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Decision Making andInvestment Planning

Potable Water

Storm and Wastewater

Roads and Sidewalks

EnvironmentalProtocols

Transit

PotableWater

Innovations and Best Practices

National Guide to SustainableMunicipal Infrastructure

www.infraguide.ca

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Developing a Water Distribution System Renewal Plan — November 2003 1

Developing a WaterDistribution SystemRenewal Plan

This document is the sixth in a series of bestpractices related to the delivery of potable water tothe public. For titles of other best practices in thisand other series, please refer to www.infraguide.ca.

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National Guide toSustainable Municipal

Infrastructure

2 Developing a Water Distribution System Renewal Plan — November 2003

Developing a Water Distribution System Renewal Plan

Issue No. 1.0

Publication Date: November 2003

© Copyright National Guide to Sustainable Municipal Infrastructure 2003

ISBN 1–897094–22–1

The contents of this publication are presented in good faith and are intended as general

guidance on matters of interest only. The publisher, the authors and the organizations to

which the authors belong make no representations or warranties, either express or implied,

as to the completeness or accuracy of the contents. All information is presented on the

condition that the persons receiving it will make their own determinations as to the

suitability of using the information for their own purposes and on the understanding that the

information is not a substitute for specific technical or professional advice or services. In no

event will the publisher, the authors or the organizations to which the authors belong, be

responsible or liable for damages of any nature or kind whatsoever resulting from the use

of, or reliance on, the contents of this publication.

Why Canada Needs InfraGuide

Canadian municipalities spend $12 to $15 billion

annually on infrastructure but it never seems to be

enough. Existing infrastructure is ageing while demand

grows for more and better roads, and improved water

and sewer systems responding both to higher

standards of safety, health and environmental

protection as well as population growth. The solution

is to change the way we plan,

design and manage

infrastructure. Only by doing

so can municipalities meet

new demands within a

fiscally responsible and

environmentally sustainable framework, while

preserving our quality of life.

This is what the National Guide to Sustainable

Municipal Infrastructure (InfraGuide) seeks to

accomplish.

In 2001, the federal government, through its

Infrastructure Canada Program (IC) and the National

Research Council (NRC), joined forces with the

Federation of Canadian Municipalities (FCM) to create

the National Guide to Sustainable Municipal

Infrastructure (InfraGuide). InfraGuide is both a new,

national network of people and a growing collection of

published best practice documents for use by decision

makers and technical personnel in the public and

private sectors. Based on Canadian experience and

research, the reports set out the best practices to

support sustainable municipal infrastructure decisions

and actions in six key areas: 1) municipal roads and

sidewalks 2) potable water 3) storm and wastewater

4) decision making and investment planning

5) environmental protocols and 6) transit. The best

practices are available on-line and in hard copy.

A Knowledge Network of Excellence

InfraGuide’s creation is made possible through

$12.5 million from Infrastructure Canada, in-kind

contributions from various facets of the industry,

technical resources, the collaborative effort of

municipal practitioners, researchers and other

experts, and a host of volunteers throughout the

country. By gathering and synthesizing the best

Canadian experience and

knowledge, InfraGuide

helps municipalities get the

maximum return on every

dollar they spend on

infrastructure — while

being mindful of the social and environmental

implications of their decisions.

Volunteer technical committees and working

groups — with the assistance of consultants and

other stakeholders — are responsible for the research

and publication of the best practices. This is a system

of shared knowledge, shared responsibility and shared

benefits. We urge you to become a part of the

InfraGuide Network of Excellence. Whether you are

a municipal plant operator, a planner or a municipal

councillor, your input is critical to the quality of

our work.

Please join us.

Contact InfraGuide toll-free at 1-866-330-3350 or visit

our Web site at www.infraguide.ca for more

information. We look forward to working with you.

Introduction

InfraGuide –

Innovations and

Best Practices


INTRODUCTION

InfraGuide – Innovations and Best Practices


The InfraGuide Best Practices Focus

TransitUrbanization places pressure on an eroding,ageing infrastructure, and raises concerns aboutdeclining air and water quality. Transit systemscontribute to reducing traffic gridlock andimproving road safety. Transit best practicesaddress the need to improve supply, influencedemand and make operational improvementswith the least environmental impact, whilemeeting social and business needs.

Potable WaterIn keeping with the adage “out of sight, out of mind”, the waterdistribution system has been neglected in many municipalities. Potablewater best practices address various approaches to enhance amunicipality’s or water utility’s ability to manage drinking water deliveryin a way that ensures public health and safety at best value and on asustainable basis. The up-to-date technical approaches and practices setout on key priority issues will assist municipalities and utilities in bothdecision making and best-in-class engineering and operational techniques.Issues such as water accountability, water use and loss, deterioration andinspection of distribution systems, renewal planning and technologies forrehabilitation of potable water systems and water quality in thedistribution systems are examined.

Decision Making and InvestmentPlanning Elected officials and senior municipaladministrators need a framework for articulatingthe value of infrastructure planning andmaintenance, while balancing social,environmental and economic factors. Decision-making and investment planning best practicestransform complex and technical material intonon-technical principles and guidelines fordecision making, and facilitate the realization of adequate funding over the life cycle of theinfrastructure. Examples include protocols fordetermining costs and benefits associated withdesired levels of service; and strategicbenchmarks, indicators or reference points forinvestment policy and planning decisions.

Environmental Protocols Environmental protocols focus on the interactionof natural systems and their effects on humanquality of life in relation to municipalinfrastructure delivery. Environmental elementsand systems include land (including flora), water,air (including noise and light) and soil. Examplepractices include how to factor in environmentalconsiderations in establishing the desired levelof municipal infrastructure service; anddefinition of local environmental conditions,challenges and opportunities with respect tomunicipal infrastructure.

Municipal Roads and SidewalksSound decision making and preventive maintenance are essential to managingmunicipal pavement infrastructure cost effectively. Municipal roads andsidewalks best practices address two priorities: front-end planning and decisionmaking to identify and manage pavement infrastructures as a component of theinfrastructure system; and a preventive approach to slow the deterioration ofexisting roadways. Example topics include timely preventative maintenance ofmunicipal roads; construction and rehabilitation of utility boxes; and progressiveimprovement of asphalt and concrete pavement repair practices.

Storm and Wastewater Ageing buried infrastructure, diminishing financialresources, stricter legislation for effluents,increasing public awareness of environmentalimpacts due to wastewater and contaminatedstormwater are challenges that municipalitieshave to deal with. Storm and wastewater bestpractices deal with buried linear infrastructure aswell as end of pipe treatment and managementissues. Examples include ways to control andreduce inflow and infiltration; how to securerelevant and consistent data sets; how to inspectand assess condition and performance ofcollections systems; treatment plant optimization;and management of biosolids.

Acknowledgements . . . . . . . . . . . . . . . . . . . . . 7

Executive Summary. . . . . . . . . . . . . . . . . . . . . . 9

1. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . .11

1.2 Purpose and Scope . . . . . . . . . . . . . . . . . . . .11

1.3 How to Use This Document . . . . . . . . . . . . .12

1.4 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

2. Rationale . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

2.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . .15

2.1.1 Ageing Infrastructure . . . . . . . . . . . . .15

2.1.2 Higher Level of Service . . . . . . . . . . .15

2.1.3 More Stringent Water Quality Legislation . . . . . . . . . . . . . . . . . . . . . .16

2.1.4 Shrinking Financial Resources . . . . .16

2.1.5 Increased Accountability . . . . . . . . .16

2.2 Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

2.3 Risks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

3. Work Description . . . . . . . . . . . . . . . . . . . 19

3.1 What Should Be Done . . . . . . . . . . . . . . . . . .19

3.2 How to Do the Work . . . . . . . . . . . . . . . . . . . .19

3.2.1 Top-Down Approach . . . . . . . . . . . . .19

3.2.2 Bottom-Up Approach . . . . . . . . . . . . .22

4. Applications and Limitations . . . . . . . . . 29

4.1 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . .29

4.1.1 Top-Down Approach . . . . . . . . . . . . .29

4.1.2 Bottom-Up Approach . . . . . . . . . . . . .29

4.1.3 Financial Plan . . . . . . . . . . . . . . . . . . .29

4.2 Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . .30

5. Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Appendix A: Application of Top-DownApproach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Appendix B: Application of Bottom-UpApproach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

TABLETable 3–1: Water Distribution SystemCondition/Performance Indicators . . . . . . . . . . .23

FIGURESFigure 2–1: Population Growth in Canada . . . . .15

Figure 3–1: Selection of Alternative Water Main Renewal Technologies . . . . . . . . . . . . . . . .26

Table of Contents


TABLE OF CONTENTS


The dedication of individuals who volunteered their

time and expertise in the interest of the National Guideto Sustainable Municipal Infrastructure is

acknowledged and much appreciated.

This best practice was developed by stakeholders

from Canadian municipalities and specialists from

across Canada, based on information from a scan of

Canadian municipalities and an extensive literature

review. The following members of the National Guide’s

Potable Water Technical Committee provided

guidance and direction in the development of this best

practice. They were assisted by the Guide Directorate

staff and by R.V. Anderson Associates Limited in

association with R.M. Loudon Ltd. and Réseau

Environnement.

