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1、Frederick Lee and Kaimin ShihMarch 2025Research ReportManaging Water Lossesin Urban Water Systems:An International Perspective2AuthorsFrederick Lee is Executive Director of the Centre for Water Technology and Policy,The University of Hong Kong.Kaimin Shih is a Professor in the Department of Civil En
2、gineering,The University of Hong Kong.AcknowledgementsThe authors would like to acknowledge the able research assistance rendered by Ada Chan and Zhou Ying in the course of preparing the earlier versions of the case reports.Kara DiFrancesco copy edited the final version of the case reports,improving
3、 their readability.Tina Tsang re-drew the city maps,granting them a consistent appearance.Angela Lee shepherded the final stages of the overall production process of this report.Ella Chan,Jill Chan,Loritta Chan and Koko Liu assisted with myriad tasks in the production process.Angela Lee is Project M
4、anager in the Centre for Water Technology and Policy.Ada Chan and Loritta Chan were formerly Post-doctoral Fellow in the Centre.Zhou Ying was a former Post-doctoral Fellow in the Department of Civil Engineering.Ella Chan,Jill Chan and Koko Liu are project staff in the Centre.About the CentreThe Cent
5、re for Water Technology and Policy at The University of Hong Kong is an inter-faculty collaborative unit between the Faculty of Engineering and Faculty of Social Sciences.Through inter-disciplinary research and analysis,the Water Centre generates professional insights on complex,multi-dimensional pr
6、oblems in the urban water sector.The strengths of engineering and social sciences disciplines are purposefully converged and fused,through innovative inter-disciplinary research design and analytical lens,to create unique diagnostic capabilities for us to deliver on those insights.The Water Centre w
7、as established in 2018 through a generous donation made jointly by Philomathia Foundation and WYNG Foundation.3PrefaceWater loss refers to the problem of fully treated tap water that is lost from a citys water supply system,either through leakages or otherwise,and which never reaches the users.Water
8、 loss is an avoidable predicament,however.As evidenced by the experiences of a number of global cities,this plight could be fixed by an effectual application of a judicious mix of technologies and policies.In Hong Kong,water loss is a sticky problem,persisting for years,in spite of vast investments
9、of a plethora of measures to contain it.The proportion of unmetered water consumption,a proxy of water loss rate,has hovered between 30 percent to 35 percent in the past twenty years.This metric denotes the percentage of total treated water that has not reached any of the three million plus billing
10、water meters in the city.In this Research Report,we purposefully situate Hong Kongs water loss problem within a larger,yet confined,international,comparative context.This global perspective should provide a backdrop,as well as some rough benchmark,for us to appreciate the scope and severity of this
11、issue in our city.We examine,through desk-top research,the question of how water losses have been managed by water supply agencies in six cities around the world.These cities were selected for the report because their combined lessons should offer us a glimpse into solutions that could inform our ow
12、n approach to tackling this longstanding conundrum.The consolidated findings gathered from these six urban water systems suggest that there are multiple ways to address a universal challenge successfully.While some cities have attributed their achievements to some forms of strategic integration and
13、effectual implementation of conventional and new technologies,other cities have ascribed their favourable outcomes to governance and institutional reforms as the main driver for improvements in performance.ContentsAcronyms and abbreviations .4 Glossary.5List of Figures.7List of Tables .8Chapter 1.In
14、troduction .9Chapter 2.Case Report on Seoul.131.Introduction.162.Policies and programs.193.Methods and technologies.21Pipe replacement.21Block management of the distribution system.24Active leak detection.25Water pressure control using the reservoir system.25Automatic Meter Reading(AMR).254.Key less
15、ons.27Chapter 3.Case Report on Berlin.291.Introduction.322.Policies and programs.343.Methods and technologies.36OptNet asset management software.36Trenchless rehabilitation.36Service connection depth.37W-Net 4.0 digitized water network.37Active leak detection.374.Key lessons.38Chapter 4.Case Report
16、on Sydney.391.Introduction.422.Policies and programs.443.Methods and technologies.47Active leak control.47Pressure management.49Improved leak/break response times.49Innovative technologies in leak detection and control.494.Key lessons.51Chapter 5.Case Report on Philadelphia.531.Introduction.562.Poli
17、cies and programs.58Adopting AWWA M36 Water Audits and Leak Detection.58Economic Level of Leakage.59Water&Sewer Line Protection Program.603.Methods and technologies.624.Key lessons.65Chapter 6.Case Report on Tokyo.661.Introduction.692.Policies and programs.723.Methods and technologies.74Leak Investi
18、gation Methods.74Pipe Replacement and Improvement of Pipe Materials.75Replacement of Water Meters.764.Key lessons.79Chapter 7.Case Report on Halifax.811.Introduction.842.Policies and programs.86Regulatory bodies.86Full adoption of IWA methodology.86Plans and targets.873.Methods and technologies.90Di
19、strict Metered Area(DMA)and SCADA.90Advanced Metering Infrastructure.924.Key lessons.93Chapter 8.Conclusion.94References.974Acronyms and abbreviationsAMI Advanced Metering InfrastructureAMR Automatic Meter ReadingAWWA American Water Works AssociationBWC Berlin Water CompanyDMA District Metering Area
20、DVGW German Association of Gas and Water ExpertsELL Economic Level of LeakageEPA Environmental Protection Agency(of the United States)GIS Geographic Information SystemHRC Halifax Regional CouncilHRWC Halifax Regional Water CommissionICT Information and Communications TechnologyILI Infrastructure Lea
21、kage IndexIPART Independent Pricing and Regulatory TribunalIRP Integrated Resource Plan IWA International Water AssociationJWWA Japan Water Works AssociationKPI Key Performance IndicatorsLIDAR Light Detection and Ranging TechnologyMHW Ministry of Health and Welfare(of Japan)MNF Minimum Night FlowNRW
22、 Non-Revenue WaterNSE Nova Scotia EnvironmentNSURB Nova Scotia Utility and Review Board NSW New South WalesPLC Power Line CommunicationPMS Pressure Management Scheme PRV Pressure Reducing ValvePWD Philadelphia Water DepartmentRWR Revenue Water RatioSCADA Supervisory Control and Data AcquisitionSWA S
23、eoul Waterworks AuthorityWRB Water Revenue Bureau(of Philadelphia)WSAA Water Services Association of AustraliaWSD Water Supplies Department(of the HKSAR Government)5GlossaryAcoustic leak detectionMicrophones or sensor technologies are used to locate leaks by characterizing sounds that are different
24、from normal water flow in the water distribution system.Advanced Metering Infrastructure systemConsidered as an upgrade to the Automatic Meter Reading(AMR)system,the Advanced Metering Infrastructure(AMI)system integrates the water meter network,communication technologies and sensors for real-time da
25、ta collection of water consumption and status data.Unlike the AMR system,the AMI system does not require utility personnel for data collection,as the data is automatically transmitted to the server.Apparent water lossApparent water loss involves water usage that should be tariffed as a revenue-gener
26、ating water.Yet,it appears as an apparent water loss due to theft,unauthorized consumption,and metering inaccuracies.Asset managementAsset management is the practice of managing the entire lifecycle(creation,maintenance,renewal,expansion,full/partial decommissioning)of a water supply system.The goal
27、 is to meet the required level of service in the most cost-effective manner by creating,acquiring,maintaining,operating,rehabilitating and disposing of assets to provide for present and future water utilities opting for water loss reduction solutions.Automatic Meter Reading systemA communication tec
28、hnology system that collects water consumption data,diagnostics and status data from water meters through communication networks such as broadband and 3G.This requires utility personnel to be in close proximity for data to be transferred to the device,and then into a database that is later sent to m
29、aster stations or AMR servers.Economic Level of LeakageThe optimum leakage level in economic terms that can minimize the total present value cost in leakage management.Infrastructure Leakage IndexThe ratio between actual real losses and estimated minimum real losses.6Leak/break response timeThe time
30、 it takes for water utilities and executing agencies to respond to a leak or break in the water distribution system.Master MeteringA master meter records water usage that passes through all the dwellings and units within an entire complex,such as a large housing estate or a commercial complex.Minimu
31、m Night FlowThe measured water flow into a district metered area in the middle of the night where water demand is at its lowest.This is a common method used to evaluate water loss in a supply network.Non-revenue waterWater produced by a citys waterworks but is“lost”from water pipeline networks befor
32、e it could reach the customers.This loss can take on the form of real losses,such as water leaks,or apparent losses,through theft or metering inaccuracies.Real lossesReal losses refer to actual physical water that leaks from the water supply system,through cracks or openings in pipes and transmissio
33、n mains.Supervisory Control and Data Acquisition systemA computer-based system architecture that makes use of data communications technology to gather,monitor and analyse real-time data.In terms of water management,the SCADA system is used for monitoring water supply distribution networks and asset
34、management to quickly identify supply system issues and to facilitate optimal response time.Water tariffsThe water price that is charged to consumers over certain time intervals according to meter readings.7List of FiguresFigure 2.1 Water supply system of SeoulFigure 2.2a Revenue water ratio(RWR)in
35、SeoulFigure 2.2b Non-revenue water ratio(NRW)in SeoulFigure 2.3a Percentage of stainless steel pipes,leakage rate and number of leakage repair cases in Seoul,1993 2014Figure 2.3b Transformation of service pipeFigure 2.4 Technologies applied in SeoulFigure 3.1 Water system in BerlinFigure 3.2 Non-rev
36、enue water(NRW)in Berlin and GermanyFigure 3.3 Legal framework of water industry in GermanyFigure 4.1 Water delivery system in SydneyFigure 4.2 Water leakage(expressed as a percentage of potable water drawn)in Sydney,2000 2020Figure 4.3 Timeline of measures to reduce water loss in SydneyFigure 5.1 S
37、ources of water in PhiladelphiaFigure 5.2 Non-revenue water(NRW)in Philadelphia,1980 2016Figure 5.3 Water system responsibilityFigure 5.4 Distribution of water real losses in the City of Philadelphia in 2012Figure 5.5 A summary of water supply system technologies deployed by the Philadelphia Water D
38、epartmentFigure 6.1 Water systems in TokyoFigure 6.2 Trends in leakage rate and time,and a staged approach to leakage management in Tokyo,2000 2020Figure 6.3 Percentage of stainless steel and lead pipes and leakage rate in Tokyo,1982 2006Figure 6.4a Novel components in the water supply system in Tok
39、yo:Ferrule with stainless steel saddleFigure 6.4b Novel components in the water supply system in Tokyo:Flexible service connectionFigure 6.4c Novel components in the water supply system in Tokyo:Saddle used with the stainless steel corrugated pipe system Figure 7.1 Water system of Halifax Regional M
40、unicipalityFigure 7.2 Timeline of technological measures adopted in Halifax since 1982 to reduce water losses8List of TablesTable 2.1 Process of RWR improvement project Table 2.2 Process of RWR management for small-size blockTable 4.1 Program investment and water savingsTable 6.1 Technical developme
41、nts in leakage prevention co-developed by the Tokyo Metropolitan Government and private companiesTable 7.1 Initial ILI calculations in 2000,after the adoption of the IWA methodologyTable 7.2 Key Performance Indicators(KPI)in the Halifax Water Integrated Resource Plan 2019 that were related to water
42、loss controlTable 7.3 Water Loss Control Target(2016 2021)9Chapter 1INTRODUCTIONChapter 1.INTRODUCTION10Water loss is a public policy problem that has been afflicting Hong Kong for more than thirty years.According to a 2018 report issued by The Ombudsman on the maintenance and risk management of gov
