Understanding and Managing Apparent Water Losses Water Services Forum - R and Water

1. Understanding and Managing Apparent Water LossesWater Services Forum - Rand Water Mthokozisi Ncube

2. Introduction 2

3. IWA Blue pages: Steps for Calculating NRW and Water Losses • Step 1: Define System Input Volume • Step 2: Define Billed Metered Consumption and Billed Unmetered Consumption; enter total in Billed Authorised Consumption and Revenue Water • Step 3: Calculate the volume of Non-Revenue Water as System Input Volume minus Revenue Water • Step 4: Define Unbilled Metered Consumption and Unbilled Unmetered Consumption; transfer total to Unbilled Authorised Consumption • Step 5: Add volumes of Billed Authorised Consumption and Unbilled Authorised Consumption; enter sum as Authorised Consumption • Step 6: Calculate Water Losses as the difference between System Input Volume and Authorised Consumption • Step 7: Assess components of Unauthorised Consumption and Metering Inaccuracies by best means available, add these and enter sum in Apparent Losses • Step 8: Calculate Real Losses as Water Losses minus Apparent Losses • Step 9: Assess components of real losses by best means available (night flow analysis, burst frequency/flow rate/duration calculations, modelling etc.), add these and cross-check with volume of Real Losses which was derived from Step 8 • In essence, apparent losses are largely unknown and estimated as a percentage of water lost (usually 20 - 30%) in South Africa

4. Apparent Water Loss Components

5. Its all about water metering … 5

6. The Revenue Management Approach Finance Driven

7. The Revenue Management Approach Finance Driven Technically Driven

8. Non-Revenue Water Management NRW

9. Metering Basics 9

10. Meter are not created equal SANS 1529-1:2006

11. Meter Flowrates and Class

12. Meter Flowrates and Class

13. Compulsory Permanent Meter Markings (SANS 1529) Serial Number Manufacturer’s Name Meter Class Permanent Flowrate Approval Number Flow Direction Nominal Working Pressure Pressure Loss (<100kPa) Meter Model Installation Orientation (H) • Meter size NOT a consideration Adapted from Van Zyl (2011). Introduction to Integrated Water Meter Management – Edition 1. Water Research Commission

14. Meter Types

15. Metering Summary • Meter specifics matter • Size (mm) is the least important • There is a meter meeting your specific requirements • Installation orientation and practices • Water Quality • Consumption Profile • There are related regulation requirements • Some day they will be enforced, do the right thing! • The better your meter info is, the better is the management of meters

16. The Weighted Meter Error Method 16

17. Weighted Metering Error Methodology Arregui, F. J., Cabrera Jr., E. and Cobacho, R. (2006) Integrated Water Meter Management. IWA Publishing

18. Consumption Patterns – Meter Logging

19. Consumption Patterns – Meter Logging

20. Consumption Profiles – Domestic Properties

21. Consumption Profiles – Bulk Consumers

22. Meter Accuracy Testing

23. Meter Testing

24. Meter Testing – Average Errors

25. Bringing it all together

26. Weighted Accuracy – 15mm meters

27. Weighted Accuracy – 20mm meters

28. Meter Accuracy varies with Age and Volume

29. Integrated Water Meter Management 29

30. Metering Systems Analysis Audits An improved meter management framework Consumer Audits Customer Information Meter Audits Meter Information Meter Verification Cost Benefit Analysis Metering (Error) Analysis Apparent Loss Assessment Meter Selection Meter Installation Meter Maintenance Quality Control Maintenance Records Integrated; On-going

31. Systems for Metering and Consumption Information • Consumer information to include • demographics information on the consumer • property information such as property type, property size, market value and category of water usage, • Meter information to include • meter specification details such as serial number, make, model, type, class, permanent flowrate (size), number of dials, initial verification information etc. • Installation details such as date, geolocation, connection/service type, etc. • Each device/customer must have a complete history with unique identifier

32. Meter Audits • The physical inspection and verification of meter details and the collection of consumption data over a period • The veracity of meter information is imperative for cost effective meter management and maintenance, among other activities • Consumer meter logging, for whatever reason, provides a wealth of information for meter management

33. Meter Audits

34. On-Site Leakage from Meter Audits

35. Consumer Audits • The verification of consumer information and the aggregation of the consumption data of each consumer category • Consumption profiles are one of two inputs to the determination of apparent losses

36. Meter Verification • The testing of meters to determine if the accuracy at specific flowrates falls within the prescribed accuracy limits • Meter testing results are the second of twoinputsin the determination of apparent losses • While important on their own, significance and context is only in combination with consumption profiles • A requirement for prudent meter selection • Initial verification results provide the starting weighted accuracy of new meters • its not 100%!

37. Meter Verification • Initial verification results must be provided by meter manufacturers • Require the actual results in your tenders • Adding additional test points at a cost might be beneficial • Meter testing of any used meters provides meter degradation rates • Consumer queries/test one way of building the required dataset • Developing a database from routine work will minimise the cost associated with assessing apparent water losses • Consolidate resources wherever possible

38. Meter Error Analysis • Evaluating the performance of homogeneous grouping of meters and consumers to inform meter selection policies

39. Meter Selection • Prudent selection is based meter testing data, consumption profiles and a cost-benefit analysis (CBA) for various consumption volumes • Meter CBA is an economic assessment to estimate the optimum meter replacement period or the benefits associated with specified period • The optimum meter replacement is based on the evaluation of the net present value of infinity meter replacements. Inputs include • the real discount rate • Cost of the meter and associated installation and administration costs • the price of the water • the annual consumption of the consumer • the initial weightedmeter error • the weightedmeter error degradation rate

40. Meter Selection

41. Meter Selection

42. Meter Installation and Maintenance From Standards, Policies, Guidelines to Practice!

43. Meter Installation and Maintenance • This is where the cookie crumbles… • The better the effort, the better the management of apparent losses • As precision instruments, meters require adherence to strict installation criteria to measure as accurately as possible • the length of straight pipeline before and after the meter • the correct installation alignment and direction • Meter maintenance is more about using a bit of common sense and the proper management and maintenance of water pipe networks • Cleaning of meter strainers, scouring of the pipelines, • (slow) opening of valves after service interruptions • Maintaining air valves

44. Quality Control • Is everything is as it should be? • Meter acceptance testing • Are you getting the correct meters? • Is the accuracy of the batch within acceptable norms? • Meter installation and replacement verification • Right meter (flowrate and meter type) at the right customer • Installation alignment and position • Correct and adequate details captured • Wherever possible upload data directly from the manufacturer to your systems

45. Assessment of Apparent Losses • Provides a quantitative validation of how well apparent water losses are being managed Meter X Meter Y Meter Z

46. Interested in Collaboration? 46

47. END Thank You