Carl YatesChair, Halifax Regional Water CommissionHalifax, Nova Scotia

Fred BuschMayor, District of Sicamous, British Columbia

Sukhi CheemaGovernment of the Northwest Territories

Normand DeAgostinisDuctile Iron Research Pipe AssociationAnjou, Quebec

Tim DennisCity of Toronto, Ontario

Dave GreenHealth Canada, Ottawa, Ontario

Piero SalvoWSA Trenchless Consultants Inc.Ottawa, Ontario

Doug SeargeantEPCOR, Edmonton, Alberta

Ernie TingTown of Markham, Ontario

Michael TobaltTechnical Advisor, NRC

In addition, the Potable Water Technical Committee

would like to thank the following individuals for their

participation in working groups and peer review:

John BarryCity of St. John’s, Newfoundland and Labrador

James HannamHalifax Regional Water CommissionHalifax, Nova Scotia

Ryan JohnsonCity of Moose Jaw, Saskatchewan

Raymond LeclercCity of Montréal, Quebec

Fern MarcuccioCity of Ottawa, Ontario

Diane SacherCity of Winnipeg, Manitoba

Doug SeargeantEPCOR Water Services, Edmonton, Alberta

Brian SherpingCity of Trois-Rivières, Quebec

Ernie TingTown of Markham, Ontario

Acknowledgements


ACKNOWLEDGEMENTS


This and other best practices could not have been

developed without the leadership and guidance of the

Project Steering Committee and the Technical

Steering Committee of the National Guide toSustainable Municipal Infrastructure, whose

memberships are as follows:

Project Steering Committee:Mike Badham, ChairCity Councillor, Regina, Saskatchewan

Stuart BriesePortage la Prairie, Manitoba

Bill CrowtherCity of Toronto, Ontario

Jim D’OrazioGreater Toronto Sewer and Watermain Contractors Association, Ontario

Derm FlynnMayor, Appleton, Newfoundland

David GeneralCambridge Bay, Nunavut

Ralph HaasUniversity of Waterloo, Ontario

Barb HarrisWhitehorse, Yukon

Robert HiltonOffice of Infrastructure, Ottawa, Ontario

Joan LougheedCity Councillor, Burlington, OntarioStakeholder Liaison Representative

René MorencyRégie des installations olympiquesMontréal, Quebec

Saeed MirzaMcGill University, Montreal, Quebec

Lee NaussCity Councillor, Lunenburg, Nova Scotia

Ric RobertshawRegion of Halton, Ontario

Dave RudbergCity of Vancouver, British Columbia

Van SimonsonCity of Saskatoon, Saskatchewan

Basile StewartMayor, Summerside, Prince Edward Island

Serge ThériaultDepartment of Environment and Local Government, New Brunswick

Alec WatersAlberta Transportation, Edmonton, Alberta

Wally WellsDillon Consulting Ltd., Ontario

Technical Steering Committee:Don BrynildsenCity of Vancouver, British Columbia

Al CepasCity of Edmonton, Alberta

Andrew CowanCity of Winnipeg, Manitoba

Tim DennisCity of Toronto, Ontario

Kulvinder DhillonProvince of Nova Scotia, Halifax, Nova Scotia

Wayne GreenCity of Toronto, Ontario

John HodgsonCity of Edmonton, Alberta

Bob LorimerLorimer & Associates, Whitehorse, Yukon

Betty Matthews-MaloneHaldimand County, Ontario

Umendra MitalCity of Surrey, British Columbia

Anne-Marie ParentCouncillor, City of Montréal, Quebec

Piero SalvoWSA Trenchless Consultants Inc., Ottawa, Ontario

Mike SheflinFormer CAO, Regional Municipality of Ottawa-Carleton, Ontario

Konrad SiuCity of Edmonton, Alberta

Carl YatesHalifax Regional Water Commission, Nova Scotia

Acknowledgements

This document describes the best practicefor developing a water distribution systemrenewal plan. It is based on a literaturereview, surveys of selected municipalitiesacross Canada, and input from Canadianwater distribution experts.

In the past, most Canadian municipalitiesfocused on the capital works required tosupport population growth. However, in light of ageing infrastructure, public demands for a higher level of service and accountability, as well as more stringent legislation andcompetition for finite financial resources,municipalities are now motivated to develop a plan for renewal of their water distributionsystems. Such a plan must address not onlythe ongoing renewal of infrastructure that hasreached the end of its useful life, but alsoupgrades to meet more demanding standards.

Two complementary approaches to thedevelopment of a water distribution systemrenewal plan — top-down and bottom-up —are reviewed. The top-down approach is usedfor strategic long-term planning of policies andprograms whereas the bottom-up approach isused for short-term capital planning ofprojects.

Top-Down Approach

Using the top-down approach, the projectedrenewal costs for a group of assets can beestimated using replacement cost andassumed life expectancy. The totalreplacement cost for a water system(including water supply, treatment, storage,distribution and pumping facilities) is typically$3,000 to $4,000 per capita. The long-termaverage annual cost for renewal of a waterdistribution system is typically one to twopercent of the total replacement cost for thesystem (AwwaRF, 2001). This assumes that theaverage life expectancy of the water systemcomponents is 50 to 100 years.

Bottom-Up Approach

The bottom-up approach requires a detailedinventory of the assets including their currentcondition, deterioration rate, and criticality. Acomprehensive renewal plan will address thefollowing needs.

■ Consider replacement of water mains andservices that do not conform to currentstandards in terms of main size, material,depth of cover as well as water servicematerial, size and depth of cover.

■ Replace or structurally rehabilitate mainsthat have high break rates or leaky joints.

■ Rehabilitate unlined iron mains with non-structural linings if they have notexperienced a high break rate but theirhydraulic capacity and/or water quality issignificantly impacted by deterioration.

■ Replace mains that are too small (even ifthey were cleaned and lined) to supplyrequired flows at adequate pressures.

■ Replace valves and hydrants that are non-standard, inoperable, or leaking.

In most cases, hydrants, valves, and waterservices are replaced when the mains arereplaced. However, in cases where a watermain is still in good condition, it might benecessary to replace some of theappurtenances.

Cost-Benefit Analyses

If the rate of deterioration can be estimated,then it is possible to predict the timing forrenewal of water mains using a cost-benefitanalysis. The timing for renewal of watermains that experience high break rates, leakyjoints, and reduced hydraulic capacity isprimarily dictated by economics. However, thetiming for renewal of water mains that do notconform to current design standards or impairwater quality is dictated by the severity of theproblem, risk, and the available funding.

Executive Summary


EXECUTIVE SUMMARY

Such a plan mustaddress not onlythe ongoingrenewal ofinfrastructure thathas reached theend of its usefullife, but alsoupgrades to meetmore demandingstandards.

Condition Rating Systems

Once the need for renewal of a water mainhas been established, municipalities shoulduse a condition rating system to assist withprioritizing their renewal program. The factorsincluded in a condition rating system will varyamong municipalities depending on the size of the municipality, the available data andspecific conditions within each system. Large municipalities should consider the need for a computerized decision supportsystem to facilitate renewal planning.

All municipalities should coordinate therenewal of their water distribution systemswith their road rehabilitation/reconstructionprogram and other upgrades that might berequired for new development/redevelopmentin order to minimize costs and disruption.

Financial Plan

A water distribution system renewal planshould include a financial plan to ensureadequate funding is available. Municipalitiesshould adopt the principles of full costrecovery, user pay, and pay as you go forrenewal of their distribution systems. An assetcondition index can be used to identify theuser rates required to maintain a distributionsystem in good condition.

Applications and Limitations

All municipalities should project their long-term renewal costs using the top-downapproach to facilitate long-term financialplanning. In addition, municipalities shoulddevelop a renewal plan using a bottom-upapproach based on the principles of riskmanagement. The development of acomprehensive renewal plan using a bottom-up approach will require investment of timeand money.

Evaluation

A renewal program should be reviewed every five to ten years to reflect the currentcondition of the system as well as theeffectiveness of various renewal technologies.Municipalities should track water main breakrates, water quality problems, fire flow rates,and leakage rates to establish deteriorationrates and the adequacy of the program.

The application of the top-down and bottom-up approaches to development of a waterdistribution system renewal plan is illustratedin appendices A and B, respectively.


Executive Summary

Municipalitiesshould adopt theprinciples of full

cost recovery, userpay, and pay as you

go for renewal oftheir distribution

systems.

1.1 Introduction

This document outlines the best practice fordeveloping a water distribution system renewalplan. For the National Guide to SustainableMunicipal Infrastructure (InfraGuide), a bestpractice is defined as state-of-the-artmethodologies and technologies for municipalinfrastructure planning, design, construction,management, assessment, maintenance, andrehabilitation that consider local, economic,environmental, and social factors.

This best practice is based on a review ofexisting literature, a survey of selectedmunicipalities across Canada, and input fromwater distribution experts across Canada.

1.2 Purpose and Scope

This document outlines the best practice for developing a renewal plan for waterdistribution mains and appurtenances (i.e., hydrants, valves, and water services). The development of a renewal plan for watersupply, wells, treatment, pumping, and storagefacilities is not addressed in this document.

It should be noted that there is a fundamentaldifference between planning the renewal ofwater distribution mains and transmissionmains.1 The primary objective of a renewalplan for distribution mains is to minimize theirlife cycle costs, while the primary objective ofa renewal plan for transmission mains is tominimize failures.2 In some cases, it is notpractical to monitor the condition oftransmission mains and accurately predict thetiming for their renewal. Therefore, it is oftennecessary to provide some redundancy in awater transmission system to allow the criticalcomponents to be taken out of service formaintenance and repairs.

The best practice presented in this documentfocuses on water distribution systems.Although most of the concepts are alsoapplicable to water transmission systems, therenewal planning for transmission systemsmust be more proactive in light of the greaterconsequences arising from their failure.

In this document, renewal of water distributionsystems includes both rehabilitation andreplacement of the system components.Although it should be recognized that propermaintenance should extend the life of adistribution system, this document does notspecifically address maintenance practices.

1. General

1.1 Introduction

1.2 Purpose and Scope


1. General

Although most ofthe concepts arealso applicable towater transmissionsystems, therenewal planningfor transmissionsystems must bemore proactive inlight of the greaterconsequencesarising from theirfailure.

1. Distribution mains meet local needs whereas transmission mains are required to transmit water from supply sources to storage,distribution mains and possibly booster pumping stations. The size threshold between the categories is not absolute but does correlatesomewhat with the size of the system.

2. There is essentially no difference in the objectives of a renewal plan for distribution and transmission mains if a risk managementphilosophy is adopted; the objective would be to minimize risks. A municipality may be prepared to accept more breaks on distributionmains, because the consequences may be limited to the costs of repairs. On the other hand, it may not be prepared to accept breakson transmission mains, because of the significant consequences.


1.3 How to Use This Document

Section 2 presents some reasons why it isprudent to develop a water distribution systemrenewal plan as well as the potential risksassociated with implementing this bestpractice. Section 3 presents twocomplementary approaches for developmentof a water distribution system renewal plan.Two examples are provided in the appendicesto illustrate these approaches. Section 4presents some of the applications andlimitations of this best practice. Finally,Section 5 describes several measures thatcan be used to evaluate the effectiveness ofthis best practice in your municipality. Referencesare provided throughout this document foradditional information on specific issues.