43、ernment water mains,the amount of freshwater lost in each year,if saved,could meet the demand of two million local residents.From the governments perspective,Hong Kongs water rate loss is relatively high by international standards because the city is particularly susceptible to high water pressure i
44、n its water distribution system and is plagued by peculiar pipeline distribution issues.The main causes,claimed by officials,include the citys hilly terrain,high density,as well as vibrations and disturbances caused to underground water mains by busy traffic and frequent roadworks.Recognized as a pe
45、rennial problem and accorded top priority concern,the Water Supplies Department said that,since the early 1990s,they have been combating the water loss problem by implementing a host of water loss control measures directed at government mainsa.These measures were informed by four globally mainstream
46、ed methods,codified by the International Water Association.They are:(i)pressure management;(ii)active leakage detection and control;(iii)speed and quality of repairs;and(4)replacement and rehabilitation of aged water mains(Water Supplies Department,2020).The Water Supplies Department has asserted th
47、at the leakage rate of government mains has been lowered from about 25%in 2000 to around 14%in 2021.This metric,however,provides only a partial view of the citys overall water loss predicament.We need to use another measure to gauge the overall efficiency of the citys entire water supply distributio
48、n network.In the case of Hong Kong,that alternative metric is the rate of unmetered freshwater consumption(UFC)which is the ratio between the amount of unmetered freshwater and the total amount of freshwater produced by the citys waterworks.The UFC rate,expressed as a percentage,gives us the most ac
49、curate and comprehensive view of the citys water loss situation,for two reasons.First,the two key parameters used in the equation are metered measurements,not estimated values susceptible to wide margins of errors.Secondly,these two parameters cover both government mains and private mains,although t
50、hey do not offer a breakdown between these two components.a The citys water supply distribution network is comprised of two major components:government mains and private mains.1.INTRODUCTIONChapter 1.INTRODUCTION11In the past twenty years,spanning from the early noughties to the early 2020s,the UFC
51、rate in Hong Kong has hovered between 30%-35%b.To fully tackle the citys overall water loss problem,policy interventions should focus on the reduction of this UFC rate,and not just the reduction of the water loss rate of government mains.As such,the governments recently proclaimed target to lower wa
52、ter leakage rate of government mains from 15%in 2019 to below 10%by 2030 would still fall short of the efforts needed to suppress the citys overall water loss rate.This target,limited to government mains,has left out a big chunk of the problem,which lies in the domain of leaky pipes buried in privat
53、e premises.For public policy analysis purposes,an international perspective on municipal management practices is always useful because it offers us a comparative view of the strengths and limitations of various approaches used to tackling such municipal management problems as water loss,which take o
54、n similar attributes in different parts of the world.Stylized successful experiences,known as international best practices,form the basis of policy learning,traversing jurisdictional boundaries and cultural divides.In the spirit of stimulating and invigorating policy debates and policy learning in H
55、ong Kong in regard to the field of water loss management,we have selected from around the world six cities that have made significant strides in suppressing the water loss rate in the past four decades.They are Berlin,Halifax,Sydney,Philadelphia,Seoul,Sydney and Tokyo.We intend to achieve two purpos
56、es with this Research Report.First,we aim at informing non-specialists and the wider community on the intricacies of water loss management from an international,comparative angle,written in as much a plain language as possible.By raising the level of water literacy of the general public on this topi
57、c,the average person should feel comfortable,even confident,to engage in policy deliberations of this problematic in a meaningful manner.Secondly,we aim at drawing up some key lessons from examining a cross-section of successful strategies in managing water loss in cities that carry social,economic
58、and physical attributes that are similar to those of Hong Kong.As such,these lessons should be considered highly relevant to Hong Kongs plight,overriding the exceptionalism argument that the government has used to excuse itself for not being able to attain water loss reduction outcomes comparable to
59、 those already accomplished by a number of cities around the world.b Calculations are based on data retrieved from the Annual Reports published by the Water Supplies Department.12To help provide an overall structure for the reader to appreciate the underlying inter-connectedness of a seemingly rando
60、m choice of cities,we purposefully arrange the six cases in a particular order to accentuate several important thematic arguments that bind them together.We first examine the water loss management experiences of the water agencies of Seoul and Berlin,to understand how they have skillfully applied cu
61、tting-edge,innovative technologies to address water leakages in their respective water distribution system.Next,we present the case of Sydney,to demonstrate the argument that the success of managing water loss does not need to rely on cutting-edge technologies.Sydneys water managers have made use of
62、 conventional methods and technologies to tackle the problem with tangible outcomes.Finally,we look at the water loss control programs of Philadelphia,Tokyo and Halifax.The water managers in these three cities share the same belief:They attribute the success of their water loss management programs l
63、ess to the technologies that they have used,but more to their water governance practices,organizational measures and effective coordination efforts among concerned stakeholders.We conclude the report with a summary of key lessons that we have learnt from the six aforementioned cities.These lessons m
64、ight offer some clues for us to contemplate on the way forward for Hong Kong.Chapter 1.INTRODUCTION13Chapter 2SEOULCase ReportSEOUL14Water providerSeoul Waterworks Authority(SWA)(public).Population servedMore than ten million residents in Seoul and the metropolitan region.Water supplyHan River.Water
65、 loss concernsPipes installed before 1984 were prone to corrosion that caused frequent leakages and degraded water quality.Further,the mountainous terrain surrounding Seoul creates pressure and pipeline distribution issues.Policies and programs:Launched the Seoul Waterworks Authority(SWA)in 1989 to
66、coordinate water-related affairs.Implemented a three-phase project to improve the revenue water ratio(RWR)Established the Water Pipe Network Optimum Control System and Standard Maintenance Guidelines and Guidelines for Water Distribution Pipe Repair Works,which drive the citys pipe replacement progr
67、ams.15Methods and technologies:Consistently implemented pipe replacement programs dating back to 1962.Adopted a block system to improve management of the water distribution system.Maintain a geographic information system(GIS)that provides spatial information of waterworks,and can analyze and predict
68、 leakage.Implemented a multi-point leak noise correlation system to increase the precision of leak detection.Use a flow monitoring system to provide real-time data on water flow and pressure created during the supply process.Accomplishments:Replaced 13,192 km out of 13,721 km of distribution pipes f
69、rom 1984 to 2013.Improved the RWR from approximately 55%to above 95%within 30 years.Decreased the annual number of leak cases from 59,438 in 1989 to 10,421 in 2013.Takeaways:Financially self-sufficient water agencies have significant incentive to minimize losses,as water loss equates to financial lo
70、ss.Utilities should develop performance indicators and metrics targeted toward their objectives and the local conditions.Progressive research and development efforts,and implementation of technical advances can help facilitate consistent,gradual improvements in water loss control.Pipe replacement pr
71、ograms can provide both water loss control and water quality benefits.161.INTRODUCTIONSeoul first introduced a modern waterworks system in 1908.Subsequently,it introduced the first modern water purification system to sustain clean and safe water for the public.The Han River,running through the cente
72、r of Seoul,supplies all the citys water needs.Mountains surround all four sides of Seoul,located at 25-40m elevation,creating pressure and pipeline distribution issues that seriously impact Seouls water supply and management system29.Moreover,many of the pipelines in Seouls water distribution system
73、 are buried deep underground,resulting in challenging excavation projects to replace or rehabilitate pipes.Climate change,rapid urbanization,and population growth,also create water shortage problems in Seoul.Improving the water sector has been a national priority for many years in South Korea(Figure
74、 2.1)92.Water supply system of SeoulSource:Seoul City Hall,2015Figure 2.1Chapter 2.SEOULHan River0 1 2 3 4 5 kmWaterworksWastewater treatment plants17Revenue water ratio(RWR)the reverse of non-revenue water ratio,based on billed water used by customers28 The Seoul Metropolitan Government launched th
75、e Seoul Waterworks Authority(SWA)in 1989 to coordinate affairs related to providing clean and safe drinking water as well as to improving the efficiency of water system.SWA is a public utility but operates as an independent local company with a self-supporting financial system dependent on water tar
76、iffs from customers.Through public-private-partnerships,SWA is increasingly engaging in overseas business with the goal to make the country a powerhouse in the global water market.Water loss control has been a dominant business management goal of SWA as water loss equates to financial loss.SWA uses“
77、Revenue water ratio(RWR)”as the performance indicators that take into consideration the financial losses associated with water loss:Chapter 2.SEOUL18c Unlike other cities featured in this Technical Report,Seoul is unique in its case for using the Revenue Water Ratio(RWR),which is the reverse of the
78、non-revenue water ratio.For the readers ease,we have generated another graph that plots the non-revenue water ratio(%)so that the reader may compare figures between different cities.Figure 2.2b 0102030405060708090100Non-revenue water ratio(%)198919982022198944.8%199835.2%20224.1%Non-revenue water ra
79、tio(NWR)in SeoulC,1989 2022Source:Seoul Metropolitan Government,2015c,KOSIS,2021.Modified by authors.Chapter 2.SEOULFigure 2.2a0102030405060708090100Revenue water ratio(%)198919982022198955.2%199864.8%202295.9%198919982022198944.8%199835.2%20224.1%Figure 2.2a Revenue water ratio(RWR)in SeoulFigure 2
80、.2b Non-revenue water ratio(NWR)in Seoulc Revenue water ratio(RWR)in Seoul,1989 2022Source:Seoul Metropolitan Government,2015c,KOSIS,2021.Modified by authors.From 1989 to 2015,the RWR of Seoul improved from 55.2%to 95%(Figure 2.2a).This improvement is attributed to continuous pipe replacement and re
81、pairing,block management of the distribution system,systematic monitoring,and leak prevention.2.POLICIES AND PROGRAMSBefore 1998,SWA mainly focused water loss control efforts on pipe replacement and leak detection.The late 90s brought a new policy aimed at improving waterworks management via an incr
82、ease of RWR,as well as controlling water quality30.The RWR improvement project included three phases initial phase,development phase,and settlement phase defined by the measures and projects in Table 2.1.The next section describes a selection of the most important methods and strategies included in
83、the three phases.19Table 2.1 Process of RWR improvement projectPhaseMeasures and projectsPhase 1:Initial phase of RWR improvement(19891995)Establishment of SWA(November,1989)Installation of district-level flow meters(1990s)Intensive maintenance of old water distribution/supply pipes(4,200 km)(199119
