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6. WATER LOSS CONTROL 2009 SUMMARY REPORT STRATÉGIE DE CONTRÔLE DES PERTES EN EAU EN 2009
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Committee recommendation
That Council receive this report for information.
Recommandation DU Comité
Que le Conseil reçoive le présent rapport pour information.
Documentation
1. Deputy City Manager's report Planning, Transit and the Environment dated 28 April 2010 (ACS2010-ICS-ESD-0018).
2. Extract of Draft Minutes, 11 May 2010.
Report to/Rapport au :
Planning and Environment Committee
Comité de l'urbanisme et de l'environnement
and Council / et au Conseil
Submitted by/Soumis par : Nancy Schepers, Deputy City Manager/Directrice municipale adjointe, Infrastructure Services and Community Sustainability/
Services d’infrastructure et Viabilité des collectivités
Contact Person/Personne ressource : Dixon Weir, General Manager / Directeur Général
Environmental Services Department / Services environnementaux
(613) 580-2424 x22002, dixon.weir@ottawa.ca
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OBJET : |
REPORT RECOMMENDATION
That the Planning and Environment Committee and Council receive this report for information.
RECOMMANDATION DU RAPPORT
Que le Comité de l’urbanisme et de l’environnement et le Conseil reçoivent le présent rapport pour information.
EXECUTIVE SUMMARY
The Drinking Water Operations Branch is responsible for the treatment and delivery of the City’s drinking water. In 2009, the City of Ottawa delivered an average of 292 ML of drinking water from two treatment plants to 825,000 customers on a daily basis. This report highlights the recent activities of the Water Loss Control program and provides updated performance measures. The report will also highlight the current status of supply side initiatives including apparent and real loss control planned for 2010.
In 2009, the active leak control program eliminated about 2,800 ML of water losses, resulting in direct operating savings of about $204,000. The Infrastructure Leakage Index (ILI) is the industry wide key performance measure of a water loss control program.
The ILI for 2009 was calculated at 3.5; this is the 5th consecutive year of improving this measure and for the 2nd year in a row, we were below our maximum target of 4.0. Industry based standards place the City of Ottawa’s water loss control program in a “good” evaluation.
As the ILI has been below our long range target of 4.0 for two consecutive years, we are updating the water loss control strategy to develop new objectives and confirm on-going programs. The review will also consider a cost-benefit analysis to ensure the updated strategy is cost effective.
Legal/Risk Management Implications
There are no legal/risk management impediments to receiving this report for information.
Financial Implications
This report has no financial implications. Funding for the continuation of the Water Loss Control program exists in capital internal order 902043 Water Loss Control program.
RÉSUMÉ
La Direction des services de l’eau potable est chargée du traitement et de la distribution de l’eau potable de la Ville d’Ottawa. En 2009, celle-ci a livré 292 ML d’eau potable en moyenne par jour à partir des deux usines de traitement à 825 000 abonnés. Le présent rapport souligne les activités récentes du programme de contrôle des pertes en eau et donne les mesures de rendement à jour. Le rapport présente également l’état actuel des initiatives en matière d’approvisionnement, y compris le contrôle des pertes apparentes et réelles prévues en 2010.
En 2009, le programme de contrôle actif des fuites a permis d’éliminer environ 2 800 ML en perte d’eau, assurant de ce fait des économies d’exploitation directes de près de 204 000 $. L’Indice des fuites de l’infrastructure (IFI) est une mesure de rendement clé de l’efficacité du programme de contrôle des pertes en eau dans l’ensemble de l’industrie. En 2009, l’IFI a été calculé à 3,5, révélant ainsi une amélioration continue pour une cinquième année consécutive, tout juste au-dessous de notre cible optimale de 4,0 et ce, pour une deuxième année de suite. Selon les normes de l’industrie, le programme de contrôle des pertes en eau de la Ville d’Ottawa se situe dans la catégorie « bonne ».
Puisque nous avons atteint notre objectif de l’IFI de moins de 4,0 depuis deux ans, nous faisons la mise à jour de la stratégie de contrôle des pertes en eau pour établir de nouveaux objectifs et confirmer nos programmes en cours. L’examen tiendra également compte d’une analyse de rentabilité pour s’assurer que la stratégie à jour est rentable.