Readers should be aware that prior to therelease of this document, InfraGuide alreadypublished several other best practices that arerelevant to water distribution system renewalplanning, including the following.

■ Best Practices for Utility-Based Data —This document presents a foundation and guide for Canadian municipalities thatwish to begin the process of identifying,storing, and managing utility-basedinformation and data.

■ Deterioration and Inspection of WaterDistribution Systems — This documentoutlines the best practice for inspectingwater distribution systems to detect anysystem deterioration. The deteriorationprocesses for distribution systems andthe factors that can affect the rate ofdeterioration are also described.

■ Selection of Technologies for theRehabilitation or Replacement of Sectionsof a Water Distribution System — Thisdocument outlines the best practice forselection of available technologies for therehabilitation or replacement of watermains and appurtenances.

■ Coordinating Infrastructure Works —Five service delivery areas are addressed

in this best practice, including coordinationpractices, corridor upgrades, restrictivepractices, approval processes/bettercommunication, and technicalconsiderations.

■ An Integrated Approach to Assessment andEvaluation of Municipal Road, Sewer andWater Networks — This document outlinesthe best practice for integrated evaluationand assessment of municipal infrastructureat a network level. The best practice isbased on a five-step process that isapplicable to roads, water distribution,sewage collection, and storm drainagesystems recognizing that decisions madeon any one of these systems could impactdecisions to be made on the other systems.

■ Planning and Defining MunicipalInfrastructure Needs — This documentoutlines the best practice for planning anddefining municipal infrastructure needsusing five methods, namely, strategicplanning, information management, buildingpublic support and acceptance, exploringnew and innovative methods for continuousimprovement, and prioritization models.

Additional best practices related to thissubject may also be available from the Guide’sWeb site <www.infraguide.ca>.

1. General

1.3 How to Use This

Document

The best practice is based on a five-

step process that isapplicable to roads,

water distribution,sewage collection,

and storm drainagesystems recognizing

that decisionsmade on any one of these

systems couldimpact decisions

to be made on theother systems.

1.4 Glossary

Asset condition index — Equal to theinfrastructure deficit divided by the totalreplacement cost for an asset or group ofassets. An asset is deemed to be in goodcondition if its asset condition index (ACI) is less than five percent, in fair condition if its ACI is five to ten percent, and in poorcondition if its ACI is greater than ten percent.

Bottom-up approach — A detailed approachfor developing a renewal plan in which thetiming for renewal of an asset is based on itscondition or performance.

Cathodic protection — A system for reducingthe rate of corrosion of a metal by making themetal a cathode. This is done by inducing asmall direct current into the metal to beprotected by attaching a sacrificial anode or using an impressed current system.“Comprehensive” cathodic protection usuallyrefers to the installation of anodes at regularintervals along an existing metallic watermain (in corrosive soil). “Hot spot” cathodicprotection usually refers to the installation ofan anode on existing metallic water mainsand/or appurtenances (in corrosive soil)when the water main or appurtenance isexposed for repair.

Infrastructure deficit — Equal to thedifference between the needed investmentand the actual investment in renewal; alsoreferred to as the backlog in renewal work.

Life cycle cost — Costs over the full life cycleof an asset, from construction, throughmaintenance and rehabilitation, toreplacement.

Rehabilitation — Upgrading the conditionor performance of an asset to extend itsservice life.

Renewal — Restoring the condition of anasset by rehabilitation or replacement.

Replacement — Replacing an asset that hasreached the end of its service life.

Top-down approach — A simplified approachfor developing a renewal plan in which theprojected renewal costs for a group of assetscan be estimated using their replacement costand theoretical life expectancy.

1. General

1.4 Glossary



2.1 Background

In the past, most Canadian municipalitiesfocused on the capital works required tosupport population growth with littleconsideration of the need to renew theirdistribution system. However, in recent years, there has been a growing need formunicipalities to develop a water distributionsystem renewal plan, because of an ageinginfrastructure, higher level of service, morestringent water quality legislation, shrinkingfinancial resources, and increasedaccountability.

2.1.1 Ageing Infrastructure

Some municipal water systems in Canadawere installed over 100 years ago. Althoughsome components of these original systemshave already been replaced, there are still

many of these original components still inservice that should be replaced. Furthermore,most Canadian municipalities experiencedsignificant population growth (post World WarII) (Figure 2–1). The infrastructureconstructed during the 1950s is now over 50years old and, in many cases, is due forrenewal in the near future. The investment inrenewal will have to increase significantlywhen the infrastructure that was constructedin the 1950s has to be renewed.

2.1.2 Higher Level of Service

The level of service expected by the Canadianpublic has increased significantly over theyears. The public now expects a continuoussupply of safe and aesthetically acceptablewater at an adequate and stable pressure.There is little tolerance for even occasional

2. Rationale

2.1 Background

Figure 2–1

Population growth in

Canada


Figure 2–1: Population growth in Canada

2. Rationale

The public nowexpects acontinuous supplyof safe andaestheticallyacceptable water at an adequate andstable pressure.


2. Rationale

2.1 Background

disruptions to the water supply. Furthermore,water demands and fire flow requirementshave increased over the years resulting in the need for larger water mains andservices in some cases. To maintain a highlevel of service, it will be necessary formunicipalities to develop and implement arenewal plan for their distribution system.

2.1.3 More Stringent Water Quality Legislation

It is now widely recognized and accepted in the water industry that water quality maydeteriorate as it travels through a distributionsystem. In many cases, renewal of a waterdistribution system is often necessary to meetthe regulatory requirements for water quality.

2.1.4 Shrinking Financial Resources

In the past, many Canadian municipalitiesrelied on grants from provincial and federalgovernments to fund major infrastructurerenewal projects. However, in recent years,there has been a significant reduction insenior government grants for renewal of waterdistribution systems. This reduction is forcingmunicipalities to move toward full costrecovery for their water distribution systemswhich, in turn, promotes the need for afinancial plan to meet renewal needs.

2.1.5 Increased Accountability

In light of the demands for a higher level ofservice and rising costs, the Canadian publicis now demanding a more transparentdecision-making process. In 1999, theGovernmental Accounting Standards Board(GASB) in the United States introduced arequirement, known as GASB34, for state andlocal governments to account for their capitalinfrastructure assets and submit an annualreport. There are similar requirements in othercountries, including the United Kingdom andAustralia. In 2002, the Ontario governmentpassed Bill 175 (The Sustainable Water andSewage Systems Act). This Act makes itmandatory for Ontario municipalities to assessand report on the full costs of providing waterand sewage services, and then to prepare andimplement plans for recovering those costs.Every municipality in Ontario will have todevelop a water distribution system renewalplan to quantify the full costs of providingwater. Similar legislation may be enacted inother parts of Canada over time.

A comprehensive water distribution systemrenewal plan provides a systematic method toaddress technical, economic, and businessissues, such as level of service, cost ofservice, and risk management. A waterdistribution system renewal plan should havethe following goals:

■ Protect public health.

■ Provide a high level of service.

■ Minimize life cycle costs.

■ Minimize risks.

■ Ensure the water distribution system issustainable.

■ Ensure renewal funding is sufficient andefficiently spent.

A comprehensivewater distribution

system renewalplan provides a

systematic methodto addresstechnical,

economic, andbusiness issues,such as level ofservice, cost of

service, and riskmanagement.


2.2 Benefits

The following list summarizes some reasonswhy it is beneficial to develop a waterdistribution system renewal plan.

■ Municipalities will be able to manage therenewal of their systems in a proactivemanner, thereby minimizing the costs forreactive measures and the risks associatedwith socio-economic impacts. In otherwords, a proactive approach shouldminimize life cycle costs and risks.

■ Municipalities will be able to quantify thelife cycle costs for their systems. This willimprove long-range planning (both technicaland financial) and risk management. Long-range planning is particularly important formunicipalities with declining populations(i.e., revenue base).

■ A comprehensive renewal plan willfacilitate transparent decision making andprovide a measure of accountability to thecustomers.

■ A comprehensive renewal plan shouldpromote full cost recovery through userrates which, in turn, will ensure stable andadequate funding and promote efficient useof resources.

■ A comprehensive renewal plan shouldenable integrated planning of municipalinfrastructure (i.e., water distributionsystems, sewage collection systems, stormdrainage systems, roads, sidewalks andother utilities) to minimize total costs anddisruptions to residents and businesses.

■ A plan is a valuable tool for educating,explaining, and demonstrating the level ofinvestment to the politicians charged withthe responsibility of approving water systembudgets and to the public who will be“paying the bill.”

2.3 Risks

There are potential risks in following this best practice.

■ Additional resources (i.e., staff andequipment) will be required to develop and maintain a renewal plan.

■ There could be a lack of support for arenewal plan from stakeholders (e.g.,operators, politicians, and the public) forthose systems that have not yetexperienced significant problems or if waterrates have to be increased to pay for it.

■ A renewal plan may not be credible if dataare lacking or if it is not based on soundengineering principles.

■ Increases in water rates to support arenewal plan could result in a decrease inwater consumption and, if not accountedfor in advance, revenue deficiencies.

2. Rationale

2.2 Benefits

2.3 Risks

In other words, aproactive approachshould minimizelife cycle costs and risks.



3. Work Description

3.1 What Should Be Done

3.2 How to Do the Work3.1 What Should Be Done

The framework for a water distribution systemrenewal plan can be described in terms ofseven questions.

1. What do you have?

2. What is it worth?

3. What is its condition?

4. What needs to be done?

5. When do you need to do it?

6. How much will it cost?

7. How will you pay for it?

There are two complementary approaches tothe development of a water distribution systemrenewal plan: top-down and bottom-up. Thesetwo approaches differ in the detail needed forpreparation and how the results can beapplied. The top-down approach uses morereadily available “system” data and is used forstrategic long-term planning of policies andprograms, whereas the bottom-up approachlooks at individual assets and is used forshort-term capital planning of projects. Short-term planning typically covers a period of lessthan 10 years and long-term planning typicallycovers a period of 10 to 100 years.