84、93)Fully established the use of district flow meters at each of the waterworks offices to measure the system(1995)Phase 2:Development phase of RWR improvement(19961999)Launch of RWR improvement team(October,1998)District-level measurement of supplied water and RWR initiated(1996 1997)Installation of
85、 smaller diameter meters,meter replacement(19962000)Minimum Night Flow(MNF)measured by dividing the Seoul pipeline network into 2,037 small blocks(1998)Official district-level RWR statistics produced for the first time(1998)Intensive management of waterworks facilities at the redevelopment and recon
86、struction sites(from 1999)Phase 3:Settlement phase of RWR improvement(2000present)Shifted to indirect supply system after reservoir establishment(20002003)Office reshuffled and RWR management responsibility transferred from waterworks task force to RWR division(January 2001)Meter-reading works entru
87、sted to private entities(July,2001)Appropriate pressure of booster pumps managed in each period(from 2002)Systematic management of disused pipes(359km)(from 2003)Block-level RWR managed after introducing the medium block system(from 2004)Scientific leak detection started using the multi-point leak n
88、oise correlation system(from 2004)Amount of water supplied analyzed and flow controlled through the flow monitoring system(from 2005)Note:MNF:Minimum night flow,RWR:revenue water ratio.Source:Seoul Metropolitan Government,2015c.Modified by authors.Chapter 2.SEOUL20In the early 20th century,Seoul lau
89、nched a“Comprehensive Water Management Plan”d that included seven promotion strategies and 23 detailed tasks for the strategies.Building a smart water supply city was one of the promotion strategies,which aimed to establish a safe tap water production and supply system,as well as optimize water supp
90、ly through the increased flow rate.Several sets of guidelines address pipe replacement in Seoul.In 2014,the Ministry of Environment published the“Water Pipe Network Optimum Control System and Standard Maintenance Guidelines”to drive the citys replacement programs94.These Guidelines require that pipe
91、s over 30 years old or pipes that will soon exceed their lifespan be evaluated based on established assessment factors.Further,the citys“Guidelines for Water Distribution Pipe Repair Works”outlines priority replacement programs.These guidelines placed high priority on replacing old pipes buried unde
92、rground near streets and main roads,and unused and abandoned pipes were removed.d Comprehensive Water Management Plan was translated from ,the original name of this plan.Chapter 2.SEOUL213.METHODS AND TECHNOLOGIESFor the last three decades,Seoul has taken a phased approach to improving RWR(Table 2.1
93、),including the following key methods and strategies described in this section:pipe replacement,block management,active leak detection,water pressure control using the water reservoir system,and automatic meter reading.Pipe replacementSeouls pipe replacement efforts date back to 1962 and continue th
94、rough today.The first program consisted of a“5-year Plan to Prevent Leaks”that included a target for reducing the leakage rate from 57%in 1961 to 35%in 1966.While only 113 km of drainpipes were replaced in the first five years,efforts expanded over time and also included supply pipe replacement94.In
95、 1984,Seoul adopted the“Old Pipe Maintenance Plan”aimed at minimizing leaks,ensuring the cleanness of the supplied tap water for households,and establishing a stable inter-regional supply system.The Plan mainly targeted old pipes made of grey cast iron,steel,PVC,or galvanized steel,which were buried
96、 before 1984 and were prone to corrosion that caused frequent leakages and degraded water quality(Figure 2.3b).The Plan also addressed old corrosion-resistant pipes that have been in use for over 40 years or other pipes with frequent leak issues.Despite these early pipe replacement programs,Seoul di
97、dnt see significant improvements from pipe replacement until the 1990s when the old pipes were replaced in large numbers.From 1991 to 1993,Seoul replaced 4,200 km of pipes,with the rate reduced to 500-600 km every year since 200094.Seoul has also upgraded piping materials over time,with improved mat
98、erials resulting in reductions in leakage rate and repair cases.Before 1987,Seoul mainly used galvanized steel pipes for supply lines,but they ceased using the material in 1994.From 1987 on,Seoul used stainless steel pipes and copper pipes for supply lines instead.By 2013,90.6%of pipelines were stai
99、nless steel as well as 72.7%of transmission mains,while 81%of trunk mains were ductile cast iron pipes(Figure 2.3a).In 2001,SWA introduced corrugated pipes to reduce the joints in the water distribution system(Figure 2.4).In Seoul,RWR denotes Revenue Water Ratio.This term refers to the proportion of
100、 tap water produced by Seoul Waterworks Authority that is billed to,and paid for by,its customers.Chapter 2.SEOUL22With the objectives of increasing RWR and improving water quality,between 1984 to 2013,Seoul replaced 13,192 km of 13,721 km of distribution pipes.The remaining old pipes were then repl
101、aced with corrosion-resistant cast iron pipe and stainless pipe by 201894,96.The application of stainless steel pipes along with other technologies led to a steep decrease in annual numbers of leak cases from 59,438 in 1989 to 10,421 in 2013,and a reduction in the leakage rate from 27%to 2.5%from 19
102、93 to 2014 reduced(Figure 2.3a).Figure 2.3a0500010000150002000025000300003500040000450005000001020304050607080901001993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013Number of leakage repair casesPercentage of stainless steel pipes(%)orleakage rate(%)Leakage ratePercentage of stainless steel pipe
103、sLeakage repair casesPercentage of stainless steel pipes,leakage rate and number of leakage repair cases in Seoul,1993 2014Source:International Stainless Steel Forum,2018.Modified by authors.Figure 2.3b 84Lead PipeCopper Pipe8587872001Now92PVC PipeCorrugatedStainlessSteel PipePE PipeStainless Steel
104、PipeTransformation of service pipeSource:International Stainless Steel Forum,2018.Modified by authors.An upgrade to using stainless steel pipes to build the water supply network has contributed to a significant reduction in the leakage rate in Seoul,suppressing it from 27.0%in 1993 to 2.5%in 2014.Ch
105、apter 2.SEOUL23Chapter 2.SEOULFigure 2.4201520102005200019951990Technologies applied in Seoul1990Installation of district-level flow meters1991Intensive maintenance of old water distribution/supply pipes1993Wide application of stainless steel pipes1996Installation of proper meters with smaller diame
106、ter;replacement of inappropriate meters1998 MNF measured by small block system Introduction of waterworks GIS2002Appropriate pressure of booster pumps;AMR2004Introduction of medium block system;scientific leak detection started using the multi-point leak noise correlation system2013ICT-based technol
107、ogies2001Introduction of corrugated pipes2003Systematic management of disused pipes2005Introduction of flow monitoring system24Block management of the distribution systemTo improve management of the water distribution system,SWA adopted a block system,dividing its pipeline network into 2,037 small b
108、locks(sub-distribution network block)and 100 middle blocks(distribution block)(Table 2.2)29.The block system more effectively controlled water flow and pressure within a small block31.In addition,SWA first introduced minimum night flow(MNF)measurements in 1999 to selected blocks,aimed at helping the
109、 block system detect leaks and improve RWR.A team of 4-5 workers conducts water leak detection in the middle of the night(01:00-04:00)one person measures the minimum flow at the flow meter-installed area,and the remaining 3-4 persons detect the leaks with listening sticks,visual inspection of roads,
110、and water meter boxes.Chapter 2.SEOULTable 2.2 Process of RWR management for the small-size blockStepGoalContentsStep 1Fundamental investigation of the blockTo make a list of the current condition of the block including separation of the block,characteristics of the block,and current conditions of f
111、acilities for water supplyStep 2Selection of blockTo select a relatively weak block with many leak cases among the separable blocksStep 3Measuring water supply and consumptionTo measure water supply and consumption in the small-size block three timesStep 4Estimation of the RWR;Plans and strategies f
112、or the RWR goalTo make strategies and plans to increase the RWR considering changes in water supply and consumptionSource:Choi,2014.Modified by authors.25Chapter 2.SEOULActive leak detectionFor leak detection,SWA conducted precise detection in areas that recorded the greatest number of leak cases ov
113、er the past three years based on a waterworks Geographic Information System(GIS),developed between 1998 and 200128.The waterworks GIS provides spatial information of the common facilities,water pipes,and attached facilities.It can help identify the hotspots by correlating the flow data with pipe age
114、,for example.Since the mid-2000s,SWA regularly conducts aerial surveys,checks underground facilities,and maintains a database for the equipment parameters.In addition,information and communications technology(ICT)was applied to the water supply system to collect more data.It allowed the remote monit
115、oring of water quality and water flow.94In 2004,Seoul introduced a multi-point leak noise correlation system to make leak detection more precise95.This system can pinpoint the locations of all leaks with high precision through the high-sensitivity sound sensors and the complete analysis of noise.SWA
116、 also uses a flow monitoring system to provide real-time data on water flow and pressure created during the supply process.Through installation of the flow monitoring system,Seoul can detect abnormal noise and the leaking point can be further identified with the accumulated statistical information28
117、.Water pressure control using a service reservoir systemUrban drinking water supply systems need to maintain consistent water pressure to provide a continuous water supply.Often times,service reservoir facilities are used to store water from treatment plants.Seoul makes use of a service reservoir sy
118、stem to effectively manage water pressure based on elevation differences resulting from the hilly and mountainous terrain.As of 2015,Seoul maintained a total of 120 service reservoirs with a capacity of 2.4 million m3.This system can control excessive water pressure,effectively reducing leakage.Auto
119、matic Meter Reading(AMR)Seoul introduced several automatic meter reading(AMR)pilot projects in 2002 to reduce labor force for meter recording and improve meter accuracy,which can reduce apparent loss(Table 2.2).Through the pilot projects,the average meter reading success rate improved from 67.8%in 2
120、002 to 86.0%in 2006129.26Chapter 2.SEOULe This refers to AMR sensors that can be immersed in water.Due to the poor communication issues associated with a separated AMR system,Seoul implemented an integrated AMR pilot project from May 2007 to June 2009.This AMR integrated water,electricity,gas,and ot
121、her utilities,and utilized power line infrastructure for networking and communication.Power line communication(PLC)technology reduced the cost for building communication networks,and was less sensitive to obstacles compared to wireless communication.In this integrated AMR system,the average meter re
122、ading success rate during the project period was 91.2%,and was more cost-effective than the separate AMR system.However,Seoul faced great challenges in attempting to implement the AMR system.The unfavorable communication environment,high cost of AMR infrastructure,and unsuitable wet type registers f
123、or AMR sensorse have stalled pilot projects in Seoul.To promote the development of AMR system,Seoul is now researching the development of additional features to improve cost-effectiveness,incorporation of the AMR with smart pipe network,and establishment of procedures to ensure communication securit
124、y.27Chapter 2.SEOUL4.KEY LESSONSSeoul has successfully improved the RWR from approximately 55%to above 95%within 30 years.It has become one of the pioneering cities on water loss management in the world.Seoul can attribute some of the citys impressive improvement in RWR to the institutional framewor
125、k,led by the Seoul Waterworks Authority.As a financially self-sufficient agency with stake in oversees public-private-partnerships,SWA faces enormous financial pressure.The corporatization of the public SWA triggered increased efforts towards controlling water losses,due to the associated financial