Répercussions juridiques - sur la gestion des risques
L’acceptation du présent rapport ne pose pas d’embuches juridiques – à la gestion des risques.
Répercussions financières
Aucune répercussion financière ne découle actuellement du présent rapport. Les fonds nécessaires à la continuation de la Stratégie de contrôle des pertes en eau existent sous la commande interne d’immobilisations 902043 – Stratégie de contrôle des pertes en eau.
BACKGROUND
The City of Ottawa has been providing drinking water services to its residents for over 125 years. During this time, the demand for drinking water has generally grown with the City’s increasing population. The drinking water infrastructure required to provide this service has also expanded in order to meet the water demand. High quality drinking water continues to be provided through an extensive network of infrastructure including water purification plants, booster pumping stations, reservoirs and tanks, watermains, hydrants and service connections.
The relationship between population, water produced and billed consumption from 1980 to 2009 is shown on Figure 1.
The
original growth development strategy for the water infrastructure was to expand
the system to ensure that adequate capacity (volume and pressure) was available
to meet customer demand. However, it is also recognized that the existing
infrastructure must be utilized efficiently and effectively in order to
minimize the financial pressures and defer the need of costly plant expansions
and the installation of large diameter transmission watermains.
In order to do so, the City has developed programs to address both the supply and demand side of the overall water demand equation. The supply side program update will be addressed in this report.
An update on the status of the demand side program is subject of the Water Efficiency Report 2010 (ACS2010-ICS-ESD-0020) that addresses the progress of the water conservation efforts.
DISCUSSION
The purpose of this report is to present the activities undertaken in 2009 as part of the water loss control program and outline those initiatives that are planned for 2010. The following is a list of some of those initiatives currently in place or planned:
- Regular maintenance of production and distribution system water meters;
- Chemical usage analysis to confirm production input volumes;
- Monitor night time water usage in closed pressure zones and communal well systems to identify system leakage;
- Technical peer review of our Standard Water Balance including an economic analysis of the Water Loss Control program;
- Review watermain break repair response procedure to ensure consistency and that repairs are undertaken in a timely manner to minimize leakage run-time;
- Prioritize watermain rehabilitation and replacement needs based on the results of the leak surveys;
- Conduct leak detection surveys on local distribution and transmission watermains;
- Account for all metered and unmetered water usage and improve the methods used to estimate unmetered usage;
- Utilize district metering areas to identify leakage for plastic pipes;
- Initiate the Advanced Meter Infrastructure project; and,
- Report on the repair of leaks on private property program.
Water Balance Summary Report
In 2005, the City adopted the Standard Water Balance as an accounting mechanism to determine the volume of non-revenue water. The Standard Water Balance Summary Report for 2009 is presented in Figure 2. The purpose is to account for all water usage from the time the water is treated to the point of consumption.
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2: Standard Water Balance Summary Report
The accounting of the various volumes that are used to determine the Standard Water Balance is continually improving. The following discussion will describe in greater detail the important aspects and changes in trends to these various categories.
System Input Volume
Figure 3 illustrates the average daily water production by month for the last three years.
As shown in Figures 1 and 3, the overall water production has decreased in spite of a growing population. The volume of water produced in 2009 dropped by about 2% from 2008.
The water production has steadily decreased since 2003 but seems to have leveled off in the past few years. The average daily water production has dropped by 21% since 2003.
It is understood that the water production rate has declined mainly due to:
· Reduced water consumption by customers;
· Successful implementation of the Water Loss Control Strategy (reduced leakage); and,
· On-going Capital programs that target infrastructure renewal and rehabilitation (reduced leakage).
Authorized Consumption
Authorized water consumption includes those volumes of water that are authorized by the City and are either billed or unbilled.
The volume of revenue water has dropped by about 5% from 2008. In order to better understand the continued reduction of revenue water, staff initiated a trend analysis of the water billing information in the fall of 2009 and observed a reduction in water consumption for all customer categories from 2001 to 2008.