Using the top-down approach, the projectedrenewal costs for a group of assets can beestimated using replacement cost andassumed life expectancy. The top-downapproach is consistent with the accrualaccounting method common in the businessworld and regulated utilities in which capitalcost expenses include depreciating the valueof an asset over its theoretical useful life.

The bottom-up approach requires a detailedinventory of the assets including the currentcondition and deterioration rate for eachasset. Although not constrained by accountingmethod, the bottom-up approach lends itselfto the cash accounting method, whichpredominates in Canadian water utilities.

With the cash accounting method, net capitaloutlays are expensed on an annual basis. To confirm that the investment in renewal issufficient to sustain the water distributionsystem over the long term, a conditionassessment is required on a regular basis.

The magnitude of projected costs for renewalof a water distribution system over the longterm can be quickly determined using the top-down approach. On the other hand, it may takeseveral years to develop a comprehensiveannual renewal plan for large systems usingthe bottom-up approach in light of the fact thata detailed inventory and condition assessmentis required. Over time, the results of thebottom-up approach can be used to refinethe top-down approach.

3.2 How to Do the Work

3.2.1 Top-Down Approach

This section describes the top-down approachto development of a water distribution systemrenewal plan. An application of the top-downapproach is demonstrated in Appendix A.


Even though a municipality may not have adetailed inventory of its water distributionsystem, it should be possible to estimate thetotal length of water main and the number ofappurtenances using the followingassumptions3:

■ total length of water main — typically 4 mto 6 m per capita;

■ total number of hydrants — typically onehydrant for every 150 m to 250 m of water main;

■ total number of valves — typically one valvefor every 100 m to 150 m of water main;

■ total number of water services — typically0.2 to 0.3 services per capita; and

■ total number of water meters — typicallyequal to the total number of water services.

3. Work Description

3. Based on studies conducted by R.V. Anderson Associates Limited for seven Canadian municipalities with populations ranging from50,000 to 500,000.

To confirm that theinvestment inrenewal is sufficientto sustain the waterdistribution systemover the long term, acondition assessmentis required on aregular basis.


To compile a complete inventory of a waterdistribution system, municipalities should alsocompile the rated capacity for each watertreatment plant, well, pumping station, andstorage facility. This information is usuallyavailable from design reports, operations and maintenance manuals, and permits.


Several methods can be used to quantify thevalue of a water distribution system (e.g.,original cost, depreciated cost, replacementcost). With the top-down of water distributionsystem components can be estimated usinginput from other municipalities, localcontractors, recent construction contracts, ortechnical reports (AwwaRF, 2001; NRC, 2002).The total replacement cost for a waterdistribution system (including supply,treatment, distribution, storage and pumping)is typically $3,000 to $4,000 per capita.4


For the top-down approach, the age of thedistribution system components is typicallythe most useful and simplest indicator ofcondition. It should be recognized that age isnot always a good indicator of condition sincemany physical, environmental and operationalfactors can affect the condition of awatermain. (e.g. pipe material, lining, coating,wall thickness, soil type and characteristics).Ideally, the total length of water main in asystem should be broken down intohomogeneous groups (e.g., differentcombinations of pipe material and soil type) toaccount for the different life expectancies ofthe groups. It is important to note here that themore detailed bottom-up approach (coveredunder section 3.2.2) requires utilities to havemore detailed data on their distribution systemso that they can eliminate as much guesswork out of their selection process.

It should also be noted that some rehabilitationtechnologies are only applicable to certain

pipe materials. For example, non-structurallinings are only applicable to unlined iron and steel mains.

Cathodic protection is applicable to ironmains, steel mains, concrete pressure pipe,and metallic appurtenances (e.g., valves,hydrants, copper services) that are installed incorrosive soil and have not been protected byother means (e.g., pipe coatings, polyethyleneencasement). Cathodic protection might alsobe applicable to metallic appurtenances onnon-metallic mains (e.g., PVC and HDPE).

If the year of construction for each waterdistribution system component is not readilyavailable, it would be reasonable to assumethe distribution system expanded at about thesame rate as the population growth in themunicipality. Historical population data can beobtained from municipal records and StatisticsCanada. The first year of municipal waterservice should also be available frommunicipal archives. The year of constructionof buildings can also be used to estimate theage of the water mains along a street.


Water mains can be renewed by variousrehabilitation or replacement technologies.(Refer to InfraGuide’s Selection ofTechnologies for the Rehabilitation orReplacement of Sections of a WaterDistribution System.)

Deteriorated mains can be replaced using opentrench or trenchless techniques. Mains canalso be rehabilitated with structural linings ifreplacement is too costly or disruptive.

Internal corrosion of unlined iron water mainscan cause water quality problems andpossible reductions in hydraulic capacity.These mains can be rehabilitated by non-structural lining if they have not experiencedhigh break rates. The feasibility of lining and/orcathodically protecting a main depends on itsstructural condition and other local factors.

3. Work Description


4. Based on studies conducted by R.V. Anderson Associates Limited for seven Canadian municipalities with populations ranging from50,000 to 500,000.

Hydrants, valves, and water services arenormally replaced within the road allowancewhen the mains are replaced or rehabilitated.However, in some cases, it may be necessaryto replace these appurtenances before themain is replaced. The life expectancy forhydrants, valves, and water services should be estimated based on local factors.


The service life of water distribution systemcomponents varies depending on severalfactors, such as construction materials, qualityof construction, soil conditions, water quality,and level of maintenance. For the purposes ofthe top-down approach, a service life can beassumed for each system component basedon industry averages. As a result, theremaining life of each component can beestimated by subtracting the age of thecomponent from its assumed service life.

To quantify the life cycle costs for a waterdistribution system, it is necessary to projectcosts for each component over at least onelife cycle. Since some components could havea life cycle of several decades, costs aretypically projected over a 100-year planninghorizon. Furthermore, life cycle costs aretypically projected in 10-year incrementscommensurate with the accuracy of theanalysis.

The projected replacement costs can becalculated and graphed using an electronicspreadsheet. A computer model can also beused to project replacement costs. Examplesinclude KANEW (AwwaRF, 1999), WARP (NRC,2001a), and Nessie (AwwaRF, 2001).


The projected costs for replacement of a waterdistribution system can be estimated bysumming the projected replacement cost foreach system component. The projected costsfor rehabilitation of iron water mains can beestimated based on the total length of ironmains to be rehabilitated and unit costs for non-structural lining. The timeframe for rehabilitationof iron water mains will depend on availablefunding and the urgency of the needs.

The long-term average annual cost forrenewal of a water distribution system istypically one to two percent of the totalreplacement cost (AwwaRF, 2001). Thisassumes the average life expectancy of thewater system components is 50 to 100 years.Since most water systems in Canadaexperienced a significant growth rate in the1950s and 1960s, it is expected that renewalcosts will increase significantly over the nextfew years as the components that wereinstalled during this period reach the end oftheir service life. The resulting “hump” incosts, when graphed is sometimes referred to as the “Nessie Curve” (AwwaRF, 2001).


An AwwaRF report (2001) states:

The challenge of funding infrastructurerenewal is not really a financial challengeso much as it is a planning challenge.Raising cash for operations and capital forreinvestment are straightforward tasks.Knowing how much reinvestment to makeand at what rate is the hard part. Without aconfident means of knowing that the rate ofreplacement has been optimized to mitigatethe impact of demographic echoes on utilityfinances, a utility cannot offer the financialmarkets complete assurance that this risk isbeing effectively managed.

Municipalities should adopt the followingprinciples when developing their waterdistribution system renewal plan.

■ Full cost recovery — all operating,maintenance, and capital renewal costsshould be recovered through water rates.

■ User pay approach — directly charge watercustomers in proportion to the cost ofproviding water service.

■ Pay as you go approach — investment inrenewal of a water distribution system willhave to be ongoing and, therefore, currentrevenue sources should be sufficient tocover this ongoing cost. However,debenture financing is commonly neededfor large one-time capital expenditures (e.g.,water treatment plant expansion) or largeemergency requirements.


3. Work Description


The challenge offunding infrastructurerenewal is not reallya financial challengeso much as it is aplanning challenge.


It is important to project renewal costs over atleast one life cycle for each component so afinancial plan can be developed thatanticipates any projected increases in costs.

One technique to assess the adequacy offunding for renewal of a water distributionsystem is referred to as the asset conditionindex (ACI).5 The ACI can be calculated in anygiven year by dividing the infrastructure deficitby the asset value. Infrastructure deficit is thedifference between the needed investment andthe actual investment, which can accumulateover time. A system is considered to be in goodcondition if the ACI is less than five percent; infair condition if the ACI is between five and tenpercent, and in poor condition if the ACI isgreater than ten percent.

Several scenarios should be analyzed toidentify the rate increases that would berequired to maintain the ACI below ten percentover the long term. It should be noted thatsmall increases in water rates over the shortterm could significantly increase revenues inthe longer term due to the compoundingeffect. In some cases, it is prudent to establisha reserve or depreciation fund so funds can beset aside for significant increases ininvestment that may be required in the future.

Another technique would be to establish alevel of service standard and estimate thelevel of funding that would be required tomaintain the system at the established level ofservice standard. The level of service standardmay vary with the criticality factor if using arisk management approach (e.g., fivebreaks/km/year for residential mains with alow criticality factor vs. one break/km/year formains that are more critical).

3.2.2 Bottom-Up Approach

Unlike the top-down approach that focuses onthe long-term costs for renewal of a group ofassets, the bottom-up approach attempts toquantify the short-term costs for renewal ofeach component in a distribution system. The bottom-up approach follows the sameframework as outlined above for the top-downapproach. An application of the bottom-upapproach is demonstrated in Appendix B.

The bottom-up approach should incorporaterisk management principles where theprobability of failure and the consequences offailure are both considered in the decision-making process. In the past, manymunicipalities have been prioritizing waterdistribution system renewal plans to minimizecapital costs without considering socio-economic costs, such as traffic impacts,impacts on sensitive customers (e.g.,hospitals), property damage, damage to otherinfrastructure, and loss of economic activity.

Adopting a risk management approach wouldimprove the level of service provided tocustomers as well as minimize life cycle costsand risks. The AwwaRF has published a report(2002) on the costs of infrastructure failure,which states:

In developing maintenance plans andmaking repair-replace-refurbish decisions,there is a choice to make between thedevelopment of lower cost water systemswith periodic failure rates that imposesocial costs on customers and systems thatminimize failure at the expense of higheroperating costs for customers (page 1).

