complementary programme of social awareness and education, the basic principles and components of which are elaborated in Chapter 5.

It is a necessary baseline for the development and relevant targeting of any type of consumer demand management measure to understand the patterns of consumer use amongst different categories of consumer, i.e. how much water is used for what purposes and the nature of the proportion of consumption that is waste. Refer benchmark consumption breakdowns given in Volume 2 sections 2.5.5 and 6.2.2 and Tables 6A and 6B. Further targeting at an individual consumer level may be appropriate by reference to consumer billing records, assuming reasonable reliability of the consumer meter stock.

Clear definitions of volumes of water may be necessary, as consumers experience great difficulty when volumes of water are quoted in litres or kilolitres. Rural communities are familiar with 25 litre containers, and thus volumes of water should be explained as follows:

• 200 litres of water equate to 8 no. 25 litre containers full of water, and

• 1 kilolitre of water equates to 40 no. 25 litre containers full of water

The more affluent communities, including urban communities, may be familiar with litres and 1000 litres, but may not necessarily equate 1 kilolitre to 1000 litres. The definition of a kilolitre should therefore be spelt out clearly.

The linkage between the container size and free basic water must also be clarified. This is particularly important amongst communities that consume less than 200 litres per household per day or less. In these instances, there should be no charge for water consumed. The WSI is therefore burdened with the cost of any water lost through leaks or consumer over-usage.

Urban consumers receiving their free basic allocation invariably pay for all water consumed, through the rising block tariff. If the consumers demand more than their free basic share per month, then any water lost internally is paid for at the highest scale of tariff they are billed for in the billing cycle. For example, if a consumer uses 30 kilolitres in one month, and 5 additional kilolitres are lost due to internal leaks or wastage, then the consumer may expect to pay:

• R0.00 for the first 6 kilolitres

• R 5.00 per kilolitre for the next 24 kilolitres

• And R 5.00 (or more) per kilolitre for the last 5 kilolitres wasted or lost

Communication with consumers must use water

volume units which they understand and can relate to



The basic objective of any consumer use reduction initiative is to change the habits and practices of consumers such that they use less water, without them having to experience any significant reduction in quality of life.

Table 3A lists the range of measures that may be employed in reducing consumer use.

Table 3A: Consumer Use Reduction Measures

Type of Measure Sub Options Education & Awareness

WC – “Torbeck” valve WC – dual flush WC – cistern dams / volume reducing devices clothes washing machine dish washing machine taps shower heads

Water Efficient Appliances

thermostatic mixing valves percussive & electronic taps urinal flushing controls Waste Control Fittings leak detection and shut off devices rainwater harvesting Reclamation and Re Use grey water recycling

Consumer Leak Repairs non pressure-compensated flow control device pressure compensated flow control device single consumer unit batch volume control device storage tanks non-prepayment volume control device prepayment water meters

Delivery Point Water Management

shares connection batch volume control devices tariff structures Financial Management credit control

3.2 Water Efficient Appliances and Installations


Any new hot and cold water services installations should be designed according to “waterwise” good practice. This is obviously a more cost effective approach than retrofitting a few years later. Waterwise domestic plumbing “designs out” such defects as dead legs, imbalances in hot and cold pressures that may cause overflow, and incorrect pipe sizing.

A wide range of low use fittings are available as listed in Table 3A. Internally the water used for flush toilets generally offers the greatest scope for savings, by reducing cistern volume in combination with dual flush mechanisms. Low cost cistern volume reducing bags are available, but as with other similar measures, there is a limit to the extent to which cistern volume can be reduced without affecting the flushing performance of an existing pan that was designed for a larger cistern.

In commercial buildings, urinals should be fitted with controllers that eliminate flushing when the toilet is not in use.

User acceptance of low use taps and showers is aided by well designed spray heads that give good wetting properties.



Opportunities for water saving are also found in hot water systems, such as point of use heaters. These offer a secondary benefit both to the consumer in lower electricity bills, but also in saving power station cooling water.

Drip irrigation systems offer the greatest water use efficiency in garden watering, but relies upon the consumer getting the installation right and using it correctly.

All water fittings, whether of low or high use type, experience deterioration with constant use (and abuse). Planned maintenance programmes in the non domestic sector need to be encouraged by WSIs, as well as waste minimisation initiatives.

3.2.2 “Waterwise” Domestic Plumbing

As required by the Regulations promulgated under the Water Services Act (Act 108 of 1997), all installations should be designed to comply with the provisions of the applicable SABS Codes of Practice. In particular SABS 0252: Water supply and drainage in buildings and SABS 0254: Installation of storage water heaters.

To be regarded as waterwise, an installation should use significantly less water than traditional installations, whilst not significantly affecting the lifestyle of the users and at the same time being perceived by householders as “value for money”. Matters that should be considered include:

� Installation design

� Choice of components

� Cost of components

� Quality of the components (see the below concerning the SABS and JASWIC)

� Quality of workmanship

In building design, traditionally the structure of the building is developed before and takes precedence over the services. Waterwise design requires that the plumbing design is determined along with the design of the structure, so that plumbing features that have negative consequences for water conservation are avoided.

“Dead legs”

A significant cause of water wastage in domestic dwellings is the “dead leg” in the hot water system, i.e. a long pipe run from the water heater to a supply point. The water that has cooled in the pipe since the previous draw is run to waste before hot water appears at the tap. As well as waste of water there is waste of energy. This waste of energy indirectly wastes more water - generating 1 kWh of electricity uses about 3 litres of water so that by avoiding the energy loss that water is also saved.

“Dead legs” should be avoided by careful siting of the components of the hot water system and, if a remote hot water supply point is essential, then some form of local heating device, such as an instantaneous heater, is preferable. All exposed hot water pipe work, particularly in roof spaces or on outside walls, should be suitably lagged to minimise heat loss.

Pipe sizing

Careful design of the system to arrive at optimum pipe sizing according to good design practice is essential if many of the water conservation measures mentioned later are to perform adequately. Flushing valves, for example, normally require a minimum of 25 mm diameter to achieve the necessary flow rate to operate efficiently.

Adopt “waterwise” good practice in the design of

new buildings



Water pressure

The pressure at which water should be supplied by the WSI has now been fixed, by Regulation, at not more than 900 kPa, but for WC/WDM should be much lower, ideally in range 200 – 300 kPa according to topography and building height. Water supplied to a point of use at a higher pressure than necessary causes wastage because more water is discharged from the tap or other fitting in a given period of time than is necessary to perform the function such as the rinsing of hands or crockery. A lower pressure will, in most cases, not detract from the utility of the supply.

Too high a pressure also increases the amount of water lost due to leakage. Whilst adequate maintenance should be done to prevent leaks, high pressures do make the problem worse when they do occur.

Pressure can be controlled by the installation of a pressure-reducing valve (PRV), preferably installed at some point close to where the supply enters the building. This will also ensure that all water supplies in the building are “balanced” i.e. that both the hot and cold water is supplied at the same pressure. This is necessary to avoid problems with the use of mixing devices, such as showers or taps which, if the supplies are not balanced, can result in water being continuously discharged from the pressure relief valve of the hot water system causing considerable wastage.

If, for some reason, a balanced system is not used, then the use of mixing fittings should be avoided and the use of certain other water-saving devices is precluded as will be discussed later.

3.2.3 Choice of Specific Components and Appliances (New Build or Retrofit)

Garden use, toilet flushing and personal hygiene are generally the largest water demands in the household situation.

Although there are many components that can affect the consumption in a domestic water installation, those related to these three demands affect it most significantly. If these are chosen carefully then in most cases this will be all that is necessary.

Toilet systems

The most common toilet system for domestic use is that which uses a cistern. For water conservation a low-volume dual-flush type of less than 7.5 litres should be used. It must be emphasised that a low volume cistern must be used with a pan designed to function satisfactorily with lower flush volumes. The use of the low-volume dual-flush or multi-flush systems is one of the areas most likely to be addressed in any new regulations or by-laws.

A low cost means of reducing cistern capacity, that, unlike “brick in cistern” is designed for the purpose, is the cistern dam / volume reducing bag (proprietary name Hippo), as shown in Figure 3.1. The pre condition of pan suitability also applies in this case.

Figure 3.1: WC Cistern Volume Reducing Bag

A less commonly used flushing system, in the domestic situation, is the flushing valve. If these are used then they should be adjusted to use as low a volume as possible and, once again, a proper choice of an appropriate pan must be made.

Focus on garden use, toilets and personal washing



In commercial buildings, a common source of significant quantities of waste is the urinal cistern, which, in its standard form, flushes regularly whether or not the urinal has been used, typically using 500 litres per day. Pressure or infra-red controlled cisterns eliminate this waste, use being limited to 4.5 litres per flush. The use of uncontrolled auto flushing mechanisms are being discouraged as their use are not regulated by demand.

Taps

Taps are probably the most commonly used terminal water fitting but are generally chosen on cost or aesthetic criteria. Water conserving spray or aerator controlled taps are designed to give comparable levels of utility whilst using less water. Taps fitted over wash-hand basins do not need to provide a high rate of flow. The effect of the aerator / flow controller is to mix air with the water to increase its bulk, whilst reducing the flow to a level which normally would probably be unacceptable to most users. However the wetting effect is increased by the aeration to the extent that it

may be even better than when using a standard tap.

Another option is to fit a purpose designed flow regulator, as shown in Figure 3.2. Many taps which appear to be fitted with a flow restricting device on the outlet may only have a flow straightener to reduce splashing, but in many cases the straightener can be easily replaced by an aerator / flow-controller.

Figure 3.2: Tap Flow Regulator

There is no advantage to be gained in fitting flow controlled taps to baths.

Mixing taps are frequently used in the kitchen and also over wash-hand basins, baths and in showers. If these are to be used then it is essential that the hot and cold water supplies be balanced, as previously mentioned. If this is not done, and there is a significant difference in the hot and cold-water pressures, cold water will push into the hot system and cause a discharge to occur from the pressure relief valve or pipe of the hot water system. This water will then run to waste.

Another option, in suitable situations, is the use of a metering tap, which delivers a pre-determined but adjustable quantity of water when operated.

Showerheads

Low flow rate showerheads should be specified for all new installations. Many showerheads deliver water at flow rates in excess of 16 �/min. An excellent shower can, however, be obtained with flow rates around 10 �/min. A number of shower heads having flow rates as low as 4,5 �/min are available and their use will show a significant water saving. Care must be taken though, to ensure that the plumbing system design is suitable for their use. The pressures must be correctly set and these fittings should only be used on a balanced pressure system otherwise the same problem will occur as with the mixer tap described above. The droplet size created should also be considered, as this should not be too small. Showerheads need to be specially designed for low flow rates to ensure that the spray pattern that they produce is correct. Most heads designed for high flow rates will not perform adequately on low flow rate systems



Water heaters

If the most is to be made of the available options for water conservation, then the main water heater in the system should be of the pressurised type rather than a combination heater. The older combination type has a much higher heat (energy) loss, which also causes water wastage as described earlier, and will not permit the use of mixing taps or low flow shower heads. Users also frequently complain because the hot water pressure is generally very low compared to the cold water pressure. This makes it very difficult to set the temperature when using the shower.

Instantaneous water heaters local to the point of use avoid the “dead leg” water loss, an added advantage being that only one (cold) pipe run is necessary. In suitable locations, solar heating with electrical back up may be an option worth considering. The saving of energy will not only reduce the electricity charges but also save the water, which would have been needed in the generation process.

Important note: For safety reasons it is essential that all pressurised water heaters are installed by suitably qualified persons and in accordance with the requirements of SABS 0254. In particular the required safety devices must be installed. Heaters designed or intended to be installed as vented systems should not be installed in a manner that can result in them becoming pressurised.

Clothes washing machines and dish washers

There is a significant variation between the volumes of water used by different models - 60 � to 240 � per standard 7 kg load. In general, front-loading machines use less water than top-loading machines.

Leak detection and flow shut-off device

This device, shown in Figure 3.3, comprises a sensor, which monitors the duration of flow every time water is used, and a valve which stops the flow when a pre-selected maximum flowing time is reached. In normal use, the flow pattern is characterised by intermittent start and stop when a water fitting is used and the flow is uninterrupted during the draw period. But where there is a continuous flow greater than the selected time, which is the character of a leak, the shut off valve is actuated and the supply is automatically shut off.

Figure 3.3: Leak Detection and Flow Shut-off Device

Garden irrigation systems

It is a common misconception that by installing an irrigation system people will save water. This will only be true if it is planned well, particularly in combination with a water-wise garden (Information on water-wise gardening can be obtained, on request, from the offices of the Department of Water Affairs and Forestry.).

Most irrigation systems seem only to make the watering process more convenient because little attention is given to the actual watering needs of the plants. The pipe sizing and type of spray must take this into account.



The most efficient systems use variations of the drip-irrigation method, which ensures that the correct amount of water is delivered to the plants and that evaporation is virtually eliminated. The linkage of soil moisture measurement instruments to automatic irrigation systems can help avoid over-watering.

When a system is planned consideration should also be given to the use of grey water and harvested rainwater (refer section 3.4).

SABS/JASWIC specifications

The South African Bureau of Standards (SABS) and the Joint Acceptance Scheme for Water Installation Components (JASWIC) are both concerned with quality standards. Both seek to maintain the observance of reasonable minimum standards of quality of the products which they have evaluated. SABS is concerned mainly with products of local manufacture but covers a wide range of technical products and practices. JASWIC confines its activities to products related to the water supply industry but evaluates all water installation components, from whatever source and country of origin against consistent agreed quality standards. Products which either bear the SABS Mark or are listed by JASWIC meet recognised standards of quality and should provide a trouble free service life.

3.2.4 Procedure (Retrofit Project)

On average it is estimated that by replacing existing plumbing fittings with more efficient fittings the total consumption can be reduced by 14% or 50% of the domestic household and commercial water use. A retrofit project should be undertaken in a systematic manner with the participation of the relevant consumers as the main stakeholders. A retrofit project is likely to be a more expensive way of making water savings than public awareness and education campaigns or tariff management and it therefore may be considered to be more appropriate in a second phase of water conservation measures. However this will be a matter for consideration of the local circumstances, possibly in conjunction with pilot trials.

Step 1 Make preliminary assessment of scope for water savings by reviewing consumption data against benchmark levels.

Step 2 Identify the stakeholders and prepare draft action plan.

Step 3 Discuss with the stakeholders and get their feedback / agreement in principle.

Step 4 Undertake buildings survey and review preliminary savings assessment.

Step 5 Draw up retrofit schedule based on benefit – cost considerations.

Step 6 Finalise plan with stakeholders.

Step 7 Implement the plan.

Step 8 Review the results against target savings and note lessons to be learned for future projects.

Step 9 Devise and agree sustainability strategy with stakeholders.


As far as the use of efficient appliances and components are concerned, there is little or no risk involved in their use if quality components are specified. The nature of the components also provides a high level of confidence that the reduction in consumption anticipated will be achieved



Box 3-1 Case Study: 38 Wale Street, Cape Town – Retrofit Project 2000 - 2001 The building has 11 stories plus two basement floors partially usedfor parking. There are shops, restaurants and cafés on the groundfloor with offices and some parking on the floors above. Several floors are occupied by staff of the CCTMC and the remainderby independent accounting firms, attorneys and the like. A water audit of the building was undertaken and an action planprepared prior to arranging for a plumbing contractor to undertakethe work. A data logger was fitted to the meter installed on themunicipal water connection some time before commencement andremained in situ until after completion. The following work was undertaken: • Replaced roof storage tank inlet valves • Adjusted all flushing valves • Replaced all old worn flushing valves • Serviced all cisterns • Eliminated automatic urinal flushing cisterns • Fitted spray type flow controllers to basin taps

The following results were obtained: • Minimum night flow reduced from 1,91 m³/h to zero • Maximum flow reduced from 5,09 m³/h to 3,32 m³/h • Mean daily demand reduced from 2,73 m³/h to 0,94 m³/h • Approximate annual savings of R52 059 for an expenditure of R78 000 • Payback period approximately 1,5 years

m³/h

0.00

1.20

2.40

3.60

4.80

6.00

Fri,02/6/ Sat,03/6/ Sun,04/6/ Mon,05/6/ Tue,06/6/ Wed,07/6/ Thur,08/6/Time period: 02/06/2000 12:30:00 AM - 08/06/2000 11:30:00 PM Mean interval: 15 minutes

Con

sum

ptio

n - 4

55m

3

Min - 1.91m3 Max - 5.09m3 Average - 2.73m3/hC-TOWN/WALE-ST/101150

m³/h

0.00

0.80

1.60

2.40

3.20

4.00

Thur,19/4/ Fri,20/4/ Sat,21/4/ Sun,22/4/ Mon,23/4/ Tue,24/4/ Wed,25/4/Time period: 19/04/2001 - 25/04/2001 11:00:00 PM Mean interval: 15 minutes

Con

sum

ptio

n - 1

57.6

1m3/

h

Min - 0m3 Max - 3.32m3 Average - 0.94m3/hC-TOWN/WALESTR/101142

Flow pattern before project

Flow pattern afterproject



3.2.6 Planned Maintenance

The results of a large number of water audits, conducted across a wide spectrum of consumer types in the Cape Town Metropolitan Area during 2001, showed that the lack of adequate maintenance of water installations is a major cause of water wastage. In order to remedy this situation it is suggested that WSIs should either encourage or require consumers, particularly those in the industrial and commercial sectors, to develop and implement planned maintenance programmes. These programmes should include key-performance indicators to enable the effectiveness of the programmes to be verified.

3.2.7 Waste Minimisation in Industry

It is outside the scope of these guidelines to cover waste minimisation in industry, but WSIs should be aware of the major savings that are achievable in industries that use drinking quality water for processes. Waste minimization is achieved by a combination of:

� Careful design of the water utilisation cycle within the premises, including re-use opportunities, maintaining separation of different quality streams for that purpose

� Use of more water efficient processes and technologies

� “Good housekeeping” such as fitting trigger gun nozzles to hoses, etc.

Reference should be made to the companion volume of guidelines on WC/WDM in the Industry, Mining and Power sectors.

3.3 Water Conserving Habits and Practices

These are generally well known and feature in most social awareness and education campaigns:

� Fix leaking taps and running cistern or header tank overflows (ball or lift valves)

� Shower rather than bath

� If dual flush cistern fitted, use it

� Use basin plugs taps to limit water used for washing rather than under running tap

� Close tap while brushing teeth

� Use bucket and brush rather than hose for washing vehicles

� Irrigate garden early morning or evening to minimise evaporation losses

� Cover swimming pool when not in use to minimise evaporation loss

� Lower water level in swimming pool slightly to reduce amount of water lost in splashing

3.4 Reclamation and Reuse

3.4.1 Secondary (Grey Water) Use

There are now a number of systems and devices, which permit the re-use of water for secondary purposes, such as garden irrigation and toilet flushing, and serious consideration should be given to their use when designing any new water installation.



A toilet cistern is available which delivers the water entering to refill the cistern, after the toilet has been flushed, via a small hand basin let into the lid, for hand washing. Only after this initial use does the water enter the cistern to be re-used for the next flush.

The secondary use of water for above ground irrigation is not recommended as this is considered by some authorities to be undesirable for health reasons.

3.4.2 Rainwater Harvesting

Many buildings, particularly in the industrial and commercial sectors, have large roof areas that are suitable for the collection of rainwater. This water can be used for various purposes including the augmentation of grey water collected for use in the irrigation of landscaped areas and in water-wise gardening projects. It should not be used for drinking or sanitary purposes.

The quantity of water that is available for collection from an impervious roof is the total quantity of the rain falling on that roof area during the rainy period less losses due to evaporation, splashing, overflowing of gutters, etc. Provided gutters are installed properly, designed to collect the roof run-off from the average storm, and are regularly maintained and unblocked, a run-off coefficient of 0,90 or above should be achievable. On that basis, a roof area of 10 m² will yield 8 litres of rainwater for each mm of rainfall.

Example: A house with a roof plan area of 50 m² (horizontal projection) located in an area with a mean annual rainfall of 900 mm has the potential to collect 50 x 900/1000 x 0,90 = 40 kilolitres of water per year, using a run-off coefficient of 0,90.

Usually it is not economically feasible to provide sufficient storage to collect all the run-off from a roofed area over a one-year cycle. Instead the required storage capacity of a rainwater tank is calculated with reference to the demand, and this is compared with the estimated supply to see whether the latter is adequate. The capacity of the tank should be calculated as follows:

Tank capacity = daily water demand x longest expected period without adequate rain.

3.5 Consumer Leak Repairs

Traditionally WSIs in South Africa have never undertaken water installation, maintenance or repair work on private property, being not unreasonably considered by the WSI to be wholly the responsibility of the owner and / or tenant. Water wasted as a result of leakage on the consumers premises has usually been considered as “consumption”, being paid for in the same way as beneficial water use. In some instances local by-laws made provision for the WSI to undertake repairs to reduce wastage in cases where consumers may have been instructed to undertake repairs but had not complied. However, such provisions were rarely enforced. Seen from the WC/WDM perspective, consumer leakage is just another form of excess consumption that offers scope for reduction, but requiring different solutions to those employed in the minimisation of inefficient or wasteful use.

Minimum night flow readings do not distinguish between

infrastructure and consumer leakage

It makes sense to tackle them concurrently

Irrespective of the legalities, the WSI must take ownership of the problem of consumer

leakage



A consumer leakage reduction programme can most readily be implemented when there is an active leakage control regime in place on the distribution network. Consumer leakage will show up on the night flow readings in just the same way as leakage on the network and will be identified as such when leak location is undertaken. Assuming there is a functioning consumer meter, it is a very simple matter to confirm that there is a leak on the consumer’s premises.

Consumer leakage reduction may also be seen as a complementary activity to the monitoring of consumer meters for malfunction / degradation referred to in sections 2.1.5 and 2.8. A sudden increase in meter reading is a strong indicator that a leak has occurred and should lead to further investigation.

The case study summarised in Box 3-2 is an example of the implementation of the above methodology.

Box 3-2: Case Study: Consumer Leak Repairs, Site C, Khayalitsha, Cape Town

The site selected for the project was Site C, Khayalitsha, shown on the above plan at the intersection of the N1 and R300. Water is supplied through a single 350 mm main.

Objectives:

• To determine the level of leakage on private property

• To determine if there is a correlation between the level of water reticulation night flows and the sewer flows

• To determine the condition of private the private water installations

• To carry out any necessary repairs to the private installations

• To reduce the general level of leakage from water installations in Site C



Work carried out:

• The meter supplying the area was fitted with a data logger which remained in place throughout the project

• The sewer flows were monitored throughout the project

• The water installations were audited and inspected for leaks

• The necessary repairs were effected

As a result of the audits it was found that there was generally a poor level of maintenance of the water installations. The individual problems found and the number instances of each are shown in the following table: Item Number found

Properties 4172

Meters found 1592

Meter function problems 9

Incorrect installations 56

Float valves reset 4163

Waste fittings leaking 142

Blocked 21

Loose cisterns 94

Taps leaking 181

Broken WC pans 9

Float valves broken 104

Pan connectors leaking 43

Tap elbows leaking 27

Rubber cones leaking 8

110 mm PVC bends leaking 7

Beta valves broken 109

Beta valves missing 5

Tap handles broken 87

The repairs were undertaken during the period July to August 1999. The graph below shows that the average flow rate dropped from approximately 450 m³/h to approximately 310 m³/h. A reduction of about 31%. From the monitoring of the sewer flow rates it was also found that there was a strong correlation between the reduction in the supply main flow rate and the sewer flows. It was, therefore assumed that most of the on-site leakage was discharged to the sewerage system.

Two problems arose toward the end of the project. It had been intended that the consumers should acknowledge that the repairs had been effected and that they would assume responsibility for the maintenance of the water installations in the future. However, they were reluctant to do this. Some consumers, on realising that their neighbours had had broken WC pans replaced at no cost, deliberately damaged their WCs in order to receive the same consideration.



Procedure: In order to implement a policy for the reduction of consumer wastage the following procedure is recommended:

• Identify the objectives of the project. Objectives should include identification of consumer usage patterns, identification of areas of consumer wastage and agreement on benchmarks.

• Identify the stakeholders for consumer wastage reduction, and form the relevant forums or steering committees. Consider the involvement of forum mentors, or experts in the fields of consumer waste reduction.

• Prepare action plans for consumer wastage reduction. These will include education and awareness campaigns, workshops on leakage identification and repairs and maintenance of domestic plumbing in sound and reasonable condition.

• Discuss the action plans with the stakeholders, and prioritise the action plans in terms of the objectives and targets. Obtain agreement of the stakeholders.

• Implement the action plans. The education and awareness campaigns should precede the leak detection and repairs component of the project. if necessary, assist householders with leak detection and repairs.

• Quantify the results in terms of consumer wastage reduction. Results should also include other benefits to the stakeholders, e.g. delay in capital investment for infrastructure, consumer savings, resulting in greater disposable income etc.

• Measure the results against the original objectives (benchmark figures), and determine the payback period of exercise.

The education and awareness campaign should include simple exercises that consumers may follow in leak identification, for example:

• Reading of water meters during periods of low consumption (late at night and early the next morning) and determining the difference in readings, which will equate to water loss plus night time consumption (toilet flushing and drinking water).

• Listening to pipes for leaks.



• Identifying unusually “green” areas in gardens.

• Looking for damp penetration on walls, where pipes are chased into walls.

• Identifying for visible leaks where pipes are above the ground, or mounted on walls.

• Inspecting sewer pipes for continuous clear water flows during periods of non consumption.

Risk Factors / Confidence One of the major problems is illustrated by the case study above in that vandalism may be attempted in order to ensure replacement of facilities by the WSI. There is also no certainty that the owners/consumers will maintain their water installations after the project has been completed. A detailed field survey should be carried out, and a database built of all properties and the condition of water installations. This database must be made accessible to the stakeholders, who could assist in minimising vandalism through direct communication or intervention. The consequences of vandalism must also be made clear to the communities at the commencement of the project.

3.6 Delivery Point Water Management


Delivery point water management comprises any method with which the WSI limits the amount of water that is supplied to an individual consumer by introducing a hydraulic restriction device. In a traditional system, the consumer effectively has unrestricted access from an “open” network that is limited only by the size of the connection and the pressure in the network at that point. For shared connections, it includes any means of regulating the amount of water customers can collect. These methods are used where customers need help to manage their water usage to a quantity they can afford and/or where there is persistent non payment coupled with high wastage.

There are two basic methods and a number of types, as listed below and summarised in Table 3B:

1. Flow control devices

(a) pressure compensated

(b) non-pressure- compensated

2. Volume control devices

(a) batch control with storage tank, single customer

(b) pre-payment water meters, single customer or shared connection

(c) non pre-payment volume limiter



Table 3B: Delivery Point Water Management Methods – Application and Selection

Method / Type Application Features

Flow control pressure compensated

Cost effective for households using between 4 and 15 kilolitres of water per month

Continuous uniform delivery of preset amount over 24 hours

Storage tank with regulator box or in line control valve types

Flow control non pressure compensated

Short term measure only for cases of non payment

Lockable ball valve

Volume control single customer For customers who demand a higher level of service than shared connections but who cannot afford a conventional full pressure or unregulated roof tank connection

Cost effective where average demand from customers paying volume related charges is more than 10 kilolitres per month.

One fill per day of preset amount, being the volume of the storage tank

Volume control pre-payment water meter

Suitable for dealing with high wasteage poor payment situations

Electronic credit control, units vary in their sophistication, e.g. in helping customer to manage consumption, e.g free basic water.

Requires computerised management system.

Volume control (pre-payment) shared connection

Should be considered only after other measures have been unsuccessful or are considered unsuitable in local circumstances

Mechanical fixed delivery volume and electronic user choice delivery volume types available.

Volume control non pre-payment Suitable for poor paying customers supplied with water at the highest service level.

Add on solenoid valve and timer to conventional customer meter.

Flow control devices are generally cheaper to install, administer, and maintain. Because flow control devices reduce the peak demands in distribution systems, which therefore can have a lower hydraulic capacity, they offer capital cost savings in the design of new systems or the reinforcement of existing reticulation networks. For example, if a system was originally designed to cater for shared connections only, it may be possible to upgrade the service level to individual household connections without any major improvements to the infrastructure downstream of the service reservoir. (The increase in average daily demand may, however, require augmentation of the supply.)

The resultant lower pressure service delivered to customers, at below the pressure in the mains, means that more care has to be taken within the reticulation pipework to ensure that airlocks do not occur.

Volume control devices allow a customer to take delivery of water at full pressure and without flow regulation up to a set volume, usually over a fixed period of time, commonly 24 hours or one month. Generally, they cannot be installed without a conventional water meter.



This means that a connection fitted with a volume control device is inherently more expensive to install and maintain (but not necessarily to administer) than a conventional metered connection. However, unlike flow control devices, for most designs, the water is delivered at the full reticulation pipework pressure. As a result, customers are unaware of volume control devices installed in their service connection unless, or until, they try to use more water than the controlled amount. When the set volume is reached, all water is normally cut-off until the start of the next period.