126、losses.The performance indicator used by SWA RWR reflect the utilitys business focus and illustrate the need to target indicators and metrics to a utilitys objectives and the local conditions.In the case of Seoul,research and development(R&D)efforts,and progressive implementation of technical advanc
127、es for water loss control led to a steady increase in RWR and decline in leakage cases over time.Seouls early efforts to control water loss in the water distribution system focused on replacing old pipes and leak detection.These pipe replacement programs also yielded water quality benefits,highlight
128、ing the potential to receive co-benefits from water loss control projects.The city then devoted much effort towards improving the RWR,which included establishment of a block system and flow monitoring system.To maintain a high RWR in Seouls water distribution system,SWA is now promoting the developm
129、ent of smart technologies for water management.Further,R&D efforts have helped prioritize and define targets for water losses,such as through the GIS system and producing guidelines.Despite the significant increase in RWR over time,the future may bring more challenges to Seouls water systems due to
130、climate change,rapid urbanization,and population growth.Thus,despite the significant increase in RWR,SWA will need to take additional measures to improve the cost-effectiveness of pipeline replacement and promote effective pressure management.The use of Revenue Water Ratio as a performance indicator
131、 accentuates Seoul Waterworks Authoritys business focus.This is a good illustration of the need to link performance indicators directly to a utilitys objectives.The governments decision to turn the Seoul Waterworks Authority into a financially self-sufficient entity provided powerful incentives for
132、utility managers to focus their attention on stemming water losses and the associated financial losses.28Chapter 2.SEOULAs one of the successful pioneering cities in addressing water leakages,Seoul has invested substantial efforts and resources towards pipe replacement technologies and leakage detec
133、tion.In particular with Seouls surrounding hilly terrain,the citys successes in tackling pipe distribution and pressure issues presents the city as an excellent reference for other global cities with similar topographies.Even though hilly terrains pose additional complications with pressure and pipe
134、line distribution issues,the successes of Seoul show that with the right technologies and strategies,water loss can be effectively controlled by substantive amounts.On this same thread on novel technologies,in the next section,we turn to another part of the world Berlin to explore the programs and s
135、trategies it has adopted in pipe replacement and asset management.The Seoul Waterworks Authority has successfully reduced water losses caused by high water pressure in its water supply network,a problem usually associated with hilly topography,by effectively operating a network of service reservoirs
136、 to control the water pressure.29Chapter 3BERLIN30Case ReportBERLINWater provider:Berlin Water Company(BWC)(currently public,formally private).Population served:3.7 million Berliners.Water supply:Nine waterworks utilizing groundwater reserves.Water loss concerns:Following reunification,the Berlin mu
137、nicipal government faced a budget deficit and a deterioration of water infrastructure in the East due to a lack of investment before the reunification.Policies and programs:Regulated by the Minister for Economic Affairs,Energy and Operations that oversees the water tariff and the Minister for Enviro
138、nment,Transport and Climate Protection that oversees water management planning,water quantity,and water quality control.Required to replace water meters once every six years under the Measurement and Calibration Law.Established standards and technical rules to guide the construction,operation,and ma
139、intenance of the water supply system based on guidelines established by the German Association of Gas and Water Experts(DVGW).31Methods and technologies:Deployed OptNet,a software for determining optimal network rehabilitation strategies that factors in technical conditions such as age and pipe mate
140、rials,hydraulic performance,and monetary valuation.Employs trenchless rehabilitation of pipes to repair or replace them.Developed W-Net 4.0,a user-friendly platform with geographic information,simulation,and data analysis tools.Carries out active leakage detection through checking the fittings in pi
141、pe networks annually and the water mains once every four years.Accomplishments:Maintained a level of non-revenue water(NRW)below 7%since 1991,with a current rate near 5%.Cut systemwide pipe breakage in half between 1996 and 2008 from 0.187 to 0.088 breaks per km per year,with a decrease in East Berl
142、in from 0.34 to 0.119 breakages per km.Takeaways:Utilizing asset management software allowed BWC to strategically investigate and prioritize pipe repair and rehabilitation after reunification,significantly reducing breakage in East Berlin.Progressive implementation of technologies such as trenchless
143、 rehabilitation and geographic information systems have helped BWC maintain an extremely low NRW rate for the last thirty years.To ensure that its system will be able to perform at a high level in the future,BWC is in the process of assessing the potential impacts of climate change on its systems,in
144、cluding the impact of extreme heat or rainfall on pipes and breakage rates.32Chapter 3.BERLIN1.INTRODUCTIONAfter the reunification of Germany,the water utilities in East Berlin and West Berlin were“re-unified”in 1992,forming todays Berlin Water Company(BWC)14.As a result of the unfavorable economic
145、situation after reunification,the Berlin municipal government faced a budget deficit in the 1990s.Water infrastructure in East Berlin was deteriorating due to a lack of investment before the reunification.To consolidate Berlins budget,the city privatized its infrastructure systems and outsourced res
146、ponsibilities,including selling 49.9%of its shares in BWC to a consortium of companies in 1999.However,the Senate of Berlin took back full control of BWC after remunicipalization in 2014.Today,the Berlin Water Company provides drinking water and drainage services to 3.7 million Berliners.Utilizing g
147、roundwater reserves,nine waterworks supply Berlin and the surrounding areas with drinking water(Figure 3.1).The waterworks extract groundwater from over 700 wells between 30 m and 170 m deep and store the water in tanks before pumping it through the 7,824 km network of municipal water pipes14.To saf
148、eguard water quality,water protection areas have been specified as buffers around water extraction points(Figure 3.1)12.Water system in BerlinSource:Berliner Wasserbetriebe,2014b.Modified by the authorsFigure 3.1Spree River0 1 2 3 4 5kmWaterworksWastewater treatment plantsWater protected area33Chapt
149、er 3.BERLINBWC assesses water loss based on non-revenue water(NRW),the water produced that is lost before it reaches the customer.Losses can be real losses(through leaks,sometimes also referred to as physical losses)or apparent losses(for example through theft or metering inaccuracies).The level of
150、NRW in Berlin has fluctuated between 5%and 7%since 1991,far below the national level(Figure 3.2).From 2010 to 2013,when BWC was undergoing remunicipalization,NRW experienced a short rising blip from 4.9%to 6.9%.The low level of NRW in Berlin was the outcome of cumulative efforts taken throughout the
151、 history of BWC,including rebuilding East Berlins networks after World War II,investing in rehabilitating the water network in West Berlin in the 1970s,and engaging in asset management and pipe replacement efforts after reunification.Berlin achieved low levels of non-revenue water ratio through cumu
152、lative efforts in four areas:Rebuilding East Berlins network;rehabilitating West Berlins network;replacing old pipes after reunification;and managing its assets.Figure 3.2NRW(Berlin)NRW(National)0246810121416199119951998200120042007201020132016LawsOrdinancesStandardsInternal company rulesDegree of d
153、etailsState responsibilityPubliclyavaliableNot publicBWCs responsibilityBoundednessFigure 3.2 Non-revenue waterf in Berlin and Germany(1991-2016)Source:StBA,2016;Knobloch,2014.Modified by the authorFigure 3.3 Legal Framework of Water Industry in Germany Source:Jagodzinski and Schlken,2014,p.6Non-rev
154、enue water ratio (%)Non-revenue water(NRW)f ratio Berlin and Germany,1991 2016Source:StBA,2016;Knobloch,2014.Modified by the authors.f The calculation of the NRW is based on the data obtained from the Germany Federal Statistics Office and calculated by the author.Non-revenue water=(Water supplied-wa
155、ter delivered to the users-waterworks own use)/Water supplied X 100%.34Chapter 3.BERLIN2.POLICIES AND PROGRAMSWhen the State of Berlin remunicipalized the Berlin Water Company,the city placed the state-owned utility under the regulatory authority of two ministers in the Berlin Senate.The Minister fo
156、r Economic Affairs,Energy and Operations regulates the water tariff,while the Minister for Environment,Transport and Climate Protection oversees water management planning,water quantity,and water quality control10,90.Apart from supervision by the Senate,various federal laws and ordinances place lega
157、l restrictions on the water utility(Figure 3.3).Most relevant to the BWC,the Measurement and Calibration Law requires the replacement of water meters once every six years to limit measurement deviations.It also specifies the quality and labeling of water measuring instruments59,88.The Antitrust Law
158、empowers the Cartel Office to investigate the operation of the water utility for price abuse concerns.If these occur,the authority will request the water utility to readjust the price.Stringent application of this Law could restrict BWC ability to raise enough funds for project works.Lastly,the Drin
159、king Water Ordinance stipulates the minimum requirements for the extraction,treatment,and distribution of drinking water as well as inspection,notification,action,monitoring,and reporting requirements120.Figure 3.3LawsOrdinancesStandardsInternal company rulesDegree of detailsState responsibilityPubl
160、iclyavaliableNot publicBWCs responsibilityBoundednessLegal framework of water industry in GermanySource:Jagodzinski and Schlken,2014,p.635Chapter 3.BERLINIn addition to the legally binding federal laws and ordinance,BWC has established standards and internal rules to guide the construction,operation
161、,and maintenance of the water supply system(Figure 3.3).These derive from guidelines established by the German Association of Gas and Water Experts(DVGW),a professional body with a quasi-legal status.DVGWs duties include:Outlining technical specifications,Documenting the best available technology,St
162、ipulating minimum qualifications required for employees in waterworks,Setting specifications for pipelines,conditions for pipe-laying,qualifications required for pipe installation enterprises,and Serving as the basis for voluntary product certifications55Two sets of DVGW guidelines specifically rela
163、te to water loss management:W392 and W400-3.The W392“Network inspection and water losses-activities,procedures and assessments”guidelines,published in 2003,outlined three pillars for a comprehensive maintenance strategy:i.Inspection regular,scheduled inspection of the system and its components;ii.Ma
164、intenance preventive and corrective;andiii.Repair and rehabilitation3336Chapter 3.BERLIN3.METHODS AND TECHNOLOGIESThe technological measures adopted by Berlin mainly focused on pipe replacement and asset management,with more recent efforts to implement more innovative technologies.During the 40-year
165、 separation between East and West Berlin,the two water utilities adopted completely different strategies in pipe network maintenance.West Berlin consistently carried out pipe replacement in the event of damage or road construction.In contrast,East Berlin focused on repairing pipes;and only replaced
166、pipes in exceptional cases87.As a result,the rate of pipe breakage in East Berlin has been higher than that in West Berlin since 1965.From 1965 1995,pipe breakage in East Berlin rose steadily from 0.09 to 0.34 breakages per km per year.Meanwhile in West Berlin,the number never exceeded 0.1 breakages
167、 per km per year during the same period.With recent efforts to improve East Berlins water infrastructure,the number of breakages has decreased to 0.119 per km in 2008.OptNet asset management softwareAfter reunification in 1989,BWC invested in improving the network of East Berlin87,which included dep