This AwwaRF report reviewed several methodsdeveloped by other industries for estimatingsocial costs, including:

■ customer outage;

■ traffic disruption;

■ flood damage; and

■ direct and indirect economic loss.

3. Work Description


5. The ACI was developed by the National Association of College and University Business Officers to quantify the significance ofdeferred maintenance for building portfolios

The bottom-upapproach shouldincorporate risk

managementprinciples wherethe probability of

failure and theconsequences of

failure are bothconsidered in thedecision-making

process.



The bottom-up approach requires a detailedinventory and condition assessment of eachcomponent. Table 3–1 summarizes some of thephysical data that should be included in aninventory of water mains. All municipalitiesshould compile the basic physical data.Municipalities should also consider the need tocompile some of the other advanced physicaldata listed in Table 3–1 to facilitate thedevelopment of a renewal plan.

In light of the significant amount of datarequired to develop a comprehensive renewalplan, municipalities should compile theinventory in electronic databases togetherwith an interface to a geographic informationsystem (GIS). This inventory should becoordinated with other applications, such as amaintenance management system. InfraGuidehas published a document entitled BestPractices for Utility-Based Data that describesa framework for managing information as wellas the basic data elements.

2. What is it worth?Ideally, the cost data incorporated into thebottom-up approach should be sufficientlyaccurate for capital budgeting purposes. If the inventory is compiled in an electronicdatabase, it is possible to develop “look-uptables” that include unit costs for replacementof water mains, valves, hydrants, and waterservices. It should be clearly indicated whetherthe unit costs include restoration, engineering,contingencies, and taxes.

The databases could also include costmultipliers to reflect the relative difficulty inconstructing water mains based on location(e.g., local road, arterial road) or environmentalconditions (e.g., high water table, difficultsoil/rock conditions). The databases could alsoinclude an estimate of the potential costsavings if a water main is replaced when theroad or a sewer is reconstructed.

3. Work Description


Table 3–1

Water Distribution System

Condition/Performance

Indicators

Factor Basic Advanced

Physical Pipe lengthPipe diameterPipe materialYear of construction

Structural Break rate

Hydraulic Fire flowInternal water pressure

C factorPressure drop when hydrant is openFlow velocity/head loss during high demand

Water quality Number of complaintsPipe lining/yearChlorine residualTurbidity

Iron concentrationLead concentration

Leakage Number of leaksLeakage volume

Type of jointIWA Infrastructure Leakage Index

Conformance to currentdesign standards

Pipe materialSeparation from sewers

Pipe depth

Importance/hazardpotential/consequence offailure

Pipe diameterPipe material

Impacts of service disruptionPublic safetyTraffic disruptionPotential property damageRepair cost

Pipe wall thicknessPipe coatingPipe manufacturerCathodic protection/yearPolyethylene encasement

Water service materialWater service diameterDensity of water servicesWater table depthRoad classification

Break trendsPit depth

Soil typeSoil resistivity

Table 3–1: Water Distribution SystemCondition/Performance Indicators



Deterioration of water distribution systemscan be described in terms of four generalcategories: structural, hydraulic capacity,leakage, and water quality. Some physical,environmental, and operational factors thatcontribute to water system deterioration areidentified in another best practice document,Deterioration and Inspection of WaterDistribution Systems.

The best practice for investigating thecondition of water distribution systems isbased on a two-phase approach. The firstphase involves a preliminary assessment ofthe potential problems using data that shouldbe collected by every municipality on a routinebasis. The second phase involves a moredetailed investigation of specific problemsbased on findings of the preliminaryassessment. Table 3–1 lists some conditionsfor structural, hydraulic capacity, leakage,and water quality performance indicators.

Municipalities with high water main breakrates should consider the need for a moredetailed analysis of water main deteriorationusing statistical or physical models.

Statistical ModelsThe National Research Council (NRC) hasconducted a comprehensive review ofstatistical models that have been developed toquantify the structural deterioration of watermains based on historical performance data(Kleiner and Rajani, 2001). The statisticalmodels have been classified into two groups:deterministic and probabilistic models.Deterministic models predict breakage ratesfor homogenous groups of water mains basedon pipe age and breakage history. Probabilisticmodels can account for other variables thatmight impact breakage rates (e.g., soil type,operating pressure, pipe vintage, number ofprevious breaks).

Physical ModelsThe NRC has also conducted a comprehensivereview of physical models that have beendeveloped to quantify the structuraldeterioration of water mains (Rajani andKleiner, 2001). Physical models have beenclassified into two groups: deterministic andprobabilistic models. These models attempt toquantify factors, such as corrosion, frost load,pipe–soil interaction, residual structuralresistance, and temperature effects.

The AwwaRF has published a report (2002b)that describes a mechanistic model that canbe used to prioritize rehabilitation andreplacement of cast iron mains. This model is made up of four modules:

■ a pipe load module to estimate themaximum probable internal and externalloads on a pipe and the resulting pipestresses;

■ a pipe deterioration module to estimate the depth of external corrosion and thetheoretical remaining strength;

■ a statistical correlation module to estimatethe residual strength of the pipe as afunction of remaining wall thickness; and

■ a pipe break module to estimate the ratio(i.e., factor of safety) of residual pipestrength to maximum stress on a pipe.

The output can be used to develop aprioritized replacement plan by ranking pipes according to their safety factor.

In some cases, old water mains may notexhibit significant deterioration, but they aretoo small (e.g., less than 150 mm diameter) tosupply current fire flow requirements or haveinadequate cover and therefore, they shouldbe considered for replacement.

3. Work Description


Municipalities withhigh water main

break rates shouldconsider the need

for a more detailedanalysis of water

main deteriorationusing statistical or

physical models.


Valves and hydrants have a renewal approachand life cycle that is different from mains. Theyshould be routinely inspected and exercised toensure they are accessible, operable, conformto current design standards, and are notleaking. Valves and hydrants that do not meetthese requirements should be repaired or, ifnecessary, replaced.

Each component should be assigned acriticality factor that reflects theconsequences of its failure. Criticality factorsmay consider traffic volumes, customer types,location (e.g., business district), hydraulicimportance, road type (e.g., bridge), etc. A transmission main would have a highercriticality factor than a distribution main on a residential street.


Figure 3–1 illustrates a flow chart for selectionof alternative water main renewaltechnologies. If a pipe does not conform tocurrent design standards or is undersized,then it should be replaced and is not acandidate for rehabilitation. Similarly, if a mainis in poor structural condition, then it is not acandidate for non-structural rehabilitation (i.e., cleaning and lining).

It is also apparent from Figure 3–1 that thereare several alternative renewal technologiesfor each condition/performance indicator. A report (NGSMI, 2003) prepared forInfraGuide documents the best practice forselection of water distribution system renewaltechnologies. Similarly, the AwwaRF (2002a)has developed a decision support system toselect the most appropriate renewaltechnology for water mains.

It should be noted that there might be severaltechnically feasible renewal technologies for a section of water main. However, thesealternative technologies may have differentlife expectancies. Therefore, the most cost-effective technology should be selected on thebasis of a life cycle analysis that determinesthe lowest present worth.6 The life cycleanalysis should not only consider costs forinfrastructure repair, rehabilitation, andreplacement, but also socio-economic costs.

3. Work Description


The life cycleanalysis should notonly consider costsfor infrastructurerepair, rehabilitation,and replacement,but also socio-economic costs.

6. Present worth analysis is a technique used to compare alternative schemes that have different costs over a certain planning period.The present worth represents the current investment that would have to be made at a specific discount (or interest) rate to pay for the initial and future cost of the works.


Figure 3–1: Selection of alternative water main renewal technologies (Adapted from AwwaRF, 2002a)3. Work Description


Figure 3–1

Selection of alternative

water main renewal

technologies


A comprehensive water distribution plan willestablish the following needs.

■ Water mains and services that do notconform to current design standards interms of pipe size and/or material, depth of cover as well as water service size,material and cover should be consideredfor replacement.

■ Replace or structurally rehabilitate mainsthat have high break rates or leaky joints.

■ Rehabilitate unlined iron mains with non-structural linings if they have notexperienced a high break rate, but theirhydraulic capacity and/or water quality issignificantly affected by deterioration.

■ Replace mains that are too small (even after being cleaned and lined) to supply therequired flows at adequate pressures.

■ Cathodically protect metallic water mains,fittings and appurtenances if they areinstalled in corrosive sols.

■ Replace or rehabilitate highly critical mainsbefore they fail.

■ Repair or replace valves and hydrants thatare non-standard, inoperable, or leaking.

Many factors will affect the selection of themost appropriate renewal technology for eachsection of water mains. It should be noted thatsome renewal technologies are not availablelocally. It should also be noted that due to thehigh mobilization costs of some rehabilitationtechnologies, they are only cost effectivewhen a significant quantity of water main is to be rehabilitated.


Cost–benefit analyses should be undertakento determine the most efficient timing for thefollowing.

■ Is it more cost effective to replace orstructurally rehabilitate a main rather thancontinue to repair it?

■ If the soil is corrosive, is it cost effective tocathodically protect a metallic water mainand/or other metallic components (e.g.,valves, hydrants, fittings) to extend their life?

■ Is it more cost effective to rehabilitate anunlined iron main rather than continue topay higher pumping costs and/or constructadditional mains to provide the requiredhydraulic capacity?

■ Is it more cost effective to rehabilitate leakyjoints in large diameter mains rather thancontinue to lose water?

■ Is it more cost effective to coordinate the work with other projects (e.g., roadreconstruction, sewer replacement) toachieve synergistic benefits?

■ Socio-economic factors (criticality) andenvironmental factors need to beconsidered. If socio-economic factors areconsidered, it may be more economical toreplace or rehabilitate a main before itever breaks.

If the rate of deterioration can be estimated,then it is possible to predict the timing forrenewal of water mains using a cost–benefitanalysis. The timing for renewal of watermains that experience high break rates, leakyjoints, and reduced hydraulic capacity isprimarily dictated by economics. However, thetiming for renewal of water mains that do notconform to current design standards or impairwater quality is dictated by the severity of theproblem and the available funding.