3.6.2 Pressure Compensated Flow Control

A pressure compensated flow control device allows a customer to take delivery of water at essentially the same flow rate regardless of the pressure in the WSI’s reticulation pipework. There are two types:

i. A customer storage tank fitted with a regulator box fitted with a break pressure float valve on the inlet and a constant head orifice on the outlet.

ii. An in-line valve similar to a drip irrigation emitter, but capable of working at pressures up to at 1000 kPa

Storage tank with regulator box

This method supplies the consumer with an agreed maximum quantity of water per day, delivered at a uniform rate over a 24-hour period, the storage tank allowing the household to use the water when it chooses. The maximum amount of water delivered to the storage tank is fairly accurately controlled. The flow into the regulator box and storage tank is at a very low rate and is generally too low to be registered accurately using conventional domestic water meters, which are therefore unsuitable. Agreement with consumers on the method of measurement for billing or calibration of the regulator box may be necessary.

With a very skewed daily demand curve, a storage tank can supply a household with up to 2,5 times it volume. With a moderately skewed demand a storage tank can supply up to 3,75 times its volume (Hazelton and Kondlo 1998). This means that a standard 200 litre plastic drum can safely be used for demands up to 500 litres per day (15 kilolitres per month) and can often be used for demands up to 750 litres per day (22.5 kilolitres per month).

There are two basic methods of controlling the quantity of water delivered per day at a uniform rate over a 24-hour period to the agreed maximum quantity. The first is to install an on site control device in a regulator box in the top of the customer storage tank. The regulator box comprises an inlet fitted with a break pressure float valve and a constant head outlet fitted with an orifice.

Equation

Maximum quantity of water delivered per day Q = k*(d^2)*(h^0,5) litres/day

Where k is a constant

d = the diameter of the orifice, mm

h = the head above the orifice, mm.

The value of ‘k’ will depend on the exact design of the orifice and on the design of float valve. Experiments with a regulator box which maintained a head of 140 mm above the orifice, gave 6,414 as the value of k, thus with that design and a head of 140 mm over the orifice, an orifice size of 1,62 mm would be necessary to deliver a maximum of 200 litres per day.



The pressure compensation is not absolute, as the inlet pressure on the float valve increases, the level of water in the regulator tank tends to rise. Experiments with one make of float valve and orifice sizes ranging from 1,5 mm to 5 mm caused an upward drift in flow of between 2,7 and 6,5% when the inlet pressure was increased from 100 to 500 kPa. Tolerances related to the manufacture of the orifice and to a lesser extent the regulator box and float valve, will also introduce flow variations. Ideally there should be a national standard for such units, that specifies the component and/or complete unit testing required.

Both vertical and horizontal plastic tanks are used. Vertical tanks are usually mounted in a yard close to the ground, on a stand or on wall brackets. Horizontal low profile tanks are mounted inside the house at ceiling height or outside on the roof. In the latter case a light coloured tank helps to keep the water cool, but sunlight may penetrate through the wall of the tank, risking algal growth. This may be avoided by using a double skin tank, black on the inside and light on the outside. The tank material needs to be UV stabilised.

Other details to be carefully considered are:

� Make sure that the regulator box is installed securely in the main tank so that it does not fall into the bottom of the tank even after the lid has been removed.

� Because the outlet pressure is low, many conventional globe valve taps fail to open as the valves get older due to the disc washers sticking to the seats. Plug valves and ball valves are preferred for this reason.

� Inlet pipes should be fitted near the outlet and an overflow provided. To stop insects getting into the tank, the overflow should have a durable fine screen fitted where it can be seen for inspection.

� Particularly with vertical tanks, and where it is difficult to fix the pipes neatly and firmly to the side of the tank so that they do not get damaged, the inlet and overflow pipes should be passed through the tank base with appropriate fittings.

� Tightly fitting tank access covers should be provided to prevent the ingress of dust and insects. The screened overflow pipe acts as a breather to allow air in and out as the tank empties and fills. Tank covers should also provided with locks or tamper revealing seals as required by the customer or WSI, as applicable - removing the orifice, for example, would allow the customer use an unlimited amount of water.

In line pressure compensated control valve

The second method of controlling the quantity of water delivered to an agreed maximum quantity per day is to install an in-line pressure compensated control valve at the customer’s off take. Unfortunately, apart from low pressure drip irrigation systems, South Africa has no experience of using such valves. The main demand for such valves is for the flow range 8 to 21 litres per hour (= 6 to 15 kilolitres per month) and their availability over this range for water scheme operating pressures is low (see DWAF 2001a, for details of some possible suppliers).

A float valve should still be fitted in the storage tank to prevent any water wastage and as back-up should the flexible diaphragm in the pressure compensated flow control valve fail, but it is not an integral part of the control system.



Table 3C: Comparison of Storage Tank / Regulator Box with In Line Control Valve

Storage Tank / Regulator Box In Line Control Valve

Theft / interference

Tank is within customer’s property and more vulnerable to by-passing regulator by making illegal connection upstream

Control valve can be installed at the boundary of customer’s property, less opportunity for by-passing the control device

Component parts

3 component parts to be tested Single device

Access to storage tank

Customer does not have access to the storage tank.

Storage tank is part of customer’s installation.

Flow regulation Once the water level rises above the orifice, the water flow into the tank gradually reduces until it becomes zero at the top water level. This is a significant disadvantage when a regulator box is used with a low profile horizontal tank which does not have an opening of 250 by 150 mm or larger extending adequately above the crown of the tank. In the shallow horizontal tank, the regulator uses up approximately 250mm of storage height, which could account for almost 30% of the storage capacity.

Water fills the tank at maximum regulated flow until the tank is full.

Blockages Less prone to blockage – low head loss through control orifice, larger area than in line control valve for same flow.

More prone to blockage – high head loss, small passage area through the valve.

Reliability Float valve in regulator box more robust than control valve, although after a water supply failure prone to sticking in fully open position.

The flexible diaphragm in the control valve may be more prone to serious failure than the float valve in the regulator box, although is backed up by float valve in the storage tank downstream

Other considerations

If designing a reticulation network to be used exclusively with pressure compensated flow controlled delivery points, hence reducing the hydraulic capacity compared with conventional design, particular attention needs to be given to designing for fire fighting demands, i.e this needs to be designed, rather than the traditional approach of spacing of hydrants and knowing that there will be sufficient in built capacity within the network.

The reticulation system will operate satisfactorily at a low working pressure, thus helping to reduce leakage losses.

3.6.3 Non Pressure Compensated Flow Control

A non-pressure- compensated flow control device delivers water at different flow rates depending on the pressure in the WSI’s reticulation pipework, e.g. a lockable three way shut-trickle-full flow ball valve.

It should be regarded only as a short-term temporary measure if the WSI needs to reduce the customer’s demand for water in the case of non payment and the WSI is not in a position to implement a more permanent solution.



Alternatives would be to cut off the customer’s supply, which should be avoided if at all possible especially given government’s free basic amount of water policy, or introduce intermittent supply rationing (see section 2.7), which could be considered if the demand from the majority of customers has to be reduced.

Two currently available lockable ball valve models deliver water at 8 and 19 litres per hour respectively at a 300 kPa pressure drop. The installation of such a device, on its own, is a harsh action if the customer only has a yard tap.

The tap discharge is only a trickle and the container needs to be brought close to the tap or short hose extension to avoid wind dispersal. The container should have a small opening to avoid dust getting into the water that has been collected. Very often it is also useful to stand the container in which water is being collected in a larger tub or bath, to catch wind blown water or overflows. Regardless of the exact situation WSIs have a responsibility, in terms of the draft regulations under section 9(1) of the Water Services Act, 1997 relating to compulsory national standards clauses 2(a) and 3(a), to provide appropriate education with respect to the collection and storage of water from a health and hygiene viewpoint.

Other factors that need to be noted when installing these devices, are that any grit in the water can block the flow and that meters tend to under-register the amount of water delivered. Blockages can usually be cleared without removing the device by opening and resetting it, but customers cannot do this themselves because the device is normally locked to prevent tampering. In areas where blockages are known to occur, WSI monitors, such as meter readers, should check the devices when they visit properties rather than waiting for a customer complaint.

Although many WSIs have already installed non-pressure - compensated flow control devices, no reports appear to have been produced which give before and after water consumption figures.

3.6.4 Batch Volume Control with Storage Tank (Single Customer)

A household connection batch volume control device allows a customer’s storage tank to be filled with water, manually or automatically, once every 24 hours, the outlet being temporarily closed during filling. By this means the system limits the amount of water delivery per day to the volume of the tank. For the customer, the outcome is similar to a pressure compensated flow control device because the internal plumbing is not subject to the pressure in the reticulation pipework.

Such connections are ideal to cater for customers who demand a higher level of service than shared connections but who cannot afford a conventional full pressure, or unregulated roof tank, household connection.

Because the water enters the tank in an unregulated manner, it is usual to fit the tank with an inlet float valve and a plunger device to seal off the tank outlet valve whilst filling is taking place. The plunger is operated by the reticulation water pressure and once filling is complete a spring returns the plunger to its normal position so that water can be withdrawn from the tank once again (original Durban tank system, see Dbn W&W 1995).

At its simplest, filling can be done manually by a water bailiff filling each tank once a day. In very high density areas Durban Water and Waste has connected up to 30 units to a single off-take point fitted with a water meter and a solenoid valve. This solenoid valve is opened and then closed again automatically by a timer once every 24 hours, for a period long enough to fill all the tanks. Because of the cut-off inlet float valves fitted to the tanks, the pipes from the off-take point are subjected to mains pressure and therefore should be designed and installed accordingly.



Batch volume control delivery does impose its own high peak demand factor. However, especially for automated installations, this peak demand can be set at a time that differs from the peak demand of the rest of the system. This also makes sense so that customers will not have their water cut off during the filling period when they want it most.

Table 3D: Advantages and Disadvantages of Batch Volume Control Devices

Advantages

Easier to administer

Water use is controlled to a consistent maximum amount each month and there are no household meters to be read.

Maximum amount of water delivered can be set equal to the free basic or any other amount agreed between the customer and the WSI. If the amount is more than the basic free amount the customer pays a fixed monthly charge.

In tightly knit communities this means no bills have to be sent to individual customers. Even if bills are sent, for community managed schemes, the bookkeeping associated with fixed monthly payments is much easier than with monthly meter readings for conventional household connections. Up to about 400 connections can practically be administered manually without needing a computer based system.

Good water loss control

Any wasteage will not cause unexpected high water bills for the customer but only a temporary shortage of water until the storage tank refills. This signals the customer that water is being wasted and should prompt action.

Losses from leaks beyond the storage tank will be less because of the low pressure in the customer’s pipework.

Safety Un-pressurised hot water geysers can be used with roof and ceiling mounted storage tanks. These are much safer than the conventional pressurised type.

Disadvantages

Inflexible Unable to supply a sudden unusually high demand without prior special arrangements being made with the WSI, e.g. during weddings or funerals.

Use limitation Not possible to use a pressure hose for washing a car or for watering any parts of a garden higher than the tank.

Customer perception of charge

Customer may be concerned that the fixed charge is based maximum possible consumption rather than actual consumption.

Despite the very positive feedback from customers where these systems have been installed on pilot projects, the fact that such units are only installed in the poor townships does lower their social acceptability, especially amongst the youth. Therefore, until such systems are well-known and accepted as a recognised method of water supply in South Africa, extensive consultation and the installation of a few demonstration units may be required before implementing a large project.

3.6.5 Prepayment Water Meters

All prepayment meters are also volume control devices in that they supply the customer with water in an unregulated manner until the credit loaded by the customer into the unit is used up.



Thereafter some models simply cut off all water until more credit is loaded. Other models can be programmed to allow the customer access over 24-hour periods to the allowed basic free amount of water. As an additional feature some units can be programmed to supply the customer with an agreed maximum quantity of water over a fixed period of time, commonly 24 hours or one month, whilst the unit is still in credit. This is done as an additional help to the customer to manage his/her own water demand.

The basic methodology used in most prepayment meters is identical to that used in the simplest form of volume control device with additional features to allow the customer to load credit onto the device, and to allow the processor to deduct the money from the credit loaded, in accordance with the WSI’s tariff structure, as water is used. However, not all prepayment meters can be programmed to deliver the basic amount of free water on a 24 hour, or even a monthly basis, or to limit the amount of water delivered over a fixed period whilst unspent credit is still stored in the unit. There are prepayment meters on the market which do not incorporate a real time clock. These can only handle uniform volume based charges, and if the WSI levies other charges these can only be finalised when the customer returns to purchase more credit.

Prepayment units cannot work on their own. They need a computerised information management system to store details of tariffs, the prepayment units installed, customer particulars, customer prepayment water meter readings, and all transactions as they take place or are reported back from any associated decentralised credit sales units. They also need a method of transferring credits purchased by customers to their prepayment units.

Prepayment systems are not off-the -shelf purchases. Before purchasing systems WSIs need to give careful consideration to what they want the system to do. Thereafter, they should check what is currently available on the market, and then issue a specification covering the features they require. Two DWAF publications: “Site evaluation of electronic prepayment water metering cost recovery systems: Final report: September 2000” and “Prepayment water meters and management systems: A booklet for local authorities and community institutions: May 2001” give additional information on how to implement prepayment systems, and on their strengths and weaknesses. The site evaluation report also suggests strategies for WSIs with limited capital finance to implement mixed systems with conventional billing and prepayment metering systems operating side by side.

Table 3E: Advantages and Disadvantages of Pre Payment Meter Systems

Advantages

Good financial control

Prepayment meters are a powerful tool for helping WSIs to control water wastage and customer debt. They also help customers to budget and, provided social issues are fully dealt with before units are installed, well-maintained prepayment metering systems are popular with customers (DWAF 2001a, p 9).

Monitoring and evaluation

Well-developed prepayment metering management systems facilitate the keeping of standardised records. This in turn facilitates monitoring, continuous evaluation, and auditing and support from services support agents and higher authorities.

Cost efficiency for higher volume users

In well-managed WSIs, in areas where the majority of customers use in excess of 20 kilolitres per month, water prepayment management systems have the potential of becoming truly cost effective.



Disadvantages

High cost in poorly managed situations

The additional capital cost of installing electronic prepayment systems over conventional cost recovery systems is at least R 1,200 per unit whilst the all-inclusive capital cost is in region of R 3-4,000 per unit (2002 prices). For an existing scheme with poor cost recovery, unauthorised connections and a poor quality of service, the total cost of installing prepayment meters complete with their management systems, by the time social issues have been fully dealt with, is likely to be even higher.

Poor water loss control

Because of the time lag between a customer purchasing credit and using the water, prepayment systems make it more difficult to quantify water losses, water theft and various other forms of fraud. This is particularly true where non-uniform tariffs are used, because quantities of water used cannot be converted directly into amounts of credit used up. As a result, to carry out accurate UAW audits it is still necessary to read the meters and capture the other data stored in the prepayment units on a regular basis, at least until the WSI has a full understanding of the system and its customers.

Lack of standardisation and integration

Unlike electricity prepayment metering systems, the credit transfer systems used for different makes of prepayment meters have not been standardised. This means that, once a WSI purchases a particular make of water prepayment meter, it cannot purchase additional units from a different manufacturer. SABS 1529 Part 9 will cover water prepayment meters, but will only deal with measurement accuracy and minimum information display issues. It will not cover standardisation and will only cover reliability and durability to a limited extent.

Currently there is no supplier of an integrated conventional and prepayment water management system. This means that final reports for mixed systems, which cover total sales, water usage and UAW, have to be calculated separately (DWAF 2001a, p 11).

Box3-3: Case History: Krugersdorp /Mogale Local Municipality

A successful introduction of a prepayment water metering system for individual household connections was the Kagiso extensions 12 and 14 of Krugersdorp/Mogale Local Municipality. Over the period 1995 to 1999, the bulk water delivered dropped from 35,000 to 23,000 kilolitres per month and net financial losses dropped from R 111,000 to R 29,000 per month as recorded on page 24 of DWAF 2000a.

3.6.6 Shared Connection Batch Volume Control

Shared connection batch volume control normally takes the form of a mechanical or electronic device that allows customers to collect water in discrete volumes from an unattended shared connection, they are also known as shared connection prepayment meters. Attended shared connections are a form of shared connection batch volume control, but with manual control.

Mechanical devices are operated by depositing a ‘credit’ token in the device. It then dispenses a fix volume of water, usually about 20 litres, for each token deposited. As a result the customer, even if he/she does not collect the water, has good control of how these ‘credits’ are managed. A disadvantage is that the water is dispensed in fixed amounts.

Electronic devices are normally operated by rechargeable or non-returnable cards or tokens which store a larger unseen water ‘credit’. When the containers are filled with water, the credit stored on the token is reduced and displayed on the dispensers. An advantage of this type of system is that the unit can dispense the exact amount of water required by the user.



A disadvantage is that, if the paying customer does not collect the water personally, he/she cannot see the water credit stored and has less control over the amount collected.

Water used for local domestic consumption from shared connections is unlikely, on average, to be more than the national government’s recommended free basic amount of 6 kilolitres per month, because of the difficulty of carrying the water home. Rather than spending capital on batch volume control devices, WSI’s first aim should be to manage the water demand from its shared standpipes through sound communication with customers, monthly checking of the bulk water delivered and constant vigilance with respect to losses. Intermittent supply rationing (see section 2.11) should also be considered. Further suggestions on how WSI’s can manage the water demand from shared connections without spending capital or lowering the level of service are given on page 12 of the DWAF publication: “Prepayment water meters and management systems: A booklet for local authorities and community institutions: May 2001”.

Although the cost of volume control devices per customer unit for shared connections is much lower than for individual household connections, customers may question that expenditure and consider that the money could be better spent on improving the level of service by installing additional connections. In such an environment customer acceptance becomes more difficult.

For small communities, with up to about 15 shared connections and with a WSI which is prepared to do its bookkeeping and UAW management without a computerised system, the capital costs and perhaps even the running costs of a mechanical prepayment system are lower than for an electronic system. However for larger schemes, where the cost of the individual units predominates rather than the cost of the management system, electronic systems are cheaper. The latest design of mechanical prepayment meter which has few moving parts is probably at least as robust, reliable and durable as electronic units. Limited evidence suggests that customers may prefer mechanical units to electronic ones although WSIs generally prefer the electronic type. Additional information on mechanical prepayment meters can be found in DWAF 2001a. The importance of adequate caretaking and maintenance, is clearly illustrated in annexures ‘A’, ‘B’ and ‘C’ of DWAF 2000a.

Shared connection electronic prepayment meters are more suitable for larger schemes or schemes in which individual household electronic prepayment units have already been installed. They need the same management system components as individual household units to allow them work. The only difference for customers is the method of transferring credits purchased to the prepayment units. For individual household units, credits purchased are transferred and stored in the unit during a single loading action. For shared connection units, the credit has to be stored semi-permanently in a customer token or card and is only deducted, in tranches equal to the value of water collected, during each visit to the dispenser. Thus the methodology of choosing, installing, and commissioning electronic shared connection units and their management system is the same as for individual household units.



Table 3F: Advantages and Disadvantages of Shared Connection Batch Volume Control

Advantages

Good financial control

Prepayment meters are a powerful tool for helping WSIs to control water wastage and customer debt. They also help customers to budget and, provided social issues are fully dealt with before units are installed, well-maintained prepayment metering systems are popular with customers (DWAF 2001a, p 9).

Monitoring and evaluation

Well-developed prepayment metering management systems facilitate the keeping of standardised records. This in turn facilitates monitoring, continuous evaluation, and auditing and support from services support agents and higher authorities.

Service delivery Water is available to customers 24 hours a day, 7 days a week, in a regulated manner.

Cost efficiency Considered to be cost effective if at least 15 households share each connection and the total number of households using the system is at least 900.

Disadvantages

High cost in poorly managed situations

The additional capital cost of installing electronic prepayment systems over conventional cost recovery systems is at least R 1,200 per unit whilst the all-inclusive capital cost is in region of R 3-4,000 per unit (2002 prices). For an existing scheme with poor cost recovery, unauthorised connections and a poor quality of service, the total cost of installing prepayment meters complete with their management systems, by the time social issues have been fully dealt with, is likely to be even higher.

Poor water loss control

Because of the time lag between a customer purchasing credit and using the water, prepayment systems make it more difficult to quantify water losses, water theft and various other forms of fraud. This is particularly true where non-uniform tariffs are used, because quantities of water used cannot be converted directly into amounts of credit used up. As a result, to carry out accurate UAW audits it is still necessary to read the meters and capture the other data stored in the prepayment units on a regular basis, at least until the WSI has a full understanding of the system and its customers.

Lack of standardisation and integration

Unlike electricity prepayment metering systems, the credit transfer systems used for different makes of prepayment meters have not been standardised. This means that, once a WSI purchases a particular make of water prepayment meter, it cannot purchase additional units from a different manufacturer. SABS 1529 Part 9 will cover water prepayment meters, but will only deal with measurement accuracy and minimum information display issues. It will not cover standardisation and will only cover reliability and durability to a limited extent.

Currently there is no supplier of an integrated conventional and prepayment water management system. This means that final reports for mixed systems, which cover total sales, water usage and UAW, have to be calculated separately (DWAF 2001a, p 11).

High maintenance commitment

An additional component in the water supply chain which can go wrong. Thus, without properly trained, motivated and managed staff a high percentage of units will be out of service at any one time

Service delivery Unlike individual household prepayment units, when shared connection prepayment meters fail they stop delivering water to customers, thus lowering the quality of service rather than increasing it. This causes dissatisfaction which sometimes leads to vandalism.



3.6.7 Non-Prepayment Volume Control

At its simplest, the device comprises a conventional mechanical water meter fitted with an electronic totalising output device, a real time clock, an electronic processor and an open-closed solenoid valve. The solenoid valve remains open unless the customer uses the pre-determined maximum quantity of water before a fixed time period, commonly 24 hours or one month, has expired. When the solenoid closes, all water is cut-off until the end of the time period, after which the solenoid valve opens again and a new period begins. Because the device operates at full mains pressure and without any flow restrictor, the customer will be unaware of its existence until it operates. Such devices can therefore be used to limit a customer’s access to the free basic amount of water allowed by the local WSA.

Units can be either battery or mains operated. The electronic processor associated with some units can be programmed so that the agreed maximum quantity and/or time period can be changed in the field. These more sophisticated processors can also be programmed to allow the customer to carry over water not used in one time period to the following time period or even later. They can also be programmed to store a series of meter readings so that the WSI can monitor a customer’s water usage pattern.

As with the installation of flow control units, attention to detail has a crucial influence on ensuring a successful outcome when volume control units are installed. Since they are not part of a conventional water supply connection, but rather an additional item, units should only be installed after a customer has signed an application form. With good marketing combined with a sound credit control policy, which would result in services being disconnected if customers used more than the free basic amount and do not pay for it, relevant customers are likely to ask for application forms to sign. The meter totalisers and electronic processors associated with volume control units are fragile. They therefore should be installed in a manner that prevents all persons except official maintenance and monitoring having access to them. Unless fully ‘potted’ they also require more maintenance if not installed in a relatively dry environment.

To be effective in controlling unaccounted-for water (UAW), maintenance staff need to be skilled and well motivated. Meter readers should continue to read the mechanical meters and the water management system should be programmed to highlight anomalies. If the units are not maintained in good working order, WSIs will have difficulty in disconnecting customers or charging them for excess usage as by installing the unit they have assumed much of the responsibility of controlling the customers maximum usage.

Unlike flow control units, volume control units are not an integral part of a reticulation systems overall design but rather an add-on that can be extremely useful:

(a) In helping WSI’s with water demand management and credit control associated with customers who do not pay for services timeously whilst still supplying them with the free basic amount, and

(b) In assisting other customers to control their own demand for water.

Because of the additional capital and maintenance costs, it is recommended that WSI’s only target customers who are not paying their bills timeously, starting with high volume users. Installing them free of charge should probably only be considered for customers who apply for units to be set at the free basic amount and who are willing to accept no carry-over of unused water to a later period. WSI’s lacking financial resources and those with low institutional capacity may be forced to start their customer water demand management by introducing intermittent supply rationing (see 2.7) or flow control units without checking which customers have on site water storage tanks (see earlier parts of this section).



Table 3G: Advantages and Disadvantages of Non Pre Payment Volume Control

Advantages

Good demand control for poor payment high service situation

They are a powerful tool for helping WSI’s to control the water demand from poor paying customers supplied with water at the highest service level. They also help customers to budget.

Compatibility with other management systems

They do not interfere with the WSI’s standard meter reading, billing and UAW management systems. Apart from this being an advantage in itself, it makes it easy to manage a mixed distribution system with some customers having conventional water meters only and others having water meters working in series with a volume control device.

Disadvantages

High capital and maintenance cost

Significant additional capital and maintenance costs when compared with conventional water meters with no additional controls

High maintenance Additional skilled and motivated maintenance staff required.

Additional management report requirements

The need to add a few additional features to the WSI’s overall water management system so that it highlights anomalies such as a customer using more water than the quantity set on the volume control device

3.6.8 Approach to Implementation

Section 9(1) of the Water Services Act 1997 states that the minimum standard for basic water supply services includes the delivery of water at a minimum flow rate of not less than 10 litres per minute. Whilst this regulation is associated with obtaining water from shared connections within 200 metres of a household, WSI’s should at all times strive to ensure that on-site water supplies also comply with this requirement.

Customer flow control devices that are installed in systems which do not include on site water storage cannot achieve meaningful control and simultaneously supply water at 10 litres per minute. Therefore rough systems, comprising flow control devices without buffer storage capacity, should only be used as an interim measure by financially weak WSIs, when customers fail to control their water demand to what they can afford or what the source or distribution system can deliver. Should the majority of customers fall into this category, intermittent supply rationing (see section 2.7) should be considered as an alternative action.

When competently engineered, systems incorporating a pressure compensated flow control device provide the best value for money service to households using between 4 and 15 kilolitres of water per month. The total monthly cost of supplying water using such systems is lower than when conventional household connections are used (see DWAF 2000b).

Systems incorporating a volume control device help both the WSI and its customer to manage the demand, provided that the WSI has properly trained, motivated and managed staff to operate the systems. The total monthly cost of supplying water using such systems is higher than for conventional household connections. Their installation is therefore only recommended for those customers with conventional metered household connections that request them because they are having problems in managing their water usage to a volume they can afford.

Conventional metered household connections only start becoming cost effective when customers use at least 10 and preferably 15 kilolitres of water per month (see DWAF 1997, p 9).



Volume control devices should only be used where the average demand from customers paying volume related charges for their water is more than 10 kilolitres per month.

Before introducing any delivery point water management for existing customers with household connections it is essential that WSI’s check that they may do so in terms of existing bylaws, otherwise the bylaws will have to be changed first. It is also essential that they negotiate with customers explaining what action they want to take, why they want to take it and to what extent they are implementing a medium-term temporary action rather than long-term solutions. They should also try to give customers a choice, even when the choices are limited.


Dbn W&W (1996) “Water for everyone” Durban Water & Waste, PO Box 1038, Durban, 4000 South Africa. pp 11.

DWAF (1997). “Implementing prepayment water metering systems”. The Director Interventions and Operations Support, Department of Water Affairs and Forestry, Pvt Bag X313, Pretoria, 0001 South Africa. Oct 1997, pp 71.

DWAF (2000a). “Site evaluation of electronic prepayment water metering cost recovery systems”. The Director Interventions and Operations Support, Department of Water Affairs and Forestry, Pvt Bag X313, PRETORIA, 0001 South Africa. Sep 2000, pp 74.

DWAF (2000b). “Water supply service levels: a guide for local authorities”. The Director Interventions and Operations Support, Department of Water Affairs and Forestry, Pvt Bag X313, Pretoria, 0001 South Africa. Nov 2000, pp 35.

DWAF (2001a). “Prepayment water meters and management systems: a booklet for local authorities and community institutions”. The Director Interventions and Operations Support, Department of Water Affairs and Forestry, Pvt Bag X313, Pretoria, 0001 South Africa. May 2001, pp 33.

DWAF (2001b). “Regulations under Section 9(1) of the Water Services Act, 1997: compulsory national standards”. The Director Interventions and Operations Support, Department of Water Affairs and Forestry, Pvt Bag X313, Pretoria, 0001 South Africa. May 2001, pp 10.

Hazelton, D and Kondlo, S (1998) “Cost recovery for water schemes to developing urban communities: A comparison of different approaches in the Umgeni Water planning area” Water Research Commission Report No. 521/1/98, Water Research Commission, PO Box 824, Pretoria, 0001 South Africa. pp 103.

SABS (2000) “Draft specification SABS 1529-9: Water meters for cold potable water part 9: Requirements for electronic indicators including prepayment units and split units, used with mechanical water meters” SABS, Pvt Bag X191, Pretoria, 0001 South Africa. Jun 2000, pp 58.

3.7 Financial Management

3.7.1 Structuring Tariffs to Encourage Water Conservation

The Water Services Act, 1997, section 10(1), requires WSIs to implement a rising block charge structure, or equivalent, for water supply services to households who have access to an uncontrolled or high volume of water.



