Managing Losses in Water Distribution Networks

Transcription

1 Managing Losses in Water Distribution Networks Calcutta, India: Mother bathing child An international strategy for an international problem Malcolm Farley Water Supply Management Workshop, Hue City, Vietnam Dubai: 12 million litres of desalinated water in Wild Wadi Water Park Managing Losses in Water Distribution Networks 2 Managing Losses in Water Distribution Networks 3 Managing Losses in Water Distribution Networks 4 Managing Losses in Water Distribution Networks 5 Managing Losses in Water Distribution Networks 6

2 Water Loss Monitoring Points Managing Losses in Water Distribution Networks 7 Challenges and Limitations Resources - Water, Staffing and Finance Public v Private Sector Utility and Customer Perception Operation and Organization Policy Changes Social, Political and Cultural Issues Dependency Culture - Donors and Consultants Motivation and Skills Security Health & Safety Managing Losses in Water Distribution Networks 8 Developing a Strategy The key to developing a strategy for any organisation is to: Ask some questions Select procedures and tools to find the solutions The same applies to water loss management exception Questions and Solutions How much water is being lost? - Water Balance Where is it being lost from? - Network Audit Why is it being lost? - Review network and operational practices How to improve performance? - Strategy development How to sustain performance? - Training and O&M Managing Losses in Water Distribution Networks 9 Managing Losses in Water Distribution Networks 10 IWA Water Losses Task Force IWA Standard Water Balance International best practice Network of members involved in water loss reduction Focused activity groups Exchange of information Key actions for implementation Contributing to publications, workshops, and conferences Authorized Consumption System Input Volume (corrected Unaccounted Water for known for Water errors) Losses Billed Authorized Consumption Unbilled Authorized Consumption Apparent (commercial) Losses Real (physical) Losses Billed Metered Consumption Billed Unmetered Consumption Unbilled Metered Consumption Unbilled Unmetered Consumption Unauthorized Consumption Customer Meter Inaccuracies and Data Handling Errors Leakage on Transmission and Distribution Mains Leakage and Overflows at Storage Tanks Leakage on Service Connections up to point of Customer Meter Revenue Water Non Revenue Water Managing Losses in Water Distribution Networks 11 Managing Losses in Water Distribution Networks 12

3 Real or apparent losses? How to prioritize? Water Balance (how much and where?) Analyze causes Real Losses Real Losses Real loss component Analysis Leakage and Overflows at Storage Tanks Background Losses Reported Bursts Unreported Bursts Excess or Hidden Losses Managing Losses in Water Distribution Networks 13 Managing Losses in Water Distribution Networks 14 Leak Volume = Awareness + Location + Repair Time x Flow Rate FLOW RATE LEAK DURATION A L R TIME Bottom-up real loss assessment 24h inflow and pressure measurements entire system (if small) sample areas within the system Area data to be collected length of mains number of service connections number of household properties number and types of non-household properties Managing Losses in Water Distribution Networks 15 Managing Losses in Water Distribution Networks 16 Zone inflow analysis Pressure Management Speed and Quality of Repairs Minimum Achievable Annual Real Losses Potentially Recoverable Real Losses Active Leakage Control Pipeline and Assets Management Selection Installation Maintenance Rehabilitation Replacement Current Annual Volume of Real Losses Managing Losses in Water Distribution Networks 17 Managing Losses in Water Distribution Networks 18

4 Network records and recording systems Update network plans and records Pipe location survey GIS Review of network operating practices Why is water being lost? Management policy Network characteristics Operational practices Technology and skills Social and cultural influences Managing Losses in Water Distribution Networks 19 Managing Losses in Water Distribution Networks 20 Improving the network Sectorization (Zoning) How to improve the network? Zoning (sectorization) District Meter Areas (small zones) Pressure management Managing Losses in Water Distribution Networks 21 Managing Losses in Water Distribution Networks 22 District Metered Area (small zone) Zonal Monitoring Volume of water Equivalent service pipe bursts Cost of lost water Prioritizing system Allows the operator to focus leak location effort to give most benefit Managing Losses in Water Distribution Networks 23 Managing Losses in Water Distribution Networks 24

