Water Services Training Group

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

Water Services Training Group

13th Annual Conference

10th September 2009


Prioritising Mains for Rehabilitation/Replacementin a Large Urban Area

Alan Curran

Technical Director

RPS Consulting Engineers

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


Background – Dublin Region Water Supply


Greater Dublin Water Supply Area – 7 LA’s

Serves a population of 1.4m

Output 546 Ml/day

Sustainable Prod. 520 Ml/day

>8,000km water main

600 DMA’s

Future Demand Shortfall Identified in 1996

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

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

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)

DMA Prioritisation(5 months)

DMA & Mains Appraisals &

Outline Design(7 months)

PHASE 1

PHASE 2

Detailed Designs and Construction

(5 years)

PHASE 3

Challenges – Urban Environment

Complexity of the Network Understanding Valve Density, Status and Connectivity

Handling Large Data Sets 8,500 km > 600 DMA’s 55,000 leak records

Density of Services CSL Risk Night Users

DMA Material and Age Mix Construction Cost Variability Access Issues – Traffic Management


Challenges - Leakage

How to Achieve Success Which is ultimately measured at DMA Level

Selecting the Correct DMA’s Mains within the DMA’s

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 DMA’s/Assets will offer SUSTAINABLE savings? Which DMA’s Offer Best VFM? Customer Side Leakage


DMA Prioritisation - Objectives


Collate & Check Data

AgreeCandidateDMA List

Characterise DMAs

Leakage/Cost

Prepare DMA Rankings

LA RankingSense Check

PrioritiseDMAs

Analyse DMALeakage

Assign LeakageTo DMA Assets

RankedDMA List

Identify TargetAssets

Prioritise DMAWork Packages

ProduceStrategy Report

StrategyReport

1. DMA Prioritisation

GISClient TelemetryBurst

RecordsNetworkModels

StakeHolders

LeakageInformation

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

DMA Prioritisation – Data



AgreeCandidateDMA List

Characterise DMAs

Leakage/Cost

Prepare DMA Rankings

LA RankingSense Check

PrioritiseDMAs

Analyse DMALeakage

Assign LeakageTo DMA Assets

RankedDMA List

Identify TargetAssets

Prioritise DMAWork Packages

ProduceStrategy Report

StrategyReport

1. Strategy Development & DMA Ranking



StakeHolders

LeakageInformation

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


Night Use Allowances

Households & Non households

MNF (m3/h)

CSP Leakage (m3/d)

Length of mains (km)

Hour – Day Factor

NNF (m3/h)

Total Leakage (m3/d)

M&C Leakage (m3/d)

M&C Leakage m3/km/d

DMA Ranking – Characterise DMA’s


Mains & Comm. Pipe Leakage

SAVINGS

Lstart

Lend

Volume of leak repairs

[R]

NRR

NRR = Lend – Lstart + R



Natural Rate of Rise in Leakage

SAVINGS



Mains Rehabilitation Works Costs

COSTS

Total Unit Cost (€ per

m)Additional LC / Enabling works

Technique Unit Costs

Leak Repair Savings

Technique selection

Local Roads Policy

Stakeholders

Base Unit Costs

Reinst Unit Cost

Social Impacts

Present Value



€ / Ml saved

Mains Rehabilitation Works Costs

- Leak Repair CostSavings

€

Mains & Comm. Pipe Leakage

Natural Rate of Rise in Leakage

Ml

DMA RANKING

COSTS SAVINGS

DMA Selection and Prioritisation

8 Ranking passes carried out Apr-July 06

Each set reviewed LA’s – DMA Integrity sense check /local knowledge cross reference LA lists Unsuitable DMA’s removed Need for High burst frequency

