dws municipal water balance guidelinemfmamirror.s3. ?· dws municipal water balance guideline ii...

Download DWS Municipal Water Balance Guidelinemfmamirror.s3. ?· DWS Municipal Water Balance Guideline ii Document…

Post on 21-Mar-2019

212 views

Category:

Documents

0 download

Embed Size (px)

TRANSCRIPT

DWS Municipal Water Balance Guideline

i

DWS Municipal Water Balance Guideline

ii

Document control

PEP: PEP: National Non-Revenue Water Assessment

Title of document: Guideline for the preparation of an IWA water balance to

determine Non-revenue Water and Water losses

PEP leader: WA Wegelin

PEP team members: RS McKenzie, Z Siqalaba

Author(s) of document: WA Wegelin, RS McKenzie, Z Siqalaba

Contributors:

Reviewer:

Report status: Final

Date: August 2014

Issued to: A Wensley

Keywords: Business Intelligence Support, Guideline, NRW, Water losses,

Version control

Version Date Comments

Draft 1

Draft 2

Final Draft

Final

DWS Municipal Water Balance Guideline

iii

ACKNOWLEDGEMENTS

The authors would like to thank the following individuals for their valuable contribution:

Mr Tim Waldron Chairman of the IWA Water Loss Task Force Specialist Group

Ms Kerry Fair GLS Consulting Engineers

Mr Trevor Westman City of Tshwane

Ms Mbalie Matiwane Johannesburg Water

Mr Brad Astrup WRP Consulting Engineers Pty Ltd

DWS Municipal Water Balance Guideline

iv

LIST OF SYMBOLS AND ABBREVIATIONS

Symbol or

abbreviation Definition

DWS Department of Water and Sanitation

ILI Infrastructure Leakage Index

IWA International Water Association

KPI Key Performance Indicator

NRW Non-Revenue Water

SIV System Input Volume

UARL Unavoidable Annual Real Losses

CARL Current Annual Real Losses

UFW or UAW Unaccounted for Water

WC/WDM Water Conservation and Water Demand Management

Consumer A consumer is a person or group of people (household) that are the

final users of products and or services generated within a social

system.

Customer A customer (also known as a client, buyer, or purchaser) is the

recipient of a good, service, product, or idea, obtained from a seller,

vendor, or supplier for a monetary or other valuable consideration.

Deemed or flat

rate consumption

Deemed or flat rate consumption is an unmetered fixed volume of

water sold to a customer on a monthly basis. Customers are deemed

to use this volume of water but the actual consumption may be more or

less.

DWS Municipal Water Balance Guideline

v

TABLE OF CONTENTS

Page

INTRODUCTION ................................................................................................................. 1

BACKGROUND .............................................................................................................................. 1

IMPLICATIONS OF WATER DEMAND MANAGEMENT AND THE WATER BALANCE ................. 3

LEGAL REQUIREMENTS ............................................................................................................... 4

WATER DISTRIBUTION SYSTEM TERMINOLOGY ...................................................................... 4

WATER BALANCE BASIC INFORMATION REQUIRED ................................................... 6

SUPPLY AREA AND SCHEMATIC ................................................................................................. 6

POPULATION, HOUSEHOLDS AND PROPERTIES SERVED ...................................................... 7

NUMBER OF CONNECTIONS ....................................................................................................... 7

Billed metered and unmetered connections ............................................................................. 7

Unbilled metered and unmetered connections ......................................................................... 8

LENGTH OF MAINS ....................................................................................................................... 9

BULK WATER SUPPLY .................................................................................................................. 9

METERED CONSUMPTION ........................................................................................................... 9

UNMETERED CONSUMPTION .................................................................................................... 10

AVERAGE SYSTEM PRESSURE ................................................................................................ 10

INTERMITTENT SUPPLY AND TIME PRESSURISED ................................................................. 10

BASIC COMPONENTS OF THE WATER BALANCE ...................................................... 13

IWA WATER BALANCE ................................................................................................................ 13

Key considerations ................................................................................................................ 13

SYSTEM INPUT VOLUME ........................................................................................................... 14

AUTHORISED CONSUMPTION ................................................................................................... 14

Billed metered consumption ................................................................................................... 15

Billed unmetered consumption ............................................................................................... 16

Unbilled metered consumption ............................................................................................... 17

Unbilled unmetered consumption ........................................................................................... 17

WATER LOSSES .......................................................................................................................... 18

COMMERCIAL OR APPARENT LOSSES .................................................................................... 18

ADVANCED COMMERCIAL OR APPARENT LOSS CALCULATIONS ........................................ 19

Unauthorised connections (theft) ........................................................................................... 19

Meter error and under registration .......................................................................................... 20

DWS Municipal Water Balance Guideline

vi

Data transfer and management errors ................................................................................... 21

CURRENT ANNUAL PHYSICAL OR REAL LOSSES (CARL) ...................................................... 21

UNAVOIDABLE ANNUAL REAL LOSSES (UARL) ....................................................................... 22

NON-REVENUE WATER .............................................................................................................. 22

POTENTIAL REAL LOSS SAVING ............................................................................................... 22

WATER SUPPLY SYSTEM ASSESSMENT ..................................................................... 23

KEY PERFORMANCE INDICATORS ........................................................................................... 23

Unit consumption ................................................................................................................... 23

Real loss indicators ................................................................................................................ 23

Infrastructure Leakage Index ................................................................................................. 24

BENCHMARKS ............................................................................................................................ 24

Basic information ................................................................................................................... 25

Water balance volumes ......................................................................................................... 25

Key performance indicators ................................................................................................... 25

COMMON MISTAKES AND RECOMMENDATIONS........................................................ 26

UNIT ERRORS ............................................................................................................................. 26

STORAGE VOLUME INCLUDED IN WATER BALANCE .............................................................. 26

MONTHLY OR ANNUAL WATER BALANCE ............................................................................... 27

DWS Municipal Water Balance Guideline

1

INTRODUCTION

Background

The National Development Plan (NDP) makes reference to the need for vigorous Water

Conservation and Water Demand Management (WC/WDM) programmes to ensure that the

national and regional water loss reduction targets are met in view of the water scarcity challenges

facing the country. These challenges are multi-dimensional in nature ranging from limited resource

availability to limitations in access due to inappropriate infrastructure management and

maintenance. Furthermore the NDP makes mention of the need for a dedicated national

WC/WDM programme which will assist in setting progressive water loss reduction targets f