168、loying OptNet asset management software.This software helps determine optimal network rehabilitation strategies by factoring in technical conditions such as pipe age and materials,hydraulic performance,and monetary valuation.BWC used OptNet to conduct an initial evaluation of the pipe network condit
169、ions in East Berlin.The assessment information was then used to identify pipes that needed immediate replacement,and to predict those likely to experience future breakages70.Trenchless rehabilitationBWC employs two trenchless rehabilitation methods to efficiently and cost-effectively repair,renew,or
170、 replace pipes.Trenchless methods eliminate the need to dig long trenches to access old or damaged pipes and dont disturb surfaces as much.The first method inserts flexible plastic pipes into the existing pipe from a manhole to reinforce the pipes structural integrity.Secondly,BWC uses“micro-tunneli
171、ng,”in which they remotely bore a tunnel for the pipes,minimizing the disturbance to road traffic and other underground pipelines54.BWC renews around 54 km of pipe network every year,and the utility renewed 30%of water mains in the 2000s13.37Chapter 3.BERLINService connection depthWhen building a ne
172、w service connection,BWC installs service pipes 1.6 m below ground to prevent them from freezing in winter,and to keep the water cool in the summer to prevent bacterial and pathogen growth.To contrast,telephone and electricity lines are installed at 0.6 m and 0.7 m depth respectively16.W-Net 4.0 dig
173、itized water networkThe water loss control focus of the utility has shifted in recent years from pipe replacement to asset management and digitization of the water network.In 2018,BWC launched a project called“W-Net 4.0”to provide a centralized platform to manage and analyze the data and information
174、 obtained from the water system.The water mains network is completely digitally mapped and sensors systematically monitor parameters such as water quality,network utilization,and the functioning of the corresponding networks35,36.Active leak detectionThe current drinking water system in Berlin is 52
175、 years old on average,with pipes comprised of a variety of materials.The company carries out active leakage detection by checking the fittings in pipe networks annually and the water mains once every four years12,16.38Chapter 3.BERLIN4.KEY LESSONSBWC strategically investigated and prioritized effect
176、ive management actions that led to its successful control of water loss.Results from an asset management assessment taken after the reunification persuaded BWC to prioritize the replacement of high-risk pipes in East Berlin.These efforts resulted in a decrease from 0.34 breakages per km in East Berl
177、in in 1995 to 0.119 breakages per km in 2008.When the NRW ratio stabilized,BWC progressively investigated other technological measures to enhance the efficiency of the water loss control programs,including trenchless technology and a data analytics and mapping platform.Clear guidelines from the Germ
178、an Association of Gas and Water Experts (DVGW)allow BWC to draw from established technical standards and the best available technologies to customize the citys standards and management strategies.Despite successful efforts to maintain an extremely low NRW rate since the 1990s,climate change and drie
179、r,hotter,and longer summers will create new challenges for BWC.The water utility is currently working with the city government on a Water Masterplan”that includes an assessment of whether the pipe network is flexible enough to deal with extreme heat and rainfall,and whether the capacity of its water
180、works should be increased.Further,BWC is looking at where it should be investing.It is concerned that restrictions on tariff levels will make it difficult to raise additional funds necessary for addressing the impacts of climate change.With the case of Seoul and Berlin,so far,we see the significant
181、impacts of new technologies in water leakage control,such as in pipe replacement,rehabilitation of pipes,and active leakage detection.These mapping and data analytics platforms can complement pipe replacement technologies,and create centralized asset management systems that can facilitate coordinate
182、d,more effective approaches to water loss control.Having software platforms that determine optimal network rehabilitation strategies based on factors such as pipe age and materials,hydraulic performance,and cost effectiveness,will henceforth improve efficiency and accuracy in active leakage control
183、and detection,and pipe replacement.The successes of Seoul and Berlin may then lead one to think-are novel,cutting-edge technologies the only solution that can promise successes in addressing water leakages?To answer this case,we turn to look at Sydney.With strategic planning and tailored approaches,
184、we learn that conventional methodologies and approaches can have their equivalent successes too.New technologies,effectively combined,could produce significant impacts on water loss management.Digital mapping and data analytics could complement pipe replacement technologies to create a centralized a
185、sset management system that offers improved efficiency and accuracy in leakage detection and control.39Chapter 4SYDNEY40Case ReportSYDNEYWater provider:Sydney Water Corporation(“Sydney Water”).Population served:Five million people in Sydney,the Illawarra and the Blue Mountains.Water supply:Blue Moun
186、tains and the Southern Highlands,with 80%supplied by the Warragamba Dam.Water loss concerns:Recent droughts and climate change-induced weather uncertainties represent a significant challenge for Sydneys urban water supply management,making every drop count.Policies and programs:Uses the Internationa
187、l Water Associations(IWAs)water budget method to estimate leakage rate.Applies the concept of Economic Level of Leakage(ELL)to identify the optimum leakage level in economic terms.Methods and technologies:Initiated an Active Leak Detection Program in 1999 and a Pressure Management Program in 2005.In
188、troduced improved leak/break response time program in 2006.Applied or piloted several innovative technologies including:a Customer Hub,advanced pipe sensing technology,and LIDAR technology.Accomplishments:Maintained a water leakage rate at approximately 10%or below since 2006.Reduced leakage by 20 b
189、illion liters of water per year,over the last two decades,attributed to the Active Leak Detection Program.Manage pressure in a quarter of Sydney Waters networkTakeaways:Water budgeting and accounting policies,such as the IWA water budget method and ELL,can drive the appropriate use of methods and te
190、chnologies to meet benchmarks.Despite the limited use of innovative technologies to date,Sydneys water leakage rate is lower than 90%of water utilities globally.Climate change threatens to increase water scarcity in Sydney,requiring further research and design efforts to test and develop innovative
191、technologies to effectively control water loss.Programs to increase the speed and quality of repair work have made a relatively small contribution to total water loss reduction in Sydney.4142Chapter 4.SYDNEY1.INTRODUCTIONSydney Water Corporation(hereafter“Sydney Water”)provides water services to mor
192、e than five million people in Sydney,the Illawarra,and the Blue Mountains22.This is the largest metropolitan population served and the highest total water demand in Australia117(Figure 4.1).Most of Sydneys drinking water comes from the Blue Mountains and the Southern Highlands,with 80%of greater Syd
193、neys water supplied by the Warragamba Dam that collects water from the Wollondilly and Coxs river systems.Sydney Water is a statutory corporation wholly owned by the New South Wales(NSW)government and operated under the provision of NSWs Water Management Act.Sydney Water has been instrumental in red
194、ucing the citys water leakage rate to less than 10%in recent years,placing the city among the top 10%of water utilities globally for minimizing leaks117.Climate change-induced weather uncertainties represent a significant challenge for urban water supply management in Sydney.High summer temperatures
195、,coupled with increasing rainfall variabilities,have exacerbated drought conditions in and around Sydney since 2003.For example,reservoir levels dropped to 51%in 2019,placing significant pressure on the citys urban water supply system117.Water loss control will be even more important under future pr
196、ojections of increased water variability and scarcity.Sydneys water managers will need to pay more attention to water loss control in the future because climate change uncertainties will exacerbate that citys water variability and scarcity.43Water delivery system in SydneySource:Sydney Water,2016Fig
197、ure 4.1Chapter 4.SYDNEY0 5 10 152025 kmWaterworksWastewater treatment plants44Chapter 4.SYDNEY2.POLICIES AND PROGRAMSSydney Water began applying water budgeting and accounting methods to aid water loss control decision making in 2002.Sydney Water defines non-revenue water as“water that has been supp
198、lied and then lost from the network infrastructure,through either unbilled(authorized)consumption,apparent losses(unauthorized consumption water theft and meter inaccuracies)and real losses(leakage)”130.Sydney Water adopted the International Water Association(IWA)water balance approach to estimate t
199、he average leakage rate in 2003106.While the water balance method provides a simple method to estimate leakage,it has a large uncertainty band of around 25%of the total water leakage ratiog.Sydney Water has maintained a water leakage rateg at approximately 10%or below since 2006(Figure 4.2)due to an
200、 array of water loss control measures(Figure 4.3).g All water balance calculations include data uncertainties,to a greater or lesser extent;and the uncertainty can be assessed by including confidence limits in the calculations.Figure 4.2024681012141620002002200420062008201020122014201620182020Water
201、leakage(%)Water leakage(expressed as a percentage of potable water drawn)in Sydney,2000 2020Sources:Water Conservation and Recycling Implementation Report 2003 2004,2004 2005,2005 2006,2006 2007,2007 2008,2008 2009,2010 2011,Water Efficiency Report 2011 2012,2012 2013,2013 2014,2014 2015,Water Conse
202、rvation Report 2017 2018,2018 2019,2019 202045Chapter 4.SYDNEYFigure 4.3Timeline of measures to reduce water loss in Sydney2020201520101995200520001999First Active Leak Detection Program2002Began applying the concept of ELL2003Began applying the IWA water balance approach to estimate average leakage
203、 rate2005Pressure Management Program initiated2006Introduced improved leak/break response time program2017Developed Customer Hub2019 Commenced advanced piping sensing technology Exploring the use of LIDAR technology to assess leakage in water pipes46Chapter 4.SYDNEYSydney Water uses the Economic Lev
204、el of Leakage(ELL)to identify the optimum leakage level in economic terms(Independent Pricing and Regulatory Tribunal,2005).From 2003 to 2015,Sydney Water estimated ELL at 105 million liters per day(ML/day)(Figure 4.4).In 2016,the utility increased ELL to 108 ML/day,based on a consideration of the s
205、hort-run cost of water,Warragamba Dams level(65%70%),and an uncertainty band set at 16 ML/day.From 2015 onwards,the leakage percentage increased slightly from 7%to 9.1%(Figure 4.2).Sydney Water attributes this rise in leakage to a period of higher-than-average temperatures and increased rainfall var
206、iability,exacerbating the regions drought conditions.Alternating conditions from hot and dry weather to wet and cold(freezing)weather causes the ground to contract and swell,especially in reactive soils.This can cause pipes to move and can result in bursts.Managing intensifying drought conditions re
207、presents a significant challenge for Sydney Water,particularly in the context of increasing variability due to climate change.Sydney Water managers have discovered that climate change has exacerbated the water leakage problem:Extreme changes in weather conditions have caused the ground to contract a
208、nd swell,leading pipes to move around and thereby increasing the risk of bursts.Chapter 4.SYDNEYSydney Water undertook three primary programs to save water and reduce real losses in the citys water network,namely,active leakage control,pressure management,and improved leak/break response times(Table
