SUSTAINABLE LEAKAGE MANAGEMENT A CASE STUDY

Transcription

1 SUSTAINABLE LEAKAGE MANAGEMENT A CASE STUDY Jeremy Thomas 1, Reg Bailey 2 1. Parsons Brinckerhoff, Brisbane, QLD, Australia 2. Watermetrics, Brisbane, QLD, Australia ABSTRACT Logan City Council implemented a city wide pressure and leakage management project (PLMP) between 2006 and 2010 in response to the SEQ regional drought. The program has been operating for a number of years with mixed results. This case study reviews the actual benefits of the project over the life of the program and identifies the conditions necessary for a sustainable leakage management program. INTRODUCTION Over the last twelve years a number of leakage initiatives have been undertaken by Logan City Council. This case study assesses these initiatives in four stages by considering the differing drivers covering the program to date. These are: Pressure management pilot project driven by asset management considerations Citywide PLMP implementation (Logan City boundary prior to amalgamation) driven by environmental and legislative requirements Transition period, significant industry upheaval and restructuring. No clear drivers Renaissance. Economic drivers. This paper will look at the anticipated benefits; the outcomes realised at the end of each stage and discuss the issues that impacted at each stage of the program. The paper will also discuss the impact on reported performance from improvements in the quality of data, monitoring infrastructure, tools and reporting facilities. This study will also consider the program's requirements in terms of people, processes, data and equipment necessary to achieve social, environmental, and economic sustainability. PILOT PRESSURE MANAGEMENT PROGRAM Pilot project history Logan Water, the water services division of Logan City Council, implemented a pilot pressure management program between 2001 and Leakage management was not a major factor in the business case. The local topography resulted in many areas of the city being subjected to pressures exceeding 100m and in some cases more than 120m static pressure. These high pressures had severe implications in terms of increasing bursts in the aging reticulation system. The main driver for the pilot pressure management program was therefore asset management rather than leakage management. Pilot project implementation The pilot DMAs were implemented with limited network modelling, no budget for pipe augmentations and boundary valve replacements, minimal input from operations staff and virtually no consultation with affected customers. Following the implementation of pressure management several customers' complained about low pressure in peak demand periods and reduced effectiveness of automatic garden sprinkler systems. The water operations staff came under immediate scrutiny and were tasked to resolve the customer's pressure problems. Since the operations staff had not been consulted during the design of the project they had no hesitation in opening up the boundary valves in three of the four pilot DMAs. The implementation of the pilot DMAs was effectively a failure and the future of pressure and leakage management in Logan appeared to be unsustainable. Pilot project review Logan Water undertook a review of the project and highlighted a number of implementation issues that contributed to the failure. Time and budget constraints The capital budget did not include the cost of augmentation of pipelines to maintain service levels or replacing boundary valves. Accelerating the implementation phase did not allow sufficient time to consult with internal and external stakeholders on the benefits of the program.

