Water Services Training Group

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Water Services Training Group

• 13th Annual Conference
• 10th September 2009

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Prioritising Mains for Rehabilitation/Replacement
in a Large Urban Area

• Alan Curran
• Technical Director
• RPS Consulting Engineers

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Presentation Outline

• Case Study
• Dublin Region Watermains Rehabilitation Project
  (DRWRP) Client Dublin City Council
• Background
• Drivers Challenges
• DMA Prioritisation
• Mains Selection
• Key Issues and Lessons Learned
• Results

Meeting the Challenges of the Changed Economic
Environment Annual Conference September 2009
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Background Dublin Region Water Supply

• Greater Dublin Water Supply Area 7 LAs
• Serves a population of 1.4m
• Output 546 Ml/day
• Sustainable Prod. 520 Ml/day
• gt8,000km water main
• 600 DMAs
• Future Demand Shortfall Identified in 1996

Meeting the Challenges of the Changed Economic
Environment Annual Conference September 2009
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Background Dublin Region Water Conservation
Project (Stage 1 and 2) - 1998-2002

• Project Achieved
• New Monitoring, Control and Data Systems
• Metering and telemetry systems
• 530 District Meter areas (DMAs)
• Pressure management in selected areas
• A regional GIS system was established
• Regional hydraulic models were constructed
• Burst Record Database
• Establishment of trained leakage control teams
• Reduction in UFW from 42.5 to 28 (64Ml/day)
• Pilot Leakage Driven Water Mains Rehabilitation
• Confirmation that Rehabilitation Essential to
• Maintain Saving
• Reduce below 28

2002-2006 ALC and Systems Well Maintained
Meeting the Challenges of the Changed Economic
Environment Annual Conference September 2009
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DRWRP Drivers and Objectives

• Overriding Purpose
• To Save water by Rehabilitating water mains
• the greatest sustainable water savings,
• in a cost effective manner
• Through an Integrated Approach
• DMA Rehabilitation
• Hot Spot Rehabilitation Isolated High Burst
  Frequency Mains
• Active Pressure Management
• DMA Optimisation
• Improved Metering infrastructure (where required)
• While Recognising Risks
• Improved Service levels may offset savings

Meeting the Challenges of the Changed Economic
Environment Annual Conference September 2009
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DRWRP Scope

• Scope
• Up to 4 of total mains length ( 280 km) limited
  by budget
• Higher rate required in long term
• New development unlikely to be targeted (separate
  issues)

Meeting the Challenges of the Changed Economic
Environment Annual Conference September 2009
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Challenges Urban Environment

• Complexity of the Network
• Understanding
• Valve Density, Status and Connectivity
• Handling Large Data Sets
• 8,500 km
• gt 600 DMAs
• 55,000 leak records
• Density of Services
• CSL Risk
• Night Users
• DMA Material and Age Mix
• Construction Cost Variability
• Access Issues Traffic Management

Meeting the Challenges of the Changed Economic
Environment Annual Conference September 2009
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Challenges - Leakage

• How to Achieve Success
• Which is ultimately measured at DMA Level
• Selecting the Correct
• DMAs
• Mains within the DMAs
• Accuracy of Leakage Calculations
• UFW does not leakage
• PCC changes with weather and temp.
• Leakage Fluctuates How do you Measure?
• Which Assets are leaking?
• Which DMAs/Assets will offer SUSTAINABLE
  savings?
• Which DMAs Offer Best VFM?
• Customer Side Leakage

Meeting the Challenges of the Changed Economic
Environment Annual Conference September 2009
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DMA Prioritisation - Objectives
1. DMA Prioritisation

• Data Collection Fitness for Purpose
  Assessment
• All 7 Authorities, All DMAs
• System Implementation for Data Management,
  Leakage Analysis and Ranking
• Characterise DMAs e.g. high leakage, high
  pressure, unit costs
• All DMAs
• Rank and identify shortlist DMAs (and reserves)
• to match available budget
• High-level identification of target mains
  within DMAs

Collate Check Data
Agree Candidate DMA List
Characterise DMAs Leakage/Cost
Analyse DMA Leakage
Prepare DMA Rankings
Assign Leakage To DMA Assets
Identify Target Assets
LA Ranking Sense Check
Prioritise DMA Work Packages
Prioritise DMAs
Produce Strategy Report
Ranked DMA List
Strategy Report
Meeting the Challenges of the Changed Economic
Environment Annual Conference September 2009
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DMA Prioritisation Data
1. Strategy Development DMA Ranking