209、 4.1).The most significant water savings resulted from the leakage control programs,which saved 24,018ML/year in 2009 2010,followed by the programs for pressure management and leak/break repairs.Active leak controlSydney Water initiated its first Active Leak Detection Program in 1999,under an operat
210、ing license granted by the NSW Government.The program included a host of measures to monitor flows in metered areas and evaluate the risks of potential leaks or breaks,including:Acoustic leak detection sensors and electronic equipment;and Active leak control measures along pipelines and assets inclu
211、ding material selection,installation,maintenance,replacement,and infrastructure network renewal(Table 4.1).Between 1999 and 2018,Sydney Water attributes a leakage reduction of 20 billion liters of water per year to this Active Leak Detection Program.3.METHODS AND TECHNOLOGIES4748Chapter 4.SYDNEYTabl
212、e 4.1 Program investment and water savingsProgramActive leak detectionPressure managementImproved leak/break response timeDescriptionAcoustically scanning for concealed leaks in buried pipes,repairing pipes identifiedInstalling pressure reducing valves in the water system to reduce the incidence of
213、leaksImproving Sydney Waters response time to repair leaks and reduce water lossYear started199920052006Year on holdOngoing20132011Reported number217,635179N/AUnitkm pipe surveyedPressure reduction schemesN/AAverage annual water savings(million liters/year)20,00010,000730Total investment(uncorrected
214、)(000s$gross,up to 2018/2019)53,18571,47924,000RemarksOngoingA quarter of Sydney Waters network is now pressure managed.Additional investment in pressure management is unlikely to bring forth any further reductions in leakage rate.Leaks reported by size and risk,repaired to standard practice.Source:
215、Sydney Water,Water Conservation Report,2018 2019,Page 44-4549Chapter 4.SYDNEYPressure managementFollowing the successful implementation of active leak control measures and a three-year study on leakage and pressure management conducted by the Water Services Association of Australia(WSAA),in 2005,Syd
216、ney Water implemented a pressure management program(Table 4.1).The study highlighted the benefits of pressure management for flow reduction and an associated cost reduction for the water utility as well as improved service for the consumer.Sydneys pressure management program has helped reduce water
217、loss,leading to a water-saving of 10 billion liters per year from 2005 to 2013.Improved leak/break response timesIn 2006,Sydney Water introduced its third measurean improved leak/break response time program,managed by TakaDus network monitoring and analytic services(Sydney Water,Water Conservation R
218、eport,2018 2019,Page 44-45)(Table 4.1).Sydney Water measures the response time as the time from receiving a break/leak notification to the time the reported water loss incident is brought under control.The Independent Pricing and Regulatory Tribunal(IPART)recommended that 90%of all leaks should be r
219、epaired within three days of a leak being detected or reported.In theory,promptly detecting leaks and completing quality repair jobs should reduce leakage volume.However,various evidence shows that the speed and quality of repair work have made a relatively small contribution to total water loss red
220、uction in Sydney(IPART,2005).At the same time,this may partly be due to the relatively small investment in this program compared to the investment in the active leak control and pressure management programs(Table 4.1).Innovative technologies in leak detection and controlSydney Water has primarily re
221、lied upon conventional leakage control methods(e.g.,active leak detection and pressure management)to reduce real water losses.However recently the utility has explored more innovative technologies,including:A Customer Hub for case management,Advanced pipe sensing technology for detecting leaks and b
222、reaks,and Light Detection and Ranging(LIDAR)technology to assess the wetness of around the water pipes.While Sydney Water has relied on conventional technologies to reduce real water losses,it has also explored the application of innovative technologies to improve its performance in managing water l
223、eakage.50Chapter 4.SYDNEYThe Customer Hub,established by Sydney Water in 2017,provides efficient communications and case management services for customers.A key component of this innovative technology is the digital meter,which can rapidly identify leaks in the water supply network.Unlike a traditio
224、nal water meter,a digital meter contains a wireless communication device that can send the reading directly to the water utility without the need for a meter reader to take a reading on site.The meters can record and promptly transmit parameters,such as flow rate,water pressure,and temperature at 30
225、-minute intervals.Also,these devices do not require additional infrastructure,allowing for installation anywhere.In 2018,Sydney Water conducted its first and only test of the digital meters within the Liverpool area of Sydney,with only 100 meters installed across the region.In the next phase,Sydney
226、Water will increase the number of digital meters in Liverpool to about 8,500.In another example of technological innovation,Sydney Water introduced an advanced pipe sensing technology for detecting leaks and breaks in 2019,co-developed by NSW Smart Sensing Network and Sydney Water.This technology is
227、 based on acoustic and pressure transient sensing that measures the vibration on the pipe or in the water column created by water leakage.The technology is currently in trial in the Sydney Central Business District.An associated research program brings together four leading research universities fro
228、m across NSW and five water utilities from Queensland,Victoria,and South Australia to assess the potential for advanced pipe sensing.Further,Sydney Water is working closely with Hunter Water,a state-owned corporation in the Lower Hunter Region in New South Wales,and several research institutes from
229、Australia to explore drone-mounted Light Detection and Ranging(LIDAR)technology to assess the wetness around water pipes.This technology compares light intensity with surface moisture to predict potential leakage in the pipelines.Other novel technologies in the trial stage include quantum sensing an
230、d hydrophone arrays,which could also provide insights for improving efficiency in water loss control management.A network of smart monitoring devices,including a combination of advanced techniques under consideration by Sydney Water,could improve water leakage management and system performance.51Cha
231、pter 4.SYDNEY4.KEY LESSONSSydney Waters programs and policies to account for water loss in the early 2000s,including the use of the IWA water budget approach and ELL,led to methods and technologies that aimed to keep water leakage at the optimum level.Sydney Water has tested and applied a variety of
232、 methods and technologies towards water loss,most prominently-active leak control,pressure management,and improved leak/break response time.Rising water scarcity and drought conditions have also helped catalyze policies,programs,and technological innovation.This drove Sydney Water to improve water u
233、se efficiency,reduce leakage,and better manage urban water demand.Primarily using conventional leak control methods,Sydney has reduced its water supply systems leakage rate to 10%,ranking it in the top 10%of water utilities for minimizing leaks.Climate change-induced weather uncertainties create man
234、y challenges for Sydneys urban water supply management.In terms of leakage,the increase in extremes and variability projected under climate change can cause Australias reactive soils to swell and contract,causing pipes to move and potentially burst.Further,high summer temperatures,together with incr
235、easing rainfall variabilities place significant pressure on the citys urban water supply system117.The climate change impacts highlight the need for Sydney to continue(and potentially expand)current research and design efforts aimed at testing and developing innovative technologies to effectively co
236、ntrol water loss.The case of Sydney illuminates that technologies do not necessarily need to be novel for effective water loss control.With a tailored approach,conventional leak control methods such as active leak control,pressure management,and improved leak/break response time can be just as succe
237、ssful.The success of conventional methodologies to tame complex problems such as water loss,requires good management.Having well-defined measures of water leakage,clarity of where priorities lie and how resources should be allocated would facilitate more efficient,accurate and targeted troubleshooti
238、ng of water leakage points.One important lesson of Sydneys successful experience in controlling water losses:The effective application of technologies requires good management.52Chapter 4.SYDNEYIn the following case studies,we turn to examples that-we think-provide good management practices in water
239、 loss control.We first begin with the case of Philadelphia.Compared to other case studies,the successes of Philadelphia are not as significant.However,Philadelphia is a pioneer in leakage control efforts in the US,and one of the first utilities to adopt the full American Water Works Association(AWWA
240、)water audit.The city of Philadelphia offers important insights on audit methodology as (1)a standard business practice for optimizing revenue,and(2)a means to evaluate the operational efficiency of water supply through analyzing sources of water losses.We will now turn to look at Philadelphia.53Cha
241、pter 5PHILADELPHIA54Case ReportPHILADELPHIAWater provider:Philadelphia Water Department(PWD)(public)Population served:1.7 million residentsWater supply:Delaware and Schuylkill RiversWater loss concerns:In the 1980s PWD discovered high levels of non-revenue water(NRW)resulting from leakage of treated
242、 water before it reached customers meters.Customer service lines represent 55%of the real water losses.Policies and programs:Established a Water Accountability Committee in 1992 to organize and sustain water loss reduction initiatives.First American water utility to,in 2000,employ American Water Wor
243、ks Association(AWWA)s M36 Water Auditing Manual.Jointly launched the Water&Sewer Line Protection Program in 2018 to protect property owners from costly water and sewer service line repairs.55Methods and technologies:Installed the largest Automatic Meter Reading(AMR)system in the United States in 199
244、9.Initiated a scoring system to prioritize water mains for replacement in 2014.Employs a traditional acoustic leak detection program with the goal to inspect the entire water systems every three years.Uses Sahara inline leak sensor technology to identify leak events to address the leakage in large d
245、iameter transmission mains buried under roads with high traffic flow and CityworksTM to improve the tracking and reassessment of customer-arranged leak repairs.Implemented a full-scale DMA monitoring system,advanced pressure management system,and inline transmission main leak detection technology to
246、 identify leak events.Accomplishments:Pioneer in implementing AMR technology and AWWA water audits.Incentivized customers to repair water and sewer service lines.Takeaways:Philadelphia maintains access to a secure supply of cheap water to meet its demands,resulting in a lack of economic justificatio
247、n for obtaining low levels of leakage.Factors beyond those related to fiscal matters(e.g.,water conservation,resource preservation)can motivate actions to drive the leakage rates to lower levels.Despite pioneering technological water loss control measures,non-revenue water has fluctuated between 30-
248、40%for the last 40 years.56Chapter 5.PHILADELPHIA1.INTRODUCTIONThe Philadelphia Water Department(PWD)is responsible for operating,maintaining,and improving the water and wastewater systems in the City of Philadelphia,Pennsylvania,USA.The utility began operations in 1801 and currently serves over 1.7
249、 million people.PWD extracts water from the Delaware and Schuylkill Rivers before distributing it through its 3,200-mileh water system,which includes 78-year-old water mains72(Figure 5.1).PWD has a history as an early pioneer of implementing water loss control technology in the US.The utility instal
250、led the largest Automatic Meter Reading(AMR)system in the United States in 1999 and has also piloted many leakage control projects since then3.Further,PWD was the first American water utility to,in 2000,employ the American Water Works Associations(AWWA)M36 Water Auditing Manual.Sources of water in P