2 Inadequate network modelling The pilot DMAs were selected and modelled using a skeletonised network model that had not been verified with field data. Inadequate operational consultation The operations staff were not committed to the objectives of the program and did not hesitate to open up the boundary valves to fix poor pressure complaints. Insufficient marketing of the program to local councillors and residents A lack of consultation, engagement, and information sharing prompted the impacted communities to engage local council members to advocate for them with the water business. With local government representatives prioritising customer service standards, the water department's objectives of reducing leakage and extending the asset life of the reticulation appeared to have little merit. The benefits of the program had clearly not been communicated to the decision makers and the impacted customers. A more effective strategy for addressing these issues was considered to be an essential component of any sustainable pressure management program for the city. CITY WIDE PRESSURE AND LEAKAGE MANAGEMENT PROGRAM IMPLEMENTATION By early 2006 it was becoming clear that South East Queensland was in a very serious drought situation. The SEQ Regional Drought Strategy identified pressure and leakage management as one of the most cost effective methods of reducing water demand. The environment became the new driver for implementing pressure and leakage management programs. In 2006 an agreement was signed between the State Government and SEQ Councils to implement PLMP programs with a 40 per cent subsidy. The State Government later introduced the Water Amendment Regulation No 6 (2006) mandating Councils in SEQ to save 60ML/d by implementing PLMP programs by August The initial environmental driver was superseded by the regulatory driver as the project was implemented. Leakage targets The feasibility study for the program estimated that the total leakage saving in Logan City as a result of the PLMP project was approximately 4.2ML/d. This was based on the extrapolation of a limited desktop analysis of the potential pressure management that could be achieved with the program. Cost estimates The desktop feasibility study also estimated that the total cost of capital works was approximately $11million. During detailed planning the number of district metered areas (DMA) doubled. A large number of pipeline augmentations were also required to address pre-existing deficiencies in the network. The final cost of the 5 year program including all procurement costs and council s internal costs for delivering the DMA project was approximately $14million. Another $18million was invested at the same time to address existing service level deficiencies in the network. The city wide PLMP program built 47 DMAs covering 1,350 km of water mains serving 76,000 properties The forecast annualised cost of operating and managing the DMAs was estimated to be $310,000 per year. Measured benefits The DMAs created through the PLMP project provide the infrastructure necessary to reduce excess network pressure and prioritise areas with high leakage for active leakage control. The reduction in leakage was calculated by looking at the change in minimum night flows (MNF) before and after implementation. Project communication It was recognised that poor communication with stakeholders was the core reason for the failure of the pilot pressure and leakage management project. Logan Water developed a Communication Action Plan with clear objectives for each stage of the program. Target stakeholder groups were identified, key messages were developed and communication actions were allocated to the responsible team members to ensure that the project advanced with significant stakeholder support. DMA planning & model development The DMAs were planned with hydraulic models using selected field data and significant stakeholder engagement. One of the key issues leading to the failure of the pilot DMAs was a lack of network modelling. Consultants were engaged to build and analyse a hydraulic model of the network to plan the most efficient DMA boundaries. The network model was verified by comparing field data with the network model outputs. A review of the outcomes suggested that 80% of the benefits of

3 a calibrated model lay in knowing the pressure and flow relationships at the proposed inlets to the DMAs. These relationships could be determined with selected field data at a small portion of the cost of a fully calibrated model. Reviewing proposed DMA boundaries A workshop was held with Logan Water planning and operational staff to review these planned DMAs. The operational staff needed to understand why certain boundaries were selected. Their local knowledge of the network was critical to ensure that the selected boundaries were functional and constructible. This process allowed the operational staff to start taking ownership of the program The planning consultants analysed the revised DMAs and identified the augmentations required to achieve fire flows and customer service levels under current demand and forecast demand on a 20 year design horizon. Reference was made to the aged pipeline replacement program and previous fire flow augmentation studies to ensure that these works were incorporated into the planned works as far as possible. Network redundancy Creating DMAs involves closing off alternative network pathways and allowing water to enter the district area through only one metered pipeline. As a result a large water supply area is vulnerable