For each customer, regardless of water usage, sudden increases in charges above the inflation rate quickly convert to a reduction in demand, so that income rarely increases significantly, and may even decrease if the increase is accompanied by a steep step for a high consumption block. If punitive charges, introduced, for example, at a time of drought, are subsequently relaxed, experience has shown that the water demand will revert to its earlier higher level, but over an extended time period.

The cost rebate / surcharge (CRC) tariff as well as the rising block (RBC) tariffs are both effective in reducing demand. CRC is less common, but has the benefit of better transparency and is preferred by National Treasury.

The key to successful tariff adjustment for demand management purposes is being able to predict, with reasonable reliability, the price elasticity of demand. A simple objective would be to ensure that the tariff restructuring does not cause a reduction in the present monetary surplus or increase the deficit in the provision of water services. In other words, the increase in effective tariff should at least counteract the reduction in consumption.

As a general rule any tariff restructuring needs to be undertaken within the context of the WSI’s overall finances for water service provision and it may well be appropriate at that time to review the tariff structure for optimal compliance with 10(1) of the Water Services Act, 1997. A broader perspective on tariff setting that encompasses but is not limited to WC/WDM is provided in Annex 6.

As the price of water (water tariff) increases, there is a corresponding decrease in demand for water. This is illustrated in Figure 3.4.

Figure 3.4: Price Elasticity

However, the demand will not remain at the lower level indefinitely. As consumers become accustomed to paying the higher tariff, consumption may tend to rise and corrective action may need to be taken.

3.7.2 Charging and Credit Control

Introduction

Together with effective cost control and tariff structures, effective charging2 and credit control is central to the financial management of WSIs, as well as water demand management. Credit control includes the ability of a WSI to control water usage to what each customer can afford.

2 Ensuring that each customer is informed of the money owed for water received

R5.00/klR4.50/kl

35kl/month 30kl/month

Water Tariff - Price Elasticity



However, these WSI financial management tools do not necessarily help customers to control water usage. Thus for many customers with household connections, but especially in the poorer areas, an appropriate water delivery point management tool, selected from section 3.6, needs to be used in combination with the financial tools to enable WSIs to provide a satisfactory and sustainable service.

Charging

Charging firstly requires a WSI to ensure that all water entering its area of supply and being delivered to customers is measured and/or controlled, so that, excluding acceptable losses, it can be accounted for. Thereafter, the WSI has to ensure that customers are charged for the water that is delivered to them (excluding the free basic amount), or for the fixed maximum quantity to which they have been given access, all in accordance with the supply agreements made with customers.

Charging does not guarantee that customers will pay for the water delivered to them. Credit control requires a WSI to ensure that all customers are given access to a basic amount of water and that, thereafter, the quantity of water delivered is controlled to the amount each customers can afford and is willing to pay for. This principle assumes that the tariff structure equitably curtails demand to the assured yield of the allocated resources and capacity of the infrastructure.

Both charging and credit control are essential for good financial management. It is therefore important that WSI’s allocate resources to both from the outset, even when the charging responsibility has not been perfectly implemented. However this must only be seen as a grace period which should not be abused. For example customers in the Moretele area of North West Province prevented the introduction of prepayment meters for shared connections when they realised that the WSI was doing very little to charge consumers with unauthorised household connections.

Credit Control

Credit control is concerned with keeping the ‘debt ratio’ low. For a WSI or a part; the debt ratio is the total money owing from water sales and associated accounts divided by the current month’s water sales and associated charges. For a single customer it is best to calculate it as the ratio of total money owing less any large amount owing for which repayment terms have been agreed, to the average value of any outstanding accounts over the previous 3 months.

If the debt ratio exceeds 3.0 urgent action is required. Target should be 2.0 maximum for users using less than 100 k�/month and 1.25 for larger consumers, starting with the largest.

Clause 27(1)(b) in the bill of rights chapter of the Constitution, requires a WSI to do its utmost to supply an adequate, assured service to all customers. However clause 36(1) provides for a supply to be cut off for a reasonable and justifiable punitive period, as permitted in the local by-laws, if a customer fails to comply with valid laws relevant to the ordered supply of water. Commitment to clause 27(1)(b) combined with good communication between a WSI and its customers should ensure minimal cut-offs, without endangering the sound financial management of the WSI. Implementation

A suitable water service provider (WSP) needs to be set up in each area being considered. In rural areas, for stand-alone schemes and the distribution portion of large schemes, community level WSPs are the best choice. Thereafter skills training should include customer care as well as managerial, booking and technical modules. Such WSPs will not be completely self-sufficient and will require regular auditing and occasional professional support. The support can be provided by a WSA, a larger WSI or a private sector services support agent (SSA).



Table 3H illustrates the close inter-relationship between technically focused charging actions and financially focused credit control actions. Regardless of the departmental set up within the WSI, these two functions must be harmonised and managed together, using an integrated information system. For a WSI with up to 60 customers receiving an invoice with a variable charge each month plus up to about a further 400 customers paying a fixed charge or a fixed no charge, it is possible to manage the system manually. However for larger WSIs an integrated computer based system is essential. The value of accurate data combined with clear reporting should not be underestimated. In remote areas a WSI could consider installing a computer, complete with a back-up system, at the operators home rather than in a specially constructed water office, to reduce the likelihood of theft. If free basic water is to be implemented, then a computer adequately programmed to deal with the free basic amount and the rising block tariff would prove to be valuable.

A necessary first action is to record the position and connectivity details of all delivery points. All water consumers (customers, proxy customers and potential customers) in the WSI’s area of supply must then be listed and categorised, and whether their supply is adequate or inadequate. This has to be done for two reasons:

1. It is a WSIs task to extend services to all those inadequately served as soon as practical and this has an important bearing on the WSI’s future capital requirements and recurrent costs

2. Combined with a knowledge of where water pipes are, it indicates where the WSI must watch out for unauthorised connections

The additional delivery point details are recorded per delivery point rather per customer because, apart from cases where a delivery point serves more than one customer, its character is related to its position rather than to the customer. Thus the customer can change but the delivery point usually remains unaltered. These additional delivery point details include the level of service and charging method. Table 3H is a matrix of the different levels of service commonly used in South Africa for domestic and small non-domestic together with their associated charging methods. In their general planning WSIs need to assess these different options and select a limited number to give their customers choice without having so many different alternatives that system is difficult to manage.

A water balance, a list of consumers from the billing system and a site comparison survey are the best ways of detecting illegal/unauthorised connections.



Table 3H: Domestic and Small Non-Domestic Consumers - Levels of Service and Charging Methods

Level of service Not a

customer

Fixed no charge

Fixed charge

Flat charge

Variable charge

Prepaid variable charge

Has own private or ‘no’ supply Inadequate X Adequate X Rudimentary Inadequate (T) X (POP) X Adequate X(POP) X Shared connection (preferably metered)

More than 200 m distance X (POP) X X RDP service – less than 200 m distance

X (POP) X X

Private arrangement with neighbour X Household connection not metered (Usage >15kl/mth)

Uncontrolled (T) X Batch volume control X(POB) X On-site pressure compensated flow control

X X

Off-take pressure compensated flow control (PO)

X X

Household connection metered (Usage <10kl/mth)

Non pressure compensated flow control(T)

X X(POB)

Uncontrolled metered connection X(T) X(POB) X Volume controlled metered connection X(LPO) X(POB) X X

Notes: Level of service qualifications in brackets apply vertically Payment category qualifications in brackets apply horizontally T = only recommended or allowed as a temporary arrangement POP = preferred option, in line with current South African policy POB = preferred option, best value for money LPO = least preferred option, because of the initial cost of such a connection

At a metered household connection, a prepaid variable charge indicates the presence of a prepayment meter. At a shared connection, a prepaid variable charge indicates the presence of a prepayment meter or an attendant.

If all households receive a basic amount of water free, regardless of the level of service, the variable charge includes a non-fixed ‘no charge’ possibility. If ‘no charge’ becomes a regular feature of such a customer’s supply, it is recommended that the customer’s supply category be changed.

Charging: Monthly Actions

Generally the monthly charging actions are self explanatory. Monthly reading of water meters is the norm in South Africa and for prepayment meters, which are more likely to develop faults, this may be desirable. The WSI should however consider the cost effectiveness of monthly reading of every meter – bi-monthly, quarterly and even annual readings with interim monthly billing done on estimates based on historical consumption are all practices found in other countries. Ideally one would adjust the frequency of meter reading according to the water used, i.e. high users, say top 10%, would be read monthly, middle range quarterly, low users such as small shops being be read every six months or even annually.



Credit Control Actions

The aims of the credit control actions are five fold. They are to ensure that:

1. A WSI is paid all the money it is owed promptly

2. Customers do not use more water than they can afford and are willing to pay for

3. Customers who have leaks on their property are warned before the leaks combined becomes serious

4. A customer whose water consumption is low, because either his/her meter is faulty or he/she is stealing water, is quickly highlighted

5. Although the WSI is financially well managed, customer cut-offs do not occur or they are rare events

If a WSI has been badly managed in the past it will first have to control high water usage customers who owe money for more than 90 days, thereafter moving on to those owing a lesser amount. Under these circumstances some low usage customers may well have money owing for about 12 months before they are helped to control their usage. In such circumstances, if write-offs cannot be considered, an agreement should be reached between the WSI and the customer for the money to be paid off, interest free. It is recommended that the rate of repayment should not be more than R10-00/mth or 20% above recent invoice values, whichever is the greater.

Credit Control Key Indicators

For a WSI’s debt ratio to improve, the charges to income ratio must drop to less than 1. A charges to income ratio of more than 1 means that the WSI’s debt ratio is deteriorating.

Exceptional rising consumption patterns suggest water losses on the customer’s property. Exceptional falling consumption patterns suggest water theft or a faulty meter.

The other credit control key indicators are self-explanatory.

Strategies to Regularise Unauthorised Connections

Strategies that can be adopted to regularise unauthorised connections include:

� Accept a down payment and subsequent part payments for connection fees

� Implement bridging financing system on introducing of a tariff scheme to those who previously had unlimited “free” water

� Assist the institution’s service delivery through outsourcing if the internal skills are limited

� Survey the exact position and determine the specifications of all unauthorised connections

� Implement conditions of contract agreements between the WSI and consumer

� Implement education, training, capacity building, advertising, workshops and information dissemination measures to change the behaviour of consumers.



References and Suggested Further reading

*ANC (2000) “ANC local government elections 2000 manifesto, together speeding up change, fighting poverty and creating a better life for all”.

<http://www.anc.org.za/elections/local00/manifesto/manifesto.html>>.

DBSA (2000) “PC-based financial modelling for municipal investment programmes: the Combined Services Model.” Development Bank of Southern Africa, PO Box 1234, Midrand, 1685 South Africa.

*DPLG (1999) “Targeting poor households in the provision of basic municipal services: A guideline for municipalities”. Department of Provincial and Local Government, Pvt Bag X804, Pretoria, 0001 South Africa. pp 41.

DWAF (1997) “Implementing prepayment water metering systems”. The Director Interventions and Operations Support, Department of Water Affairs and Forestry, Pvt Bag X313, Pretoria, 0001 South Africa. Oct 1997, pp 71.

DWAF (2000a) “Model water services bylaws” The Director Interventions and Operations Support, Department of Water Affairs and Forestry, Pvt Bag X313, Pretoria, 0001 South Africa. Aug 2000, pp 58.

DWAF (2000b) “Site evaluation of electronic prepayment water metering cost recovery systems”. Directorate Water Services Intervention and Operations Support, Department of Water Affairs and Forestry, Pvt Bag X313, Pretoria 0001. Sep 2000, pp 74.

DWAF (2000c) “Water supply service levels: A guide for local authorities”. The Director Interventions and Operations Support, Department of Water Affairs and Forestry, Pvt Bag X313, Pretoria, 0001 South Africa. Nov 2000, pp 35.

*DWAF (2001a) “Prepayment water meters and management systems: A booklet for local authorities and community institutions complete with contact details for suppliers of equipment and services for cost recovery and the management of water distribution systems”. The Director Interventions and Operations Support, Department of Water Affairs and Forestry, Pvt Bag X313, Pretoria, 0001 South Africa. May 2001, pp 33.

*DWAF (2001b) “Free basic water: Guideline for local authorities: Version 2.3” The Director Interventions and Operations Support, Department of Water Affairs and Forestry, Pvt Bag X313, Pretoria, 0001 South Africa. Jun 2001, pp 28.

DWAF (2001c) “Guidelines for, compulsory national standards and measures to conserve water, gazetted in terms of Section 9(1) of the Water Services Act, (108 of 1997)”. The Director Interventions and Operations Support, Department of Water Affairs and Forestry, Pvt Bag X313, Pretoria, 0001 South Africa. Jun 2001, pp 23.

DWAF (2001d) “Guidelines for, norms and standards for water services tariffs, gazetted in terms of Section 10 the Water Services Act, (108 of 1997)” The Director Interventions and Operations Support, Department of Water Affairs and Forestry, Pvt Bag X313, Pretoria, 0001 South Africa. Jul 2001, pp 11.

*Hazelton D (2001) “Implementing South Africa’s free basic amount of water policy”. The 6th Annual Water Africa Conference 2001, VW Conference Centre, Midrand. Terrapinn, Pvt Bag X65, Bryanston, 2021 South Africa. Sep 2001, pp 24.

*RDSN (2000) “Water for all: 50 litres per person per day free”. Rural Development Services Network, Pvt Bag X67, Braamfontein, 2017 South Africa, pp 2.



SABS (1999) “SABS 0306:1999: Code of practice for the management of potable water in distribution systems” SABS, Pvt Bag X191, Pretoria, 0001 South Africa. pp 116 + 2 stiffy diskettes.

Department of Water Affairs and Forestry (1997). “Implementing prepayment water metering systems”. The Director Interventions and Operations Support, Department of Water Affairs and Forestry, P/Bag X313, PRETORIA, 0001 South Africa. Oct 1997, pp 71.

Department of Water Affairs and Forestry (2000). “Water supply service levels: a guide for local authorities”. The Director Interventions and Operations Support, Department of Water Affairs and Forestry, P/Bag X313, PRETORIA, 0001 South Africa. Nov 2000, pp 35.

Department of Water Affairs and Forestry (2001). “Prepayment water meters and management systems: a booklet for local authorities and community institutions”. The Director Interventions and Operations Support, Department of Water Affairs and Forestry, P/Bag X313, PRETORIA, 0001 South Africa. Apr 2001, pp 33.

Department of Water Affairs and Forestry (2001). “Draft regulations under Section 9(1) of the Water Services Act, 1997: compulsory national standards”. The Director Interventions and Operations Support, Department of Water Affairs and Forestry, P/Bag X313, PRETORIA, 0001 South Africa. May 2001, pp 10.

Hemson, D (2001). “Free water?” An unpublished e-mail from Dr David Hemson, Social Policy Program, University of Durban-Westville, P/Bag X54001, DURBAN, 4000 South Africa. Feb 2001, pp 2.

*Indicates documents that explicitly consider the government’s free basic amount of water policy or related topics

CHAPTER 4

RETURN FLOW MANAGEMENT



CHAPTER 4: RETURN FLOW MANAGEMENT

4.1 Minimising Infiltration, Inflow and Exfiltration


Infiltration of groundwater into sewers and sewer connections to buildings occurs when the sewer is below the groundwater table and water enters through defective joints, broken or cracked pipes, poorly constructed manholes, etc. Exfiltration is basically the consequence of similar defects but in the situation where the sewer is above the water table. Exfiltration is exacerbated when the sewer is surcharged, such as when subject to excessive surface water inflow.

Inflow of surface water, also sometimes termed ingress, into a sewer that is intended to convey sanitary sewage / wastewater, may occur either through piped connections from surface water inlets, rainwater downpipes and the like, and through defects in the sewerage network, such as broken or missing manhole covers. Some of these points of ingress may have been intentionally devised to solve problems of surface water drainage, but thereby causing problems of overloading of the sanitary sewer network and merely serving to cause other problems further downstream. Instances of sanitary sewers being used as a temporary flood relief measure by residents lifting manhole covers in areas that are prone to ponding during heavy rainfall may also be found.

Having assessed the general extent and severity of infiltration, inflow and exfiltration (ref Volume 2 Sections 3.4 and Chapter 7), the significant defects are then localised through a process of progressively narrowing the area of search, by analysis flow data and other evidence.

Minimising exfiltration and infiltration may involve the repair of localised defects of a significant nature, or it could form part of an integrated sewer rehabilitation programme, using “no-dig” techniques as appropriate. Minimising inflow requires the identification of the stormwater access points and sealing them off. Regulations intended to prevent unauthorised discharge of stormwater into the sanitary sewer system may need to tightened and enforced.

When eliminating any point of surface water inflow into the sanitary sewerage system, it is necessary to ensure that the alternative route for these inflows does not create a greater problem.

Technical measures may need to be accompanied public awareness and education programmes to reduce instances of abuse of the sanitary sewerage system by the public (refer Chapter 5 for guidance).

4.1.2 Location of Defects

The location of significant defects is based on the principle of progressively narrowing the area of search, by obtaining and intelligently reviewing flow and sewage strength analytical data, in conjunction with any recorded or anecdotal data on the structural condition of the sewerage network. Infiltration defects need to be correlated with data on groundwater levels.

Measurement of flows at various parts of the network is facilitated by the existence of pumping stations, as described in section 3.4.2 of Volume 2 of these guidelines. In-sewer flow measurement, using temporary flow monitoring equipment, can be also be used.



Having identified the sewer lengths that appear to be the prone to infiltration, inflow or exfiltration, CCTV, photographic and visual inspections can all be used to assist in locating specific defects. Smoke tests can facilitate the identification of sources of stormwater inflow - the use of low pressure, non-toxic and non-staining smoke is relatively inexpensive and safe.

Dye testing is another method used to assist with confirmation of suspected inflow sources. When carried out in dry weather, storm water is simulated by using flush water from a water hydrant.

Chemical and biological testing at manholes is an aid to the detection of infiltration if the strength of the sewage is seen to be weakening downstream. The normal variation in sewage strength coupled with inaccuracies in sampling and analytical procedures do make this a fairly coarse method, however. In coastal areas, conductivity measurements can be used to assess the extent and location of saline groundwater infiltration.

4.1.3 Pipeline Rehabilitation

Various sewer rehabilitation techniques are available and each has to be evaluated in terms of the specific conditions under consideration. These techniques include:

Excavation and Replacement, Traditional Open Trench Construction

This is an expensive process involving considerable disruption in built-up areas. It is the solution to replace pipelines which have lost their structural integrity.

Chemical Grouting

This involves the placement or injection of a grout material on, in, or outside sewer pipe joints to prevent exfiltration or infiltration. Accessibility to sewers for workers is required to undertake internal grouting by hand. Remote control mechanical packers that compress the grout into the pipe can be used within sewers that do not have structural problems.

Pipe Lining

Polyethylene and glass reinforced polyester mortar pipe lining and systems are used to seal/repair extensively cracked pipes, thus minimising surface disruption. Designs may be either be fully structural, i.e. not relying at all on the integrity of the original sewer, non-structural, or composite.

Pipe Bursting

Pipe bursting is an on line pipe replacement method that is used when either the original sewer is structurally unsound and/or up-sizing for hydraulic capacity reasons is required. A new pipe is jacked into the old pipe, causing the old pipe to break, and move outwards into the original pipe trench.

Cement Mortar and Epoxy Mortar

Mortar linings are centrifugally applied to the interior surface of existing pipes. These linings are applicable to deteriorated round pipe which is structurally sound.

4.1.4 Procedure for Implementation

The following procedure is applicable to the reduction of infiltration, exfiltration and surface water inflows only. A WSI should consider the desirability and need for a broader scope of investigation and remediation to deal concurrently with structural and hydraulic deficiencies:



Step 1 Extend the return flow audit as per Volume 2 section 3.4 into the network as necessary at pumping stations and key points on the network using temporary flow measurement equipment.

Step 2 Obtain geotechnical and hydrogeological data and determine extent of sewer network that is below water table and subject to possible infiltration.

Step 3 Based on the findings of (1) and (2), undertake manhole inspections and in conjunction with other known data on sewer condition decide which sewer lengths are most likely to be prone to infltration and exfiltration. Draw up schedule of sewer inspections and further investigations.

Step 4 Undertake CCTV, physical inspections, dye and smoke tests as appropriate and analyse results. Note: observe "confined space" safety procedures. Decide on which significant defects need to be repaired having due regard to cost-benefit.

Step 5 Consider need for public awareness and education campaign

Step 6 Prepare schedule of repair works and specifications and scope of any public awareness programme. Finalise cost estimates and implementation plan.

Step 7 Procure works that are to be outsourced and implement measures.

Step 8 Review flows and compare with expected results, consider second pass if necessary.

4.1.5 Procedure for Maintenance and Sustainability

No special measures other than good asset management practice.


Risk factors:

Since it will not be financially realistic to survey the whole sewer network, there is a risk that significant defect(s) may exist in parts of the network that initial screening process has excluded from internal sewer inspections.

Overall confidence factor: High.

References, Further Reading

Sewer Rehabilitation Manual, Water Research Centre, UK,1990

4.2 Wastewater Re-use

Residential water usage can be separated into two categories, indoor and outdoor usage. In South Africa, the split between indoor and outdoor usage is dependent on the category of consumer as illustrated in Volume 2 Table 6A.

A partial re-use system can reduce residential water consumption by up to 25% and reduce the load on the sewer system by up to 50% (Milne, 1979). An example of the partial re-use system is given in Figure 4.1. A total re-use system can achieve a 50% reduction in water demand as illustrated in Figure 4.2.

Examples of re-use measures are given in Table 4A.



4.3 Tariff Management – “Polluter Pays” Principle

The same water which is supplied to domestic consumers is also supplied to non domestic consumers and the costs of production and distribution are the same. The wastewater which is discharged by consumers is much more variable and the cost of treatment differs accordingly. The cost of wastewater collection and disposal can be sub-divided as follows:

� The cost of conveying the waste to the treatment plant, which depends on volume

� The cost of providing the necessary hydraulic capacity at the treatment works, which is also volume dependent

� The cost of biological treatment (or chemical if applicable), which depends on the organic strength of the waste, typically measured as BOD or COD

� The cost of sludge treatment and disposal, which depends partly on the organic waste strength as above (which determines the amount of biosynthesised solid matter), and partly on the non organic fraction of the total amount of solid matter

For all domestic and most commercial premises, the wastewater can be regarded as “domestic equivalent and it is neither practical nor profitable to attempt to apply different waste charges to such consumers. The biological treatment and sludge disposal costs can simply be converted into and added to the cost of conveyance to arrive at an equivalent volumetric charge which represents the full cost of providing the sewerage and wastewater treatment service. This can be expected to be not much less than the cost of providing the potable water, per kl.

For dischargers of “industrial waste”, by which is meant discharged water which has been utilised in an industrial process and which has therefore very different chemical and biological characteristics, the application of the “polluter pays” principle requires that the waste charge reflects the strength and its impact on the costs of treatment and sludge disposal. Various formulae are used to relate the above cost components and these can be found in the literature. Each WSI must consider whether the amount of industrial waste is sufficient in volume and impact on the treatment works to justify the introduction of a variable charging system on polluter pays principles. For full and proper implementation, an industrial waste control unit needs to be established which takes regular samples for analysis, both for regulatory compliance and for charging purposes. A simpler method is to establish different volumetric charges according to the type of waste, based on typical waste characteristics for each type industry. However this may be seen as contrary to water conservation, since it does not provide a financial inducement for industry to adopt internal practices which minimise contamination, in accordance with the hierarchy of pollution prevention policy.



Figure 4.1: Partial Wastewater Re-use System

ResidentialWater Use

Indoor Consumption Outdoor Consumption

Cooking &Drinking

Bathing &Showering Laundry

Consumed Sewer Filter &Holding Tank Toilet

Sewer

GardenWatering

SwimmingPools

CarWashing

Water Table Evaporation StormwaterSystem



Rain Water Ground Water

Filter & Tank Pump

ResidentialWater Use

IndoorConsumption

OutdoorConsumption

Cooking &Drinking

Bathing &Showering Laundry

Filter &Holding TankMaceratorConsumed

Toilet

Septic TankSub-surfaceTreatment

Water Table

GardenWatering

SwimmingPools

Pool Cover

CarWashing

Evaporation StormwaterSystem

Figure 4.2: Total Wastewater Re-use System



Table 4A: Examples of On-Site Re-use (Milne, 1979)

RE-USE

Legend ORIGINAL SOURCE

Toile

ta

Irrig

atio

n

Sprin

kler

Kitc

hen

sink

gr

inde

r

Car

was

h

Laun

dry

Pool

Show

er/tu

b

Bat

hroo

m s

ink

Dis

hwas

her

Drin

king

Coo

king

Fire

figh

ting

Rai

nwat

er

Gro

undw

ater

0 Re-usable directly (without treatment) Toilet 2 2 2 2f

1 1 1 1 0

Re-usable with settling and/or filtering (primary treatment)

Irrigation*b

2 Re-usable with settling, filtering, and Sprinkler 1 1 1 0

chemical treatment usually chlorination (secondary treatment)

Kitchen sink grinder

1 0 1

Carwash* 0° 1

Laundryd 1 0° 1° 0

Notes Pool 2 0

* Very difficult to collect Shower/tub 1 0° 1° 1 0

° Special soaps required Bathroom sinke 0 0° 1°

a Small valves & underwater moving parts may cause clogging problem

Dishwasher 1 0° 1° 0 0

b Large orifice: unpressurised open hose or channel

Drinking* (spillage)

0 0 1 0 0 0

c Small orifice: pressurised Cooking 1 0 1 0 0 0 0

d Assumes no nappies with faecal matter Fire fighting 0 0

e Shaving and brushing teeth Rainwater 0 0 0 0 0 0 0 0 0 0 1 1 1 0

f Septic tank and leach field Groundwater 0 0 0 0 0 0 0 0 0 0 1 1 1

CHAPTER 5

SOCIAL AWARENESS AND EDUCATION



CHAPTER 5: SOCIAL AWARENESS AND EDUCATION

5.1 Introduction

“Water demand management is 50% technical, 50% social awareness.”3

One of major obstacles to the implementation of integrated water resources management, and water conservation and demand management at a local level, is the level of awareness and understanding about these topics amongst both consumers and water services institutions/authorities.

Demand management is generally concerned with both technical interventions and raising awareness. As social awareness is often implemented in conjunction with other measures, gauging its impact on consumer demand is not easy, sometimes making it a less attractive option compared to others that appear to provide faster results. Awareness raising may be perceived as difficult to implement, or simply about making posters or pamphlets. Those involved in raising awareness around water issues generally do not approach it from “marketing perspective” that is needed to promote a product or a concept.

Raising awareness about water demand has to be approached in a strategic manner. Changing the mindsets and behaviour of both water users and managers is a fundamental component of WC/WDM. It is in fact one of the first steps that must be taken in an integrated WC/WDM strategy in order to achieve the acceptability and buy-in necessary for technical measures to succeed. Water users should not be the only targets of education and awareness campaigns; rather campaigns should be specifically targeted to all stakeholders, including WSIs and local government.

Raising awareness about WC/WDM issues facilitates changes in behaviour as, through the education of stakeholders, knowledge about the subject increases. The effectiveness of any awareness campaign is ultimately measured by the results of the implemented WC/WDM measures.

To be successful in achieving the desired behaviour change in water use patterns, an awareness / education campaign has to be integrated, ongoing, relevant and targeted. Campaigns need time, energy and resources, and those promoting them need to adopt a single, consistent message. Preliminary research is therefore necessary to develop an understanding of the characteristics, conditions and dynamics of the context/community in which awareness raising needs to be conducted.

In this chapter on Social Awareness and Education, the misperceptions around WC/WDM will be examined, highlighting the need to develop an effective and integrated social awareness campaign. Some of the basic guidelines and principles of a successful social awareness and education campaign are then introduced. Finally, an approach to raising awareness, through a survey on knowledge, attitudes and practices, which informs the development of a communication strategy, will be outlined.

5.1.1 Constraints and Misperceptions Amongst the factors hindering the successful implementation of WC/WDM are social constraints and misperceptions. Understanding mindsets and misperceptions is critical to the development of a successful and targeted campaign.

3 Hannes Buckle, Rand Water.

Technical measures will succeed only if there is a viable strategy for education and consumer awareness

which reaches all stakeholders



The low level of payment for water services and the low level of awareness of the need for and the benefits of WC/WDM are two of the main challenges to WC/WDM in South Africa.

Other misperceptions hindering the implementation of WC/WDM include:

� WC/WDM will lead to an increase in consumer water bills

� WC/WDM will lead to the introduction or implementation of a billing system

� WC/WDM will lead to a decrease in revenue for water services institutions

� WC/WDM will lead to reduced service levels

� WC/WDM is often perceived only as drought relief mechanisms

� WC/WDM is perceived as punitive measures for consumers

Obstacles to implementing WC/WDM are often found in the local authorities. Municipalities are either unable or unwilling to implement basic WDM measures, because of a lack of capacity (both human and financial) and awareness of WDM. Efforts to raise awareness and understanding within municipalities around the social aspects of WDM are frustrated by high staff turnover and the recent restructuring of local government. There is also a lack of political will and support for WC/WDM at a broader level, beyond consumers and water institutions. The resistance to change within the water services sector needs to be addressed as well as the lack of co-operation and integration between institutions in the water sector.