programme agreed

Ranked List of 60 for Field Validation

Shortlist agreed matching DMAs “non-responsive” to ALC


Mains Selection - Objectives




StakeHolders

LeakageInformation

DMA Appraisal Reports

2. Mains Prioritisation

Data Validation Candidate DMA’s

Data Analysis

Field Assessment

DMA Integrity

Step Testing

Meter/PRV Audits

Detailed Data Verification

Asset DataBurst

Records

LeakageAnalysis &

Assignment

Mains Scoring

Solutions

Other DataPipe Samples

No Action

Rehabilitation

Pressure Management

Validate/Improve Data in

Candidate DMA’s

Field Work

Desk Top

Operations Staff Interview

Leakage & Asset Data

Detailed Analysis and Scoring

Recommend Solution

Mains Prioritisation – Validation




StakeHolders

LeakageInformation

DMA Appraisal Reports

2. Mains Prioritisation

Data Validation Candidate DMA’s

Data Analysis

Field Assessment

DMA Integrity

Step Testing

Meter/PRV Audits

Detailed Data Verification

Asset DataBurst

Records

LeakageAnalysis &

Assignment

Mains Scoring

Solutions

Other DataPipe Samples

No Action

Rehabilitation

Pressure Management

60 Short-listed DMAs and Reserves only (40/20)

Integrity of the DMA’s 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

Mains Selection – DMA Integrity

Mains Selection – Assets

Mains Selection – Bursts

Mains Selection – Step Tests

STEP TEST ASSESSMENT FOR:-DMA REF:-DMA NAMEDATE VERIFIED:-

Step 1 Step 2 Step 3 Step 4 Step 5 TotalBASE DATA

No. Domestic Addresses 66 180 127 77 214 664No. Commercial Addresses 107 144 31 45 168 495No Buildings/Connections 72 135 109 71 106 493Exceptional Night Use (m3/Hr) 0.2 0.0 0.0 0.1 0.0 0.3

Bursts 57 55 9 9 28 158Mains and Mains Fittings Leaks 28 37 4 3 9 81Comms and Comms Fittings Leaks 27 17 4 5 9 62Customer Supply Pipe and CSP Fittings Leaks 2 1 1 1 10 15

Length Target Mains (m) 713 1,182 3 446 1,148 3,492GIS Length of Mains (m) 2,172 1,665 887 458 1,731 6,914Length Mains Missing from GIS (m) 0 0 0 0 0 0Total Length of Mains (m) 2,172 1,665 887 458 1,731 6,914

Current DRWRP Project 14.00 9.68 8.87 8.46 2.91 43.92DRWCP Study - 1.05 18.65 2.10 4.50 26.30

Hour to Day Factor 20.3 20.3 20.3 20.3 20.3 20.3

Background Water Useage (m3/hr) 1.15 1.46 0.46 0.56 1.72 5.36Consumer Losses (m3/hr) 0.14 0.38 0.27 0.16 0.45 1.40Consumer service & plumbing (m3/hr) 0.05 0.08 0.04 0.03 0.08 0.30Total 1.34 1.93 0.77 0.76 2.26 7.06

Current DRWRP Project m3/hr 12.66 7.76 8.09 7.70 0.65 36.86

DRWCP Study (includes CSL) m3/hr - 0.53 17.79 1.37 1.95 21.64

m3/Km/d 118.30 94.54 185.20 340.93 7.66 108.22

DC000102Camden Street Upper19/12/2006

Mains & Coms Leakage

Legitimate Usage & Consumer Losses

FLOW DROPS (m3/Hr)

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


Mains Scoring – L6/07 - Appendix 5

Length[m]

2 2 1 0 0 1 0

Score 0 0.05 0.1 0 19881 0.4 1 1 19732 0.8 2 2 19583 1.2 3 3 19484 1.6 4 4 1938

5 2 5 5 1928

Weighting

(0 – 5)Material

Phy

sica

l Con

dition Soil

Cor

rosi

vity

Bur

st

Fre

quen

cy

Data (existing pipe)

Hea

d lo

ss

Impo

rtan

ce

Age

Parameters / Scores

Tot

al W

eigh

ted

Scor

e

Lea

kage

Mains Scoring – L6/07 - Appendix 5Length

[m]

2 2 1 0 0 1 0Score of 15 and above considered for rehabilitation unless non target main.

Score 0 0.05 0.1 0 19881 0.4 1 1 19732 0.8 2 2 19583 1.2 3 3 19484 1.6 4 4 1938 Phase

1€751.0

1,891

5 2 5 5 1928 Phase 2

€668.01,216

DMA Totals 6,914 TOTAL €1,419.0 3,107

DC000102 - Step 1 182 Ductile Iron 5 5 1 NA NA 1 NA 22 NA - NA No - - - Non target main

DC000102 - Step 1 713 Ferrous 5 5 4 NA NA 5 NA 29 NA €325.6 NA Yes

556 157 713

This main has a high burst frequency and this combined with pipe sample graded "condition 4", it is recommended that this main is put forward for Rehab.