Table 1: Drinking Water Consumption Reduction 2001- 2008
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Customer Category |
% Reduction 2001 to 2008 |
Consumption Reduction (m3) 2001 – 2008 |
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Single Family Residential |
7% |
2,800,000 |
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Multi Family Residential |
8% |
2,300,000 |
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Industrial, Commercial, Institutional (ICI) |
6% |
1,700,000 |
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Total Consumption Reduction 2001-2008 |
6,800,000 |
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The trend analysis also revealed that weather patterns have an effect on outdoor water usage and that from 2001 to 2008 there has been higher precipitation and lower mean temperatures during the summer months.
In summary, the trend analysis identified the following factors that may have contributed to the reduction in water consumption by our customers:
· An increasing awareness and adoption of environmentally-friendly habits that result in lower water consumption (shorter showers, washing full loads of laundry or dishes, etc.);
· Installation of more efficient plumbing fixtures and appliances, such as low flow toilets, front-loading clothes washing machines, water efficient dishwashers, etc.;
· Weather patterns that have discouraged outdoor water usage (higher rainfall, lower temperatures, fewer consecutive dry day periods); and
· City of Ottawa Water Efficiency Strategy (public education, retrofit program, toilet rebate program, etc.).
While in the short-term, these water demand reductions create revenue shortfalls and difficulties in projecting future water demands; in the longer term, these reductions allow for an increase in the capacity of the City’s existing infrastructure. This increase in servicing capacity assists with the City’s goal of intensification and reduces capital spending for infrastructure expansion projects.
In 2009, the gap between the ‘system input volume’ and ‘authorized consumption’ volume rose from 13% in 2008 to 17% in 2009 (this gap is identified in the water balance as water losses). The increase from 2008 to 2009 is due to improved accounting methods used to estimate ‘unbilled unmetered authorized consumption’ and ‘customer meter inaccuracies’, which led to an increase in the reported volume of ‘apparent losses’. It is important to note that the increase in the gap was not caused by more leakage, but rather it was caused by an increase of ‘apparent losses’.
In 2009, the method used for estimating volume of ‘unbilled authorized consumption’ was reviewed and improved by measuring various flow rates used to calculate this volume. Unbilled authorized consumption includes water used for water distribution operation and maintenance activities (flushing and commissioning of watermains, hydrant flow testing, flushing watermains to maintain water quality), temporary service water use, fire fighting and some service water for City facilities such as parks, outdoor rinks, pools and splash pads.
Apparent Losses
Apparent water losses can be categorized as “unauthorized consumption” and “customer meter inaccuracies”. Apparent losses represent a far smaller portion of the water “lost” within the system, but it represents larger revenue potential to the City depending on the actual source of those losses.
If it were possible to capture and eliminate all of the apparent losses, the potential revenue gains would amount to approximately $3,563,216[1] annually using the water rate of $1.264/m3 for 2009[2]. It is important to note that a reduction in apparent losses does not necessarily lead to real financial savings since the reduction may be due to better accounting methods for those losses and the reallocation of volumes within the water balance.
Water Loss Control Strategies
The water loss control strategies that are in place to reduce apparent losses include the following:
Reduction of Unauthorized Water Usage
Through the course of our normal service delivery, field staff will note and report instances of unauthorized water consumption such as open water meter bypass valves and unauthorized water connections.
When a bypass valve is found open or to have been opened, it is closed and “sealed”. The building owner is later notified of this infraction and issued a fine.
If an authorized connection to the water system is discovered, the building owner is notified of the infraction and that the connection must be removed. Otherwise, the owner risks having the water supply to the building interrupted until the correction is effected.
Large Water Meter Maintenance and Change-Out Program
Large volume services represent approximately 55% of the City’s overall water demand. Due to their significance to the overall revenue stream, an enhanced level of maintenance and service exists for these meters. They are changed out every 3 to 6 years depending on the meter size; the larger the meter the earlier the change-out.
To measure the effectiveness of the large water meter change-out program, water consumption information before the change-out is compared against water consumption information after the meter is replaced. When water consumption information from 2007 was compared to 2009, we noted a reduction in water consumption of about 299,000 m3 for customer accounts affected by the change-out program[3].
Although it is assumed that the accuracy and overall capture of water consumption has increased, these accounts have seen a reduction in their consumption. This observation is consistent with the overall city trend of decreasing water consumption as discussed earlier.