Ineffective WC/WDM strategies relate to a lack of information and understanding of consumer characteristics, service levels and their use patterns and demands, resulting in inappropriately targeted measures. In addition, the causes of water demand need to be clearly understood in order to develop effective campaigns. The importance of undertaking a competent water audit, as set out in Volume 2, cannot be over-emphasised.

Finally, the links between WC/WDM and other water priorities need to be explicit, clarifying the role of WC/WDM in the broader water management context. Foremost amongst these is the fact that decreasing the amount of water that is used and wasted will make more water available within existing resources to supply water to those who presently do not enjoy an adequate water service. The financial benefit to the community in delaying expenditure for expensive supply-side measures is another important message that needs to be conveyed.

5.1.2 Principles of a Social Awareness and Education Campaign

The successful implementation of WC/WDM ultimately requires a change in the behaviour of water users and managers. Water users and managers need to understand both the need for water demand management in terms of the status of water resources in the region/locally, and the benefits, individually and collectively, of the proposed measures.

Achieving a change in behaviour is directly related to information. Providing information creates awareness around an issue. With sufficient information and a strong campaign, knowledge is deepened, gradually creating a change in attitudes and education, and finally, behaviour change. The degree of behaviour change achieved will depend completely on the nature and effectiveness of the campaign.

Awareness raising must be about both correcting

negative misperceptions and promoting the positive

benefits of water conservation



The following criteria are central in achieving behaviour change (Almedom, 1996:116 in Duncker, 2000:28; Leach, 2001):

� Facilitation – the new practice/behaviour should make life easier for the person adopting it

� Understanding – the new practice/behaviour should make sense in the context of existing local knowledge and cultural beliefs

� Approval – important and respected people in the community should approve of and have adopted the new practice/behaviour

� Ability to make change happen – it should be physically possible for the person to make the changes

� Legislation has a limited effect – an integrated approach, which requires more than few brochures or posters at the problem, is vital to developing a “conservation (or demand management) culture”

� Developing a new culture is complex and takes time, expertise and money

� Consumers don’t believe everything you tell them - they need to relate to the message and believe it to get involved

Figure 5.1: Achieving behaviour change through awareness and education4

5.2 Approach to Awareness-Raising

5.2.1 Six Step Process

A simplified six-step process is described here of the process to increase awareness of WC/WDM issues within a particular WSI.

Step 1. Identify Stakeholders

All users of water and those involved with the protection of the water resource should be identified. These stakeholders must be aware of their as well as other stakeholders mandates.

4 After: Sarah De Villiers Leach, Rand Water

AWARENESS(INFORMATION)

EDUCATION (KNOWLEDGE

AND ATTITUDES)

BEHAVIOUR



Step 2. Build Awareness of WC/WDM

Stakeholder groups should be made aware of WC/WDM, and the process that will follow. A Briefing Document should be circulated to stakeholders before workshops and information sessions. Preferably the documents and workshops should be in the language(s) of the participants. Lists of stakeholders can be used to monitor whether all stakeholders are included.

Step 3. Establish a Process of Change

The long-term needs of stakeholders must be expressed with regard to WC/WDM issues in order for the stakeholders to feel that it will lead to more equitable water use as well as meet their needs. Aspects such as current water use patterns, the various WC/WDM measures and their associated effectiveness must be shared. Questionnaires can assist in assessing stakeholders’ related views on WC/WDM issues.

Step 4. Identify Conflicting Needs

Conflicts between stakeholders’ long-term needs and the possible implementation of WC/WDM measures and their associated effects must be determined. The stakeholders must be introduced to a consensus based approach whereby these conflicts are resolved in order to achieve a “win-win” situation. Expert advice on WC/WDM aspects can facilitate this process.

Step 5. Develop a Common Objective

A workshop that uses a consensus seeking process where stakeholders are provided with options to address these conflicts. A range of options should be made available for consideration.

The monitoring process should assess whether the common objectives are still in line with the stakeholders needs, the principles of equity, beneficial, and sustainable use.

Step 6. Establish Interim Objectives

Interim objectives in line with the long-term objectives should be determined. The reason why long-term objectives cannot be met in the short-term should be explained. A check list combined with scenario analysis should be used to assess whether the areas of conflict and consensus will or have been addressed.

5.2.2 Knowledge, Attitudes and Practises (KAP) Survey

A successful awareness/education campaign is one that is targeted towards a particular group. It is therefore necessary to develop an understanding of the characteristics, conditions and dynamics of the context/community in which awareness raising will be conducted, e.g. using a KAP Survey. A communication strategy is then developed, based on the findings of this research, to raise awareness and ultimately change the behaviour of the target group, in line with common objectives.

The KAP tool focuses on identifying people’s behaviour regarding a particular subject and provides a model for facilitating change on an individual basis, to incorporate new practices that are being introduced, such as WDM. KAP is also useful in identifying the factors that influence behaviour (Duncker, 2000). KAP has been widely used in hygiene and sanitation studies in South Africa and is a useful tool in developing consumer demand management interventions.



The KAP tool is used for (Duncker, 2000):

� Determining the needs of the community with respect to water supplies and services

� Gathering information on the level of knowledge of the community members about water conservation/demand management and related problems

� Gathering information on the existing attitudes towards water conservation/demand management in the community

� Gathering information on the existing water conservation/demand management practices in the community

As an evaluation tool, KAP is also useful for:

� Assessing the effectiveness of WC/DM interventions in changing water management/use practices that prevailed in a community prior to intervention

5.2.3 Methodology for a KAP Survey (after Duncker, 2000)

1. Baseline information

Basic information is first needed to identify the scope of the study area, including:

� Geographical information: where is the area/community you want to study? What is the status of water resources in the area?

� Demographics: how much do I know about the people in the community/area?

� Existing problems and priorities: what are the existing problems and priorities concerning water resources (e.g. quantity, quality, supply, etc) in the study area?

� Existing water supply and sanitation services: are water supply and sanitation services available to the community?

� Aims and objectives: what is the purpose of this study?

� Intended output: what do you want to do with the information?

� Resources: what resources are required to complete the study successfully? (e.g. human resources, financial resources, stationery, computers, etc.)

2. Entry into the community

� Government level – begin at the district or local government level and work through these channels to access appropriate communities

� Local level – local councils should be able to provide you with more accurate information regarding the community, social structures and community representatives/leaders

� Community level – talk to local people in the community to find out about social structures and the right contacts in the community. Establish whether local government and/or traditional structures exist in the community and how they function. Key community contacts might include committees (established around a specific project or in general), the Chief, the Headman, key people (e.g. religious leaders, respected figures), other organisations (e.g. civic forums, women’s groups, etc) and political parties.



3. Relationship with the community

A good relationship with the community is one of the most important elements of a project. Many communities have been let down by development projects in South Africa and tend to view consultants with some degree of suspicion/distrust.

� Explain the history of your organisation including good and bad experiences

� Involve the community in the project, use their input and feedback as valuable information and explain the timeframe of the project

� Be sure not to create expectations you cannot meet

4. Techniques

There is a range of techniques for gathering information about community water use practices. The following are specific for gathering information from the community about their water resources and use:

� Community walk observation – to familiarise the viewer with the physical context of the community; this can take a number of hours.

- Interviewers should prepare a list of points to observe, according to a schedule which they complete during the walk.

- Interviewers should draw a rough map of the area noting key features and resources.

- Note the atmosphere of the community

- Best time to conduct the walk is at dawn or dusk when people tend to use water

- The observation schedule might include location of water resources, access to water resources, water use practices, water users, signs of leakage, etc.

� Focus group discussions – people from similar backgrounds or experiences are brought together to discuss a particular topic

- Use focus groups to explore issues related to water conservation/demand in the community; to explore more qualitative information; to explore the extent of community co-operation and willingness to change; to identify concerns and needs regarding water; to identify cultural beliefs/values/taboos

- Keep focus groups of common interests and disciplines together (this might offer a less inhibited opportunity for marginalized groups, e.g. women, to express their views)

- 8-10 is an ideal group size but do not force or prevent participation

- Prepare a guide to assist the interviewer in directing the group, but do not interrupt the flow of conversation

- The interviewer should remain neutral

- Begin by introducing the interviewer, and explain the purpose of the study and exercise as well as the fact that there are no right/wrong answers

- Thank participants for their participation



� Interview with household or individual

- Semi-structured using interview schedule as a guide

- Should be informal and relaxed

- Take care not to offend or overstep cultural taboos

� Household questionnaire – suited for gathering quantitative information

5. What to do with the data?

� Data analysis – important to check and cross-check information

� Results – results should be presented to show an ordered (not interpreted) picture of the information you gathered

� Interpretation – to determine what the results mean and how significant they are in the context of consumer water demand; possibly reflect comments made by community members here

� Presenting the findings – be balanced in presenting positive and negative findings

- Format of the report will depend on target audiences

- Extracts from the report can be prepared and circulated to stakeholders and key people in the community

- Short articles can be prepared for local/regional networks and other international research institutions

6. Implementing the findings

� What needs to be done to improve the situation regarding water conservation and demand management in the community you studied?

� Examples of activities might include:

- Water conservation awareness and education to facilitate behaviour change in the community

- Water conservation programmes and workshops to actively encourage or initiate behaviour change

- Recommend policies and strategies for WC/WDM using the results and data to substantiate recommendations

5.3 A Communication Campaign

5.3.1 Basic Principles

Communication is a crucial element of a successful water demand management programme. Consumers and water managers need information on which to base decisions regarding their water usage patterns in a way that is credible to which they can relate to the information. To promote water demand management successfully, information and concepts have to be marketed to target audiences, based on a sound understanding of local conditions.



Box 5-1: The Seven Cs of Communication

Credibility: Communication starts with a climate of belief. The receiver must have confidence in the sender and a high regard for the sender’s competence on the subject

Context: the context must provide for participation and feedback. It must confirm, not contradict, the message

Content: the message must have meaning for the receiver, must be compatible with the person’s value system and have relevance for the receiver’s situation

Clarity: the message must be put in simple terms

Consistency: communication is an ending process. It requires repetition, because it contributes to both factual and attitudinal learning

Channels: the verbal and non-verbal communication message should be clear and the two should supplement (and not contradict) each other

Capability of the audience: communication must take into the capability of the audience. Communication is most effective when it requires the least effort on the part of the recipient

Source: DWAF (2001:15)

Although there is a range of options for a communication campaign, the key elements of the campaign and communication tools will be determined by the requirements of the local community and the message that needs to be conveyed.

Basic elements in any communication campaign include (Mvula Trust, 2001):

� The audience – a particular group of people who have been identified as the target for receiving messages in order to bring behaviour change

� The messages – specific pieces of information which have been identified as necessary and appropriate for the audience to act on a topic

� The communication vehicle – the kind of media, material or tool used to carry the messages

� The communication strategy – when each of these elements (audience, message, vehicle) is well researched, planned, implemented and evaluated

5.3.2 Developing a Communication Campaign

Mvula Trust has prepared a report that examines the key elements of a communication strategy in the context of rural water supply and sanitation in South Africa (see Mvula Trust, 2001, report in draft). This useful approach is relevant for water conservation and demand management in a similar context.

1. The Audience

� There is no ‘public in general’ – identify target audiences

� Communication is about ensuring the audience is moved to action but the relationship between awareness and action is neither simple nor causal



� Two aspects of the audience need to be researched before developing a communication campaign (e.g. through a KAP Survey):

- External factors are those that impact on the audience and the environment in which behaviour change occurs. This involves identifying barriers to change in the audience’s environment which the communication strategy will seek to address. External factors may include:

� Community level: gender - men and women have different water needs; language, literacy and numeracy; cultural norms and local practices – messages must not contradict values and beliefs or create misunderstandings

� Institutional level: capacity and functioning of local institutions – WSIs need to create an enabling environment for water conservation and demand management; institutions themselves require awareness raising to undertake their functions

� Provincial and national level: legislation and policy; mechanisms are needed to bridge the gap between policy and implementation

- Internal factors involves understanding and incorporating how the thinking and capacity of the audience impacts on their actions:

� Self-esteem and capacity: enhanced through an empowering participatory process

� Knowledge: drawing on community knowledge and getting audiences to take responsibility for that knowledge (i.e. take action)

� Attitudes and beliefs: aim to address negative attitudes and dependency

� Feeling, arousing and evoking - subjects that touch people at an emotional level and are directly relevant get the greatest attention and influence behaviour

2. Message research and design

� There is no ‘one-message-fits-all’

� Message design through a workshop format is necessary because the messages we think are right might not be the most effective messages. Workshops should be attended by the project team, a creative team / individual, topic experts, community representatives and other stakeholders. Workshops should:

- Prioritise and identify the messages, which should be short sharp and focused - a diverse or inconsistent range of messages will divide the impact of the campaign

- Prepare accurate, positive and easily understood information

- Be concluded with a brief containing broad messages in order of priority, the background to and detailed information required in relation to each message

� Beware of unintentional messages that could cause offence or defeat the purpose of the campaign

� Establish the primary objective/vision of the campaign - is the purpose of the campaign to inform customers about what the local authority is doing about water demand management or is it about raising awareness of water users to water demand management?



3. Choosing the communication vehicle

� Choice of the vehicle will be guided by the message and the audience. Different audience(s) and different message(s) require a combination of communication vehicles

� The audience should understand:

- Why we are doing it: why is water demand management necessary, what are the benefits both collectively and individually?

- Why is it necessary: what will happen if we don’t manage our water demand, what are the problems, present and future?

- What can you do: specific steps that customers can take individually to help implement water demand management

- What we’re doing: what are water managers doing in the area to manage demand (e.g. fixing leaks, pressure management etc.) and assist customers in managing their demand?

� Three categories of communication vehicles:

- Mass media:

� reaches wide audiences

� low interaction,

� cannot carry complex messages,

� best to repeat a few simple messages (e.g. radio – appropriate to rural South Africa);

� will not necessarily receive a positive response

� must be supported by local interventions

- Educational materials:

� can carry complex messages;

� works well within contained environments (schools);

� can trigger interest and raise awareness

� can’t change behaviour and should be part of a broader process

- Educational tools:

� participatory and face-to-face methodologies that reach highly specific audiences,

� high interaction,

� may carry complex messages;

� tools don’t carry specific messages but are rather a set of processes which can be applied to different sets of messages;

� especially relevant in rural areas;

� most effective in bringing about behaviour change;

� encourages participatory and experiential learning;

� empowers learners and builds capacity and self-esteem;

� if not used properly can disempower audiences



The Mvula Trust report provides a useful series of checklists for each phase in the development of a communication strategy. These should be referred to when developing a strategy. In addition, the following provide useful tools for conveying specific information or messages:

� Public presentations and seminars –

� to present more detailed or technical information to groups who require it;

� information presented must be clear and focussed;

� target audiences for presentations might include ratepayers, stakeholders, larger water users or those directly involved in the water sector (e.g. horticulturalists and plumbers) and educational institutions

� Informative water billing – he most frequent contact a water authority has with their customers is through the water bill; using this means to communicate the benefits of demand management can be very effective, for example:

� information on individual and local water consumption figures, showing the success or failure of a campaign

� information on dam levels, rainfall and the status of local water resources

� information should be clearly and unambiguously presented on water bills showing the consumption period, consumption during comparative periods over previous years, average consumption patterns etc.

� informative leaflets can also be included with water bills as part of the communication strategy, logos and slogans may also be printed on the bill to reinforce the message

� School education - bring water demand management communication into school education provide many opportunities and advantages for conveying the message as well as promoting educational materials and activities

� Community extension training – providing free training to community members in the water cycle, water saving practices and even basic plumbing skills which trainees can use/disseminate in their communities

� Customer advisory services – the availability of water authority staff on the telephone to advise on water saving measures; need to advertise this service for it to be used; staff to walk through communities and advise on water saving measures/techniques

� Special events – can be used to enhance an awareness campaign by drawing attention to the objectives (e.g. a Mayor’s award for the best example of water saving in the community)

4. Planning for Awareness-Raising

Tables 5A and 5B provide examples of the planning of an awareness-raising campaign in chart form and a typical budget, events and activities being scheduled on a weekly basis (Stewart Scott, 2000).



Table 5A: Example of an Awareness-Raising Planning Chart

Date: Week starting ...........................

Objective Advertising Sales promotion

Personal interaction Publicity

To create a visible and positive image for the municipality

Radio Local paper

Banners Community visits Customer care activities

Radio Newspaper Posters

To create awareness about the project and its aims

Radio and local paper

Community visits

Radio Newspaper Posters

To educate local residents about the total water cycle, economical use and health tips

Informative billing

Workshops School visits

Radio Newspaper Posters Info booklet

To create a culture of regular payment for services provided

Radio Local paper

Competitions Radio Newspaper Posters

Table 5B: Awareness-Raising Budget: Example

Medium Monthly/weekly budget

Radio R

Press R

Informative signage/graphics R

Training: materials, facilitator, transport, eats, drinks R

Prize-giving competitions

Gift (television)

R500 spot prize

Refreshments

R

5 Community workshops: materials, facilitator, transport, eats, drinks

R

Information booklet: Zulu and English R

Pamphlets R

Posters, banners R

Estimated or projected total Rx



Box 5-2: Case Study – Raising Awareness through Education: 2020 Vision for Water (DWAF)

The 2020 Vision for Water (VfW) Project is an education project in the National Water Conservation Campaign. Its purpose is to raise the levels of awareness of all South Africans on the value of water and environmental education in order to conserve our natural resources. The project focuses on children in schools and local government. 2020 Vision for Water is also closely linked to the principles and strategies of Outcomes-Based Education and acknowledges the importance of integrating environmental projects into the formal school curriculum.

Vision: To heighten the awareness of the water crisis in South Africa and develop life skills and

value systems that will promote the efficient, equitable and sustainable use of water by all South Africans

Goals: • integrate water education into the formal curriculum • develop appropriate resource materials about water and water conservation • train teachers, water inspectors and other relevant persons to conduct water audits in

schools and homes • facilitate energy audits with Eskom and other partners • facilitate waste audits with DEAT and other partners • establish an international collaborative network of resource audits in schools and homes • maintain a database of schools who participated per province and which type of water

project they undertook

The 2020 Vision for Water Project is facilitated through:

• Partnerships with stakeholder groups such as Depts of Health, Education and Environment and Tourism as well as Local Government District Municipalities and households that stand to benefit from environmental education and by conserving water.

• Active learning strategies for environmental education, water and sanitation such as water quality and water quantity studies for communities and schools

Key elements of the 2020 Vision for Water Project include:

• Active learning for the environment – developing a School Environmental Policy and Management Plan

• Water-wise creation awareness – 2020 VfW is introduced to the various stakeholders (e.g. school principals, teachers and school children), the different types of activities are explained as well as benefits to the school and other implications Awareness Creation Tools and Activities: Plays, poems, quotations, posters, hydrological cycle, awareness creation pack, water quality and quantity studies, wetland studies and water and plat studies

• A resource pack has been prepared as part of the 2020 VfW Project for Active Learning in water and environmental education in South African Schools and Communities. The pack, which could serve as a “starter kit” for groups wanting to participate in the 2020 WfW project, includes examples of awareness creation tools and activities that can be used in schools and communities, as well as a list of contact organisations and a glossary.




DWAF, 2001. Guidelines on the Establishment and Management of Catchment Forums in support of integrated water resource management, sub-series no. MS 6.1 draft.

DWAF, 2001. 2020 Vision for Water Project, a resource pack for Active Learning in Water and Environmental Conservation in South African Schools and Communities, Department of Water Affairs and Forestry, Pretoria.

De Villiers Leach, S. 1999. Marketing and Communications: Establishing regional marketing capacity for implementing WC/WDM communication and education programmes, original manuscript.

De Villiers Leach, S. 2001. personal communication, Rand Water, Johannesburg.

Duncker, L. 2000. The KAP Tool for Hygiene – A Manual on: Knowledge, Attitudes and Practices Study for Hygiene Awareness in the Rural Areas of South Africa, Water Research Commission, TT144/00.

Mvula Trust, 2001. Assessment of the Feasibility of Approaches to Groundwater Awareness-raising: key elements and recommendations, draft, Project 4: Increased Awareness of Groundwater in Community Water Supply and Sanitation, NORAD-assisted Sustainable Development of Groundwater Resources under the CWSS Programme.

Stewart Scott, 2000. Package for Cost Recovery Project (CRP), version 1.

White, S. 1998. Wise Water Management: A Demand Management Manual for Water Utilities, Water Services Association of Australia, research report no. 86.

Carl Bro International (2001). Guidelines for Stakeholder Participation in Integrated Water Resources Management in Water Management Areas of South Africa. (Second Draft).

CHAPTER 6

MANAGEMENT AND INSTITUTIONAL ASPECTS



CHAPTER 6: MANAGEMENT AND INSTITUTIONAL ASPECTS

6.1 Institutional Strengthening and Capacity Building

6.1.1 Capacity Building The institutional capacity of a WSI is its ability to perform its duties and functions in terms of the Constitution and relevant legislation, and, in the context of these guidelines, the expertise to devise, plan and implement a WC/WDM programme.

Capacity building is the sum of efforts needed to nurture, enhance and utilise the skills and capabilities of people and institutions at all levels so that they can provide services effectively and efficiently and in a way that contributes towards the goal of sustainable development. At the basic conceptual level, building capacity is about empowering people and organisations to solve their problems, rather than attempting to fix those problems directly.

The principal objective of capacity building for sustainable water resources management is to improve the quality of decision-making, sector efficiency, and managerial performance in the planning and implementation of programmes and projects.

Assessing and building capacity is a multi-dimensional and consequently a multi-disciplinary endeavour. There are six key dimensions of “capacity”:

(1) Dimensions of local political and decision-making capacity (“governance”).

(2) Dimensions of administrative capacity (human resources, organisational structure, skills development requirements, organisational culture, financial management, information management).

(3) Dimensions of financial capacity (revenue base, expenditure requirements).

(4) Dimensions of technical capacity related to water services (engineering, operations and maintenance of infrastructure).

(5) Dimensions of developmental capacity (policy-making and programme design capacity).

(6) Dimensions of social capital (the role of development forums and water committees, and their interaction with local government).

In order to identify the required interventions, the problem areas must first be identified. These will be found amongst the following subject areas:

(1) Information systems

- extent and condition of assets

- operational data

- other management information

(2) Tariffs and billing systems

(3) Administering indigent policies

(4) Staff skills levels

(5) Operations and maintenance

(6) Payment culture

(7) Management of water services in rural areas, especially farmland

(8) Water conservation and demand management



Interventions should be aimed at ensuring that there is adequate management information on demographics, financial, infrastructure and water resources.

Interventions relating to tariffs and payments will require political support to address the culture of not paying for services, where this situation prevails. Various approaches could include the coercive, incentive and municipal performance approaches.

Indigent policies require funds for implementation and management, subsidies and other cross-funding sources will need to be investigated.

Skills assessment is an important stage of capacity building to help identify training needs.

The implementation of the WC/WDM business plan as developed in accordance with Volume 2 of these guidelines will require specific interventions in human resource capacity and supporting tools.

6.1.2 Community Involvement Water resource planning under current legislation and in line with the IWRM approach emphasises an open process that gives all affected groups an opportunity to express their interests and concerns. Involving the community in goal development and implementation also serves an important public education function, and can greatly enhance the success of capacity building programs. Ongoing involvement helps maintain and build support for achieving capacity building goals and “getting the word out” about the effort.

Participants can act as a focus group for exploring specific capacity building measures and also can provide valuable linkages to key groups, consumers, businesses, and institutions, involved in implementing certain capacity building measures. Participants also can offer input on the level of satisfaction with the system’s programs. Finally, community groups can assist the water system in monitoring results and adjusting program implementation. For many water systems, involving the community in water system planning will be a new experience.

Community involvement does not have to consume excessive time or resources. Even a few “town hall” meetings or “brainstorming” sessions can be helpful. Most system managers will find that involving members of the community in developing goals, implementing programs, and evaluating results is a very worthwhile investment. Further guidance is given in Chapter 5 and in other guidelines series within the IWRM project.

6.1.3 Capacity Building Approach

The various stages in capacity building are illustrated in Figure 6.1

Figure 6.2 illustrates that, at community level, a co-ordinated strategy for community involvement and for building organisational capacity for the management of services needs to be initiated. This requires the simultaneous initiation of a community development process which aims to gain the community’s understanding of, and commitment and support for the establishment of capacity required for services management. It should be understood that, especially in the case of small and rural communities, establishing the capacity for services management alone, without building the capacity of communities and gaining their support, is not adequate. This implies that organisational development for services management as well as the initiation of a community development process are required to establish capacity for long-term sustainable service provision, management and maintenance.



Figure 6.1: Stages of Capacity Building

Figure 6.2: Organisational and Community Development

Assessment of capacity building

needs Immediate support to

capacity building

Assessment of existing

resources and

Detailed definition of development needs

Planning and implementation of capacity building programme

Monitoring and evaluation PHASE 4

PHASE 3

PHASE 2

PHASE 1

Capacity for inter-sectoral (services) management

Management & Administration

Technical Financial

UnderstandingCommitment

Support

Structures Systems Policies

Staff

Local Governance

Local EconomyLocal Civil

S i

Organisational Capacity

Community Involvement

Core Components

ProcessWhich builds:

Organisational Development

Community Development



6.1.4 Outsourcing The successful implementation of a WC/WDM plan will rely, inter alia, upon the deployment of sufficient and appropriately skilled human resources. It is unlikely that a WSI would have, within its own employment, all of these resources and in most cases it is likely that some outsourcing will be required.

The implementation of WC/WDM will generally have two phases:

1. The provision of the necessary infrastructure, establishment of information systems and procedures, initiation of WC/WDM campaigns, achievement of initial targets

2. The ongoing maintenance of the WC/WDM regime and its further planned development

The first phase will require a more intensive and greater effort over a shorter time period and involves a number of one-off tasks. Outsourcing may be envisaged in both stages and can include:

• Project management

• Updating of infrastructure asset records to the required standard

• Installation of flow meters, replacement and repair of valves, other minor works

• Hydraulic modelling of reticulation networks including field measurements – temporary flow and pressure logging

• Undertaking consumer surveys and development of awareness campaigns

• Leakage assessment, development of leakage reduction programmes, design of pressure management regimes

• Leakage detection and repair including consumer leak repairs

• Retrofitting of water saving appliances

Some of the above tasks may be successfully undertaken by emerging contractors. The work must be broken down into manageable tasks to allow the emerging contractors equal opportunity to gain experience in minor works. The approach adopted should include the preparation of a comprehensive Terms of Reference (TOR) for the particular WC/WDM outsourcing project where the following criteria should be considered:

• The WSI should ultimately retain ‘ownership’ of its system’s operation and performance irrespective of what is outsourced

• The institutional capacity of the WSI is strengthened prior to the termination of the project

• Knowledge sharing measures are implemented that ensure all have access to the knowledge added as a result of the outsourcing exercise

• There is a system in place such that documented knowledge can be inherited, not only by the WSI once the service provider’s contract ends, but by officials involved with that particular discipline at any stage in the future. Quality Systems are a tool to assist with this requirement (see Section 6.1.3)

• In order to facilitate sustainability of the interventions brought about through any outsourcing exercises, the obligations of the recipient of these measures (i.e. the WSI) to continue with any applicable ongoing operations must be clearly defined.

• A key performance indicator for the SP should be the employment and development of emerging contractors during the execution of minor works.



A comparison of the different levels of internal and external capabilities required when considering the procurement of services and equipment by a WSI are given in Table 6A.

Table 6A: WSI Capability and Procurement Levels

Level In-house (internal) capabilities/support

External capabilities/ support

Procurement relationships

1 Maximum Internal Capabilities. Carries out all planning, design, procurement, management of new operational practices, preparation of specifications, tenders, etc. for contract works and supervises all installations and construction. High level of expertise, resources available internally.

Minimum External Support only for limited specialised services/tasks/equipment.

Between the WSI and suppliers of services and equipment.

2 Moderate Internal Capabilities. Various expertise available but not for the full spectrum of WC/WDM services required.

Moderate External Support for those gaps in the Institution’s capabilities. The external project management services are combined with other technical services to provide a single professional services package.

Between the WSI and suppliers of services and equipment.

3. Minimal Internal Capabilities. Must at least have the senior internal capacity to supervise the main contract with the lead service provider on a macro level.

Maximum External Support. Project management and specialist support provided totally by the external service providers. High level of expertise of support personnel required as well as ability to co-ordinate between contract packages.

Varies as some contractual relationships can be between the WSI and suppliers and some contractual relationships can be between the lead service provider and other service providers.

The outsourcing of what may be seen as operational tasks that are traditionally within the sphere of the WSI may represent a significant shift in management approach. A framework for institutionalising “strategic adaptive management” has been developed in order to overcome the inherent weakness of bureaucracies that may have an in built resistance to change that serves to discourage innovation. This framework is described in Annex 7.