DC000102 - Step 1 668 Post 85 Plastic 5 5 1 NA NA 0 NA 21 NA - NA No - - - Non target MDPE or HPPE and dates from 2002

DC000102 - Step 1 608 Other 2 5 1 NA NA 0 NA 15 NA - NA No - - - Non target main


DC000102 - Step 2 1,182 Ferrous 5 4 5 NA NA 5 NA 28 NA €471.3 NA Yes

663 369 1,032

Pipe sample graded "Condition Grade 5" indicating urgent replacement or renovation. There is also a high burst frequency so this main was recommended for rehab.

DC000102 - Step 2 339 Post 85 Plastic 5 4 1 NA NA 0 NA 19 NA - NA No - - - Non target MOPVC from 1996 and 2002

DC000102 - Step 3 3 Ferrous 0 5 5 NA NA 5 NA 20 NA - NA No - - - Low burst frequency and a very short length of main,so this is not recommended for rehab

DC000102 - Step 3 884 Post 85 Plastic 4 5 1 NA NA 0 NA 19 NA - NA No - - - Non target main of MDPE from 2002


DC000102 - Step 4 446 Ferrous 5 5 4 NA NA 5 NA 29 NA €203.2 NA Yes

445

-

445

Pipe sample graded "Condition Grade 5" indicating urgent replacement or renovation. There is also a high burst frequency so this main was recommended for rehab.

DC000102 - Step 4 7 Post 85 Plastic 0 5 1 NA NA 0 NA 11 NA - NA No - - - Non target main


DC000102 - Step 5 1,148 Ferrous 5 0 3 NA NA 5 NA 18 NA €418.8 NA Yes

227 690 917

Overall score is ablove the target threshold, the Pipe sample graded "Condition Grade 5" indicating urgent replacement or renovation. This combined with a high burst frequency has resulted in the main being recommended for rehab.

DC000102 - Step 5 85 Post 85 Plastic 5 0 1 NA NA 0 NA 11 NA - NA No - - - Non target main and there has only been two leaks

Dublin Region Watermains

Rehabilitation Project -

Contract 7

Camden Street Upper

Len

gth

Mai

ns fo

r R

ehab

- P

hase

1 (m

)

Com

men

ts

Rec

omm

ende

d in

2.2

R

epor

t

Weighting

Indi

cative

pay

back

(0 – 5)Material

Phy

sica

l Con

dition Soil

Cor

rosi

vity

Bur

st

Fre

quen

cy

Scheme Name DMA name Scheme/ DMA/ Works ref.

Data (existing pipe)

Len

gth

Mai

ns fo

r R

ehab

- P

hase

2 (m

)

Len

gth

Mai

ns fo

r R

ehab

(m

)

Indi

cative

rat

ing

Hea

d lo

ss

Est

imat

ed c

ost

(€ 0

00's

)

Impo

rtan

ce

Age

Parameters / Scores

Tot

al W

eigh

ted

Scor

e

Lea

kage

Results – Skelly’s Lane

UFW SUMMARY REPORT FOR:-

65.0

65.0

69.6

0.0

100.0

200.0

300.0

400.0

500.0

600.0

700.0

800.0

900.0

To

tal

UF

W(m

3/d

ay)

CSL

Mains & Comms

PHASE 1

DC000109 - Skelly's Lane 468.2TOTAL TARGET UFW

(m3/day) =

POST-CONSTRUCTIONVALIDATION

Results – Crumlin Cross

UFW SUMMARY REPORT FOR:-

83.6

83.6

74.6

0.0

200.0

400.0

600.0

800.0

1000.0

1200.0

To

tal

UF

W(m

3/d

ay

)

CSL

Mains & Comms

PHASE 1

DC000028 - Crumlin Cross 828.8TOTAL TARGET UFW

(m3/day) =

POST-CONSTRUCTIONVALIDATION

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


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

Conclusions


Conclusions – DRWRP Results

Post 5 Contracts Total Length Rehabilitated – 51km > 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


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