• GIS
• Network
• DMA Boundaries
• Geodirectory - Properties
• Other Network Information
• Pressure Management
• Schematics
• Telemetry
• Flow and Pressure
• DMA Leakage Sheets (ESPB)
• Leak Repair Records
• NRR
• Repeat Leak History
• Network Models
• AZNP
• Detailed Design
• Historical Rehabilitation Unit Costs

Collate Check Data
Meeting the Challenges of the Changed Economic
Environment Annual Conference September 2009
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DMA Ranking Characterise DMAs
SAVINGS
Mains Comm. Pipe Leakage
Meeting the Challenges of the Changed Economic
Environment Annual Conference September 2009
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DMA Ranking Characterise DMAs
SAVINGS
Natural Rate of Rise in Leakage
Meeting the Challenges of the Changed Economic
Environment Annual Conference September 2009
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DMA Ranking Characterise DMAs
COSTS
Mains Rehabilitation Works Costs
Meeting the Challenges of the Changed Economic
Environment Annual Conference September 2009
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DMA Ranking Characterise DMAs
COSTS
SAVINGS
Mains Comm. Pipe Leakage
Mains Rehabilitation Works Costs
/ Ml saved

Ml

• Leak Repair Cost
• Savings

Natural Rate of Rise in Leakage
DMA RANKING
Meeting the Challenges of the Changed Economic
Environment Annual Conference September 2009
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DMA Selection and Prioritisation

• 8 Ranking passes carried out Apr-July 06
• Each set reviewed LAs
• DMA Integrity
• sense check /local knowledge
• cross reference LA lists
• Unsuitable DMAs removed
• Need for High burst frequency programme agreed
• Ranked List of 60 for Field Validation
• Shortlist agreed matching DMAs non-responsive
  to ALC

Meeting the Challenges of the Changed Economic
Environment Annual Conference September 2009
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Mains Selection - Objectives

• Validate/Improve Data in Candidate DMAs
• Field Work
• Desk Top
• Operations Staff Interview
• Leakage Asset Data
• Detailed Analysis and Scoring
• Recommend Solution

Meeting the Challenges of the Changed Economic
Environment Annual Conference September 2009
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Mains Prioritisation Validation

• 60 Short-listed DMAs and Reserves only (40/20)
• Integrity of the DMAs
• Meter / PRV audits,
• BV checks,
• PZT,
• Leakage Assignment
• Step-testing,
• Burst Geo-referencing and Assignement
• Operations Interview
• Data Review Leakage, Burst History, Customer
  Side Leakage Assessment

Meeting the Challenges of the Changed Economic
Environment Annual Conference September 2009
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Mains Selection DMA Integrity
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Mains Selection Assets
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Mains Selection Bursts
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Mains Selection Step Tests
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Mains Selection Data Assessment Scoring

• All available information considered
• Burst Frequency
• Leakage
• Historical Performance
• Operations Knowledge
• Data Assessment and Scoring Applied
• Scoring Indicative
• Solution Recommended
• Further Investigation
• Do not Progress
• Pressure Mgt
• Rehabilitation Full or Partial
• Combination

Meeting the Challenges of the Changed Economic
Environment Annual Conference September 2009
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Mains Scoring L6/07 - Appendix 5
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Mains Scoring L6/07 - Appendix 5
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Results Skellys Lane
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Results Crumlin Cross
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Conclusions

• Good Data is Key to Sound Investment Decisions
• Use Best Available
• Non Domestic metering
• Pipe Samples - Opportunistic
• Improve Existing
• Geo-reference Burst Records
• Maintain GiS
• Maintain Telemetry Records
• Optimise DMA Sizes
• Develop NRR Calculations
• Burst Records
• ALC and Leakage History
• Use Scoring as Guide

Meeting the Challenges of the Changed Economic
Environment Annual Conference September 2009
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Conclusions

• Enormous Challenge
• Integrated Approach Essential
• Ongoing Active Leakage Control
• Pressure Management
• Data Improvements and Understanding of Components
  of Demand
• Demand Management
• Sustained Asset Renewal
• Mains Services??
• Rehabilitation only Part of the Solution

Meeting the Challenges of the Changed Economic
Environment Annual Conference September 2009
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Conclusions DRWRP Results

• Post 5 Contracts
• Total Length Rehabilitated 51km
• gt 4,000 New Boundary Boxes
• Total Savings 7.9 Ml/day
• Pipe Rehabilitation 2.1 Ml/day
• Pressure Mgt. 2.4 Ml/day
• DMA Optimisation/Metering 3.4 Ml/day
• Pilot DMA 100 Rehab
• Majority Leakage Private Side
• Public Network Leakage Minimal
• Integrated Approach Achieving Success

Meeting the Challenges of the Changed Economic
Environment Annual Conference September 2009