Many WC/WDM interventions require integration with the existing organisational, institutional and communication structures or networks of the WSI and therefore the type of service contract must reflect this. This integrated process will require the service provider to interface with and rely upon the performance of officials within the organisation, such persons being unlikely to be bound through the means of a written contract to achieve explicit benchmarks or performance indicators.

In such an environment a “psychological contract” has advantages over a conventional written contract. Modifying Ivancevich and Matteson’s (1996) definition of a psychological contract between an individual and the organisation as follows:

“The psychological contract is an unwritten agreement between the external agent and the organisation which specifies what each expects to give to and receive from the other”.



The psychological contract covers explicit as well as implicit aspects and ideally, the willing contributions of one party would perfectly match what the other party wanted to receive. Psychological contracts are not static as either party’s expectations can change as can either party’s ability or willingness to continue meeting expectations.

If the psychological contract or the “spirit of the agreement” is to dominate implementation of WC/WDM measures through outsourcing rather than the “letter of the agreement”, then an adaptive management approach is essential. Both parties will therefore need to be more attuned to each other’s needs and expectations as well as consider themselves as partners committed to the successful implementation of the WC/WDM plan. The adaptive management style would provide a more conducive environment for WC/WDM psychological contracts to succeed.

6.1.5 Institutional Culture/Ethic and Communication

Organisations are able to operate efficiently only when shared values exist among the employees. These values are the conscious, affective desires or wants of people that guide behaviour. The relevance of institutional culture and ethics to WC/WDM projects and interventions in a WSI are such that they influence the complex interpersonal interactions and communication within an organisation as well as between organisations.

The successful implementation and sustainability of WC/WDM measures rely on the co-operation between people, teams, sections, departments and other organisations. Individualistic culture and more power that is invested in the individual, (i.e. Western management style) has a tendency to inhibit co-operation. However, an over emphasis on a collectivist culture, lack of control of the individual and low levels of utilisation associated with African/Ubuntu management styles can lead to low productivity and lack of timely decision making.

The approach adopted for the successful implementation of WC/WDM projects as well as to ensure their sustainability would require the inclusion of the ‘best’ of the various management styles. Rather than an emphasis on one or other trait, the emphasis should be on a continuum where there is a flow and blending of the management styles whereby the outer extremes previously mentioned are discouraged and the middle ‘blends’ that encourage co-operation and productivity are rewarded.

Further elaboration and a comparative analysis describing Japanese, Western and African management, juxtaposed with Ubuntu is included in Annex 7.

References and Suggested Further Reading Ivancevich JM & Matteson MT (1996). Organisational Behaviour and Management. Irwin RD Press.

Van der Walt SEA (2000). An Evaluation of Ubuntu as an Afrocentric Management (and) Communication Approach. DPhil (Communication Management) Thesis. University of Pretoria.

Government Gazette Vol. 418 No. 21126, 26 April 2000. General Notice 1689 of 2000. Department of Provincial and Local Government. White Paper on MSP. Section 5 Capacity Building.

Rossouw AMM & Crous PC (2000). Rapid Capacity Building for Water and Waste Management at Local Authority and District Council Level. Water Research Commission Report WRC 982/1/00.



6.2 Human Resources Development

6.2.1 Performance Management

Performance appraisal is the ongoing process of evaluating and managing both the behaviour and outcomes in the workplace. Organisations use various terms to describe this process, such as performance review, annual appraisal, performance evaluation, employee evaluation and merit evaluation.

Performance management, a broader term than performance appraisal, originates from total quality management (TQM) programmes using all of the management tools, including performance appraisal, to ensure achievement of performance goals. Tools such as reward systems, job design, leadership and training should join performance appraisals as part of a comprehensive approach to performance.

Performance management, with its emphasis on total quality management, attempts to allocate decision making and responsibility further down the organisational hierarchy. A model which indicates the performance management process is given in Figure 6.3.

Figure 6.3: The Performance Management Process

The main features of this model are:

� The mission statement, which defines the business the organisation is in (its purpose) and the direction in which it is going

� Strategies – statements of intent which provide explicit guidance on the future behaviour and performance required to achieve the mission of the enterprise

� Objectives – which state in precise terms the performance goals of the organisation

� Values – what is regarded as important by the organisation with regard to how it conducts its affairs (e.g. performance, teamwork, innovation, the development of people)

Mission

Strategies

Objectives Values

CriticalSuccessFactors

Total RewardSystem

Better Performance

PerformanceIndicators and

Standards

PerformanceImprovementProgrammes

Succession ofPlanning

PerformanceReview

Identificationof Potential



� Critical success factors – which spell out the factors contributing to successful performance and the standards to be met

� Performance indicators – which are worked out in association with the critical success factors and enable progress towards achieving objectives and implementing values to be monitored and the final results to be evaluated

� Performance review – which reviews individual performance, qualities and competencies against relevant objectives, values, critical success factors and performance indicators; identifies potential and development needs

� Performance-related pay, which links rewards explicitly to performance and can take the form of merit pay, individual bonuses, group bonuses and other variable payments related to corporate or group performance (e.g. profit schemes, gain sharing)

� Performance improvement programmes – which are concerned with improving motivation and commitment by means other than financial reward (e.g. training, career development, succession planning and promotion processes, coaching, counselling)

6.2.2 Management Development Training and management development are different because management development tends to focus on a broad range of skills, whereas training programmes focus on a smaller number of technical skills. For example, a training programme for leak detection operators is designed to upgrade their technical skills, but a development programme for water loss control managers would focus on a wide variety of interpersonal and managerial decision-making skills, such as planning, organising, leading, communicating, motivating and scheduling.

Managers generally use a combination of technical, conceptual, and human-relations skills. Top management would tend to use more conceptual skills than technical while the opposite would be true for first-line managers.

A management development programme should consist of the following phases:

• Phase 1 – Need Assessment

Generally conducted at three levels relating to organisational analysis, operations (tasks) analysis and person analysis.

The current needs of managers can be assessed through surveys, interviews, assessment centres and performance appraisal data. Long-range development needs of mangers should generally be linked to Human Resource and strategic planning of the organisation.

• Phase 2 – Conducting Management Development Programmes

The needs assessment should have identified a performance gap, (i.e. the difference between desired and actual performance) or another specific set of developmental needs.

Various techniques can be used including: on-the-job techniques, job rotation, enlarged and enriched job responsibilities, mentoring and so on.

• Phase 3 – Evaluation

This process establishes whether the new skills and attitudes or a body of knowledge has been learnt. A method of evaluation is the levels of evaluation method which identifies to the amount of knowledge gained through tests, behavioural changes as well as organisational and goals achieved.



Successful development programmes for managers must consider the following:

• Performance Appraisal

Developmental needs of current managers are most effectively identified through objective, results-oriented appraisal techniques.

• Long-Range Planning

Development activities should also be based on the future needs of managers and skills required to fulfil future job responsibility.

• Top Management Support

Any development activities must receive a strong endorsement from top management.

• Climates for Change

Managers must be able to transfer new skills and abilities to the work environment.

• Professional Staff

Membership in professional associations help keep practitioners up to date.

A model for the development of managers is illustrated in Figure 6.4.

Figure 6.4: Model for Development of Managers

A useful tool that can be used to help identify both the training and development requirements of water services institutions is a computerised human resource planning and management system developed for the Water Research Commission (HRPMS Version 2). HRPMS Version 2 allows for a matching process between a job analysis module that details criteria for generic positions and an employee profile that details the qualifications, abilities, knowledge and competencies of existing managers.

AssessmentPhase

Training and DevelopmentPhase

EvaluationPhase

AssessInstructional

Needs

DeriveObjectives

Develop Criteria

Pre-Test Trainees

Monitor Training

Evaluate Training

Evaluate Transfer

Select Training Mediaand Learning Principles

Conduct Training




Carrell MR, Elbert NF, Hatfield RD, Grobler PA, Marx M & van der Schyf S (1998). Human Resource Management in South Africa. Prentice Hall South Africa (Pty) Ltd.

Stewart Scott (2001). Human Resources Planning and Management System (HRPMS). WRC Report TT146/00.

6.3 Benchmarking and Performance Indicators

6.3.1 Introduction

Benchmarking is a process for continuous improvement and involves the measurement of performance against particular criteria related to an activity, generally using measurable performance indicators. The measurement of performance by itself does not tell whether the performance is good or bad as it must be compared with other measurements. In order to make a meaningful comparison, there must be a clear definition of the indicator and a value that is assigned to the indicator which represents an acceptable target to aspire to. This value is defined as the benchmark value.

The following criteria should be considered in determining the performance indicators for WSI’s:

• The set of indicators should cover the full range of activities.

• Be capable of representing the true situation without bias.

• Be clearly defined with a unique interpretation.

• Should not overlap.

• Be readily calculated from available data, or if not available, readily obtainable.

• Capable of being audited.

• Be easy to understand, by specialists as well as lay people.

• Refer to a defined time period, usually one year.

If the indicators are to be used for external comparisons, they should in addition:

• Be referenced to a defined geographical area.

• Be applicable to the full range of water boards with different characteristics and stages of development.

• Be limited in number.

6.3.2 Methodology The methodology recommended is to commence with the establishment of performance indicators that are measured against internally determined and realistic targets, having due regard to guideline values such as those given for water losses and water use efficiency in the WC/WDM Planning Framework guidelines. The next stage would be to establish links with one or more benchmark partners of similar profile to share experiences and ideas with the partners. The objective of the benchmark partner model is to try to bring all the partners up to the level of the best performing partner in each indicator.

Examples of some KPIs related to WSIs are given in Table 6B.



Table 6B: Examples of KPIs related to WSIs

Service Delivery Computation Unit Timing Water supply: House connection.

Number of houses and businesses served with potable water / total number of houses and businesses x 100.

%. Annual

Water supply: Yard or communal tap.

Number of houses and businesses served / total number of houses and businesses x 100.

% Annual

Customer Response: General.

Number of repeat calls where the customer has not received satisfaction / total number of calls x 100.

% Quarter

Service Reliability Total period in hours during the reporting period for which service was disrupted as a result of a supply infrastructure failure / total number of hours in period x 100.

% Month

Average Water Tariff: Bulk Water

Total amount paid for potable water for the year / the total volume put into service in megalitres.

R/M� Annual

Average Water Tariff: Retail Water

Total amount charged for potable water for the year / the total volume put into service in megalitres.

R/M� Annual

Rate of Return on Assets

Net income excluding interest received / average net book value of assets x 100

% Year-to-date

Financial Operating Performance

Net income / operating revenue x 100 % Year-to-date

Gross Margin Ratio Gross income (profit) / net revenue x 100 % Year-to-date

Current Liquidity Ratio

Current assets / current liabilities # Year-to-date

Debt Service Ratio Net income excluding interest paid and depreciation / total debt service

# Annual

Total Debt Ratio Total debt / total assets # Annual Pump Energy Efficiency

Total energy consumption for pumping in kWh / megalitres pumped times the static head

kWh/M� Month

Utilised Distribution Capacity (Installed)

Utilised in M�/d / installed M�/d x 100 % Annual

Utilised Distribution Capacity (Available)

Utilised in M�/d / available M�/d x 100 % Annual

Consumer Meter Coverage

Number of metered connections / total number of connections x 100

% Annual

Water Quality Number of compliant samples / total samples analysed

No. Annual

Non Revenue Water – water billed but not paid for

Unpaid bills more than 3 months / total billed amount

%

Non Revenue Water – apparent Losses

Apparent losses / total water supplied % Annual

Non Revenue Water– real losses

Real losses / number of connections litres/ conn.da

y

Annual

Notes on Non Revenue Water - Real Losses:

� Real losses comprise leakage and overflows from water containing structures plus leakage from distribution pipes and connections. If the former is deemed to be negligible, then the preferred indicator for distribution losses alone is Infrastructure Leakage Index (ILI).



As explained in section 5.4 of Volume 2 of these guidelines, percentage of total water input is the least appropriate means of measuring (real) leakage losses, since it takes no account of the wide variation in technical circumstances between different systems. Even worse, it increases when consumer use and consumer waste goes down and reduces when consumer use and waste goes up!

� A useful monitoring indicator is also provided by the comparative ratio: Ram = Qad/Qmnf; as illustrated by the following example:

If the average demand flow rate Qad for a given area is, say, 1000 units, and the minimum night flow rate Qmnf is 10 units, then Ram is 10. However, if Qad increases to 150 units while Qmnf becomes 50 units, then Ram is 3. The implication is that the closer Ram approaches the value 1, the worse is the condition of the distribution system.

� Other useful action indicators are based on the ratios Vadd/Vb and Qmnf/Vb and can be employed in a month-by-month comparison of successive years for an area, or just for a single property or group of properties. If the consumption of an area or a property increases but the revenue from it decreases, then either losses are occurring or theft is taking place. In either event, an investigation is necessary. Each water services authority is encouraged to develop its own ratio indicators as the early warning part of its water loss control programme.

Vadd average daily demand volume

Vb billing volume

References and Suggested Further Reading Alegre et al (2000). Performance Indicators for Water Services, IWA

Pybus P, (2001). Guidelines for the Implementation of Benchmarking Practices in the Provision of Water Services in South Africa. WRC Project K5/1053.

SABS 0306-1999. The management of potable water in distribution systems.

Wolmsley J, Carden M, Revenga C, Sagona F & Smith M (2001). Indicators of sustainable development for catchment management in South Africa – Review of indicators from around the world. Water SA Vol. 27 No. pp 539 – 550.

6.4 Information Systems

In view of the importance of good information to water conservation and demand management, this section of the guideline provides an overview of the subject.

6.4.1 Introduction / Basic Principles Information systems comprise all forms of records in paper and digital form that enable water service managers to monitor:

• Consumer numbers and profiles

• The service provided to consumers

• The extent, condition and performance of infrastructure assets

• The resources deployed and their costs

• Water fed into supply and utilised by consumers



As with any other aspect of water service provision, water conservation and demand management is practised more efficiently and effectively if there is a competent knowledge base of the infrastructure assets, their condition and performance, and of the characteristics of and water used by consumers. The poorer the quality of these basic data, the more difficult it is to set and achieve realistic loss reduction targets.

It is often the case that the introduction of demand management marks the first shift from re-active to pro-active mode of system management and there will be an obvious need to rectify deficiencies in data coverage and quality. These data are essentially the same as those needed for monitoring consumer service levels, operational efficiency and investment planning. The processing of that data into relevant reports and performance indicators will vary, however, according to the needs of the operation or management function concerned.

A unified information system is an essential foundation for an integrated network management approach. It is therefore highly desirable that any initiative to improve information systems considers the broader needs of the water service, even if not all components are put into place at the outset.

It also follows that the cost of improvements to information systems should not be seen as a part of the cost of WC/WDM specifically. Start up funding for the implementation of WC/WDM should be obtained, supported by a strong motivation for improvement of efficiencies, capacitating of municipality staff and sustainability of interventions.

6.4.2 General Approach / Methodology The information required as output may in some cases be derived directly from a single source of raw data, e.g. the quantity of water produced over a given period by a water treatment plant is obtained directly from the outlet flow meter. But other outputs require data from more than one source that may be captured and transmitted by quite different means before being brought together and processed in some way to create the output in the form required.

A conceptual model of this process is shown in Figure 6.5.

Output data can exist in a variety of formats that would be standardised within any one organisation. Outputs denoted as ‘reports’ range from simple spreadsheets and data schedules that are used internally for routine monitoring and control, to formal reports that may be provided to council members, board of management, or external organisations.

Figure 6.5: Information Management – from Input to Output

Information Management Systems

Hourly, daily,

monthly, quarterly and annual

summary ‘reports’

plus

on-request interrogation

Inputs: capture of raw data

Data Transfer:manual

portable PC hard wire

radio telephone

Data Processing Outputs:

GIS other databases

spreadsheets manual forms

reports



An attempt to define the operation and management information needs of a small – medium water undertaking, such as a typical South African municipality, defining the raw data required for each output and the means by which such data is captured, relayed and processed is given in Annex 8. The output forms should be universally applicable, but the means of data capture, transfer and processing will vary according to local circumstances. The tables exclude the flow of routine operational control data, e.g. at pump sets and treatment plants, although where a SCADA system is provided it would probably generate exception reports to specified individuals.

In an idealised situation all raw data would be accessible via a fully integrated management information system that would link operational SCADA systems with those that presently have to fulfil administrative and financial as well as technical functions. The entire information management system should be driven in-house by a suitably trained information management technician. Until such time as such an ambition may be realised in the future, we must be able to achieve the same end through a form of integration that will require manual intervention at various points, although preferably not necessitating duplication of data entry.

6.4.3 Procedure: Step 1 Identify all existing sources of relevant information in technical, administrative

and financial departments, the format of the information and who is responsible for collecting it. Draw flow chart(s) to show inputs, processing and outputs.

Step 2 Identify gaps / inefficiencies in data collection / processing / reporting.

Step 3 Draw amended flow chart and devise new data collection / reporting formats.

Step 4 Determine level of automated data capture and processing to be adopted - range of options from mainly manual paper based data capture system but with use of standard office spreadsheet and database software for data collation and presentation, to fully integrated management information system.

Step 5 Implement / procure according to type of system.

6.4.4 Asset Records

Location(s) of Records and Access

A common problem encountered is that records are held in a number of different locations, according to need, but this can be the cause of contradictory information developing, simply because each individual, group or department will have its own requirements as to the form in which the information is held and procedures for up-dating.

Regrettably, managers have in the past failed to recognise the value in having good asset records and have allowed a situation to develop where this essential information is either not available at all within the organisation, or reliance is placed on consultants who were responsible for the initial implementation of schemes. In the latter case it is certain that the record drawings will be out of date, even if their status is noted as “as constructed”.

At an early stage it is important, therefore, to review the total information database that exists or is intended to be developed and determine which staff/groups use each element of the information. A decision can then be made as to the location for each element and, equally important, the responsibilities for up-dating and procedures for so doing.

If at all possible, the need for duplication of records should be avoided, for obvious reasons. The advent of computerised systems, if properly set up and maintained, can facilitate access to central records by several users in different locations.



Records Review and Initial Up-Dating

It is recommended that, as a first step, all physical asset records are cross referenced and checked, since contradictory and unreliable information may exist, e.g. project contract drawings being used in the absence of certified ‘as-built’ records.

Discussion with operations staff can be particularly fruitful in resolving queries and determining how a system has developed over time. Often information exists in the form of personal knowledge of the staff and workforce, which can be extended to retired staff still resident in the area. It is important that this knowledge is utilised in the up-dating exercise.

The data must also be verified in the field, through walking the infrastructure routes, checking for the existence and locations of valves and manholes, identifying obvious connections and tie-in points and exposing the infrastructure at strategic points to prove the existence of the infrastructure. In certain instances, field verification may be the only information or data source. The process of hydraulic modelling discussed in section 6.4.6 will also assist in the validation of record data and identify anomalies within the records themselves and between the records and physical measurements on site. Once the records have been checked through, it is essential that procedures are introduced so that in the future they are updated on a regular basis, as a matter of routine.

Valve Audit

The records up-dating exercise is more than just registering the extent of the fixed assets. It is a fundamental part of getting to understand how the system operates. On the surface, generally only the valve positions are evident and a valuable activity is to operate the valves to find out what effect there is on distribution, make repairs, excavate locally at junctions, to help determine the connectivity.

Digital Mapping

To transfer paper map records into digital format, it will be necessary to have up-to-date digital mapping of the distribution area. Digital mapping is available from the Government Printer for South Africa. In situations where up-to-date digital mapping is not available, the local authority may have to engage a specialist survey company to carry out an aerial survey and prepare digital maps.

Generally maps are available 1:50000 and in some cases 1:10000 or 1:5000.

Geographical Information Systems

Geographical Information Systems (GIS) connect the geographic elements of digital maps to a computer database and allow the true spatial aspects of features to be modelled. The database may contain any information about a particular asset and may link directly to other asset data. Such a database structure can be interrogated independently of the geographic data and can be used to solve asset or operational problems. This interrogation can be undertaken on individual assets or over combinations of assets within a discrete area.

ArcInfo and Regis are typical GIS packages available in South Africa. The records review and up-dating should ideally precede the implementation of GIS, so that the quality of the data within the GIS is as good as is practicable and that errors and anomalies in paper records are not merely carried forward into digital format in perpetuity.

The GIS has many features which can provide information in forms not previously possible, however to make use of such features there is a substantial data input effort required, the extent of which should not be under-estimated when planning their introduction. Data capture process will entail the following:



� Identification of infrastructure components on the ground. The positions of valves will most likely indicate the position of a watermain, and the positions of manholes will most likely indicate the likelihood of a stormwater or sewer pipe.

� The pipework configuration relative to the valves and manholes must need to be determined. This may require additional excavations leading to connections and junctions.

� Ideally, the positions of the valves, manholes and pipelines should be captured using a hand-held GPS, so that the information could be downloaded onto a suitable GIS platform.

� A detailed description of each valve, accompanied by a digital photo should be documented. This forms a basis of a valve audit.

� A spreadsheet should be developed, capturing information relating to the size and location of valves, the valve type, date of installation, date of last service, servicing interval, and condition at time of last inspection.

� All information captured in the field must be captured onto the GIS system, and linked to the relevant photos and spreadsheets.

� If pressure readings or loggings are available, then these should be linked to installations, so that it could be viewed using a hyperlink or pop-up menu.

� The information captured onto the GIS will identify the need for further field verification, should anomalies in pipe configurations and connections be identified. The information gathered should be fed back to the data capturer.

� The field verification and data capture process is an iterative one, and depending on the complexity of the infrastructure network, some reasonable assumptions must also be made for the purposes of completing the picture.

In rural areas, the need for sophisticated data management systems is less than within towns and cities. It is also worth noting that the cost of digital maps will be much greater in relative terms, for a given network length or customer base. Aerial photos taken during population census exercises, or election planning may be useful in identifying key infrastructure components and pipeline routes. In many instances, these aerial photos may prove to be advantageous when plotting rudimentary water and sewerage infrastructure as the high cost of implementing a full GIS may not be warranted on smaller rural settlements.

6.4.5 Asset (Infrastructure) Maintenance Management Systems The key elements of a maintenance management system are:

• An inventory of all equipment and infrastructures that require preventive or corrective maintenance

• Works orders, as they are essential for issuing, recording and following up maintenance tasks

• Preventive maintenance is the only way to ensure reliable operation of equipment and comprises:

⇒ Maintenance procedures (i.e. based on O&M manuals and experience)

⇒ Scheduling (i.e. based on time, usage, etc.)

⇒ Monitoring (i.e. current on-line or historic)



• Feedback and control of planned maintenance activities according to schedule

• Resource management to ensure its optimal and “legal” utilisation

• Records of maintenance history to provide information about equipment reliability and replacement.

Computerised management systems provide ready access to information, thereby fulfilling the needs of management by supporting the human decision-making process, providing models which identify applicable types of data, and therefore limiting the capture and storage of unnecessary data. These factors all play a part in the institutional strengthening process related to Water Demand Management. These management systems allow interactive and fast access to data as well as assisting managers in retaining control. Managers can handle more subordinates leading to wider spans of supervision and yet still rapidly apprising them of the consequences of any decisions taken and allowing them to take timely corrective measures.

Management of the asset base has historically been dependent on the subjective assessments of those responsible for day-to-day operation and maintenance of the assets. But there is a requirement for the asset base to also be managed from higher levels of the organisation in a way which will ensure that future investment delivers maximum benefit for customers and shareholders alike that includes the minimisation of physical and non-physical water losses.

A computerised asset management system generally comprises three major constituents, namely (i) inventory, (ii) programmed action and, (iii) optimisation.

Inventory details include the identification, specification and situation of the assets that would typically be held in an asset register. Programmed action includes details of when, how and how often (or how much) the asset should be inspected, maintained or tested. Optimisation indicates to the manager why and to what extent inspecting, maintaining or testing of the asset should entail as well as indicating the extent of related potential benefits.

6.4.6 Hydraulic Modelling of Water Reticulation Systems

Introduction

Water supply and distribution systems are complex networks of pipes, reservoirs, pumping stations, control valves, etc., which have often developed over many years. These systems have traditionally been difficult to manage efficiently because of the complexity of demand, operating regime and performance criteria, especially when any system enhancements to deal with future conditions are under evaluation.

Over the last 25 years, the mathematical modelling of these systems has been developed such that it has now become an important management tool. In this section the role and benefits of hydraulic modelling and the practical requirements for its implementation are described.

It is important to appreciate that the type of detailed 24 hour simulation model used for reticulation network operational purposes needs to have a high degree of accuracy to reflect their complexity, if it is to be of practical value. A less rigorous modelling approach can be utilised in the design of new systems under peak demand conditions, but will not serve as an effective operational support tool. Validation by means of field testing and adjustments is an essential feature of a competent distribution network model.



The Need for a Hydraulic Model

A hydraulic model is not an essential requirement in all circumstances and, as with the introduction of any other new technology or system, a case should be made for it by an objective evaluation process. However there are certain needs which are much more readily met cost-effectively with the use of a hydraulic model. These may be identified as:

- Design of leakage control zones in areas of complex connectivity (inner urban areas)

- Optimisation of system boundaries in conjunction with pressure-reduction and pump optimisation schemes, including specifying PRV characteristics

- Optimisation of rehabilitation measures and pipe replacement programmes

- Investigation of feasibility of transfers across local authority boundaries

- Checking the impact of proposed new demands on the levels of service to existing consumers

- Design of new infrastructure if needed in relation to the above

- Performance of the system under fire fighting conditions.

In all probability at least one if not more of the above needs is likely to be found in most local authorities, so as a general rule one would expect the provision of a hydraulic model to be a significant priority. But it is emphasised that if leakage reduction only is required and if configuration of the network is such that a significant number of leakage control zones can be set up from visual inspection and trial valving by an experienced leakage control engineer, then a model may not be required.

In rural areas, hydraulic modelling is less likely to be needed for leakage control purposes.

Model Structure

When computing power was less than it is now, it was common practice to build a simplified “skeleton” model, modelling only the pipes which, by visual examination, carried most flow. Typically this would be based on size, e.g. 150 mm and upwards. However nowadays computing power s no longer a constraint and the use of GIS mains records has facilitated the building of “all mains” models efficiently. The detail of a model is generally assessed in terms of number of connections per node. In all mains modelling of reticulation networks, the nodal density is typically in the region of 20 connections per node, whereas in strategic models the nodal density may be up to 500 connections per node. Strategic models will generally exclude pipework of less than 200 mm diameter and will therefore be more appropriate as a planning tool, whereas the detailed models which comprise all or the majority of mains may be used also as an operational tool.

Models that are linked to a GIS enable faster data entry, but whereas a GIS must necessarily hold every pipe in its database, i.e. a node at each end of a length of pipe, this can be too detailed for the uses to which the model will be put and does not improve accuracy. On the contrary it can make validation and stability more difficult to achieve.

Benefits and Use

As well as meeting specific local authority needs, hydraulic models have a number of other important beneficial uses.

The primary benefit, if the model is soundly built, is in the thorough understanding of hydraulic conditions in the network that can only be revealed through modelling.



Coupled with this is the identification and resolution of system anomalies and general operational problem solving that becomes possible.

Benefits are gained at each stage of model development:

(i) Model Construction

• Collation and cross reference of all available records.

• Identification of anomalies and contradictions in records.

• Verification of system boundaries and operation methodology.

(ii) Model Validation

• Identification of system anomalies

- zone valving not water tight

- restrictions in supply network

- incorrect records relating to mains size etc.

• Validation of system demands

- accurate assessment of leakage levels

- identification of unknown and illicit usage

• Assessment of mains condition through pipe roughness values

(iii) Model Use

In addition to specific needs previously mentioned:

• assessment of levels of service to customers

• design of major extensions to the network

• technical support and justification for funding applications

• investigation of mains redundancy and related quality problems (water age)

• investigation of impact of mains failure scenarios and solutions to same

It is important that the uses to which the model is likely to be put are identified at the outset and advised to the engineer or consultant responsible for model building, since this will affect the level of detail and how certain features are built within the model.

The Process

Building a validated computer model includes the following basic steps:

(i) Collection and Input of System Data:

Sources: Initial head profile

Reservoirs: Top water level, ground level, area, depth, controls

Pumps: Characteristic head flow, data, control data, and settings

Pipes: Length, diameter (internal), roughness coefficient (initial estimate based on age and material)

Nodes: Ground levels

Control Valves: Characteristic data, control data and settings

The input of data directly from an existing GIS should be approached with caution, unless it is known the GIS was developed under a good quality control regime.



The process of digitising from paper plans is a tedious task often delegated to junior technicians, students etc. and the frequency of error is significant, this is compounded if there has been no validation of the original paper records by operations personnel. Thus what is already inaccurate becomes more inaccurate through the process of transition, i.e. in that case garbage out > garbage in!

(ii) Demand Analysis:

Allocation of metered users to nodes on the basis of total annual metered consumption of metered users in the associated nodal areas.

Allocation of non-metered domestic and non-domestic users to nodes on the basis of property numbers in the associated nodal area.