251、hiladelphiaFigure 5.1Philadelphia Water Department was the first American water utility that put into practice,in 2000,the leakage control methods prescribed in American Water Works Associations M36 Water Auditing Manual.h 2,800 miles are small distribution mains.Their sizes are ranged from 6 to 12
252、inches while 400 miles are large transmission mains which range in size from 16 to 93 inches(Blumgart,2018).Schuylkill RiverDelaware River012345 kmWaterworksSource:Philadelphia Water Department,2019,p.657Chapter 5.PHILADELPHIAHowever,PWD faces high levels of non-revenue water,which they discovered i
253、n the 1980s when around 125 million gallons(equivalent to 473 million liters)treated water per day was not recorded by customer meters26.As shown in Figure 5.2,the non-revenue water ratio in Philadelphia has fluctuated between 30%and 40%from the 1980s to 2010s.It reached the lowest level,at 30%,in 2
254、006,2008,and 2009.Since 2012,the ratio went up again,reaching 38%in 2016.Figure 5.220253035404519801985199019952000200520102015Non-revenue water(%)Non-revenue water(NRW)in Philadelphia,1980 2016Source:Philadelphia Water Department,2012;AWWA,2017;Modified by the authors.58Chapter 5.PHILADELPHIA2.POLI
255、CIES AND PROGRAMSPWD is a municipal utility that operates under regulatory requirements from federal,state,and municipal agencies.The utility must comply with regulations on water quality set by the United States Environmental Protection Agency(EPA)and water resources planning requirements set by th
256、e Pennsylvania Department of Environment Protection.The Water Revenue Bureau(WRB),under the citys Department of Revenue,regulates water charges and fees.WRB also performs all functions relating to the reading of water meters,customer accounts,and water charge collection(Philadelphia Water Department
257、 2011 and 2012).At the operational level,PWD and the WRB work closely to formulate and execute programs to promote water efficiency,including non-revenue water reduction.However,there is no hard target for water loss reduction6.PWD,together with WRB,established a multi-disciplinary Water Accountabil
258、ity Committee in 1992 to organize and sustain water loss reduction initiatives.The goal of the Water Accountability Committee is to promote a high level of efficiency in the water delivery and billing processes,and to perform strategic planning necessary to implement lasting improvements to water an
259、d revenue loss reduction.The committee also networks with water industry professionals on water loss control.For instance,in 2001,they contracted international experts to conduct a Leakage Management Assessment project in the city.Adopting AWWA M36 Water Audits and Leak DetectionAnnual water audits
260、have been a standard business practice for PWD since 2000.To effectively measure internal leakage and revenue loss,in 1998,Philadelphia developed a water audit system based on the first edition of the American Water Works Association(AWWA)s Manual M36.It then issued its first comprehensive water aud
261、it in 2000,which enabled PWD to gain a more complete picture of its systems operations,accurately track the citys water consumption and losses,and locate the leaks.The water audit itemizes the source and costs of real losses,such as tank overflows/operators errors,reported and unreported leaks,leaka
262、ge from transmission main leaks and breaks,distribution main leaks and breaks,etc.The collection of these audit data and the application of the Water Loss Control Planning Guide Worksheet in M36 have facilitated the development of a long-term water loss control program for Philadelphia.This program
263、includes measures such as investing in an Automatic Meter Reading(AMR)system,identifying data gaps,and organizing leak detection surveys,described in Section 3.Philadelphia Water Department issued its first comprehensive water audit in 2000.The water audit helped provide a complete and accurate pict
264、ure of water consumption and losses in Philadelphia.59Chapter 5.PHILADELPHIAEconomic Level of LeakagePhiladelphia does not have much economic justification to attain low leakage levels,resulting in a high Infrastructure Leakage Index(ILI)-the ratio between actual real losses and an estimate of the m
265、inimum real losses that could be technically achieved in the system.In 2010,PWD experienced an ILI of 7.5,indicating real leakage levels 7.5 times greater than the minimum real losses that could be achieved.This means that any leakage reduction below an ILI of 7.5 was not financially justified based
266、 on the cost of water lost.PWD used this information to update its leakage component analysis and target-setting evaluationi.PWD managers use the optimum leakage level below which the costs of reducing leakage further exceed the benefits of saving water,known as the Economic Level of Leakage(ELL),to
267、 aid in decision-making2.Philadelphia faces a high ELL,for three main reasons.First to investigate water leaks,Philadelphia charges a higher cost of USD 253 per km in comparison with USD 140 per km in Halifax and USD 124 per km for typical leak detection contractors.Second,PWD has faced low marginal
268、 costs of water,due to secure access to sufficient supplies in conjunction with decreasing demands due to a declining municipal population.Third,PWD does not own the water pipes connecting mains in the street to houses and businesses(Figure 5.3),thus the city doesnt have the authority to fix them.Si
269、nce water meters are installed inside the premises of residences and not at points of connection with the water mains,leaks are often not reflected in customers water bills and go undetected.Even if customers detect a leak outside their home,they do not have any incentive to repair the pipes since t
270、heir the leakage does not affect their bill.Further,some of the pipes are buried underground with high repair costs9.As a result,customer service lines represent 55%of the real losses(Figure 5.4).Importantly though,PWD is facing increasing pressure to reduce leakage.The marginal production costs of
271、water increased substantially from USD 240/million gallons in 2010 to USD 345/million gallons in 201277.Further,other factors(e.g.,water conservation,resource preservation)seem to motivate PWD to drive the leakage rate to a lower level.i Infrastructure Leakage Index(ILI)refers to the ratio between a
272、ctual real losses and estimated minimum real losses,the latter of which is calculated through a formula developed by the International Water Association Water Loss Task Force.This is a performance indicator of real(physical)water losses from the supply networks,and was intended to be an index that c
273、an be used to compare leakage levels across different cities.However as the index was developed using European cities as case studies,the measure is not as relevant or accurate for Asian cities that have a much higher density.In Philadelphia,leakages in customers service pipes accounted for 55%of th
274、e citys total water losses in the 2010s.Customers,however,did not have any incentives to repair the service pipes because the losses caused by these leakages were not included in their water bills.60PWD ResponsibilityCustomer ResponsibilitySanitary and Storm LateralSanitary and Storm SewerChapter 5.
275、PHILADELPHIAWater&Sewer Line Protection ProgramThe high levels of service losses from customer service lines provoked PWD and Philadelphia Energy Authority to develop the Water&Sewer Line Protection Program to motivate customers to repair their pipes.The program allows property owners to sign up for
276、 a low-cost protection plan which covers the cost of repair and replacement of the service pipe.This program provides a subsidy to property owners to help pay for a portion of the cost of repair.In turn,it helps PWD manage the delivery cost of leaky service pipes.Figure 5.3Water System Responsibilit
277、ySource:Philadelphia Water Department,2014a,p.2.Chapter 5.PHILADELPHIA3%55%21%21%Customer Service LinesTransmission Main Leaks/BreaksBackground LeakageOthersFigure 5.4Distribution of water real losses in the City of Philadelphia in 2012Source:Philadelphia Water Department,2012;Modified by the author
278、s.6162Chapter 5.PHILADELPHIA3.METHODS AND TECHNOLOGIESThe City of Philadelphia operates one of the oldest water distribution systems in the United States.Approximately 71%of its pipelines are made of unlined cast iron and were installed between 1880 and 193072.The leakage management efforts of the P
279、WD focus on proactive leakage management,i.e.,finding and repairing leaks while they exist in the unreported stage and minimizing excessive background leakage.Containing unreported leaks to economically low levels minimizes the time leaks go unnoticed,which can be weeks or months.This is particularl
280、y important since losses from many small,hidden,and long-running leaks can exceed the loss from large water mains breaks61.Early water loss control efforts began in Philadelphia in the 1990s.An expansion of the water main replacement program and leak detection program,as well as a switch from quarte
281、rly to monthly billing,led to a notable decline in the NRW rate for the 1994 1998 period2.PWD also signed a contract in 1997 to install the largest AMR system in the United States.The AMR system reads meters remotely,greatly reducing data handling errors and the number of inaccurate water bill estim
282、ates,which has helped PWD address unauthorized uses of water and reduce apparent losses.After these early efforts,the NRW rate increased in 1998,requiring further leak management and detection efforts.PWD piloted District Metered Areas(DMA)from 2006 to 2009 and subsequently implemented a full-scale
283、DMA monitoring and advanced pressure management system.PWD also implemented a traditional acoustic leak detection program with an annual survey goal equivalent to one-third of the total length of the pipeline.In other words,over three years,PWD inspects the entire length of water mains79.To detect l
284、eakage in large diameter transmission mains buried under high traffic roads,PWD conducts Sahara inline leak sensor technology pipeline inspections,which entail the insertion of a sensor into larger taps to locate leaks,pockets of trapped gas,and structural defects in large mains60.Philadelphias Auto
285、matic Meter Reading system has helped reduce apparent losses by greatly reducing the number of inaccurate water bill estimates and identifying unauthorized uses of water.63Chapter 5.PHILADELPHIAPWD has implemented more technologically advanced asset and data management activities over time.In 2014,P
286、WD initiated a scoring system to prioritize water mains for replacement,based on pipe age and the number of recent leaks and breaks.The utility established a goal to replace 22 miles of high-priority water mains every year18.PWD also improved the tracking and reassessment of customer-arranged leak r
287、epairs with the application of CityworksTM,a GIS-centric management solution77.The Philadelphia Streets Department also uses CityworksTM,allowing the departments to compare maintenance activities and identify points of overlap and mutual involvement,such as when leak repairs affect streets and traff
288、ic.Most recently,Philadelphia began deploying Advanced Metering Infrastructure(AMI)that automatically transmits daily water meter readings to PWD.64Chapter 5.PHILADELPHIAFigure 5.5A summary of water supply system technologies deployed by the Philadelphia Water Department2010201520202005200019951950s
289、1950sCathodic Protection Program 1995Main Replacement Program1999Installed Automatic Meter Reading(AMR)system2006 Pilot District Metered Area(DMA)Introduced Sahara to detect leakage in transmission mains2014Implemented the Cityworks2018AMI pilot demonstration2009 Obtained GIS and asset management so
290、ftware Launched improved scheduling and tracking of leakage repairs2008Implemented a new customer billing system2019Launched AMI upgrade programSources:Philadelphia Water Department,2012,Philadelphia Water Department,2014a,Centre for Neighbourhood Technology,2014,Water Finance&Management,201965Chapt
291、er 5.PHILADELPHIA4.KEY LESSONSPWD and its customers have lacked economic incentives to significantly reduce leakage.Philadelphia maintains access to a secure supply of cheap water to meet its demands,resulting in a lack of economic justification for low levels of leakage.Until recently,customers lac
292、ked incentives to repair pipes outside their households,since the leaked water was not metered and did not affect their water bills.In response,PWD jointly developed the Water&Sewer Line Protection Program to provide economic incentives for customers to initiate repairs.Despite the lack of fiscal mo