Advanced Meter Infrastructure (AMI) Project
We expect to award the contract for the supply and installation of a City-wide AMI project in the first half of 2010. The implementation period will take place over approximately two and a half years. The AMI system will replace obsolete meter reading technology and will eliminate estimated meter reading values, therefore ensuring that accurate consumption data are used for water billing and accounting purposes.
While the main business drivers for the AMI project are improved customer service, financial management and cost effectiveness, a 2007 pilot project demonstrated that advanced metering technology can be used to calculate the amount of distribution system leakage with greater accuracy. The availability of higher resolution data will also be used to validate hydraulic models, to identify daily and hourly water use patterns and to monitor the effects of targeted water conservation measures.
Reduction of Unmetered Properties
A concern had previously been identified that not all properties receiving drinking water were being billed for their water consumption.
To this end, a review of water billing accounts against the property tax database has been completed. Unmetered properties identified as part of this process have now been rectified by the installation of a water meter on their service line.
In order to maintain this verification on an ongoing basis, a reconciliation of the tax and water accounts takes place at least annually when an update is received from the Municipal Property Assessment Corporation (MPAC). In addition, when a new property tax account is created it is automatically checked against the water account. These measures should ensure timely detection of unmetered accounts in either system.
Real Losses
Real Losses is defined as the amount of leakage within the water distribution system.
The real loss component of the water losses is valued at about $1,156,904 per year using the marginal cost of water of $0.073/m3.
The International Water Association (IWA) and the American Water Works Association (AWWA) have together developed a series of industry standard performance indicators based on a water system’s specific characteristics to identify the most achievable level of water loss from leakage for that system. The primary performance indicator, the Infrastructure Leakage Index (ILI) compares an estimate of current leakage to an amount of “unavoidable” leakage. The ILI for Ottawa in 2009 was calculated at 3.5, compared to 3.7 in 2008. In other words, the real losses in Ottawa are 3.5 times more than the lowest unavoidable level of water losses.
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Leakage cannot be completely eliminated from a distribution system of 2,600 km of watermains. It would also not be cost effective to attempt to do so. Recognizing this situation and the need to include an assessment of the source water supply into developing a cost effective Water Loss Control Program, the IWA and AWWA guidelines suggest that for service providers that have a water source that is sufficient to meet the long-term needs of the community and have implemented good water control practices and effective maintenance programs, that an appropriate ILI should be no greater than 4.0. The City has met and surpassed that target for the past 2 years; which means that the City’s Water Loss Control program is considered to be in the industry performance status condition known as “Good”.
While industry standards suggest that the City’s current water loss control situation is in the ‘Good” category, staff are currently conducting a more detailed analysis of the water loss control strategies to re-evaluate the cost effectiveness of further reducing the ILI target and to confirm the cost effectiveness of other water loss control strategies.
Preliminary results suggest that we are managing leakage responsibly and cost effectively. Due to the relatively low marginal cost of water, not all typical water loss control strategies are cost effective here in Ottawa. While the implementation of strategies like the installation of permanent district meter areas or pressure management (pressure reduction) would further reduce the volume of water losses from the system, the expenditures to put these measures into place and the resources necessary to manage them would not provide the City with a cost effective payback. Further economic analyses will take place in 2010 to identify additional measures that are both feasible and cost effective.
Other Operational Performance Indicators
For 2009, with an ILI of 3.5, the volume of real losses is 210 L/service connection/day or 12.5 m3/km of watermain/day.
Real Loss (Leakage) Control Initiatives
The four leakage management activities are shown on Figure 5.
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Figure 5: Real Loss Control Initiatives
We continue to focus on the four different aspects of leakage management activities:
- Active Leak Control (which includes District Metered Areas);
- Pressure Management;
- Speed and Quality of Repairs; and
- Pipeline Asset Management.
Active Leak Control
Leaks are currently investigated either reactively (reported leaks) or proactively (leak surveys). The active leak control program is intended to locate leaks before they surface and to initiate repairs in a timely manner. The active leak control survey of the central water distribution system and communal well systems for all metallic watermains (1,775 km) was completed in 2009. The survey identified 52 leaks on watermains, 69 leaks on service connections and 28 leaks on other appurtenances within the water distribution system.
In 2009, we realized an estimated savings of $204,000[4] by proactively identifying and repairing leaks. The total costs to implement this program in 2009 were $126,350. Since we can confirm that the program is cost effective, we will continue to utilize leak surveys in 2010 to actively detect and repair system leakage.