Calculation of total metered demand for all zones established permanently or temporarily in the field test by applying user category profiles and summing contributions from all metered categories users to derive the dynamic metered demand estimation.

Estimation of non-metered demand volumes and patterns, including leakage, from the zone meter output and the dynamic metered demand estimation.

(iii) Monitoring of Flows and Pressures in the System - this activity, usually referred to as the field test, incorporates:

Acquiring, programming, installing, checking and downloading flow and pressure data loggers.

Surveying of all the pressure monitoring locations to ±0.01 m.

The numbers of loggers required for modelling purposes will be greater than that needed for continuous monitoring of zones. It may be expected therefore that a local authority will purchase a number of loggers and hire the remainder.

(iv) Model Validation:

Calibration of the numerical model to the real system includes flow balancing, identification of system anomalies, testing different roughness coefficient values (especially on cast iron pipes) trialing of demand at discrete nodes to simulate unreported bursts.

Anomalies and system deficiencies should be validated in the field. It may be necessary to retest if there are excessive anomalies or backlog of bursts in order to calibrate for reasonably normal operating conditions. Good agreement between modelled and measured values is usually taken to be within 5% for flow and within a standard deviation of 1m for pressure.

It is worth noting in this context that model validation within the specified tolerance can be achieved by making adjustments which are not, in fact, backed by evidence in the field. Whilst it is reasonable to make a number of assumptions which can be said to fall within the sphere of the exercise of engineering judgement, experience has revealed that a not insignificant proportion of models which appeared to be calibrated at the time, have not been robust enough to perform satisfactorily under changed demand circumstances, due to underlying deficiencies in the model build.

(v) Documentation and Maintenance

It is essential, if the investment in the model is to be fully realised through its utilisation in future years that the model build is fully documented so that new engineers can understand the ‘audit trail’ leading back to the raw data.



It is equally important that the model should be updated whenever new information is provided, on completion of new developments and other system additions and to reflect changes in operational strategy. Full re-calibration should be undertaken periodically depending on the model size and extent of changes.

Internal procedures should be established so that model maintenance is carried out as a matter of routine on a regular basis.

Modelling Software

A wide range of modelling packages varying in sophistication, user-friendliness and cost are available commercially. A review of these is provided in Annex 9.

6.5 Consumer Meter Reading

Accurate monthly meter reading is a fundamental requirement for good demand management and financial management, yet it frequently gives problems, particularly to larger WSIs. There are many options available in South Africa as listed and compared in Table 6C.



Table 6C: Meter Reading Methods

Method Comments

Self-reading by customer with or without self invoicing from a table chart of amounts of water used versus invoiced amounts

This is how tax returns are done. Requires random auditing and auditing based on credit control reports

Manual reading and writing of reading into book with or without site invoicing

Each reading has to be manually recorded in the WSI’s management system

Programmed manual reading and recording of reading in a handheld computer with or without site invoicing. Programmed means the meter readers route is planned before he/she leave base.

A recommended choice once there are sufficient meters to be read to keep the unit used about half the month or more. Readings are downloaded automatically into the WSI’s information management system. Site invoicing is simple and with very useful, in areas without postal deliveries, where some customers without post boxes have uncontrolled metered connections.

Programmed photo-meter-reading with a special digital camera

A new untried method for South Africa. Only recommended where a WSI is having problems with meter readers using the previous method. Currently, each reading has to be manually recorded in the WSI’s management system. Photos of meters must be correctly referenced to the meter to prevent confusion, due to the large number of similarly looking photos.

Programmed scan-meter-reading with a handheld computer with or without site charging

Like photo-meter-reading, this method ensures that the meter reader actually visits each meter. Readings are downloaded automatically into the WSI’s information management system. Not used in South Africa because of additional maintenance and current capital cost, which is twice that of a photo-meter-reading system.

Smart technology reading of end of month reading any day after the end of the month with a hand-held or lap-top computer

Usually tied into a prepayment metering system. Highly recommended for water loss control, if a prepayment system is being used. Note: not all prepayment systems support this technology

Pass by customer’s property and automatically read meter with a hand-held or lap-top computer

Again, usually tied into a prepayment metering system. Has the advantage that the meter reader does not have to enter the customer’s property.

Automatic meter reading (AMR) from the WSI’s office by radio, powerline carrier, telephone land lines or cellphone

The most expensive form of meter reading but for large WSIs can be appropriate for bulk meters and the meters associated with very large consumers

Water meter readings must not be accepted at face value. The meter reading must be downloaded onto a spreadsheet for interrogation and validation. The spreadsheet must contain previous meter readings, so that a comparison could be made with previous water consumptions, or a water consumption pattern determined. A simple sensitivity analysis or variance report will highlight anomalies, and may flag the need for a review of the meter reading.



Each meter will be given a unique number that links it to a pressure or demand zone, which will facilitate WC/WDM. Most water billing systems are able to facilitate these checks and interrogations with their built in routines. The older billing systems are slowly losing their popularity with municipalities due to their inflexibilities, and replaced with systems that could facilitate WC/WDM with greater ease.

6.6 Drought Management

The term drought is commonly understood to mean an extended period without significant rainfall that threatens the existence of natural flora and fauna and necessitates the curtailment of normal water use for household and economic purposes.

Statistically a drought is an event that has a probability of occurrence of 50 years or more, but if resource and demand management planning policies have failed to secure continuity of normal supply to consumers, then drought management measures may need to be introduced under less frequent dry weather events.

Generally, groundwater supplies are less susceptible to drought than river intakes or surface-water impoundments. The susceptibility of both surface-water and groundwater systems may be heightened by:

(a) The lack of knowledge about the nature of legal entitlements to water from these sources

(b) The basis on which the water quantity entitlement was established

(c) The degree to which the water supply would be reduced in the event of a water shortage

Because of these uncertainties and the limitations on traditional approaches to long-term drought protection, many water utilities are forced to consider demand management alternatives aimed both at controlling growth in water demand over time and at achieving significant temporary reductions in water use during periods of drought. The demand management options that can substantially reduce future water use and enhance the level of drought protection may include:

� Public campaigns to educate consumers on how to modify water use habits to reduce water consumption.

� Promotion or mandatory requirement of the use of water-saving devices and appliances.

� Promotion on mandatory requirement of low-water-using urban landscaping.

� Adoption of efficient marginal costs pricing strategies to discourage inefficient uses of urban water.

� Adoption of zoning and growth policies to control the number of water users served by the water supply system.

These long-term conservation alternatives in combination with some unconventional supply augmentation alternatives have the potential for providing adequate future water supply for urban areas at the minimum cost while enhancing the ability to withstand the effects of droughts.

During periods of drought, water utility must carry the burden of responsibility for uninterrupted supply can take a number of emergency actions in order to minimise the risk of running out of water.



Such drought management measures may be (1) planned prior to the onset of drought or developed ad hoc after a drought becomes apparent, and (2) oriented toward reducing water demand or toward provision of supplemental (emergency) sources of supply. These actions, whether aimed at increasing supply or reducing demand, may result in temporary increase in the cost of water supply or may cause the urban economies and consumers to suffer significant economic losses.

There are four types of response to droughts:

• Short-term

(i) Reduction of water use on losses

(ii) Emergency water supplies

� Long-term

(iii) Non emergency conservation programmes

(iv) Augmentation of water supplies

A drought plan could consist of all four categories of adjustments. The drought plan must initially allow for the existing system to support the established uses of water during normal supply conditions. The assurance of supply must be planned by acquiring and developing new sources, as well as by pursuing conservation strategies for achieving permanent modification of demand. Once the plan for balancing the demand and supply during normal supply years is developed, the selection of the optimal adjustments for drought conditions is based on the assessment of the risk and magnitude of water shortages under drought conditions.

The comparison of short-term and long-term adjustments to drought is assessed by estimating the expected present value of the cost of coping with drought emergencies during a prescribed period. This coping cost is determined on the basis of the probability of water shortages and the cost of coping with them

For each year of planning period, minimum-cost drought response plans are formulated for a range of possible supply deficits. The probability of occurrence of each deficit is assigned to the cost of the corresponding emergency response plan. In this manner, a higher coping cost in any given year is associated with a higher deficit having lower probability of occurrence.

The expected value of the total coping cost during a planning period T is found by summing the present worth of the expected values of coping costs in each future year according to the formula:

T k

E(TC) = ∑∑ pit Cit (1 + r) – t

t = 1 i = 1

In which E(TC) = the present worth of the expected value of the cost of coping with shortages during the planning period T;pit = the probability of water shortages in year t, which shortage would call for expenditure Cit to cope with it; i = discrete levels of probability (e.g. 0.01 for a 100-year drought, 0,10 for a 10-year drought, etc.), i = 1 … k; t = year of the planning period; r = discount rate.

The present worth of the expected value of the long-term cost of coping with water shortages is inversely related to the investment expenditure on the long-term supply augmentation and demand-reduction projects. Any long-term alternative will affect the size of future deficits, thus resulting in a different expected value of the cost of coping with droughts. The optimal solution is found at a point where the incremental cost of the long-term adjustments equal the decremental costs to cope with droughts.



However, these cost trade-offs do not have the absolute equivalence of monetary values. The relatively “certain” costs of supply augmentation or conservation programs are compared with relatively “uncertain” expenditures and economic losses associated with drought emergencies. In some situations, water planners may choose to compensate for the differences in uncertainty by assigning weights to each category, thus possibly accepting long-term protection alternatives which are less cost-effective.

Box 6-1: The socio-economic effects water restrictions on local authorities and selected industries in South Africa (WRC Project No. 168/1/89)

Water demand management techniques can be successfully applied through the implementation of water conservation measures that have proved to be the most effective during times of drought. Lessons that have been learnt from past water restrictions, which are relevant to future water conservation efforts, are;

⇒ An overall reduction in water use varies from 1 to 50%. However, when water usage is reduced beyond 30% it can have a detrimental effect on the user from both a financial and motivational perspective.

⇒ Voluntary reduction in water use fails to achieve the level of savings that mandatory water savings can.

⇒ The most effective method of water conservation is an altered tariff system, restriction of watering times, the banning of hosepipe usage and allotting quotas to industry and bulk consumers.

⇒ The most effective methods of motivation are pamphlets/newsletters, an altered tariff system and punitive measures.

⇒ The major interventions required to reduce both physical and non-physical losses from the pipe networks are leak detection/monitoring, replacing old plumbing and the repair/monitoring of meters.

⇒ The most effective methods of saving water used by commerce and industry are technical adjustments, recycle/re-use and promotion campaigns.

Although the interventions implemented during the drought in the mid-1980’s achieved savings in water use that also reduced the growth rate in water usage after the drought had ended, there is little or no incentive for consumers to continue to retain these water wise practices adopted during the drought. New customers also do not necessarily have the experience of saving water in a drought situation and, therefore, have even less incentive to be efficient in water use when there is not a drought.

Many water demand management and conservation strategies are usually based on the hypothetical assumption that people are going to behave in a predictable manner. However, there is a need for a sense of reality as predicted hypothetical behaviours are seldom realised. The overwhelming advantages of analysing research on past water restriction in order to facilitate future water conservation strategies are:

• Relevant aspects have been covered/researched

• It has provided a simulation of reality in predicting water demand management measures

• It identifies areas of tolerance and areas of resistance

• It clearly identifies that an over-reaction can be counter productive.

An understanding is that water restrictions were imposed under exceptional circumstances. However, the cautious interpretation of research about the restrictions can facilitate the development of plausible water demand management interventions.

Water demand management interventions can be described by a continuum from mild voluntary reductions through to harsh mandatory water savings.




Baumann DD, Boland JJ & Hanemann WM (1998). Urban Water Demand Management and Planning. McGraw-Hill.

Schlemmer L, Stewart G & Whittles J (1989). The socio-economic effects of water restrictions on local authorities, selected, industrial and commercial establishments and other private agencies. Water Research Commission Report No. 168/1/89.

ANNEXES ANNEX 1: GUIDELINES ON INPUTS AND COSTS OF SOME WC/WDM AND RELATED

ACTIVITIES A1 ANNEX 2: FLOW METER TYPES AND SELECTION A6 ANNEX 3: METHODS OF LOCATING LEAKS IN WATER RETICULATION

SYSTEMS A9 ANNEX 4: SUPPLEMENTARY INFORMATION ON ASSET MANAGEMENT OF FLOW

METERS A13 ANNEX 5: CODES AND STANDARDS APPLICABLE TO DEVELOPMENT OF NEW

INFRASTRUCTURE A17 ANNEX 6: GENERAL METHODOLOGY FOR SETTING WATER SERVICE TARIFFS A20 ANNEX 7: INNOVATIVE MANAGEMENT APPROACHES A34 ANNEX 8: INFORMATION MANAGEMENT NEEDS – WATER SUPPLY AND

DISTRIBUTION [EXCLUDING FIXED ASSETS A38 ANNEX 9: CHARACTERISTICS OF HYDRAULIC MODELLING SOFTWARE

PACKAGES A42

ANNEX 1

VOLUME 3: WSI IMPLEMENTATION GUIDE MARCH 2004 PAGE A1

Annex 1: Guidelines on Inputs and Costs of Some WC/WDM and Related Activities

Notes:

1. All costs are based on 2004 prices and should be regarded as approximate / indicative. In a specific case, estimates must be based on the particular scope and performance requirements, local factors and quotations or previous out-turn costs for similar works, services and equipment.

2. Installation costs assume that the work is outsourced to a Contractor and includes

VAT at 14%

3. All discounted cash flow and incremental cost calculations use test discount rate of 7% per annum over 21 years – first year implementation followed by 20 years operation and maintenance. Refer spreadsheets included with Volume 2 Annex 8.

4. At the time of drafting, cost and resource input information from the IWRM pilot

projects has still to be received and analysed for inclusion in Annex 1. Alien Plant Clearance:

Approximate initial clearance cost R3,500 per hectare

Approximate annual maintenance cost R750 per hectare

Assume 100 mm of net additional run-off generated = 1,000 kl per hectare

The costs of alien plant clearance at 2004 prices are likely to be in the range of R2,500 to R4,500 per hectare, depending on the nature of the invasion and terrain. Annual maintenance costs are likely to be in the order of 20-30% of initial clearance. A typical average incremental cost would be R1.00 per kl per 100 mm of additional run-off generated.

The net additional run-off must take account of any evaporation and other downstream losses between the area of clearance and the point of abstraction of the additional water that is generated.

The Working for Water Programme can be referred to for preliminary cost estimates of a situation assessment survey. The cost per ha is greatest for small areas. Accessibility and the degree and type of invasion also have a significant effect on the cost.

Control operations are a major investment so it is essential to minimise them by ensuring that productivity (e.g. workdays per hectare) is maximised.

The costs of control operations can be divided into: initial clearing, first follow-up, second follow-up, further follow-ups and annual maintenance. The actual direct costs per hectare will depend on the density of the invasion, the species involved and their control requirements, the location of the invasion and logistical requirements. Working for Water have developed norms and standards for man-hours and costs of control operations which are available for many areas of the country and could be adapted, where necessary, for the local situation.

There are some general rules of thumb:

ANNEX 1


� Field mapping costs roughly R12-R18 per ha, including conversion of the data to a format suitable for a geographic information system. Costs for the equivalent data preparation using aerial photography or videography are of the order of R6 per ha.

� About 30-40% of the total cost will be the initial clearing with the remainder going to the follow-ups except for a small amount for long-term maintenance. Long-term maintenance costs are not well known but are considered to be in the range R15-R50 per hectare cleared.

� The cost of controlling dense invasions can range from 10-100 times that of light invasions. This is why it is environmentally and economically sound to control light invasions, followed by medium and finally dense invasions.

� Lightly invaded areas will rarely require additional restoration of the indigenous vegetation but densely invaded areas will generally require restoration work.

� The total cost may be as high as R5,000 per hectare over a period of three to five years

� Maintenance is generally 50 to 60% of the cost of the initial clearing exercise for the first maintenance activity and thereafter between 20 to 30% of the initial cleaning exercise for every subsequent maintenance activity.

The costs per hectare are also dependent on the level of experience of the control teams. The initial costs are high because of the need to purchase equipment and train the staff who typically come from the unemployed and lack even basic skills. Working for Water have a structured programme which begins with employees on a payroll and works systematically to changing the employment to a contract basis with the ultimate goal being independent contractors who employ their own staff. The approach adopted by different organisations will differ but this is a useful and practical approach to follow.

Infrastructure Information:

Review and Updating Consumer Register and Consumer Profiling

Varies considerably, depending on the competence of the existing database, anything between 0.2 and 1 technician days per 100 consumers.

Updating Water Mains Records

Depends on the quality and extent of the existing records and the format of the records, e.g. GIS. Checking the existing records with knowledgeable operations personnel and annotating the existing records can vary between 0.2 and 1.0 technician days per km of pipeline. Digitising into a GIS adds a further 0.2 days per km.

Review and Updating of Consumer Meter Database, Report on Meter Stock

The database can be very poor due to lack of database maintenance and inadequacy of database design (lack of fields), time input may vary between 1 and 4 technician days per 100 meters.

Preparing a report on the meter stock, allow 5-10 engineer/technician days depending on size of stock, plus cost of testing representative sample of meters.

ANNEX 1


Hydraulic Modelling of Distribution Networks

For a fully validated model in an urban area, allow between 1.5 (large network) and 2.5 (small network) days per 100 connections, to which must be added the cost of procuring or hiring instrumentation (data loggers, hydrant caps, temporary flow meters) for the field tests. Modelling rural networks takes less time per connection.

Replacement of Buried Sluice Valves:

Table A1A: Approximate Valve Replacement Costs, Rand

Valve Diameter,

mm

Cost of Valve and Pipe Fittings

Total Cost with Civil Works, Installation

and Commissioning

75 1,000 4,000 100 1,500 5,000 150 3,000 7,500 200 5,000 10,000 250 7,000 12,500 300 9,000 15,000

Replacement of Consumer Meters:

Table A1B: Approximate Consumer Meter Replacement Costs, Rand

Meter Diameter,

mm

Cost of Meter and Fittings


and Commissioning

15/20 300 1,500 25 400 1,800 40 900 2,500

System Flow Meters:

The costs in Table A1C assume the provision of a bypass. Costs will be less if no bypass is fitted. The costs relate to the diameter of the meter and not the main in which it is installed, which will normally be larger.

Table A1C: Approximate Meter Installation Costs, Rand

Meter Size, mm

Cost of Meter, Valves, Strainer and

Pipe Fittings


and Commissioning

50 1,500 5,000 75 3,000 12,000

100 4,000 20,000 150 7,000 25,000 200 9,000 35,000 250 12,000 40,000 300 17,000 50,000 350 24,000 70,000

ANNEX 1


Data loggers:

single channel R13,000

dual channel (pressure & flow) R18,000

Sectorisation and Active Leakage Control:

The initial cost of sectorisation and leakage control zone establishment comprises:

1. Design of the sectorisation scheme

2. Checking and replacing or repairing boundary valves

3. Installation of zone meters and any short lengths of main

4. Pressure zero test

5. Locate leaks and repair them

A typical installation cost including meter for a 1,000 property zone would comprise:

Design scheme (proportion allocated to one zone) 10,000

Check boundary and step test valves for satisfactory operation, allow for replacement of 5 valves

35,000

Install new meter, 150 mm 25,000

Pressure zero test including trouble shooting 25,000

Leak location, allow 3 passes 40,000

Repair leaks, allow 10 services & 1 main 15,000

Total R150,000

These costs exclude the provision of IT hardware and software and purchase of leak detection equipment, however the estimate for leak location would be adequate for outsourcing to a specialist service provider, assuming that the contract was for more than one zone.

The cost of zone maintenance comprises:

1. Regular monitoring of zone inflows

2. Search and repair new leaks when need for intervention is triggered by zone monitoring

Item (1) can be allowed at R2,000 per year if telemetry is used, but if data loggers have to be visited on a weekly basis and downloaded, it would be greater, say R5,000 per year.

The cost of intervention is dependent on the rate of propagation of new leaks, which is in turn dependent on the structural condition of the infrastructure and operating pressure. For a zone of 1000 properties in reasonable condition less than one intervention per year should be required, in addition to reported leaks (passive leakage control), allow leak location at R15,000 and leak repair at R3,000, say.

The total cost of zone maintenance on the above basis is in the region of R20-25,000 per year, but is often argued that the cost of zone maintenance leak repairs should not be included in financial appraisals, since they are not additional leaks. It will be remembered that the objective of active leakage control is to minimise the time between a new leak occurring and its repair.

ANNEX 1


The fact that a WSI establishes an active leakage control programme does not actually increase the number of leaks to be repaired, in the longer term.

Pressure Reduction:

The cost of pressure reduction, using a PRV installation, comprises:

1. Any reconfiguration of the network needed to isolate the pressure reduced zone from the rest of the supply area, if applicable

2. The PRV itself.

(1) May not be required at all or could be significant, requiring a form of sectorisation and associated investigative work. Whereas, for active leakage control, sectors need to be sufficiently small to be able to discriminate new leaks on a night flow meter reading, the larger the pressure reduced zone the more cost effective the installation. For example one PRV could regulate pressures in two or more leakage control zones.

Table A1C: Approximate PRV Installation Costs, Rand

PRV Size, mm

Cost of Fixed Outlet Pressure PRV and Pipe

Fittings

Total Cost with Civil Works,

Installation and Commissioning

80 20,000 35,000 100 25,000 40,000 150 35,000 55,000 200 45,000 70,000

If dual outlet or flow modulation is necessary, add R25,000 and R40,000 respectively.

The cost of a PRV installation is reduced if it is combined with a sector zone meter in a common chamber.

Regular PRV maintenance is essential, allow R5,000 per year to include telemetry telephone charges.

Consumer KAP Survey (representative sample) and Education & Awareness Programme:

Between 20 and 50 surveyor days for KAP survey, depending on size of municipality.

Development and initiation of education and awareness programme, range R100-200,000.

ANNEX 2


Annex 2: Flow Meter Types and Selection Generalised accuracy (signature) curves for a mechanical turbine, electronic ultrasonic, differential pressure averaging pitot and differential pressure orifice plate are illustrated in Figure A2.1.

Figure A2.1: Flow Meter Accuracy Curves

Table A2A: Comparison of Water Meter Types Water meter types

Parameters Velocity

Positive Displacement

Electro-magnetic

Differential Pressure Vortex Ultrasonic

Error (%)

(under ideal conditions)

± 0.2 to ±1 ±0.2 to ±0.5 ±0.2 to ±1 ±0.5 to ± 1 ±1 over measureme

nt range

±1 to ±2

over measurement range

over measuremen

t range

over measureme

nt range

over measuremen

t range

over

Re 20000

over measuremen

t range

Linearity (%) ±0.5 to ±1 over

measurement range

±0.1 to ±0.3

over measuremen

t range

±0.5 to ±1

over measureme

nt range

Dependent on differential

pressure measuremen

t

±1

over measureme

nt range

±0.1 to ±1

over measuremen

t range

Repeatability (%) ±0.02 to ±0.5 over measurement range

±0,2

over measuremen

t range

±0.1 to ±0.2 Dependent on differential

pressure measuremen

t

±0.1 to ±1

over measureme

nt range

±0.2 to ±1

over measuremen

t range

Operational turn down ratio (hydraulics)

100 to 150:1

10 to 250:1 10 to 100:1 3 or 4:1 4 to 40:1 5 to 100:1

Flow Rate % of Maximum Flow

0

5

10

15

% D

iffe

renc

e of

Act

ual F

low

-50 403020 50 60 70 80 90 10010

ULTRA SONIC (Time of flight)

TURBINE

ORIFICE PLATE (100mm T-type)

Diamond-Shape AVERAGING PITOT

ANNEX 2


Pressure drop at maximum flow

1-2 velocity heads

1-2 velocity heads

Minimal 4-6 velocity heads

1-2 velocity heads

Minimal

Minimum velocity (m/s)

0.8 0.2 Below 0.1 Depends on maximum velocity

About 0.4 0.1

(with sensors in contact with water)

Maximum velocity (m/s)

9 5 12.5 8 9 10

Diameter (mm) 5 to 600 3 to 1000 2 to 3000 6 to 2600 12 to 300 6 to 3000

Flow direction Bi-directional

Uni-directional

Bi-directional

Some meters bi-directional

Uni-directional

Bi-directional

Water meter types

Parameters Velocity

Positive Displacement

Electro-magnetic

Differential Pressure Vortex Ultrasonic

Number pipe diameter required upstream

5 to 20 0 5 to 10 5 to 80 1 to 40 10 to 50

Number pipe diameter required downstream

3 to 10 0 0 to 5 5 to 8 5 2 to 5

Filter requirement Required Required Not required

Not required Not required Not required

Installation costs 3 3 3 2 to 4 3 1 to 3

Calibration costs 4 3 3 1 to 4 3 1 to 3

Operation costs 3 3 1 2 to 3 3 1

Maintenance costs 4 3 3 2 to 3 3 3

Spares costs 4 4 3 1 to 3 3 2

Cost Ratios:

1 signifies low (i.e. least costly)

5 signifies high (i.e. most costly)

ANNEX 2


Table A2B: Meter Selection Methods, Applications and Data Sources Method Application Data Sources

Average demands (Management Meters) Average demands (Buildings)

- - - -

“Red book” (1991) Van Schalkwyk (1997) SABS 0252 (1994) BS6700 (1987)

Instantaneous peak demands

- “Red book” (1991)

(Management Meters) - Booyens (2000) - Johnson (1999)

Theoretical Provisional meter selection for planning and design exercises for new installations

Peak demands (buildings) Minimum demands

- - -

SABS0252 (1994) SABS0306 (1999) WRc (1980)

Semi-empirical (theoretical)

First approximation of a meter replacement for an existing installation associated with preliminary maintenance surveys

Average demands Instantaneous peak demands Minimum demands

- - -

Existing meter readings or consumptions from billing system As per Theoretical method above As per maintenance records or theory

Empirical Detailed maintenance surveys to reduce “lost” water due to incorrectly sized existing meters

Average, minimum and maximum demands Seasonal adjustment to demand profiles

- - -

Electronically logged data of demand profiles Manually read hourly meter readings Monthly billing records

ANNEX 3


Annex 3: Methods of Locating Leaks in Water Reticulation Systems

A3.1 Step Testing A method that is used in conjunction with sub-district and zone metering is step testing. In this method, sections of the zone are isolated at night by closing intermediate valves in sequence, whilst reading the zone meter, as illustrated by the example in Figure 3.1. In a section with significantly higher than average leakage, the reduction in flow through the zone meter will be greater than in a section without significant leakage. This appears as a “step” in the flow trace.

Figure A3.1: Example of Step Test Result

ANNEX 3


The three basic types of step tests are:

i. Christmas Tree: This method gives a reverse opening sequence whereby valves are closed in a predetermined sequence commencing at a point the furthers from the monitoring point. When a significant drop in flow or increase in pressure occurs then the location of the leak can be assumed to be between the two previous set of valves operated upon. This method may not be practical in situations where low night flows are of very short duration.

ii. Open and Close: This is a method where each section is turned off and on again for a brief period so that the supply is interrupted for only a short time. The results are much more difficult to analyse but the procedure may be necessary to better maintain supplies for essential services.

iii. Double Locking: For this test, as the metered supply is cut off to a section an alternative supply is made available from outside the district. This is ideal where it can be arranged but requires more labour and an assurance that all valves, not only the boundary valves, close drop-tight.

Step testing relies upon not just boundary valves but also step test valves to be drop tight. An alternative to step testing that avoids the need for replacing step test valves in an older network is the use of acoustic loggers. Arguably, however, such valves should be attended to anyway since they are there for a purpose, namely the ability to limit the number of consumers whose supply has to be cut off when repairs are carried out on the network.

Step testing assumes that there is a limited number of significant leaks that will show up on the flow trace. If there is high general leakage then these steps may be much less distinct. In such a case it is necessary to make a first pass of general sounding all fittings and to locate and repair as many as can be found before repeating the step test.

Step testing only reduces the area of search from a whole zone of, say, 1,500 properties, to a part zone of, say, 300 properties. It is still necessary to employ specific leak location techniques to pinpoint the leak(s) within the step tested section.

A3.2 Acoustic Methods – General The sound of water escaping from a defect has been the basis of leak location for many decades and remains the basis of most modern methods. It will be appreciated that the nature and intensity of the noise is dependent on the characteristics of the defect aperture and how much water is escaping (imagine a whistle). Unfortunately it is the smaller leaks that generally make more noise than the larger ones and in a high leakage area that has not been tackled previously, it is often advisable to start with the tried and tested method of sounding all fittings and usually checking inside all valve, hydrant and meter chambers. Once this has been done and the repairs completed, more sophisticated methods can then be effective.

A3.3 Sounding of Fittings Fittings on water mains and service connections are “sounded” by inspectors. This sounding is basically listening for the characteristic noise of leaking water using a form of stethoscope or an electronic listening device with amplifier. Other acoustic devices include a geophone / ground microphone that registers the vibration generated by the leak.