to a single point of failure in the network. A number of redundancy options were considered to provide robust water supply systems however the only option that allowed hot standby capabilities was a fully redundant standby inlet. Apart from improving the reliability of the DMA, it was also realised that the cost of establishing the standby inlet was offset by the reduction in pipeline augmentations required to meet fire flow requirements in the DMA. The duty and standby inlets allow for routine and breakdown maintenance to be carried out on the inlets without disrupting water supplies in the DMA. Fire flow tests The most significant argument against the implementation of pressure management came from the fire protection industry. It was argued that pressure management would reduce the fire fighting capacity of the water supply network. Logan Water engaged with the local Queensland Fire and Rescue Services (QFRS) department at an early stage of the project to try and correct this perception. The local QFRS officers were briefed on the planned project and invited to participate in the testing of the existing open networks fire fighting capacity. This process had two significant benefits. The first was the experience and understanding gained by the fire fighters on how the pressure management system responds to fire flow demands. The second benefit is the credibility that is given to statements that the program has not diminished the capacity of the system to provide the water flow necessary for fighting fires. The program had in fact acted as a catalyst to resolve existing deficiencies and significantly improve the fire fighting capacity of the network. Customer communication The flow meter pits and pipeline augmentations were retrofitted into an established urban water supply network. The civil works have significant impacts on the residents. Water supply is interrupted, footpaths are dug up, roads are closed and traffic flow is disrupted. It was essential that the construction stage of the project did not create negative public perceptions of the program before pressure management had even started. A comprehensive customer communication program was developed to ensure that the community were fully informed of all project activities taking place in their area. The local councillors were briefed on the proposed works before any construction activity started in their divisions. Businesses and institutions affected by traffic disruptions and water supply shutdowns were consulted to identify times that minimised the impact of construction works. There were very few complaints from the public with regards to the program as a result of this proactive communication process. DMA commissioning The failure of boundary valves had been a significant problem during the pilot project. The task of checking the integrity of boundary valves was pursued by Logan Water operations staff as soon as the boundaries had been identified in the design stage. Checking that the valves sealed resulted in a number of closed valves being detected in the network. More than 80% of the valves in newer areas less than 20 years old were in good working order. On the other hand up to 80% of boundary valves in older areas had to be replaced. The DMA boundary valves were closed and Zero Pressure Tests (ZPT) were conducted as soon as the new flow meters were installed and powered up. The DMAs remained locked down as soon as a successful ZPT was completed. Flow modulated pressure management was then implemented in the zone using the pressure and flow relationship established to guide the selection of the control set points. Fire flow tests were conducted by Logan Water to verify that the flow

4 modulated pressure management system was working as designed and that there were no detected pressure failures in the system. The DMA was then operational and monitored for another two weeks. The pressure and flow setpoints were optimised based on pressures recorded at the critical point during varying demands into the DMA. Implementation program sustainability This systematic approach to planning and implementing the city wide PLMP program resulted in a DMA system that achieved measurable leakage and burst rate reductions while maintaining customer service levels. The DMA system was embraced by the operational staff and adopted as the preferred arrangement for managing the water supply network. There were limited customer complaints and most were easily resolved. The implementation of the city wide PLMP program was considered to be a success and expected to be sustainable. Measured benefits of the citywide program The project involved the creation of 47 district metered areas. The pressure and flow rate in each DMA is measured and recorded in the corporate SCADA system. The reduction in leakage is measured by analysing the change in minimum night flows into a DMA. An example is presented in Figure 1. The reduction in bursts is measured by the change in pipeline repairs over the period. A full data set required for a comprehensive analysis of bust frequency was not available. This component is not examined further in this case study. The forecast and realised leakage levels for the city wide program are presented in Figure 2. Realised leakage figures have been derived from historic data and adjusted for known errors. The difference between these figures and historically reported leakage performance are discussed later in this paper. The four periods of the analysis are described as follows: Period 1: The planning period for the