5 Design constraints and aids DMA (Zone) Maintenance Design constraints network pressures critical points too many closed valves traditional values and reluctance intermittent supply Design benefits pressure testing network model extra meters or redesign boundary education and awareness training restore supply in pilot DMA Boundary integrity - record changes - mark boundary valves - educate staff! Plant and equipment - meter checks - instrumentation checks Managing Losses in Water Distribution Networks 25 Managing Losses in Water Distribution Networks 26 Zone night flow data Pressure management Occurrence of large burst & repair One-off reduction in leakage Pressure Management Area (PMA) Design within DMA Cost beneficial Fast payback Managing Losses in Water Distribution Networks 27 Managing Losses in Water Distribution Networks 28 Active leakage control Leakage monitoring (zones) Analysis of data Leak detection programs: - leak localizing (noise loggers) - survey (correlator/sounding) -leak location Leak Localizing (noise loggers) Managing Losses in Water Distribution Networks 29 Managing Losses in Water Distribution Networks 30

6 Leak Location (traditional) Leak Location (new technology) Managing Losses in Water Distribution Networks 31 Managing Losses in Water Distribution Networks 32 Infrastructure management and repairs Illegal connections, theft and fraud Managing Losses in Water Distribution Networks 33 Managing Losses in Water Distribution Networks 34 Customer meter under- registration Customer metering policy: Measurement accuracy Meter type Installation procedure In situ or workshop testing Customer use pattern and plumbing (tanks filling, trickles and drips etc.) Billing and collection Tariff structure and charging policy political/social factors encourages demand management low income concerns (health/hygiene) can encourage damage and bypass Meter reading and revenue collection integral part of strategy supervision and checks Managing Losses in Water Distribution Networks 35 Managing Losses in Water Distribution Networks 36

7 Maintaining the strategy Case Study 1. Bahamas Training and skills transfer Workshops Technology transfer Field training O&M programme Managing Losses in Water Distribution Networks 37 Managing Losses in Water Distribution Networks 38 Technical Problems Issues for Improvement Direct pumping into the system (6 PS) Fixed speed pumps No surge control Limited storage (~100 ML) and gravity supply Effect on burst rate Additional sources Address pumping regime Increase storage Utilise cross-department skills Improve Quality Assurance and O&M policies Customer metering policy Managing Losses in Water Distribution Networks 39 Managing Losses in Water Distribution Networks 40 Action Plan (1) Pressure Management System Optimisation (PRVs, PCVs, SRVs, gravity flow) Telemetry Infrastructure Management Infrastructure Audit GIS Standards QA/QC Action Plan (2) Active Leakage Control Monitoring and Testing Equipment Meter Sizing/Calibration NRW Reduction: Pilot Project / Performance-Based Contract Leak Repairs Re-organisation Establish standards Outsourcing (internally/externally) QA/QC Technical Assistance/Training Managing Losses in Water Distribution Networks 41 Managing Losses in Water Distribution Networks 42

8 Project characteristics Duration: 4 years Reduction of real and apparent losses Outsourced to private contractors Total cost: US$ 27 M Includes establishment/refurbishment of 80 DMA zones and selective mains replacement Managing Losses in Water Distribution Networks 43 Managing Losses in Water Distribution Networks 44 Conclusions Real losses can be calculated from top-down and bottom-up approach After knowing HOW MUCH? and WHERE FROM? the water loss reduction strategy can be designed Strategy addresses real and apparent losses Case studies demonstrate similar costs and benefits Strategy can be applied to any organisation anywhere in the world Case Study 2. Rarotonga - Cook Islands Managing Losses in Water Distribution Networks 45 Managing Losses in Water Distribution Networks 46 Rarotonga - main features 13 upland spring sources Limited storage (2.5 Ml reservoir) No active leakage control Coastal ring sub-mains, no zoning Some planned replacement High local and tourist demand ( l/h/d) Successive drought years Planned pipe replacement and dammed valley augmentation Managing Losses in Water Distribution Networks 47 Managing Losses in Water Distribution Networks 48

9 Managing Losses in Water Distribution Networks 49 Managing Losses in Water Distribution Networks 50 Rarotonga network Short and Medium Term Action Plans Bulk meters at sources Create source supply zones Use zones for water loss monitoring Set up customer use studies Set up pilot study areas Introduce leakage control teams Empower with equipment, vehicles and knowledge Conduct awareness seminars and training Plan network improvements while upgrading Plan water conservation programmes Managing Losses in Water Distribution Networks 51 Managing Losses in Water Distribution Networks 52 Conclusions Real losses can be calculated from top-down and bottom-up approach After knowing HOW MUCH? and WHERE FROM? the water loss reduction strategy can be designed Strategy addresses real and apparent losses Case studies demonstrate similar costs and benefits Strategy can be applied to any organisation anywhere in the world Losses in Water Distribution Networks A Practitioner s Guide to Assessment, Monitoring and Control Authors: Malcolm Farley and Stuart Trow ISBN: April pages Hardback Price: Order online at: Managing Losses in Water Distribution Networks 53 Managing Losses in Water Distribution Networks 54

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