ANNEX 3


A3.4 Acoustic (Noise) Loggers Acoustic (noise) loggers are strategically placed within the distribution network on valves and hydrants. The loggers are pre-set to record during the period that coincides with the minimum night flow, when background noise is likely to be lower. Noise amplitude will vary due to random effects, but there is always a consistent minimum due to the constant noise of leakage. Noise generated by a leak tends to have reasonably consistent loudness (amplitude). The location of the leak is established from the simultaneous analysis noise recorded by the various loggers as well as their location during the survey.

A3.5 Leak Noise Correlators Leak sound correlators are used to identify, by interpolation, the location of a leak between two points on the water main to which sensors are attached. Leak noise correlators are most effective on metallic pipes. On AC/FC and uPVC pipes the sensors must be closer together and interpretation of the readouts requires greater skill.

If a WSI intends to purchase a correlator, rather than employing a specialist firm to carry out leak location, it is essential that on-site trials are conducted by the staff who will use the equipment. Their preference and success with a particular unit should be the primary motivation for purchase, rather than price or the supplier’s claims or apparent advanced features.

A3.6 Other Methods ⇒ Hydrogen injection

Hydrogen injection can be used when acoustic methods are proving unsuccessful due to low leak noise and/or high background noise. A hydrogen gas mixture is injected and the leak is located by following the route of the water main at the surface with a gas detector.

Figure A3.2: Leak Detection using Hydrogen Injection

⇒ Intelligent pigging

Intelligent pigging utilises the principles of ultrasonic or magnetic-flux to determine the position of leaks within large diameter steel pipelines. Although intelligent pigging is well established in the oil and gas industry it has yet to be adopted by the water industry to any great extent.

ANNEX 3


⇒ Statistical pipeline leak detection

The method detects leaks in pipelines using computer calculations of statistical probability. The system checks for unusual trends in flow and pressure and is reputed to be sensitive enough to be able to trace leaks as small as 0,5 percent of the total flow through the pipeline. This system has been cost effectively applied to oil and gas pipelines but has still to be adopted by the water industry.

⇒ Network analysis utilising inverse problem solving

Leak detection in water-distribution systems can be accomplished by solving an inverse problem using measurements of pressure and/or flow. The problem is formulated with equivalent orifice areas of possible leaks as the unknowns. This method will not substitute the more traditional leak surveys but can serve as a guide that would assist the more conventional methods.

⇒ Infrared spectroscopy

An image of the pipe underground is established from the latent heat reflected from the pipe. This method is not applicable for areas which have numerous underground services because of their side spectrum of emitting sources.

⇒ Subsurface interface radar (SIR)

This method which “sees” into the ground up to a depth of 6 metres is reputed to be able to locate leaks within pipes. However, a pilot study conducted within an established urban area revealed that the SIR only had an approximately 64% success in locating pipes. The equipment is complicated and expensive requiring a considerable level of technical expertise to operate. The cost effectiveness of this method of leak detection has still to be established.

⇒ Tanker method for distribution systems with intermittent supply

Leak detection within water distribution systems that are consistently subject to intermittent water supply because of insufficient availability of water and/or very poor condition of the distribution system require the following approach:

i. Comprehensive mapping of the distribution network using pipe locations and acoustic noise sounding equipment.

ii. Isolation of a small area of approximately 100 connections or 500 m pipe length using values in the network and at consumer meters.

iii. Injection of water from a mobile water tanker and pumping equipment into the isolated area through a water meter with a data logger installed. Installation of pressure gauges or loggers on either side of the isolation point also facilitates determining of the area is isolated.

iv. Undertake leak detection using any of the previously mentioned methods such as acoustic sounding sticks and correlators.

v. After location and repair of the leaks redo the test to compare minimum flows before and after.

ANNEX 4


Annex 4: Supplementary Information on Asset Management of Flow Meters

A4.1 Meter Accuracy Accuracy envelopes are used to define the band within which the meter’s accuracy curve is expected to be situated as well as its specified flow range.

The South African Standard Specifications SABS 1529-1 (1994) as well as the International Standards ISO 4064 (1993) provide a generic definition of this accuracy envelope from the minimum flow rate (qmin) up to their maximum or overload flow rate (qs) as follows:

• qmin is the lowest flow rate at which the meter is required to give indications within the permissible tolerance and is specified as a ratio of the permanent flow rate (qp) for various metrological classes of water meters.

• qp is the flow rate for which the meter is designed and at which the meter is required to operate in a satisfactory manner for a short period of time without deterioration. This short period of time is specified by some manufacturers as 24 h in the life of the meter.

• qs is the rate that is equal to 2 qp and also represents the highest flow rate at which the meter is required to operate in a satisfactory manner for a short period of time without deterioration. This short period of time is specified by some manufacturers as 24 h in the life of the meter.

• Between qmin and qp, a transitional flow rate (qt) is specified dividing the flow range into two separate permissible tolerance zones.

• qt is also specified as a ratio of qp for various metrological classes of water meters.

qp is also referred to as qn and qs as qmax in the International Standards ISO 4064 (1993).

A4.2 Life Cycle Management

The water meter should be managed throughout its life cycle. After the meter has been selected and purchased, it usually goes through the following steps in its life cycle:

� Stock - The meter is placed in stock and pertinent records are kept regarding the meter’s particulars and inventory details.

� Installation request - A formal request for installation of a new meter is received and after the receipt of the prescribed payment and documentation/ plans, the meter is issued to the plumber for installation.

� Removal request - An existing meter could be required to be removed because of planned maintenance scheduling, the meter ceases to function properly or stops. The old meter is then exchanged for a new meter after the prescribed documentation has been completed.

� Movement recording - Details of meters issued, installed and returned to the workshop/depot are recorded.

� Testing & repairs - Meters returned to the workshop are inspected, tested, repaired/refurbished and tested again. Testing of meters are usually conducted in terms of SABS 1529. All test results are recorded. Meters that pass the prescribed tests are returned to stock and those that fail are scrapped.

ANNEX 4


The keeping and updating of meter records facilitates the management process and should include at least the following:

- meter serial number

- meter type and size

- stock reading

- stock date

- scrapped date

- town planning allotment area

- water supply area (reservoir)

- installation reading

- date installed

- change slip number

- consumer code (Treasurer’s rate scale)

- name and address of consumer (current)

- meter reading route numbers (current and history)

- replacement meter number

- reason for replacement

- test results

Meters do not necessarily stay in one place for the duration of their useful life. The decision as to when to move (remove) this asset can be dictated by an event such as a failure or reduction in performance. Systems should therefore be put in place in order to detect such anomalies. These systems could be manual, electronic or a mixture of both. Variations in consumptions that exceed the statistical limits established from historic data or meter readings are usually indicative of problems.

The water audit and balance are also useful tools to help identify problematic meters. Planned and routing maintenance schedules help pre-empt or reduce serviceability problems.

Any system of meter records should provide such basic data for each meter as size, make, type, date of purchase, where the meter is located at all times, and information on all tests and repairs. One method of maintaining such records is by use of a meter history card. Basic meter data is inserted at the top of the form, and the remainder of the card is designed to record the various installations and test and repair work in chronological order. Each line of the test and repair record section is divided into two segments, the upper being used to record the test results for the meter on its removal from service and the lower to record the final test results before the meter is reinstalled. These meter history cards are filed in sequence, either according to the manufacturer’s serial number or the utility’s number, if the utility has its own system of meter numbers. Although this method of maintaining meter records is a good one, it requires transcribing information from other primary records.

Integration with data that is available on billing systems can facilitate access to related consumer information.

A useful method to manage revenue meters that monitor the large water demands is briefly described as follows:

ANNEX 4


1. Obtain billing records of the largest consumers.

2. Analyse and rank the top 100 (say) consumers.

3. Prepare a list of the meters and consumer details for these large users.

4. Schedule regular recordings (i.e. weekly) of the meters as well as analysis of their consumptions.

5. Inspect and replace those meters that exceed pre-determined statistical limits.

A useful summary format to aid the management of large district (non-revenue) meters is illustrated in the example below:

District: ………………………….. Meter: ……………

Dat

e on

Con

sum

ptio

n (M

�� )

Ave

rage

day

for

wee

k

Peak

Ave

rage

day

for

mon

th

Rat

io p

eak/

ave

rage

da

y

Rat

io m

axim

um

wee

k/av

erag

e da

y

Rat

io m

inim

um

wee

k/av

erag

e da

y

Com

men

ts

25.6.00 22,708 3,244 9,00 1,126

2.7.00 18,018 2,574 7,38 0,894

9.7.00 19,572 2,796 8,28

16.7.00 19,348 2,764 8,10

23.7.00 21,161 3,023 9,18 2,880 3,188

30.7.00 17,801 2,543 8,64

6.8.00 10,227 1,461 7,38

The application of confidence limits facilitate the determination of the applicable limits with which water demands/usage would be expected to be found.

For large number of data (i.e. ≥ 30) then the confidence (fiducial) limit for this data can be determined by theformula:

S ± zc σs

Where S = sample mean

σs = standard deviation (standard error)

Zc = from table below

Confidence level

99.73%

99% 98%

96% 95.45%

95% 90% 80% 68.27%

50%

zc 3.00 2.58 2.33

2.05 2.00 1.96 1.645

1.28 1.00 0.6745

Generally the 95% confidence level is used, i.e. S ± 1,96σs

ANNEX 4


Box A4-1: Example of a computerised water meter management system

Water Meter Replacement Feedback Form

Inventory details of this module include:

⇒ Identification – The meter’s serial number and type are identified ⇒ Specification – The meter’s size and accuracy envelope is specified ⇒ Situation – The meter’s previous and current location addresses are recorded

Data and facilities required for determining programmed action include: ⇒ When – Installation, removal and testing dates with associated meter readings ⇒ How – Flow ranges for testing with associated calibration standards as illustrated in

Figure 3.4.2(b) ⇒ How often – Reporting facilities help identify those meters requiring periodic removal and

testing. (or much)

Water Meter Testing Details Form The optimisation of the meter refurbishment programme also facilitates the establishment of the following:

- The optimal frequency for the removal of water meters of a specific size and type - The cost of water lost through failed (i.e. stopped) meters - The cost of water lost through inaccurate meters

ANNEX 5


Annex 5: Codes and Standards Applicable to Development of New Infrastructure

Guidelines and legal requirements associated with the development of water infrastructure:

Table A5A

Description Guide Legal Requirements

Potable Water Drinking Water Standards

SABS 241 Water Services Act (No. 108 of 1997)

Basic Water and Sanitation Provision

“Red Book” Guidelines for the provision of Engineering Services and Amenities in Residential Township Development

Water Services Act

Water Losses SABS 0306 : 1999 Water Services Act

Metering - SABS 1529

- SABS 0306

- Water Services Act

- Trade Metrology Act

Medium-Pressure Pipes - SABS 1200L

Erf connections - SABS 1200LF

Pipe Bedding - SABS 1200LB

Valves - SABS 1200LK

Steel Pipe and Linings - SABS 1200LN

Fire Fighting - SABS 090

- Red Book

Health and Safety Regulations - Occupational Health and Safety Act No. 85

- Compensation for Occupational Injuries and Diseases Act 130

Employment Regulations - Basic Conditions of Employment Act 75

- Employment Equity Act 55

- Skills Development Act 97

Hazardous Materials Regulations - Occupational Health and Safety Act

- Government Gazette No. 665 dated 1/11/99

ANNEX 5


Compulsory specification for water supply components: The SABS is currently preparing a compulsory specification for water supply components that will include normative reference to existing SABS specifications or parts thereof. This compulsory specification will be referred to by current legislation with the aim of protecting the consumer, as well as the protection of South Africa’s valuable water resources.

Example of some of the SABS specifications which are proposed to be referred to in the new compulsory specifications for water supply components are listed in Table A5B.

Table A5B: SABS Specifications Proposed in New Compulsory Specification for Water Supply Components Project Number

SABS Number Title

3527/54884 SABS-ISO 49 Malleable cast-iron pipe fittings 3527/50120 SABS 1551-1 Check valves PT 1 PN series 3527/50140 SABS 144 Cast-iron reflux valves 3527/50070 SABS 198 Pressure-control valves – hot water systems 3527/53240 SABS 1808-15 Backflow preventers – reduced pressure 3527/50590 SABS 1509 Flushing devices – WC cisterns 3527/50030 SABS 664 Cast-iron gate valves for waterworks 3527/50300 SABS 665 Cast-iron gate valves for general purpose 3527/50020 SABS 226 Water taps – metallic 3527/53882 SABS 1529-5 Water meters – Part 5 3527/50160 SABS 821 Water closet flushing cisterns 3527/50110 SABS 1240 Flush valves for water closets 3527/50180 SABS 1021 Polyacetal water taps 3527/50540 SABS 1480 Single-control mixer taps 3527/50130 SABS 191 Cast-steel gate valves 3527/50190 SABS 776 Copper-alloy gate valves 3527/50420 SABS 1056-3 Ball valves – Part 3 – Light pattern type 3527/50580 SABS 752 Float valves 3527/50060 SABS 1067-1 Copper based fittings for copper tubes Part 1 – Compressor

fittings 3527/50870 SABS 1067-2 Copper based fittings for copper tubes Part 2 – Capillary

solder fittings 3527/51500 SABS 546 Cast-iron fittings for asbestos-cement pipes 3527/54861 SABS 1733-1 WC Flushing systems (low-capacity flush) Part 1 – systems

including flushing cisterns 3527/54907 SABS 1808-5 Water supply and distribution components Part 5 - Flexible

connectors 3527/54897 SABS 1808 8 Water supply and distribution components Part 8 – Tap

converter (metering) 3527/54898 SABS 1808 9 Water supply and distribution components Part 9 – Tap

(metering) 3527/54899 SABS 1808 10 Water supply and distribution components Part 10 – Valves

(copper alloy) (non-return) 3527/54900 SABS 1808/16 Water supply and distribution components Part 16 – Drinking

fountain 3527/54901 SABS 1808/30 Water supply and distribution components Part 30 – Taps

(laboratory) 3527/54896 SABS 1733 - 2 WC Flushing systems (low-capacity flush) systems including

flush valves not (started yet) 3527/54903 SABS 1808-32 Water supply and distribution components Part 32 – Valves

(float) 3527/54905 SABS 1808 53 Water supply and distribution components Part 53 – Drain

cocks for hot water

ANNEX 5


Project Number

SABS Number Title

3527/????? SABS 1806-26 Water supply and distribution components Part 26 – Backflow preventers – double check

3527/53848 SABS 1808-31 Water supply and distribution components Part 31 – Valves (control) (Hydraulically operated)

3527/54851 SABS 1808-35 Water supply and distribution components Part 35 – Valves and taps (electronic)

3527/54852 SABS 1808-37 Water supply and distribution components Part 37 – Valves and taps (electronic)

3527/54854 SABS 1808-40 Water supply and distribution components Part 40 – Cocks (draw off) (range) and (tank)

3527/54823 SABS 1808-13 Water supply and distribution components Part 13 – Diaphragm valves nominal diameter 15-300 mm

ANNEX 6


Annex 6: General Methodology for Setting Water Service Tariffs

A6.1 Basic Principles

Tariff setting is governed by section 10(1) of the Water Services Act, 1997, and/or the Local Government Municipal Systems Act, 2000. Tariff structures must take into account the need to:

� Supply all households with at least a basic amount of water at an adequate level of service,

� Recover all the costs required to ensure sustainable delivery from the existing infrastructure in so far as this is compatible with the need to supply all with a basic amount of water,

� Make provision for the extension and enlargement of the infrastructure, when the demand arises, by generating a surplus from the tariffs applied for high volume use,

� Encourage water conservation and demand management,

� Promote equitable local economic development, and

� Disclose fully the extent of subsidies.

National government policy for non domestic users is to charge the actual cost of water provision, whilst ensuring that water tariffs do not stifle economic growth. Although the scope of tariff structures, drawn up in conformity with the draft regulations and general government policy, is limited in its ability to maximise income, good design can be used to improve:

� Equity

� Cost recovery optimisation (=minimising deficits and maximising surpluses),

� Transparency

� Income stability

� Ease of implementation

There is a degree of conflict between improving equity and optimising cost recovery. However, with care, tariff structures can be developed which both maximise benefits and control deficits, this being accompanied by appropriate choice of delivery method (see section 3.6.8). By this means poor and low income households can have access to a higher level of service, or more water to use, whilst reducing the required subsidy.

When setting tariffs, a WSI should differentiate between at least the following levels of water services and categories of customer:

a. supplies to households through shared delivery points - commonly referred to as an RDP level of service.

b. supplies to individual households through batch volume or pressure-compensated flow control devices - such supplies together with connections privately shared by a few households are regarded as an intermediate level of service.

ANNEX 6


c. Supplies to individual households through uncontrolled connections or cumulative volume control devices - such supplies including those fitted with cumulative as distinct from batch volume control devices are regarded as a high level of service.

d. Non domestic customers.

For consumption above the free basic amount, application of the equity criterion would mean lower tariffs being applicable to the lower levels of service. For consumption within the free basic amount, equity may be achieved by charging a graded connection fee for higher levels of service. The connection fee for supplies to individual households through batch volume or pressure compensated control devices should be kept low so as not to discriminate unfairly against poor households and to help and encourage them to obtain the level of service which gives best value for money.

A6.2 Types of Water Charge

Cost rebate/surcharge charge (CRC). A method of setting tariffs that has all the advantages of rising block charge (RBC) but which is simpler to use, and which results in excellent transparency.

Fixed charge. The monthly charge for the right to a fixed maximum volume of water per day. The ‘invoiced amount’ can be based on ‘rising block charges’ (RBC) or cost rebate charges (CRC).

Flat charge. A fixed monthly charge, equal to the final invoiced amount, used to invoice a group of customers who have access to an uncontrolled volume of water from a particular level of service, irrespective of the volume of water delivered to each customer. Section 10(1) of the Water Services Act, 1997, implies that flat charges may only be used for billing customers with individual household connections for up to 2 years after the regulations take effect.

Graded flat charge. A flat charge where the exact amount invoiced to different customers is adjusted dependent on assumed customer benefits. For example, on a shared connection scheme, customers living closer to the connection may be invoiced more than those living more distant, on the assumption that those living closer have a better service and are likely to use more water.

Primary fixed charge. A fixed monthly charge billed irrespective of the volume of water delivered, used in conjunction with a volume based charge to arrive at the final billed amount. For equity reasons, fixed charges are not recommended for use with household billing tied to ‘rising block charges’ (RBC) but only with household billing system tied to true costs used in conjunction with a rebate/surcharge system. See ‘cost rebate/surcharge charge’ (CRC).

Rebate. A reduction in the total billed amount which results in a lower invoiced amount. Rebates become a transparent subsidy when the billed amount reflects the true cost of delivery. With respect to household billing, rebates are usually allowed for equity reasons. In accordance with current national government policy, the same rebate should be given to all households who control their consumption tightly. For other customers, including industries, rebates may be allowed in cases of exceptionally efficient water usage in areas where water demand exceeds local resources or the capacity of existing infrastructure.

Rising block charge (RBC). A volume based charge per kilolitre of water used that applies to particular blocks of water delivered to a customer over a 30 day period and increasing in steps as the amount of water delivered increases.

ANNEX 6


The definition relates to a 30 day period and not to a calendar month and an adjustment must be made if the meter is not read on the same day each month. RBC is used both as an equity creating and a water demand management tool. However setting the blocks for optimal cost recovery is difficult and the resulting cross subsidisation lacks transparency because RBCs give no indication of water delivery costs.

Surcharge. An increase in the total billed amount which results in a higher invoiced amount. Surcharges become a transparent levy when the billed amount reflects the true cost of delivery. With respect to household billing, surcharges are usually levied as a solidarity tax to offset at least a portion of the losses incurred by an WSI when it allows rebates. For other customers, including industries, surcharges may be levied in cases of water wastage or inadequate investment in water demand management technologies.

Uniform charge. A volume based charge that remains the same regardless of how little of how much water is used.

A6.3 Information Needed for Tariff Setting

Before setting tariffs, a WSI needs to develop a good understanding of its current and future costs, current customer consumption patterns, price elasticity, current and future payment levels and the availability of external sources of recurrent income and capital funds. Hopefully this will have already have been done when the WSI made its submissions to its WSA for inclusion in the WSA’s water services development plan (WSDP). Below are notes directly related to costing and cash flow:

“Current costs” are required to indicate the income required to balance current expenditure. They should be divided into fixed and variable costs as described in the definitions section and then further divided to differentiate between the levels of service and categories of customer as set out in the principles section.

An understanding of “future costs” is required as one factor in estimating what surplus income, if any, needs to be generated. This will mainly depend on the future need to upgrade, refurbish or replace, or to extend or enlarge the existing infrastructure.

Details of “current customer consumption patterns” are required as one factor in calculating expected income from any proposed variable tariffs, because the income generated will depend on customer consumption patterns from different levels of service, and categories of customer.

An understanding of “price elasticity” is required to predict how customer consumption patterns are likely to change as soon as new tariffs are introduced. This is currently very important in South Africa because of the introduction of the new free basic amount of water policy. The details of current customer consumption patterns combined with price elasticity will indicate the total costs that will be incurred by the WSI and the total income the tariffs will generate assuming 100% payment levels. An understanding of current payment levels is therefore also required to estimate the total expected income.

If “current payment levels” are not at least 95% the WSI needs to set challenging achievable targets to improve them and then re-adjust expected customer consumption patterns to allow for the effects of the improved payment levels.

“Availability of external sources of recurrent income”: WSIs with an average domestic water consumption of 4,5 kilolitres per person per month (= 150 litres per person per day), or more, should strive to be fully self-sufficient with respect to recurrent costs.

ANNEX 6


WSIs with lower consumption levels are likely to need, and should receive, some external income support for recurrent costs, to enable them to provide all households with a basic amount of water free, and other households with additional water at equitable tariffs. However, if this income is not made available the WSI may well be forced, perhaps unjustly, and contrary to government policy, to provide only poor households with the basic amount of free water. The appropriate amount of external income will depend on the levels of service provided to customers and to what extent the average domestic water consumption is below 4,5 kilolitres per person per month. (If a significant percentage of customers are consuming less than 10,0 kilolitres per household per month, the use of pressure compensated flow control devices or batch volume control devices should be investigated as the appropriate level of service for these customers. Otherwise, if a higher level of service is provided, the WSI could be classified as over capitalised.)

“Availability of external sources of capital funds”: Planning what capital expenditure is required and enquiring what types of finance may be available for planned expenditure needs to start early, since lead times to finalise funding agreements are usually measured in years rather than months. In addition, finance being sought is more likely to be approved, by local government and the funder, if the WSI is managing its current infrastructure well and is financially sound. Thus assuming that all WSIs will be seeking some grant or loan finance for capital expenditure over the next 5 years, they should all budget to generate a small surplus each year. Indeed, the surplus generated from tariff income should ideally be high enough to prevent a steep increase in tariffs after a new loan has been obtained. WSAs and local government institutions that are responsible for paying out recurrent-cost subsidies should respond positively to well motivated applications from WSIs for assistance and monitor any assistance given.

A6.4 Analysing Recurrent Costs

Before a WSI develops its tariffs, it is essential that it has a clear understanding of its current and future recurrent costs. To be sustainable, especially since the introduction of the free basic amount of water policy, it is also especially important that WSIs keep their costs low and affordable for all customers. Otherwise charges to high volume use customers will rise and they will reduce their demand, beyond any planned water demand management targets. This will cause the WSI to lose water sales from which it would otherwise have generated a surplus. A good understanding of costs is therefore needed for controlling total costs as well as for tariff development.

To establish current recurrent costs, a WSI should examine its expenditure over the previous twelve months, differentiating between the different levels of service it provides and separating out ‘fixed costs’ from ‘variable costs’ for each of these levels. It is always important to know which costs are ‘fixed’ and which are ‘variable’, but at a time when the number of low volume users is likely to rise and the volume of water used by high volume users is likely to fall, it becomes even more important, since it is the ‘fixed costs’ that cause a WSI to spend more money than it receives in income when the average demand per customer drops. Dividing the costs between ‘fixed costs’ and ‘variable costs’ allows a WSI to calculate what deficit or surplus is generated from sales at different levels of consumption.

‘Fixed costs’ include capital repayment charges and the cost of reading meters and sending out invoices. An allowance for non-payment by customers may also be a significant fixed cost. ‘Variable costs’ include electricity consumption charges associated with water pumps and the maintenance of such pumps because the wear associated with such items is roughly proportional to the number of hours they operate.

ANNEX 6


When a WSI purchases its bulk water from an external organisation, the cost of the bulk water it sells to customers is a ‘variable cost’. Losses / unaccounted-for water should be included within ‘fixed costs’, even though, through WC/WDM initiatives, it may be possible to reduce them. Once all the fixed costs have been established, the total fixed costs for each level of service are divided by the number of months represented by the figures and by the total number of registered customers for that level of service, to obtain the fixed cost per customer per month.

When the recurrent costs for the previous year have been established and split up as set out above the WSI has to consider what changes are likely to occur in the coming year. For example, has the WSI instituted any plans to reduce unaccounted-for water? If so, can any reduction in the fixed charge be allowed for the coming year? The customer non-payment allowance is another fixed charge that WSIs need to target for reduction, if more than 5%. However, as control of non-payment improves, the water demand will drop, and it is therefore necessary to link the likely drop in demand with the improved control before the net gain can be established. This net gain may be less than 1/3 of the amount by which the non-payments are reduced. Therefore, if in doubt, plan to reduce the non-payment losses, but ignore both the gains from this reduction and losses due to reduced water demand. Then, when tariffs are set for next year, the gains and losses will be included automatically. What are the inflationary pressures on the different cost components, both fixed and variable? All expected increases in costs must be added to the costs established from last years expenditure. Are any loan finance charges likely to change? Once these adjustments have been applied, a WSI has the estimated costs required to set tariffs for the coming year.

Figure A6.1 represents tentative, typical, year 2000, costs per month per customer of delivering water for different levels of service. The point where the line meets the y-axis represents the different fixed costs and the slope of the line represents the different ‘variable costs’. Except in the case of the rudimentary supply (eg handpumps, protected springs etc) the graphs represent WSIs which purchase their bulk water from an external organisation. WSIs producing their own bulk water will tend to have higher ‘fixed costs’ and lower ‘variable costs’ with total average delivery costs generally being lower.

All the levels of service reflect WSIs which have obtained varying amounts of grant finance to help them construct the infrastructure or, especially in the case of the conventional household connections, some of the infrastructure is relatively old and, therefore, attracts no finance charges, since it has been fully paid for. The important issue initially is to establish the true costs and to record them as accurately as possible. If any costs vary considerably from those in Fig A6.1, the WSI could check their costs. If it does not find anything wrong and its costs are higher, it could check if there are any areas where costs could be reduced effectively in the medium term.

ANNEX 6


Fig A6.1a Rudimentary Fig A6.1b Shared Standpipe Fig A6.1c Controlled Household Tanks Fig A6.1d Conventional Household

Connections

Fig A6.1 Typical Unit Costs of Providing Water Service

A6.5 Examining Customer Water Usage and Usage Distributions for Intermediate and High Levels of Service

The next step is to examine customer water usage distributions. As will be shown below, if water usage for an RDP level of service is excessive, the resulting amount of un-recovered costs will be excessive. For a higher level of service, involving a greater capital investment, too few high-volume customers will put great strain on a WSI’s finances.

Under current government policy, customers obtaining their water from rudimentary infrastructure should not have to pay for the water they use. Therefore WSIs need to know the cost of maintaining such infrastructure to ensure that it remains reliable until it is upgraded and allow for this expenditure in their budgeting.

When an RDP level of service is used as intended, the water demand never rises significantly above 6 kilolitres per customer per month. Cost recovery, and especially equitable cost recovery, from this level of service is also difficult and expensive. Thus DWAF is advising Local Government to focus on the management of the water demand from such infrastructure, using good customer relations, rather than spending money on cost recovery.

ANNEX 6


Thereafter, the first option is to contain costs, as well as the water demand, to an acceptable level, to allow all customers to obtain their water free, as the amount will not be significantly above the free basic amount of 6 kilolitres agreed by cabinet, and to allow for this expenditure in their overall budgeting.

If this is not possible the next choice is to target poor families (DPLG 1999) for the free service and motivate other customers to pay a flat or graded flat charge for the service.

If the problem is only excessive demand, intermittent supply rationing, as described in section 3.5 or by employing a water bailiff to lock each delivery point, is probably the best option to negotiate with customers. Other options to recover an agreed percentage of cost are coupon or cash operated attended vending, or mechanical or electronic prepayment vending. Note: customers may object to the expenditure of money on water demand management or cost recovery, on the grounds that this money could be better used to start upgrading the level of service. This is a reasonable viewpoint, and the WSI should consider if they can honestly use it to persuade customers to be more interested in water demand management and/or paying the flat charge. Whatever the outcome, it is important to allow for any shortfall between costs and cost recovery in the budget.