program, actual leakage levels here were benchmarked at a DMA level prior to any leak repairs or pressure management. Forecast leak reductions were projected from these levels. Period 2: The implementation period. Actual leakage levels here are benchmarked at the end of the commissioning of DMAs, pressure management and leak repairs. Period 3: The transition period. The millennium drought in Queensland broke at the beginning of this period resulting in the final stage of pressure management not being implemented. While all DMAs were monitored through SCADA, analysis and tracking tools were never completed and further pressure management opportunities were not identified. DMA performance was not tracked. There was significant business transition as part of the water reform and leakage levels were not assessed during this period. Period 4: Renaissance period. Operational drivers and the escalating cost of water have put pressure on reducing leakage levels again. The DMA pressure and flow data has been analysed and active leakage control is being reintroduced. Pressure before = 1020 kpa Pressure management introduced Pressure after = 750 kpa MNF before = 2.9L/s MNF after = 1.9L/s Figure 1: Graph of change in minimum night flow with reduction in network pressure

5 Leakage (ML/annum) Planning Period Implementation Period Business Transition Period (no analysis or reporting) Renaissance Period 0 Jan 09 Jul 09 Jan 10 Jul 10 Jan 11 Jul 11 Jan 12 Jul 12 Jan 13 Jul 13 Date Assessed Leakage Path 2006 Forecast Leakage Path Economic Leakage Level 2010 Forecast Leakage Path Figure 2: Forecast, realised and economic leakage paths Economic level of leakage A basic economic leakage level of leakage has been derived for comparison. The economic level of leakage is calculated for each DMA by establishing the leakage rate of rise, cost of active leakage control, and the marginal cost of water. It is clear from the data presented that the full projected benefits and water savings were not realised. The breaking of the drought during the program removed the immediate environmental driver to reduce pressure to minimum levels and achieve the forecast leakage reductions. Legislative drivers were also relaxed as a consequence of the replenished supply sources. TRANSITION PERIOD Impacts of the Water Reform The Queensland Government commenced changing the structure of the SEQ urban water industry dramatically in The changes have often seen reversals of previous decisions and there is a strong sentiment that this has impacted negatively on the industry. A summary of some of the changes is listed below. Seventeen existing SEQ service providers amalgamate to form ten entities. All bulk water functions are mandatorily moved to the state under the control of three new State-owned Statutory Authorities. Establishment of the three independent retail water and wastewater service entities : o Unitywater (servicing Sunshine Coast and Moreton local government areas) o Queensland Urban Utilities (servicing Brisbane, Ipswich, Somerset, Lockyer Valley, Scenic Rim local government areas) o Allconnex Water (servicing Gold Coast, Redlands, Logan local government areas) Legislation requiring local government distribution retail entities is repealed. Allconnex owners decide to return to individual local government management of urban water services. Allconnex dissolved. Logan, Gold Coast and Redland City's re-establish local control of urban water service. Business environment During this extended transition period of merging and segregating the water utility structure of Logan there was little focus on leakage management. The drought had broken towards the end of the implementation of the pressure and leakage management project (PLMP) covering the old Logan area (before amalgamation added areas of the Gold Coast and Beaudesert networks) and the scarcity of water resources was no longer a significant driver. Operational resources were also stretched and with rains and flooding more prevalent these resources were more focussed on the drainage and wastewater systems as a priority.

6 While the captial improvements for the PLMP were completed and commissioned, supporting tools like exception reporting were not. Plans to manage reticulation pressure to minimum levels as a final stage of the PLMP was not undertaken. Supporting resources were also withdrawn as part of efficiency measures and budgetary pressures which were an integral part of the ongoing restructuring. While an escalating price path had been published for bulk water cost increases (required to fund significant drought driven water grid infrastructure) the impacts were not yet tangible. RENAISSANCE PERIOD Driven by new legislative reporting requirements under the Water Netserv Plan (as prescribed under The South-East Queensland Water Distribution and Retail Restructuring Act 2009; Chapter 4B) a review of PLMP leakage reporting functionality was initiated by Logan's water operations branch. During this assessment a significant leak draining to a stormwater pipe and likely running for an extended period was identified and repaired by operational staff. Data for the DMA in which the leak occurred was analysed and is presented in Figure 2. Minimum night flows and leakage for this DMA were benchmarked at the end of Period 2 (commissioning). However there was no active monitoring and unreported leakage increased to a significant level in this DMA before operational intervention identified the leak made the repair. Flows then returned to the previous benchmark levels. The value of the