To minimize costs and disruption, the proposedwater main renewal program should becoordinated with sewer and roadreconstruction projects as well as upgradesthat might be required for newdevelopment/redevelopment. In addition,the individual sections of water main to berenewed should be grouped according togeographic area to minimize cost anddisruption.

In most cases, hydrants, valves, and waterservices are replaced when the mains arereplaced. However, when a water main is stillin good condition, it might be necessary toreplace some appurtenances before replacingthe water main.

3. Work Description


Once the need for renewal of a water mainhas been established, municipalities shoulduse a condition rating system to assist withprioritizing a renewal program. Several factorscan be used to quantify the condition orperformance of a water main in terms ofstructural condition, hydraulic capacity,leakage, and water quality. The conditionrating systems should also incorporateinformation on the importance and hazardpotential of each water main.

The number of factors to be included in acondition rating system will vary amongmunicipalities depending on the size of themunicipality, the data available and thespecific conditions within each system. Large municipalities should consider the need for a computerized decision supportsystem to facilitate renewal planning.


The projected renewal costs for waterdistribution system components can beestimated using input from othermunicipalities, local contractors, recentconstruction contracts, and technical reports(AwwaRF, 2001; NRC, 2002). Note that costestimates for some renewal technologies are very site specific.

The projected renewal costs should becompared with those estimated using the top-down approach to ensure the short-term planis consistent with the long-term plan.


User rates are the preferred source of revenuefor renewal to ensure a stable and adequatelevel of funding is available and to promoteefficient use of the resources. In some cases,municipalities have added a surcharge to thewater bills to generate added revenues tocover the cost for renewal of the distributionsystem (e.g., cast iron replacement programs)and to enhance awareness for the need forsuch programs.

Since water distribution system renewalprograms are ongoing and the investmentrequirements do not change radically year toyear, the use of current funds is preferred.Municipalities should track the renewal costsfor their water distribution system separatelyin their capital budget to ensure spending issufficient and efficient.

Affordability is the concept of ability to pay,as opposed to willingness to pay, to whichdecision makers are more sensitive.Affordability is often evaluated by expressingwater charges as a percentage of medianhousehold income (MHI). The U.S.Environmental Protection Agency providesinformation on drinking water affordability(EPA, 1997) with affordable water generallyconsidered being one to two percent of theMHI. A British study (Sawkins, J.W. andDickie, V.A., 2002) cited a benchmarkaffordability level for water plus sewagecharges of three percent of MHI. The 2000median Canadian family income was $51,000(Statistics Canada, 2002), which at 1.5 percentwould mean an annual water bill of $765should be affordable, on average. Of course,local conditions will vary.

Sometimes, water costs are compared withother services to encourage approval ofhigher rates. Often, water plus sewer costsare in the same range as cable or satellite TV services, which many find affordable.


3. Work Description


Often, water plussewer costs are inthe same range as

cable or satellite TV services, which

many find affordable.

4.1 Applications

All municipalities across Canada should beusing both the top-down and bottom-upapproaches for developing a water distributionsystem renewal plan. These approaches mustbe tailored for each municipality to reflect thesize and age (i.e. condition) of their system. Insome cases, particularly small municipalitieswhere in-house expertise in renewal planningis not present, it may be necessary to retain aqualified engineering consultant to assist withthe development of renewal plans.

Ideally, a comprehensive water distributionrenewal plan would be in place before seriousdeficiencies accumulate, allowing an orderedapproach to be developed. A comprehensivewater distribution system renewal planbecomes particularly important for thosemunicipalities that already have a significantbacklog of renewal work to be completed.Furthermore, a renewal plan is critical forthose municipalities that are expecting adecline in population and revenue base. For those municipalities not experiencingsignificant problems, a renewal plan shouldidentify opportunities for improving themanagement of their systems.

4.1.1 Top-Down Approach

All municipalities should project their long-term renewal costs using the top-downapproach. For small municipalities, the top-down approach can be applied using an electronic spreadsheet. For largermunicipalities, computer models such asKANEW, WARP, and Nessie can be used.Regardless of the tools used, it is prudent toillustrate graphically the projected renewalcosts to communicate clearly the magnitudeof projected increases in costs.

4.1.2 Bottom-Up Approach

All municipalities should develop a waterdistribution system renewal plan using abottom-up approach based on the principles of risk management. All municipalities shouldcompile an inventory of their distributionsystem to facilitate operation andmaintenance as well as renewal planning. This inventory should include a criticalityfactor for each component.

Life cycle cost analyses should be conductedto identify the optimum timing for renewal of each component as well as the mostappropriate renewal technology. The life cycle cost analyses should consider socio-economic costs.

All municipalities should implement acondition rating system to facilitate renewalplanning using the bottom-up approach. The number of condition rating parameters,performance criteria, and technology toolswill vary among municipalities depending onphysical, environmental, and operationalfactors. Large municipalities should considerthe need for a computerized decision supportsystem to facilitate renewal planning.

4.1.3 Financial Plan

All municipalities should recognize that afinancial plan setting out annual investmentlevels, revenue sources, and financing optionsis an integral part of the long-term renewalplan to ensure adequate funds are available tosustain the distribution system. It is criticalthat all stakeholders adopt this financial plan,together with the long-term renewal plan thatidentifies infrastructure renewal needs,reasons, and priorities.

4. Applications and Limitations

4.1 Applications



All municipalitiesacross Canadashould be usingboth the top-downand bottom-upapproaches fordeveloping a waterdistribution systemrenewal plan.



4.2 Limitations

4.2 Limitations

Municipalities may be challenged to develop a comprehensive water distribution systemrenewal plan due to lack of data, tools,resources, and a standard approach. Ongoingeducation of all stakeholders is necessary todevelop and maintain a water distributionsystem renewal plan. Municipalities shouldstrive to maintain an adequate complement ofqualified and highly motivated staff to managetheir water distribution systems.

The plan will only be as good as the data.Municipalities with incomplete inventory dataor insufficient performance data will havesome limitations until they are able tocomplete data acquisition.

The bottom-up approach will requireinvestment of time and money.

The following points describe severalmeasures that can be used to evaluate theeffectiveness of the practices outlined inSection 3.

■ Compare and rationalize the projectedrenewal costs derived using the top-downand bottom-up approaches.

■ Track water main break rates, water qualityparameters, customer complaints, andleakage to establish deterioration rates.

■ Monitor the infrastructure deficit and assetcondition index (ACI).

■ Conduct pilot studies to assess theeffectiveness of various renewaltechnologies.

■ Monitor spending on renewal of thedistribution system to ensure it is sufficientand efficient. In particular, monitor thespending on reactive maintenance toensure it is not increasing dramatically overtime (i.e., the spending on reactivemaintenance should not increasedramatically if the investment in renewal is sufficient).

■ Monitor disruptions to service in terms ofthe number of customers affected (as wellas customer class) and the time spent out of service.

■ Conduct customer satisfaction surveys.

A water distribution system renewal programshould be updated every five to ten years toreflect the current condition of the system aswell as the updated renewal programs for theroads and sewers.


5. Evaluation5. Evaluation



A. Application of Top-Down Approach

Figure A–1

Population growth in

Small CityIntroduction

This appendix describes an example of thetop-down approach for developing a waterdistribution system renewal plan. This exampleis based on a fictitious municipality (referredto as Small City) with a population of 30,000and a population growth rate as shown inFigure A–1. Small City experienced significantgrowth in the 1950s.

It should be noted that the assumptions usedin this example (e.g., unit costs, lifeexpectancies) are only provided for illustrativepurposes. Municipalities should use unit costsand life expectancies that are appropriate fortheir systems.

Appendix A: Application of Top-Down Approach

Figure A–1: Population growth in Small City



Small City has approximately 150 km of watermains (i.e., 5 m per capita). The total length ofwater mains is broken down as follows:

■ 60 percent are unlined cast iron(constructed prior to 1960);

■ 20 percent are lined ductile iron(constructed between 1960 and 1980); and

■ 20 percent are PVC (constructed since1980).

Small City has approximately 1500 valves,1000 hydrants, as well as 8600 water servicesand meters.


Table A–1 summarizes the estimatedreplacement cost for the water distributionsystem components. The total replacementcost for the water distribution system in SmallCity is approximately $100 million or $3,333 percapita.


Table A–1

Replacement cost of water

system components in

Small City

Figure A–2

Replacement cost

breakdown for water

system components in

Small City

Figure A–2: Replacement cost breakdown for water system components in Small City

Table A–1: Replacement cost of water system components in Small City

Figure A–2 illustrates the breakdown of thetotal replacement cost for the waterdistribution system in terms of the variousasset groups. It is apparent the water mains

account for 75 percent of the totalreplacement cost with appurtenancesrepresenting the remaining costs.

QQuuaannttiittyy UUnniitt CCoosstt RReeppllaacceemmeennttCCoosstt ((mmiilllliioonn $$))

Water mains 150 km $500/m $75.0

Hydrants 1000 $3,500 each $3.5

Valves 1500 $1,500 each $2.3

Water services 8600 $2,000 each $17.2

Water meters 8600 $240 each $2.1

TToottaall RReeppllaacceemmeenntt CCoosstt $$110000..00



Table A–2

Average annual renewal

cost for water system for

Small City

Table A–3

Small City – Expansion of

water distribution system

The average annual costs for replacement of the water distribution system over the longterm can be estimated by dividing thereplacement cost by the assumed lifeexpectancy. In this case, the average annualcost for replacement of the water distributionsystem components is estimated to be $1.33 million or $44 per capita. The weightedaverage life expectancy of the components is75 years. This would suggest that 1.3 percentof the distribution system should be replacedeach year on average (i.e., 1/75 years).

To project the replacement costs over the long term (i.e., at least one life cycle), it isnecessary to estimate the historical growthrate of the system. In this example, it has beenassumed that the water distribution systemwas expanded at the same rate as thepopulation growth.

Table A–3 summarizes the length of watermain as well as the number of hydrants,valves, and water services constructed ineach decade over the past 100 years. It hasbeen assumed that a municipal water systemwas first implemented in 1900 in Small City.