293、tivation,PWD has invested substantial time,money,and effort into water loss control programs,policies,and technologies.This may indicate that the utility is more motivated by water conservation,resource preservation,or other factors.As the first utility in the US to adopt the AWWA water audit,Philad
294、elphia has demonstrated the benefits of applying audit methodology as both a standard business practice for optimizing revenue,and a means to evaluate the operational efficiency of water supply through analyzing sources of water losses.Despite pioneering technological water loss control measures,NRW
295、 has fluctuated between 30%and 40%for the last 40 years in Philadelphia.This likely relates to the high Economic Level of Leakage(ELL)the optimum leakage level below which the costs of reducing leakage further exceed the benefits of saving water leakage.Nevertheless,as one of the first utilities to
296、adopt the AWWA water audit,pioneer leakage control efforts and install the largest AMR facility in the US,the case of Philadelphia offers important foundational blocks for cities around the world to build upon in water loss control.In the next section,we turn to Tokyo.Tokyo is one of the most succes
297、sful cities in the world in addressing water leakages,with an impressive reduction in water leakages from 80%to 3.2%from 1945 to 2018.As we learn in the next chapter,the successes of Tokyo do lie in novel technologies,but also clear priorities,a phased approach and strong coordination between releva
298、nt enterprises,utilities and customers.Even though Philadelphia was a pioneer in adopting water loss control measures,the lack of economic incentives for both the utility and its customers to reduce leakages has resulted in relatively high levels of non-revenue water.66Chapter 6TOKYO67Case ReportTOK
299、YOWater provider:Tokyo Metropolitan Government Bureau of Waterworks(public)Population served:Approximately 13 million residents in Tokyo.Water supply:Tonegawa,Arakawa,and Tama River systems.Water loss concerns:Damage from World War II and frequent earthquakes resulted in a leakage rate of 80%in the
300、1940s prompting emergency leakage preventive measures.The aging system required significant pipe replacement and upgrades to further reduce water loss.Policies and programs:Implements leakage prevention activities under three categories:corrective measures,preventive measures,and technological devel
301、opment following guidelines produced by the Japan Water Works Association.Required to replace domestic and industrial water service pipes when they reach their 40-year lifespan through the Local Public Enterprise Act.Required to replace water meters every eight years through the Japanese Measurement
302、 Act68Methods and technologies:Employs two types of leakage investigation methods Minimum Night Flow(MNF)measurement method and acoustic leakage sound detection method.Established a mobile team for prompt repair of burst pipes and other visible leakages and for scheduling leakage detection and repai
303、r for citizens.Replaced aging pipes and fittings using a phased approach over several decades.Accomplishments:Decreased the leakage rate from approximately 80%to 3.2%from 1945 to 2018.Replaced all lead pipes with stainless-steel pipes over twenty years.Takeaways:Effective legislation and supervision
304、 by the government can help to promote leakage prevention.Replacement of aging pipes and fittings in the water distribution network not only enhances leakage preventions,but also provides safeguards for public health.Applying different measures according to the challenges defined in different stages
305、 over time can result in a gradual,but continual,reduction in leakage.Regular monitoring is important for identifying issues and taking appropriate corrective measures in a timely manner.Chapter 6.TOKYO691.INTRODUCTIONTokyo Metropolitan Government Bureau of Waterworks,a city-owned public utility,pro
306、vides water service to approximately 13 million residents of Tokyo.The citys water supply system has a long tradition that dates to the 16th century(Figure 6.1).The Tonegawa,Arakawa,and Tama River systems supply most of the water in Tokyo.With the prevalence of cholera in the 19th century,Tokyo unde
307、rwent significant improvements to sustain a clean and stable water supply and modernize the water supply system.From then on,Tokyo advanced the construction of waterworks facilities to deal with increasing water consumption.In Tokyo,Non-Revenue Water(NRW)includes unbilled authorized consumption,appa
308、rent losses,and real losses.Apparent loss include erroneous meter readings,faulty signal calibrations as well as unauthorized water consumption.Real losses are actual water leaks from storage systems,the transmission and distribution mains,as well as service lines.Illegal connections are rare and ap
309、parent loss is at the lowest possible level in Tokyo.Thus,the Bureau of Waterworks has focused on reducing leakage as a parameter for evaluating the efficiency of the water supply system.From 1945 to 2018,the leakage rate dropped from approximately 80%to 3.2%.The significant reduction was largely du
310、e to a phased technical approach for controlling water losses(Figure 6.2)57.In 1913,the Bureau of Waterworks began searching for and repairing leaks for the first time.Following these efforts,the Bureau emphasized different measures according to the challenges defined in different stages over time(F
311、igure 6.2)37.Damages from World War II and the occurrence of frequent earthquakes resulted in a leakage rate of 80%in the 1940s,prompting the Bureau of Waterworks to carry out emergency leakage preventive measures to repair war damage.Through intensive repair activities and labor forces focused on r
312、educing visible leakages above the ground,the leakage rate dropped to 30%within five years.After repairing the damages from the war,Tokyo shifted its focus from leakage detection to the prevention of leakage,particularly through piping upgrades and replacement.With these continual efforts to control
313、 leakages,overtime,this gradually led to a decreasing leakage rate of less than 5%today(Figure 6.2).Chapter 6.TOKYO70Water systems in TokyoSource:Bureau of Waterworks,2018Figure 6.1Tama RiverTone RiverSagami River Arakawa River012345kmWaterworksWastewater treatment plantsChapter 6.TOKYO71Figure 6.20
314、10203040506070809020002002200420062008201020122014201620182020Leakage ratio(%)Stage 1Stage 2Stage 4Stage 5Stage 6Stage 3Trends in leakage rate and time,and a staged approach to leakage management in Tokyo,2000 2020StagePeriodLeakage rate Focus/EmphasisMethod11945 195130%Decrease aboveground visible
315、leakageIntensive repair activities21951 196030-20%Decrease underground leakageZoning,accurate piping maps,training&utilizing good quality equipment for detection31960 196425-20%Prevention recurrence of leakageIncrease in leakage control work,starting replacement of deteriorated pipes,use of ductile
316、cast iron pipe(DCIP)41960 198220-12%Leakage control workRevision of working method&acceleration of pipe replacement work51982 200312-5%Improve service pipesIntroduction of stainless steel service pipes which are strong and durable62003 201895%Infrastructure Leakage Index(ILI)and total losses per ser
317、vice connection:ILI is the ratio between actual real losses and an estimate of the minimum real lossesTotal losses measure the sum of distribution losses and supply pipe losses per day and this is divided by total connections(liters per connection per day)ILI 3.0Losses 200 liters/connection/dayNight
318、 Flow Analysis to assess possible leakage or unwanted customer internal plumbing losses:Average nighttime liters per residential service connection(liters/connection)50 liters/service connectionTransmission Main Upgrades Meters replaced/year(m/yr):%of mains in poor condition95%Source:Halifax Water,2
319、020c.89Chapter 7.HALIFAXHalifax Water also developed eight“critical success factors”l to support the utilitys vision statementsm.To track the utilitys performance,Halifax Water developed organizational indicators and targets that they annually report to the Halifax Regional Council(HRC)in a Corporat
320、e Balanced Scorecard.One of these indicators include Water Loss Control,which is measured in leakage liters per service connection per day.It is one of the organizational indicators used to evaluate“Effective asset management”(Table 7.3)44.To provide incentives for workers to maintain high levels of
321、 services,Halifax Water uses a subset of organizational indicators to determine monetary rewards for employees through an Organizational Award Program.l Critical success factors:1.High Quality Drinking Water;2.Service Excellence;3.Responsible Financial Management;4.Effective Asset Management;5.Workp
322、lace Safety and Security;6.Regulatory Compliance;7.Environmental Stewardship;8.Motivated and Satisfied Employeesm The vision statements are:-We will provide our customers with high quality water,wastewater and stormwater services.-Through the adoption of best practices,we will place the highest valu
323、e on public health,customer service,fiscal responsibility,workplace safety and security,asset management,regulatory compliance,and stewardship of the environment.-We will fully engage employees through teamwork,innovation,and professional development.n This target is adjusted according to the latest
324、 IWA methodology.Of note,these indicators differ from the key performance indicators(KPI)of 200 liters/connection/day and should be reconciled to ensure consistency.Halifax Water has developed a set of organizational indicators and targets to help measure and monitor the performance of its staff in
325、regard to water loss control.Table 6.3 Water Loss Control Target(2016 2021).YearTarget n(Liters/Service Connection/Day)Leakage Actual(Liters/Service Connection/Day)2016/17180-1902232017/18180-1901982018/19180-1901852019/20N/A1772020/21160-170193Source:Halifax Water,2018a;2020a.Actual leakage provide
326、d by Halifax Water.Compiled by the author.90Chapter 7.HALIFAXBefore the merger,Halifax Water and the regional systems used various degrees of technological measures,with the Central Region putting the greatest efforts towards leakage management).From 1982 1997 the Central Region experienced a substa
327、ntial decline of unaccounted-for-water from 44.3%to 11.8%.This decrease resulted from the progressive application of leakage control technologies,including:An Acoustic Leak Detection Program District Metering Areas and SCADA,Master and Zone Metering,and Noise CorrelatorsThe timeline in Figure 7.2 sh
328、ows other methods and technologies applied for water loss control,with the major efforts described below.District Metered Area(DMA)and SCADAHalifax Water adopted a comprehensive DMA design in 2000 that considered various factors,such as minimum nighttime flow velocities,water quality,and peak daytim
329、e demand69.The water system is divided into 75 DMAs,and each DMA is monitored by a SCADA system.A sudden increase in nighttime flow implies a possible leakage21.The SCADA offers real-time flow monitoring of large customers.The combined application of DMAs and SCADA enables active leak detection19,13
330、2.3.METHODS AND TECHNOLOGIES91Chapter 7.HALIFAX20201980201019902000Figure 7.2Timeline of technological measures adopted in Halifax since 1982 to reduce water losses1982Acoustic Leak Detection Program(Central)1992Noise Correlator(Central)2000 AprilIWA method water audit-systemwide leakage survey2000
331、Develop DMAs,PRV pressure management,expand SCADA Review of large-meter customers2004Monitor flows to large customers in real time2010Utilize trenchless technology2017Install Advanced Metering Infrastructure(AMI)2002Utility and Review Board approve special water rate2005DMA and PMA implementation in
332、 Darmouth-East1985SCADA and Master&Zone Metering(Central)Sources:Brothers,2001a;2001b,Centre for Neighbourhood Technology,2014,Halifax Water,2018a,2018b,2018c;2020c,Vassos,Huston and Blin,2018.92Chapter 7.HALIFAXAdvanced Metering InfrastructureIn 2014,Halifax Water undertook a feasibility study of A
333、dvanced Metering Infrastructure(AMI)to investigate its costs and benefits39.The study found that AMI could improve meter accuracy by increasing the frequency of meter reading to every hour,versus the current quarterly manual meter readings.In addition,Halifax Water could bill monthly instead of quarterly,allowing customers to detect abnormal increases in water usage more quickly(a potential sign o
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