Whilst it is reasonable to use flat, or graded flat, charges as a cost recovery method for rudimentary and RDP service levels, because customers benefit more or less equally and water demand management is not usually an issue, as can be seen from Figures A6.2, when used with uncontrolled household connections it can be extremely unfair and financially unsound. This is because a customer who controlled his/her water usage to a low level, as well as paying a high tariff, would allow the WSI to make a surplus from his/her discipline. So there is no incentive to save water. Rather, at least in the short term until intermittent supply rationing is introduced, no matter how much water the customer uses, or wastes, he/she pays no extra money and gets it at a cheap tariff. Although some income for the WSI is preferable to none, it is not surprising that, in terms of clause 13 of the compulsory national standards and measures to conserve water, all household connections must be fitted with a water meter or a control device within two years of promulgation. Clause 6 of the norms and standards for tariffs regulations make increasing ‘effective tariffs1’ compulsory for uncontrolled household connections.

1 The invoiced amount per kilolitre of water delivered

ANNEX 6


Figures 6.2a&b: Flat Charge (short term use only)

Figures 6.2c&d: Rising Block Charges (RBC)

Figures A6.2e&f: Cost Rebate / Surcharge Charges (CRC)

Figure A6.2 Characteristics of Tariffs and Invoice Amounts for Different Charging Methods (Conventional Household Connections)

ANNEX 6


For all service levels for which the WSI decides to use increasing ‘effective tariffs’ it is essential to check the frequency distribution of customers’ water usage, whilst also differentiating between different levels of service and categories of customer which are subject to different tariff structures. Otherwise even rough budgeting is not possible.

In the same manner as recurrent costs, frequency distributions are best established by checking last year’s consumption figures and considering any changes that are likely to occur in the coming year. For example when a free basic amount of policy is implemented it can be assumed that all customers using less than the free amount will now increase their consumption to that amount. When tariffs are increased, customers are likely to reduce consumption and it is important for WSI to understand their customers and to be able to predict roughly what that reduction will be. If the WSI wishes to reduce the non-payment component of its ‘fixed cost’ costs from last year’s figure, it will also be necessary estimate where the corresponding loss in water demand is likely to take place. An acceptable compromise is to ignore both. The closure of a large industry or mine in an area served by a small WSI can severely reduce water demand. In such a case the WSI should try and predict the reduction, ensure that all households have access to at least a basic amount of water, keep tariff increases to a minimum and seek additional revenue from an external source.

A6.6 Using Increasing Effective Tariff Structures

Any variable tariffs will cause an unstable income if there are large jumps in the invoiced amount for insignificant changes in the volume of water used by the customer. Thus WSIs should always strive to keep changes in invoiced amounts smooth as water usage increases, whilst having some uneven transitions in the tariffs (see figure A6.2d & f). Providing 6 kilolitres per month free and then charging a tariff close to the true cost for a consumption of 7 kilolitres, as was done in Durban to optimise invoicing costs, encourages fraudulent meter reading and an unstable income. In an area with an equitable tariff structure before the free basic amount of water policy was introduced, an average household income 30% above the average for the whole country and a non domestic consumption of 40% of the total consumption, the income from the first 6 kilolitres of water delivered to all households comprised 7,6% of the municipality’s total income from water. Under such circumstances insisting that all households who use 7 kilolitres must pay the full amount they were paying before the free basic amount of water policy was introduced is not recommended.

The most common form of equitable tariff used in South Africa, which is also an effective water demand management tool, is the Rising Block Charge (RBC). The regulations for norms and standards for water services tariffs state that such tariffs must include at least three blocks. Traditionally some municipalities have used up to ten blocks. Since the introduction of the free basic amount of water policy, it has been necessary to set the first block after the free block reasonably high in order to achieve effective cost recovery (see Fig A6.2c and the sample deficit/surplus calculation set out in table A6A). The alternative, which is contrary to government policy, is to cross-subsidise domestic users heavily from industrial and other institutional users. In this case, five blocks above the zero block are sufficient to prevent excessive steps between blocks.

RBCs can be made effective if chosen carefully, but they are difficult to develop because the steps have to be set roughly in exponential or logistic growth curve steps. This is normally done subconsciously by trial and error, rather than mathematically. Thereafter, because different blocks have different charges, it is laborious to calculate invoiceable amounts for different water consumptions. This in turn increases the difficulty of setting the steps.

However the greatest objection to their use is their lack of transparency (see the sample RBC based invoices set out in Table A6E).

ANNEX 6


This is contrary to clause 74(2)(i) of the Local Government: Municipal Systems Act, 2000, relating to tariff policy, which states that “the extent of subsidisation of tariffs for poor households and other categories of users should be fully disclosed”.

Figure A6.2e shows the Cost Rebate/Surplus Charge (CRC) tariff. It comprises a true cost charge used with a different rebate or surcharge depending on the consumption level. The rebate/surcharge percentages are easier to set than block charges because a single straight line function for each is adequate. Thereafter, invoiceable amounts for different water consumptions are calculated with a single figure, the rebate or the surcharge. To be effective within the framework of the free basic water policy, the zero rebate point must be reached as soon as possible, consistent with equity, with a smooth growth in the invoiced amount as the consumption increases above the free basic amount. In figure A6.2e, the zero rebate point has been reached at a consumption of 18 kilolitres per 30 day period.

Apart from making it simpler to set tariffs, this method has excellent transparency. As a result, National Treasury prefers the CRC method of tariff setting to the RBC method, although they are unlikely to make it compulsory. Because of the transparency, as detailed in reference Hazelton 2001, this method can be used with equal simplicity to calculate equitable WSI subsidies.

A6.7 Balancing the Books If a WSI is to be sustainable, its income must at least equal its long-term recurrent costs plus any required capital expenditure that cannot be covered by grants or favourable loan finance. However as long as all reasonable endeavours are taken to control costs and to achieve full cost recovery through its water tariffs, it should be acknowledged that a WSI may, where feasible, make up any income shortfall by using any source of funds, including national government equitable share transfers, local authority rates and/or metro/district authority levies.

When a WSI carries out deficit/surplus calculations and it is only possible to achieve a surplus by increasing tariffs by more than the inflation rate, other alternatives need to be considered carefully. Can any costs be reduced? Can income from external sources be increased?

Benchmarking, i.e. comparing the WSIs fixed and variable costs against other similar WSIs, will give an indication of which alternative is the more rational to pursue. However average water costs per kilolitre cannot be used for benchmarking because it is more dependent on average demand than any other factor. The sample calculations below also indicate that, for high levels of service, it is extremely difficult for WSIs to recover the full recurrent costs of delivering domestic water, unless the average water usage is at least 18 kilolitres per household per month. For lower levels of service, the free basic water policy makes what was an extremely difficult task an impossible one for almost all WSIs.

A6.8 Worked Example DWAF’s “Free basic water: Guideline for local authorities” (DWAF 2001b) has a worked example of a municipality, largely urban in character, in which the water consaumption distribution from conventional household connections is as shown in Fig A6.3.

ANNEX 6


Figure A6.3: Household Water Use Distribution – Urban Area Example

Tables A6A and A6B show the resultant deficit/surplus produced assuming the Fig A6.3 distribution, and the water costs and charges depicted in Fig A6.2c&d and A6.2e&f for rising block and cost rebate/surcharge tariffs respectively. It can be seen that, despite the WSIs reasonable costs structure and the quickly rising water tariffs for households using above the free basic amount, the surplus generated is low. This indicates that making a surplus from the sale of domestic water without cross-subsidisation from industrial users is difficult, even in relatively high income areas.

Table A6A: Sample Deficit / Surplus Calculation – Urban Area RBC Tariff No of customers in each block 2 500 3 000 2 000 2 000 500 10 000

Cost to WSI of supplying water R/m

111 250 211 800 199 200 268 800 91 850 882 900

Charges to customers R/m 0 129 600 211 800 393 600 176 925 911 925

(Deficit)/surplus R/m (111 250) (82 200) 12 600 124 800 85 075 29 025

(Deficit)/surplus % (100,00) (38,81) 6,33 46,53 92,62 3,29

Note: The right hand column contains totals and the overall deficit/surplus

Table A6B: Sample Deficit / Surplus Calculation – Urban Area CRC Tariff No of customers in each block 2 500 3 000 2 000 2 000 500 10 000


111 250 211 800 199 200 268 800 91 850 882 900


(Deficit)/surplus R/m (111 250) (70 600) 31 125 126 000 83 717 58 992

(Deficit)/surplus (Rebate/surchrge) %

(100,00) (33,33) 15,63 46,88 91,15 6,68


The small additional surplus in Table A6B over that in Table A6A has been achieved by the charges reaching the break even point earlier, at a usage of 18 k�/month rather than at 23 k�/month.

DWAFs “Free basic water: Guideline for local authorities” (DWAF 2001b) has a further worked example of a municipality which is largely rural in character and in which all households have access to water from conventional household connections. The water consumption distribution is as shown in Fig A6.4.

ANNEX 6


Figure A6.4: Household Water Use Distribution – Rural Area Example

Table A6C shows the deficit/surplus produced assuming the distribution as Fig A6.4 and the water costs and cost rebate/surcharge charges depicted in Figure 6.2e&f. The resulting deficit is R167 529 per month, R16,75 per month per customer. This is partially because, whilst the average water usage between Figs A6.3 and A6.4 has decreased over 30%, the WSIs delivery costs have only decreased by 20%. As a general comment, one could conclude that the WSI is over-capitalised.

Table A6D depicts the same WSI but assumes that it has installed controlled household tanks rather than conventional household connections for the first two blocks of customers. The resulting deficit is now R106 650 per month or R10,60 per customer; a reduction of 36%. In addition, the customers in the block using an average of 14 kilolitres of water are now paying on average R39,00 per month rather than R47,07 per month for the same quantity of water; a reduction of 17%.

Table A6C: Sample Deficit / Surplus Calculation – Rural Area CRC Tariff, Conventional Household Connections

No of customers in each block 4 500 3 100 1 400 800 200 10 000


200 250 218 860 139 440 107 520 36 740 702 810


(Deficit)/surplus R/m (200 250) (72 953) 21 788 50 400 33 487 (167 529)

(Deficit)/surplus (Rebate/surcharge) %

(100,00) (33,33) 15,63 46,88 91,15 (23,84)


ANNEX 6


Table A6D: Sample Deficit / Surplus Calculation – Rural Area CRC Tariff, Controlled Household Tanks

No of customers in each block 4 500 3 100 1 400 800 200 10 000


151 875 181 350 139 440 107 520 36 740 616 925


(Deficit)/surplus R/m

(151 875) (60 450) 21 788 50 400 33 487 (106 650)

(Deficit)/surplus (Rebate/surcharge) %

(100,00) (33,33) 15,63 46,88 91,15 (17,29)


Tables A6E and A6F are outline examples of typical invoices using the RBC and CRC method of charging respectively. Each table gives figures for four levels of consumption. As per common practice, they assume that the different tariffs for different volumes of usage relate to households rather than to each person in the household. As household sizes in South Africa can vary between 1 and 11 persons (Hazelton 2001), this means that, even ignoring that some customer units comprise more than one household, there is a strong case, for equity reasons, to gradually change the tariffs so that they relate to usage per person.

Provided RBC invoices give details of the charges for each step they indicate clearly how the price of water per kilolitre increases as usage increases. However, it gives no indication of what it costs the WSI to deliver the water. Therefore the customer does not know whether he/she is receiving a subsidy or generating a surplus for the WSI to use elsewhere when he receives his/her invoice.

Single CRC invoices on the other hand do not give an indication of how the WSIs effective tariffs increase as usage increases unless each invoice gives summary details of the rebate/surcharge system. However, once a customer knows that the invoiced costs reflect true costs, he/she knows what it costs the WSI to deliver the water and whether he/she is receiving a subsidy or generating a surplus for the WSI to use elsewhere.

Table A6E: Typical Outline Invoice – RBC Method of Charging

Meter reading: 05/09/2001 4367 7845 615 1639

05/10/2001 4362 7831 586 1586

Consumption k� 5 14 29 53

No of days between meter readings 30 30 30 30

Step 1: 0 to 6 k� @ R0,00/k� Rand 0,00 0,00 0,00 0,00

Step 2: 7 to 18 k� @ R5,40/k� Rand 43,20 64,80 64,80

Step 3: 19 to 30 k� @ R6,85/k� Rand 75,35 82,20

Step 4: 31 to 42 k� @ R8,30/k� Rand 99,60

Step 5: 43 to 54 k� @ R9,75/k� Rand 107,25

Step 6: 55 k� & above

@ R11,20/k�

Rand

Total this invoice excl VAT Rand 0,00 43,20 140,15 353,85

ANNEX 6


Table A6F: Typical Outline Invoice – CRC Method of Charging

Meter reading: 05/09/2001 4367 7845 615 1639

05/10/2001 4362 7831 586 1586

Consumption k� 5 14 29 53

No of days between meter readings 30 30 30 30

Fixed cost Rand 30,00 30,00 30,00 30,00

Variable cost @ R2,90/k� Rand 14,50 40,60 84,10 153,70

Total cost Rand 44,50 70,60 114,10 183,70

(Rebate)/Surcharge % (100,00) (33,33) 28,65 91,15

(Rebate)/Surcharge Rand (44,50) (23,53) 32,68 167,43

Total this invoice excl VAT Rand 0,00 47,07 146,78 351,13

ANNEX 7


Annex 7: Innovative Management Approaches

A7.1 Strategic Adaptive Management The following five factors are critical for the successful institutionalisation of strategic adaptive management as illustrated in Figure A7.1.

Figure A7.1 A Framework for Institutionalising Strategic Adaptive Management (Rogers et al, 2000)

1. Integrated operations. Ensure that all stakeholders within, between and outside institutions integrate their respective activities as well as support others involved in such a process.

2. Strategic knowledge management. Making effective decisions from knowledge and wisdom that has been obtained from complex data and volumes of information.

3. Decision making. Facilitate decision making through a joint forum that will entrench intra-institutional integration and reduce the chances of overall operations becoming a self-serving bureaucracy.

4. Common knowledge, purpose and process. Reduction of conflict and increased co-operation by ensuring that all stakeholders operate from a common knowledge base and with united purpose.

5. Nurturing institutional environment. The promotion of a culture that encourages sharing of responsibility, sharing stewardship, learning-by-doing, critical reflection, dealing with uncertainty and balance demands for altruism with personal incentives.

Van der Walt (2000) recognises the need to encourage diverse perspectives while at the same time being sensitive to cultural difference and similarities, and to integrate the positive aspects of both into the mechanisms of the organisation.

A contrast of leadership style, organisational structure in conventional bureaucracies and adaptive organisations is given in Table A7A.

CommonKnowledgePurpose &Process

Implementation

Feedback of data and understanding

IntegratedOperations(Logistics,Research andMonitoring)

DecisionMaking

Collap

sing c

omple

xity.

Decisi

on su

ppor

t

StrategicKnowledgeManagement

ANNEX 7


Table A7A: Comparison of Leadership Style, Organisational Structure and Culture (Rogers et al, 2000)

Issue Conventional bureaucracies Adaptive organisations Leadership style

Primarily command-and-control Primarily to co-ordinate and facilitate

Transactional/paper shuffling Generative (designer, teacher, steward)

Structure Functional hierarchies Dynamic teams with blurred boundaries Vertical communication Horizontal dialogue Work for one boss Work with colleagues across boundaries

Culture Thinking at the top, doing at the bottom

Develop common purpose through collaborative goal setting

Collect data and manage information

Generate, modify and transfer knowledge

Follow rules and regulations Driven by vision and values Internal competition Integrated operations across stakeholder-

service provider boundaries This-is-our-product/empire

syndrome Enthusiastic sharing of knowledge (trust and openness)

Observe and criticise mistakes Learn and adapt through hypothesis testing and critical reflection

Rather make no decision than a wrong one

Recognise when new knowledge allows you to make the next better decision

View uncertainty, complexity and change as threats

Treat uncertainty, complexity and change as opportunities for learning and improvement

A7.2 Influence of Cultural on Management Style

A comparative analysis describing Japanese, Western and African management, juxtaposed with Ubuntu is given in Table A7B.

Table A7B: Comparison of Management Styles

Japanese Western African Ubuntu Perceived significance of titles; important average power distance; power of the elder

Significance of titles unimportant; below average power distance

Titles/status important; above average power distance

Title unimportant; below average power distance; power of the elder

Kinship and business ties relatively strong

Kinship and business ties relatively weak

Kinship and business ties relatively strong

Kinship and business ties; very strong extended family; shared values

Established educational infrastructure. Higher education based wholly on ability. Alma mater and year of graduation important points of identification. A generalist model predominates at university, followed by an apprenticeship at specific company

Established educational infrastructure. Higher education open to majority. Alumni networks and university ties secondary to individual accomplishments. Pre-dominance of technical training in business schools

Weak/absent educational infrastructure. Educated elite (educated in the US, Europe or former Russia)

Developmental focus; integrates traditional and Westernised education; age is an important source of wisdom

ANNEX 7


Japanese Western African Ubuntu

Very high on masculinity index; materialistic; differentiated sex roles; decisiveness; sympathy for the achiever; a “live-to-work” philosophy

Scores “average” on masculinity index

Scores “low” on masculinity index: people orientated; inter-dependence; sympathy for the unfortunate; intuition; a “work-to-live” philosophy

Scores “low” on masculinity index: people orientated interdependence; sympathy for the unfortunate; intuitive integration between work and home; extended family

Collectivistic culture: view themselves as group members and less as individuals

Individualistic culture: view themselves as individuals who together form a group; self-reliant

Collectivist culture, but not as collective as the Japanese. Group afficiation more important than individuality

High collectivist culture. Group affiliation much more important than individuality (an individual emerges out of a group); dependent

High face-saving culture: preserving one’s prestige/ dignity

Low face-saving culture: very direct

High face-saving culture High face-saving culture; dignity; inclusive group orientation; greatest fear is rejection by group

Are less accustomed to using the law to resolve conflicts: shun win-lose situations and believe all matters can be resolved through compromise and reconciliation. Never use attorneys in negotiations

Use the law in resolving conflicts. Businesses use attorneys to negotiate or assist in negotiations

Law available to the elite; seen as luxury

Justice is a sense of fairness, do what is right and moral; laws must be in tune with values

High-context culture: information implicitly contained

Low-context culture: information explicitly conveyed

High-context culture: organisation information on a “need to know”

High-context culture: information implicitly conveyed; unconditional dialogue

Leaders in development/ utilisation of modern technology

In forefront with develop-ment/utilisation of modern technology

Lagging behind in effective utilisation and management of foreign technology

Low utilisation and management of foreign technology

Greater emphasis on qualitative techniques – relates to Confucian dynamism index – high CD society: long-term (future) oriented

Very low Confucian dynamism society – want to satisfy needs here and now

Emphasis on qualitative techniques; belief in non-control over the self

Power not determined by monetary value

The more the individual has, the more powerful he is

Very poor communities; number of children equals wealth

The more the communal person is prepared to give and share, the more respected he/she becomes

Concept of time; proud of heritage; future oriented

Concept of time: infinite – the past is gone – look to the future; want to control future

Concept of time: past is important, live from day-to-day; not future oriented; destiny

Concept of time: circular view of time (past is more important than the future) accept destiny

ANNEX 7


Western management models cannot merely be adopted or cited in African third world countries, but rather culture should play a central role.

The concept of Ubuntu is the belief in the central sacredness, and foremost priority of the human being in all his/her conduct, throughout his/her life. Furthermore, it does not exist unless there is interaction between people in a community, manifesting through the actions of people.

A more humane and softer approach to management in general is required in South Africa where there are unique problems typical to a first and third world environment.

Management needs to be adapting in today’s fast and unpredictable environment based on knowledge management. It needs to focus on cross-cultural and cross-disciplinary education of leaders as well as where new emerging work culture, human information technology resources take centre stage.

Exogenous influences can also inhibit co-operation through de-motivation of officials. Where possible those individuals and organisations that could potentially have negative influence on co-operation should be included in the knowledge sharing and communication process.

In formulation of a communication strategy the following should be determined:

� Basic knowledge of consumer behaviour (e.g. socio-cultural environment, family and social class, decision maker, etc.) in the target market;

� The composition of the target market (e.g. gender, age, language, etc.)

� The level of awareness and interest in the target market (e.g. if unaware and low interest, repetitive advertising or if aware than reminder advertising would be used);

� The pursuasibility of target market (i.e. are the men or women more easily persuaded, and who are the decision making unit in the household?).

ANNEX 8


Annex 8: Information Management Needs – Water Supply And Distribution [excluding fixed assets]

Output

Uni

ts/

indi

cato

rs

Purpose

Prio

rity

Freq

uenc

y Raw Data Required

Data Source/ Capture

Dat

a Tr

ansf

er

Dat

a Pr

oces

sing

Remarks

Numbers of consumers sub-divided by category population

no. OP/SM AM/D

1 annually connected properties

manual databases

manual entry into GIS

GIS Link with electoral register, census?

Raw water abstracted m3 per period

OP/SM 2 monthly annually

flows at abstraction points

meter radio SCADA

Quantity of water produced from WTWs Annual, monthly averages and peak days

m3 per period m3/d

�/cap/d

OP/SM AM/D

1 monthly annually

flows on outlets from WTWs

meter hard wire SCADA Presented graphically with trend analysis

Quantity of water into supply ditto as above sub-divided by supply area

as above OP/SM AM/D

1 daily monthly annually

flows on outlets from service reservoirs, clear water tanks

meter PSTN SCADA

Water Audit – Measured water consumed

m3 per period

OP AM/D

B

1 quarterly annually

volumes of water taken by consumers

consumer meter readings (Psion)

hand (meter reader)

consumer meter database

Water Audit – Unmeasured water consumed

m3 per period

OP AM/D

1 annually numbers of properties, population, consumption estimates

from consumer register (above)

manually, hydraulic model if applicable

Water Audit – Losses (UFW) m3/d �/conn.d m3/km.hr

OP AM/D

1 annually water produced and consumed

see above see above manually UFW from primary metering – mass balance Sub-division into real and apparent losses and system & consumer side losses

Reservoir levels

% full OP/SM 1 daily water levels depth sensor radio SCADA

Quality of water produced % non-compliant

OP/SM AM/D

1 daily monthly

analyses of samples

WTW lab WTW lab Exception reporting of regular sampling

ANNEX 8


Output

Uni

ts/

indi

cato

rs

Purpose

Prio

rity

Freq

uenc

y Raw Data Required


Dat

a Tr

ansf

er

Dat

a Pr

oces

sing

Remarks

annually Quality of water consumed % non-

compliant OP/LN AM/D

1 monthly annually

analyses of samples

WTW lab WTW lab Exception reporting of regular sampling NB validity of sampling procedure

Performance of distribution network – Pressures

% length < 15m @ peak

OP/LN AM/D

2 monthly annually

pressure readings / model simulations

data logger manual Hydraulic model or logger software

Consumer complaint of low pressure not necessarily indicative of hydraulic deficiency

Performance of distribution network – Structural failures

no. per period

OP/LN AM/D

2 monthly annually

nos. of repairs, types, locations, samples taken

manually by repair crew / supervisor Job Sheets

manual entry into database

database software

Need to distinguish between third party damage, reported and unreported bursts

Performance of distribution network – Interruptions to supply

nos. of consumers

without water per

period

OP AM

3 monthly annually

burst repairs times to complete nos. properties affected

Job Sheet as above

Service level typically 8 hours

Performance of distribution network – Leakage sub-divided by supply area/DMA

�/conn.d m3/km.hr

OP AM/D

1/2 monthly annually

flows into DMAs, pipe lengths, properties, consumer meter readings

data loggers GIS consumer meter database

telemetry manual manipulation of databases

s/sheet and/or proprietary software SCADA??

Priority 1 if critical to continuity of supply UFW from DMA data Trend analysis by zone

Leakage control activity - step tests - leaks located - waste notices issued

no. per period

OP 2/3 monthly annually

nos. of operations Job Sheet manual Priority 2 if critical to continuity of supply

Maintenance activity - valve operation - hydrant flushing - air scouring - pump maintenance - PRV maintenance

no. per period

OP/LN AM/M

3 monthly annually

nos. of operations Job Sheet manual

ANNEX 8


Output

Uni

ts/

indi

cato

rs

Purpose

Prio

rity

Freq

uenc

y Raw Data Required


Dat

a Tr

ansf

er

Dat

a Pr

oces

sing

Remarks

Extent and condition of assets - mains lengths/dia/material/age - service reservoirs - pumping stations, civil, M&E - consumer meters

lengths, capacities,

nos. as appropriate

AM/D 2 annually asset statistics various

GIS Job Sheets Pipe sample test reports

Asset register, 5 year rolling table + one page summary of additions & rehab during year

GIS up-dating - new mains, other system assets. - incident data (from Job Sheets) - new/replaced consumer meters

schedule of data

awaiting entry

OP AMD

1 quarterly annually

data entry activity Job Sheets

Internal resources deployed - production - distribution - management & supervision - plant & transportation

schedules OP AM

2 monthly annually

resources personnel time sheets Job Sheets

Ideally distribution manpower should be sub-divided by nature of activity e.g. to know cost of ALC

External resources & procurement - contractors, consultants, etc - plant hire - materials purchased

schedule and costs

OP AM

2 monthly annually

resources suppliers invoices

Energy used in pumping - abstraction & treatment - distribution

MwH per

period

OP AM

2 annually power consumed, water production statistics

Eskom accounts flow meters

manual from SCADA

manual / s/sheet

Chemicals used for treatment - at WTW - within distribution (if any)

cost and/or tonnes per

period

OP AM

2 annually tonnages and costs, water production statistics

suppliers invoices flow meters

manual from SCADA

manual / s/sheet

Cost of operation and maintenance - abstraction & treatment - distribution

total cost cost per m3

water (a)produced

and

OP AM

1 annually

ANNEX 8


Output

Uni

ts/

indi

cato

rs

Purpose

Prio

rity

Freq

uenc

y Raw Data Required


Dat

a Tr

ansf

er

Dat

a Pr

oces

sing

Remarks

(b)delivered

Consumer contacts, reports of: - no water - poor pressure - dirty water - visible leak - satisfaction - other

no. per period

OP AM

2/3 annually telephone records, correspondence

manual by secretarial and operations personnel as applicable

manual into data base

database software

Although desirable to have a record, is not an objective measure of consumer perception or service quality See network performance for results of investigation of reports by consumers

ANNEX 9


Annex 9: Characteristics of Hydraulic Modelling Software Packages

Software Advantages Disadvantages EPANET • Free

• Open file structure, flexible input • Good visual output • Easy to use results analysis • User programming functions • Popular package for integration with GIS eg MapInfo, StruMap

• No intrinsic GIS capability • No validation capability • Cannot model separate inlet / outlet reservoirs interactively • Only straight lines between nodes • Simplistic pump & valve routines

INFOWORKS WS (formerly WESNET) www.wallingfordsoftware.com

• Workgroup model management system with version control and audit trail

• Import / export of data from / to GIS • Water quality module included • Auto-calibration module • Sediment module • Model building tools – auto-elevation, auto demand allocation,

spatial analysis, model merging, interactive query analysis, thematic mapping

• Good pump and valve simulation • Uses MapInfo cartographic functionality

• Expensive

H2ONet PICCOLO • WATNET, KYPIPE & LIQSS to PICCOLO converts available

• Unique command language to enable user to customise the modelling environment and import / export of data

• fire flow, optimisation and water quality modules • Surge analysis components available • Allows isolated nodes to occur for flexible model preparation and

data review • Can vary leakage according to pressure conditions • Up to 65,000 pipe capacity • 5 different reservoir inlet / outlet types available • Network skeletonisation function • Model merging function • Allows import of graphical backgrounds • Flexible editing tools

• Expensive • Pumps & valves can only be controlled by tank level or nodal

pressure • Poor graph editing and presentation

ANNEX 9


STRUMAP & HARP www.geodysys.com

• True geographic representation • Uses StruMap cartographic functionality • Import of data from GIS • Model building tools – auto network simplification, spatial

analysis • Flexible, uses EPANET solver • Relatively inexpensive

• Less built in functionality than other packages • Simplistic modelling of pumps and reservoirs

SYNERGEE (formerly Stoner) www.stoner.com

• On line graphical output • Network can be edited via geographic window • Can digitise directly into package from mains records or import

data from(& export to GIS) • MS Access may be used for model construction • Can overlay onto map base, true geographic representation • Added functionality modules for:

- area isolation (impact of isolating a main) - customer management (link creation from customer

information) - GIS integration (auto generation of modes) - on-line module (auto transfer operational data from

telemetry) - sub-system management simplification of network)

• Expensive • Added functionality at etra cost • Some editing facilities awkward, e.g. profiles • Validation comparison poor, no error analysis • Large auto report files use up memory • Not as functional as some other packages

WATNET • Digitised input, true geographic representation • Import / export from/to GIS • Uses MapInfo cartographic functions • Large number of features and valve types modelled

• Slow run times • Poor tolerance control • Crude validation analysis • Poor pump and valve simulation • Only 5 standard demand types • No local head loss coefficients • Closed file structure • Less functionality than other packages

Note: The above applicable to software characteristics as at January 2002 and is subject to change

department of water affairs and forestry - … doc/irwm 1/water conserv... · 2008-03-11 ·...

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