Table A–2: Average annual renewal cost for water system for Small City

Table A–3: Small City – Expansion of water distribution system


Table A–2 summarizes the life expectancy ofeach of the water distribution systemcomponents in Small City.

Year 1901 1911 1921 1931 1941 1951 1961 1971 1981 1991 2001

Population 5,179 6,950 8,474 10,006 11,096 13,161 17,587 20,798 23,934 27,030 30,000

WWaatteerr mmaaiinnss mmaatteerriiaall Cast Iron Ductile Iron PVC TToottaall

Length of Watermains (km)

35 42 50 55 66 88 104 120 135 150

No. of Hydrants 232 282 334 370 439 586 693 798 901 1,000

No. of Valves 347 424 500 555 658 879 1,040 1,197 1,351 1,500

No. of Water Servicesand Meters

1,992 2,429 2,869 3,181 3,773 5,042 5,962 6,861 7,749 8,600

WWaatteerr SSyysstteemm

RReeppllaacceemmeennttCCoosstt ((mmiilllliioonn $$))

SSeerrvviiccee LLiiffee((yyeeaarrss))

AAvveerraaggee AAnnnnuuaallIInnvveessttmmeenntt((mmiilllliioonn $$))

Water mains $75.0 80 $0.94

Hydrants $3.5 80 $0.04

Valves $2.3 80 $0.03

Water services $17.2 80 $0.22

Water meters $22.1 20 $0.10

$$110000..00 ((wweeiigghhtteedd aavveerraaggee)) 7755 $$11..33



For the purposes of this example, it has beenassumed the water mains will be replaced atthe end of their assumed life expectancy. Insome cases, when the soil is corrosive, it maybe cost effective to install cathodic protectionon iron and steel mains (as well as metalliccomponents associated with non-metallicmains) to reduce the rate of external corrosionand increase life expectancy.

Small City experiences rusty water complaintsin the older parts of its system that areserviced by unlined cast iron mains. For thisexample, it has been assumed that 50 percentof the unlined cast iron mains will berehabilitated by cleaning and lining over thenext 20 years and the other 50 percent will bereplaced over the next 20 years due to highbreak rates.


The projected replacement costs for the waterdistribution system are based on the age ofthe components (Table A–3), their assumed lifeexpectancy (Table A–2), and the unit costs forreplacement (Table A–1). The remaining life foreach component is equal to the differencebetween life expectancy and current age.


Figure A–3 illustrates the projected costs forrehabilitation and replacement of the waterdistribution system over the next 100 years.This analysis does not include any allowancefor inflation.


Figure A–3

Life cycle costs for water

system in Small City

Figure A–3: Life cycle costs for water system in Small City

It is apparent from Figure A–3 that theprojected replacement costs over the nextdecade are high, since it has been assumedthat a significant percentage of the system hasalready reached the end of its service life. It isalso apparent that the replacement costs are

expected to increase significantly within thenext 20 to 30 years as the infrastructureinstalled in the 1950s reaches the end of itsservice life. The average annual cost over thisperiod is estimated to be $1.66 million.


Small City currently invests $1.5 million peryear in the renewal of its water distributionsystem. The total annual water budget is $3million. This includes operation, maintenance,and renewal of the water supply anddistribution system. However, the budget doesnot include works required to supportpopulation growth, since developers fundthese works. Small City’s water budget isfunded entirely by water rates.

To cover the projected $1.66 million annualcosts for renewal of the water distributionsystem, Small City will have to increaserevenues by $160,000. To do this, the city willhave to increase water rates by about fivepercent (i.e., [$3.16 million/$3.0 million] - 1).

Figure A–4 illustrates the projected costs andcurrent revenues for water distribution systemrenewal assuming their operating costsremain constant and debt remains minimal.It is apparent the current revenues will beinadequate.



Figure A–4

Annual costs and

revenures for Scenario 1

Figure A–4: Annual costs and revenues for Scenario 1


Figure A–5 illustrates the cumulative costs andcumulative revenues (assuming revenuesremain constant) over the next 100 years. Thedifference between the cumulative costs andcumulative revenues (i.e., the infrastructuredeficit) would reach a maximum of $36 millionby 2040.

Figure A–6 illustrates the asset conditionindex7 (ACI) assuming revenues remainconstant. It is apparent the ACI exceeds 20 percent due to the significant backlog ofrenewal work. By 2040, the ACI would exceed35 percent if revenues are not increased and,by that time, the level of service would beunacceptable.

Figure A–5: Cumulative costs and revenues for Scenario 1, Small City

Figure A–6: Asset condition index vs. time (Scenario 1)

7. Asset condition index = infrastructure deficit/total replacement cost.


Figure A–5

Cumulative costs and

revenues for Scenario 1,

Small City

FIgure A–6

Asset condition index vs.

time (Scenario1)


Scenario 2

One method to generate sufficient revenues to cover the projected costs is outlined below.It has been assumed that water rates areincreased by one percent per year over thenext 10 years. In this case, the water rates in2011 and beyond will be 11 percent greaterthan the current rates. The average annualrevenues over the next 100 years would be$1.81 million compared to the average annualcost of $1.66 million.

Figure A–7 illustrates the projected costs andrevenues for Small City. The average annualrevenues match the average annual costsover the next 100 years.


Figure A–7

Annual costs and

revenues for Scenario 2

Figure A–7: Annual costs and revenues for Scenario 2


Figure A–8 illustrates the cumulative costs and cumulative revenues. It is apparent theinfrastructure deficit is less than that indicatedin Figure A–5.

Figure A–9 illustrates the asset condition indexassuming the water rates are increased byone percent per year over the next 10 years. It is apparent the ACI would be less than thatshown in Figure A–6. However, the ACI wouldstill reach 25 percent in 2040 and, therefore,additional rate increases would be warrantedby 2030.

Figure A–8: Cumulative costs and revenues for Scenario 2, Small City

Figure A–9: Asset condition index vs. time (Scenario 2)


Figure A–8

Cumulative costs and

revenues for Scenario 2,

Small City

Figure A–9

Asset condition index vs.

time (Scenario 2)

Introduction

This section describes an example of thebottom-up approach to development of awater distribution system renewal plan. Itincludes 20 sections of water main withdifferent sizes, materials, ages, and conditionsto demonstrate the range of considerations.

It should be noted that the assumptions andapproach used in this example are onlyprovided for illustrative purposes.Municipalities should use an approach that is appropriate for their system.


Table B–1 presents a basic inventory of 20sections of water main with the followingmaterials:

■ eight sections of unlined cast iron (CI-U);

■ two sections of lined cast iron (CI-L);

■ two sections of lined steel (STL);

■ two sections of asbestos cement (AC);

■ three sections of lined ductile iron (DI); and

■ three sections of polyvinyl chloride (PVC).

The total length of water mains is 1,517 m.


Table B–1 presents a summary of thereplacement cost for each of the 20 sections ofwater main based on the following unit costs.

The total replacement cost for these 20 sections of water main is $552,000.


B. Application of Bottom-Up Approach

Appendix B: Application of Bottom-Up Approach

Pipe Dia. (mm) Unit Cost ($/m)

150 $350

200 $360

250 $380

300 $410



Table B–1 also summarizes the break rate and C factor for each of the 20 sections ofwater main. Since the cast iron mains are not lined, they are heavily tuberculated and, consequently, the Hazen-Williams C factors are relatively low. Furthermore, themunicipality receives rusty water complaintswhenever hydrants are opened in those areas serviced by unlined cast iron mains.

Table B–1 indicates there are two sections ofcast iron water main that do not conform tocurrent design standards in terms of the maindiameter (i.e., 150 mm is normally the minimumsize for fire protection in single familyresidential areas).


Table B–1


Inventory

Table B–1: Water Distribution System Inventory

1 55 100 CI-U $350 $19,250 0 0.00 50

2 45 100 CI-U $350 $15,750 1 2.22 50

3 114 150 CI-U $350 $39,900 1 0.88 60

4 98 150 CI-U $350 $34,300 1 1.02 60

5 103 150 CI-U $350 $36,050 0 0.00 60

6 89 150 CI-U $350 $31,150 3 3.37 60

7 85 200 CI-U $360 $30,600 3 3.53 70

8 71 200 CI-U $360 $25,560 1 1.41 70

9 57 200 CI-L $360 $20,520 0 0.00 110

10 82 250 CI-L $380 $31,160 0 0.00 110

11 68 150 DI $350 $23,800 0 0.00 100

12 22 150 DI $350 $7,700 0 0.00 100

13 98 150 DI $350 $34,300 0 0.00 100

14 74 150 AC $360 $26,640 3 4.05 100

15 66 200 AC $350 $23,100 0 0.00 110

16 80 300 STL $410 $32,800 0 0.00 120

17 110 300 STL $410 $45,100 0 0.00 120

18 27 150 PVC $350 $9,450 0 0.00 100

19 47 200 PVC $360 $16,920 0 0.00 110

20 126 250 PVC $380 $47,880 0 0.00 110

TToottaall 11551177 $$555511,,993300 1133

LLiinnkk IIDD LLeennggtthh DDiiaa.. MMaatteerriiaall UUnniitt CCoosstt RReeppllaaccee NNoo.. ooff BBrreeaakkss// CC FFaaccttoorr((mm)) ((mmmm)) CCoosstt BBrreeaakkss kkmm//yyrr


Table B–2 summarizes the renewalrequirements.

Mains that do not conform to current designstandards

Two sections of 100 mm unlined cast ironwater main should be replaced with largermains when the roads are reconstructed orsooner if fire protection is deemed inadequate.

Mains that have high break rates

An economic analysis was conducted for thismunicipality to determine when it is more costeffective to replace a water main rather thancontinuing to repair it. Based on this analysis,a water main with a break rate of greater than3.0 breaks per km per year should be replacedas soon as possible. As a result, two sectionsof unlined cast iron and one section ofasbestos cement water main should bereplaced in this example.

Mains that do not have adequate hydrauliccapacity and/or cause water quality problems

Four other sections of unlined cast iron mainshould be cleaned and lined to restorehydraulic capacity and mitigate water qualityproblems. The municipality should identifywhether services are substandard, such aslead services or those that are less than 19 mm, since this would affect the decisionto rehabilitate them.