Other leakage management options are also being reviewed at this time to determine if any additional leak detection activities could be implemented to provide similar financial benefits.
Leaks on Private Property
During the course of the leak survey activity, numerous leaks were identified on water service lines on private property. These leaks on private property contribute to the City’s real losses and associated ILI.
As the City is not responsible or authorized to fix leaks on private property, when a leak on private property is identified, the property owner is given a letter stating that a leak was found on their property and noting that they are responsible for the repair. For those property owners who do not repair their leaks, they run the risk of damage to their home and/or adjacent property.
Staff has implemented a program that requires property owners to make the necessary repairs to their water service within a 3-month timeframe. Owners are reminded every 30 days to repair their leak and that if the repair is not complete within the 3-month timeframe, their water supply will be turned off and remain off until the leak is repaired. The program allows for time extensions to be granted for those property owners that demonstrate extenuating circumstances.
In 2009, 89 water service leaks on private property were identified. To date 84 (94%) of the leaks have been repaired, three are turned off (vacant properties), and the two remaining properties have been granted extensions to repair the leaks by June 1st, 2010.
With the exception of the properties granted extensions and a few services that were replaced in conjunction with the Lead Service Replacement program, property owners conducted repairs within the specified timeframe. This process will continue to be utilized as a leakage management tool to address and minimize private property leakage.
Leak Surveys on Large Diameter Watermains
The City operates and maintains about 200 km of large diameter watermains (610 mm and larger) within the central distribution system. The implementation of an annual Large Diameter Leak Detection program will allow the City to proactively identify leaks and schedule repairs with minimal disruption to the customers.
In 2007, a pilot project was initiated to perform leak surveys on large diameter watermains in order to evaluate the effectiveness of current and available technology. The results from the pilot project indicate there are reliable cost-effective options to conduct leak surveys on large diameter watermains, which are critical components of the water infrastructure.
In 2010, the City plans to conduct leak surveys on transmission watermains (1220 mm in diameter) at two locations over a distance of about 5 km each. The proposed locations include the watermain feeding Orleans between Blair Road and the Orleans Reservoir, and the watermain that feeds Kanata and Stittsville located between Moodie Drive and Eagleson Road.
District Metered Areas (DMAs)
Another method of Active Leak Control is the use of District Metered Areas. In the 2008 Water Loss report, we identified that this tool is appropriate for identifying leaks in areas with plastic watermains. In 2009, four temporary DMAs were monitored in the spring – one in the 2E pressure zone (Ward 19), two in the 3W pressure zone (Wards 6 and 23), and one in the Barrhaven pressure zone (Ward 22). In the fall, two new DMAs were monitored in the 3W pressure zone in the Bridlewood community (Ward 23).
The monitoring sessions conducted in the spring were follow-up investigations to validate similar testing conducted in the fall of 2008. In all cases, the results of the monitoring showed that the night flows recorded were within the expected range for systems with no significant water leakage concerns.
In 2009, an evaluation was undertaken to determine whether permanent DMAs would be a feasible and cost effective measure to implement. It was shown that larger metering devices and piping configurations would be required to implement this measure and that it would not be cost effective to do so. Therefore, we will continue to conduct DMA monitoring using temporary installations for the immediate future. These installation requirements will form part of the City’s standard specifications and designs.
Staff also continues to monitor the night flow in communal well systems (Carp, Vars, Munster Hamlet, Richmond-Kings Park, and Greely-Shadow Ridge) and the three closed pressure zones (Morgan’s Grant, Meadowlands and Montreal Road) using the reports generated from the Water Production’s SCADA (Supervisory Control and Data Acquisition) system. These reports are reviewed on a regular basis.
When the night flow exceeds the maximum threshold criteria, leak detection staff is dispatched to the zone to identify potential leaks. The regular monitoring of night flows leads to a reduction in the leak run time, which leads to an overall reduction in real losses.
Pressure Management
The amount of leakage from any distribution system is directly related to the water pressure. If it is possible to reduce the operating pressure in the distribution system with little or no change in service level, leakage from the system can be reduced.
The benefits of pressure management are greater in areas where plastic watermains have been installed and where distribution system pressures are high. Our experience to date has shown that plastic pipe failures are related more to improper installation rather than general pipe degradation and leakage due to high pressures. The majority of the plastic watermains in the system is fairly new and based on our temporary DMA results, is relatively leak free. As a result, no consideration is being given to pressure management for areas with plastic infrastructure at this time.
An economic analysis was undertaken to determine whether pressure management would be a feasible and cost-effective strategy for water loss control for the areas where metallic pipes have been installed in the water distribution system. The analysis concluded that generally speaking, the payback period to implement pressure management in the Ottawa water distribution system was too long, and therefore not recommended. Pressure management can still be useful in particular situations, including areas where watermain breaks are more frequent. Montreal Road Pressure Zone was identified in the 2008 report as a possible candidate for pressure management. The analysis is currently underway and will be reported in the 2010 update.
In the interim, we will continue to monitor and review areas of the system where the watermain break frequency is high to determine if pressure management would be economically beneficial and feasible.
Speed and Quality of Repair
The speed and quality of repairs are centered on the reduction of the leakage run time. The volume of water lost in any leak is calculated as the product of the leakage flow rate multiplied by the run time. Shortening the leakage run time through earlier detection will reduce the volume of lost water. Detecting leaks before they become visible on the surface is an important means of shortening leakage run time. In 2009, the Active Leak Survey program identified approximately 20% of the system failures, thereby reducing the leakage run time.
The City’s Drinking Water Quality Management System has set out a policy committed to the safety and quality of the drinking water, and as such, standard operating procedures have been developed to maintain the quality of drinking water within the distribution system.
Those procedures include the repair of watermains to ensure that water quality is maintained throughout the repair and also to ensure that the watermains are repaired consistently using high quality materials and methodology. The City is committed to keeping informed on the latest industry research and to ensure that our training programs reflect industry best practices.
Pipeline Asset Management
The City currently has a progressive watermain replacement and renewal capital program in place. Funds are allocated annually to replace and rehabilitate watermains based on a priority matrix comprised of many factors such as age and watermain break history. There are also other capital programs that aim to improve pipe condition through rehabilitation, such as the Structural Relining and Cathodic Protection programs.
Although difficult to estimate the contribution of individual projects to water loss reduction, the watermain replacement program and other rehabilitation programs have contributed significantly to both the maintenance of a high level of service delivery as well as the reduction of water losses or leakage in the system. The continued capital investment in infr4astructure renewal and rehabilitation helps to reduce the amount of water produced at the purification plants, and has contributed to the overall reduction in water production as observed for the last few years.
CONCLUSION
All performance indicators associated with the Water Loss Control program confirm that the City is effectively reducing water losses through the combination of various operational management activities:
· ILI has decreased from 3.7 in 2008 to 3.5 in 2009;
· Volume of water captured through repairs to the water distribution system resulted in $204,000 in savings;
· Volume of non-revenue water can be expressed as 210 L/service connection/day or as 12.5 m3/km of watermain/day.
These positive improvements can be attributed to our customers and staff involvement in both the Water Efficiency Program and the Water Loss Control Strategy activities.
RURAL IMPLICATIONS
Rural villages serviced by a communal well system owned and operated by the City benefit from this program through reduced water losses in those systems.
CONSULTATION
Public consultation was not required for this update.
COMMENTS BY THE WARD COUNCILLOR(S)
This program is implemented city-wide.
LEGAL/RISK MANAGEMENT IMPLICATIONS
There are no legal/risk management impediments to receiving this report for information.
CITY STRATEGIC PLAN
The Water Loss Control program helps to achieve the City’s strategic plan for Infrastructure Renewal. The program aims to reduce overall water losses within the distribution system. By reducing these losses, the water purification plants produce less water, therefore, deferring capital investments required to expand the water purification plants and distribution system.
TECHNICAL IMPLICATIONS
There are no technical implications.
FINANCIAL IMPLICATIONS
This report has no financial implications. Funding for the continuation of the Water Loss Control program exists in capital internal order 902043 Water Loss Control program.
DISPOSITION
The Environmental Services Department will continue to implement the Water Loss Control program in 2010. Staff will prepare a summary report related to the program’s performance to Committee and Council on an annual basis.