Mains and appurtenances that should becathodically protected (retrofit with anodes or impressed current system)

A corrosion survey should be conducted toconfirm the corrosiveness of the soil and aneconomic analysis should be conducted toconfirm that it is cost effective to cathodicallyprotect metallic components. Based on thissurvey and analysis, it was determined thattwo sections of steel water main, two sectionsof ductile iron main and two sections of linedcast iron should be cathodically protected.


The proposed water main renewal programshould be coordinated with roadreconstruction projects and upgrades that might be required for newdevelopment/redevelopment.

The following condition rating system wasused to determine the overall point rating foreach section of watermain as summarized inTable B–2.



Structural Score Breaks/km/year1 0 – 0.30

2 0.31 – 0.60

3 0.61 – 0.90

4 0.91 – 1.20

5 1.21 – 1.50

6 1.50 – 1.80

7 1.81 – 2.10

8 2.11 – 2.40

9 2.41 – 2.70

10 > 2.70

Importance Score Pipe Dia. (mm)1 < 150

2 200

3 250

4 300

5 > 300

Water QualityScore Pipe Material

1 Others

5 CI-U

Hydraulic CapacityScore C Factor

1 > 100

2 91 – 100

3 81 – 90

4 71 – 80

5 < 71


The total score for each section of water main is equal to the sum of the scores for thestructural, hydraulic capacity, water quality,and importance factors. In this case, themaximum score would be 25 (poor condition)and the minimum score would be 4 (goodcondition). The structural score accounts for40 percent of the total score whereas theother factors each account for 20 percentof the total score.

It is apparent from Table B–2 that the unlinedcast iron mains with high break rates are thehighest priority for replacement.


Table B–3 summarizes the recommendedrenewal program assuming the works willbe completed over the next 10 years. Theaverage annual renewal cost over thisperiod is $20,360.

For purposes of comparison, the long-termaverage annual renewal cost for these 20 sections of water main is estimated to be $7,900 assuming the average lifeexpectancy is 70 years.


Table B–2


Renewal Requirements

Table B–2: Water Distribution System Renewal Requirements

RReeppllaaccee mmaaiinnss tthhaatt aarree ttoooo ssmmaallll ttoo ssuuppppllyy rreeqquuiirreedd ffiirree ffllooww

1 55 100 CI-U $350 $19,250 0 0.00 50 1 5 5 1 1122

2 45 100 CI-U $350 $15,750 1 2.22 50 8 5 5 1 1199

110000 $$3355,,000000

RReeppllaaccee mmaaiinnss tthhaatt hhaavvee hhiigghh bbrreeaakk rraatteess

6 89 150 CI-U $350 $31,150 3 3.37 60 10 5 5 1 2211

7 85 200 CI-U $360 $30,600 3 3.53 70 10 5 5 2 2222

14 74 150 AC $350 $25,900 3 4.05 100 10 2 1 1 1144

224488 $$8877,,665500

RReehhaabbiilliittaattee mmaaiinnss tthhaatt ddoo nnoott hhaavvee aaddeeqquuaattee hhyyddrraauulliicc ccaappaacciittyy aanndd//oorr ccaauussee wwaatteerr qquuaalliittyy pprroobblleemmss

3 114 150 CI-U $150 $17,100 1 0.88 60 3 5 5 1 1144

4 98 150 CI-U $150 $14,700 1 1.02 60 4 5 5 1 1155

5 103 150 CI-U $150 $15,450 0 0.00 60 1 5 5 1 1122

8 71 200 CI-U $150 $10,650 1 1.41 70 5 5 5 2 1177

338866 $$5577,,990000

CCaatthhooddiiccaallllyy pprrootteecctt sstteeeell aanndd iirroonn mmaaiinnss iinn ccoorrrroossiivvee ssooiillss ((aass wwaarrrraanntteedd bbyy ccoorrrroossiioonn ssuurrvveeyyss))

9 57 200 CI-L $55 $3,135 0 0.00 110 1 1 1 2 55

10 82 250 CI-L $55 $4,510 0 0.00 110 1 1 1 3 66

11 68 150 DI-L $55 $3,740 0 0.00 100 1 2 1 1 55

12 22 150 DI-L $55 $1,210 0 0.00 100 1 2 1 1 55

15 80 300 STL $55 $4,400 0 0.00 120 1 1 1 4 77

16 110 300 STL $55 $6,050 0 0.00 120 1 1 1 4 77

441199 $$2233,,004455

Link Length Dia. Material Unit Replace No. of Breaks/ C Break C Water Dia. TotalID (m) (mm) Cost Cost Breaks km/yr Factor Rate Factor Quality


It has been assumed the renewal costs will berecovered through user rates. An analysis ofthe impact of the costs on customers should

be carried out and a strategy for implementingthe need charges developed. This wouldinclude warning customers of changes inrates as well as a public information programdemonstrating the need for investments.



Table B–3

Renewal Program

(10 Years)

Table B–3: Renewal Program (10 Years)

RReeppllaaccee mmaaiinnss tthhaatt aarree ttoooo ssmmaallll ttoo ssuuppppllyy rreeqquuiirreedd ffiirree ffllooww

1 55 100 CI-U $350 $19,250 12 $19,250

2 45 100 CI-U $350 $15,750 19 $15,750

110000 $$3355,,000000

RReeppllaaccee mmaaiinnss tthhaatt hhaavvee hhiigghh bbrreeaakk rraatteess

6 89 150 CI-U $350 $31,150 21 $15,575 $15,575

7 85 200 CI-U $360 $30,600 22 $15,300 $15,300

14 74 150 AC $350 $25,900 14 $25,900

224488 $$8877,,665500

RReehhaabbiilliittaattee mmaaiinnss tthhaatt ddoo nnoott hhaavvee aaddeeqquuaattee hhyyddrraauulliicc ccaappaacciittyy aanndd//oorr ccaauussee wwaatteerr qquuaalliittyy pprroobblleemmss

3 114 150 CI-U $150 $17,100 14 $17,100

4 98 150 CI-U $150 $14,700 15 $14,700

5 103 150 CI-U $150 $15,450 12 $15,450

8 71 200 CI-U $150 $10,650 17 $10,650

338866 $$5577,,990000

CCaatthhooddiiccaallllyy pprrootteecctt sstteeeell aanndd iirroonn mmaaiinnss iinn ccoorrrroossiivvee ssooiillss ((aass wwaarrrraanntteedd bbyy ccoorrrroossiioonn ssuurrvveeyyss))

9 57 200 CI-L $55 $3,135 5 $3,135

10 82 250 CI-L $55 $4,510 6 $4,510

11 68 150 DI-L $55 $3,740 5 $3,740

12 22 150 DI-L $55 $1,210 5 $1,210

15 80 300 STL $55 $4,400 7 $4,400

16 110 300 STL $55 $6,050 7 $6,050

441199 $$2233,,004455

TToottaall $$220033,,559955 $$1199,,997755 $$2211,,662255 $$1188,,443355 $$1199,,881100 $$2255,,990000 $$1199,,449900 $$2255,,335500 $$1177,,110000 $$1199,,225500 $$1166,,666600

Link Length Dia. Material Unit Replace Total 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013ID (m) (mm) Cost Cost Score



AwwaRF (American Water Works Association

Research Foundation), 1987. Water Main Evaluationfor Rehabilitation/Replacement. Denver, Colorado.

____, 1990. Assessment of Existing and DevelopingWater Main Rehabilitation Practices. Denver,

Colorado.

____,,1999. Quantifying Future Rehabilitation andReplacement Needs of Water Mains. Denver,

Colorado.

____, 2001. Financial and Economic Optimization of Water Main Replacement Programs. Denver,

Colorado.

____, 2002a. Decision Support System for DistributionSystem Piping Renewal. Denver, Colorado.

____, 2002b. Prioritizing Water Main Replacement andRehabilitation. Denver, Colorado.

____, 2002c. Costs of Infrastructure Failure. Denver,

Colorado.

Canada, Statistics Canada, 2002. The Daily, July 18,

2002. Ottawa, Ontario.

Kleiner, Y. and B. Rajani, 2001. Comprehensive Reviewof Structural Deterioration of Water Mains: StatisticalModels. IRC, Ottawa, Ontario.

NACUBO (National Association of College and

University Business Officers), 1990. Managing theFacilities Portfolio. Washington, DC

NGSMI (National Guide to Sustainable Municipal

Infrastructure), 2002a. InfraGuide, Best Practices forUtility Based Data. Ottawa, Ontario.

____, 2002b. InfraGuide, Deterioration and Inspectionof Water Distribution Systems. Ottawa, Ontario.

____, 2002c. InfraGuide, Coordination of InfrastructureWorks to Minimize Disruption and Maximize Value.Ottawa, Ontario.

____, 2003a. InfraGuide, Selection of Technologies forthe Rehabilitation and Replacement of a WaterDistribution System. Ottawa, Ontario.

____, 2003b. InfraGuide, An Integrated Approach toAssessment and Evaluation of Municipal Road, Sewer

and Water Networks. Ottawa, Ontario.

NRC (National Research Council Canada), 2002.

Construction and Rehabilitation Costs for Buried Pipewith a Focus on Trenchless Technologies. Ottawa,

Ontario.

Rajani, B. and Y. Kleiner, 2001a. WARP – Water MainRenewal Planner. Proceedings of the International

Conference on Underground Infrastructure Research,

Kitchener, Ontario, June 11-13, 2001. IRC, Ottawa,

Ontario.

Rajani, B. and Y. Kleiner, 2001b. ComprehensiveReview of Structural Deterioration of Water Mains:Physically Based Models. IRC, Ottawa, Ontario.

Sawkins, J.W. and V.A. Dickie, 2002. Affordability ofWater and Sewerage Services in Great Britain.Edinburgh, Scotland

United States, EPA (Environmental Protection Agency),

1997. Information on Developing Affordability Criteriafor Drinking Water. Washington, DC

EPA, 2001. 1999 Drinking Water Infrastructure NeedsSurvey – Modeling the Cost of Infrastructure.Washington, DC

WRc (Water Research Centre), 1989. Planning theRehabilitation of Water Distribution Systems.ISBN 0-902-156-80-2, Wiltshire, UK

ReferencesReferences

Notes


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