water lost through this single leak was in excess of $450,000 in bulk water costs alone. A similar rate of rise was observed soon after which initiated further active leakage interventions. While improvements to the analysis and reporting facilities were already underway, the scale of the avoidable loss from this single unreported leak highlighted the value of sustained effort and a coordinated response to leakage within the business. Economic environment At the planning stage of the PLMP the primary objective was environmental, i.e. the need to reduce water use and water loss driven by the dwindling resources through an unprecedented drought. Despite significant subsidies a detailed cost benefit assessment was required to support the program given the significant costs involved. The outcome of this analysis was a payback period of between 7.5 and 15 years depending on the value of bulk water adopted. The current price of bulk water has had a considerable impact on the value of leakage over the period of this case study. Figure 3 highlights the value or cost to Logan in bulk water charges at a fixed level over time. The costs indicated are based on the current assessed leakage level of 1112 ML/a. Over a 10 year period the value of the water lost through leakage assuming this constant level will increase from $2.4m to $6.2m. This is a significant and dynamic economic driver ClearSCADA Monitoring Leak Discovered L/s Minimum Night Flow (L/s) ClearSCADA Commencement 5.80 L/s Implementation Benchmark 2 Benchmark MNF at Implementation 3.16 L/s Leak Repaired 3.43 L/s 0 10/8/10 18/11/10 26/2/11 6/6/11 14/9/11 23/12/11 1/4/12 10/7/12 18/10/12 26/1/13 6/5/13 Figure 2: Rate of Rise Observed in DMA10

7 Millions $7.000 $6.000 $5.000 $4.000 $3.000 $2.000 $1.000 $0.000 Cost of Leakage at Current Levels $2.339m ($1.22/kL) $4.568m ($2.38/kL) $6.169m ($3.22/kL) As a result of quality control criteria introduced in 2009 into the free Australian Water Balance software, there is evidence from the most recent results that systematic errors have been identified and eliminated by several service providers. Logan has also introduced quality control measures and invested heavily in new monitoring infrastructure to support more accurate assessment of leakage performance. Figure 3: Rising cost of leakage Analysis & Reporting Challenges Undertaking a leakage analysis is a data-intensive exercise, and involves collating information that is typically spread across a number of business units. In Logan s case there have been significant challenges in collating and analysing data from across the business. This data is typically collected, stored and processed in a format specifically for use by the business unit collecting and using the data as part of their primary function. A common example of this is the metered customer use recorded for billing purposes. The manual collection of billing data typically rolls over a service provider area throughout the year in a quarterly cycle. Accurately assessing customer use from billing system outputs and comparing against bulk water volumes for a fixed period, i.e. calendar or financial year, will inevitably involve an element of estimation for a significant number of customer meters which introduces a significant opportunity for error. A large number of service providers including Logan supply leakage performance statistics to the National Water Commission (NWC). These are published annually in the National Performance Report. What is apparent from these leakage figures is that a large proportion of utilities are reporting figures at or even significantly beyond world class performance (World Bank Institute's best performance category: A1). Using the Infrastructure Leakage Index (ILI) as an example, an A1 performance range for ILI is between 1 and 2; several utilities, including Logan have been reporting ILIs of less than 0.5. A detailed study of Low ILIs in and , for the Water Services Association of Australia (WSAA) in 2009 showed that low ILIs (less than 0.7) were caused by one or more systematic errors in the water balance (bulk metering, no customer meter lag calculation, premature calculations with estimated consumption data, use of number of properties rather than number of service connections, inappropriate methods of estimating average pressure, etc.) Development of Tools A number of tools are being developed by Logan to maintain and improve leakage management and ensure the full and ongoing benefits of their PLMP investment are realised. A leakage exception tool has been integrated into their SCADA system to utilise DMA minimum night flows, asset data and demographical information to analyse and rank leakage by DMA on a daily basis. The algorithms are based on the snapshot ILI 'improved intermediate' methodology developed by Allan Lambert, an international water loss expert. An integrated SCADA water balance is also under development to verify bulk meter volumes and identify leakage on trunk mains. DISCUSSION The efficient assessment and management of water loss and leakage is a significant challenge for every water service provider. Dynamic and conflicting drivers are also a significant issue when considering the business environment that utilities are often operating in. Factors than can contribute positively to leakage management include: Regulatory. Performance or efficiency targets which can in turn be driven by a combination of social, economic or environmental drivers. Environmental. Climate change, droughts and floods can all contribute to water security and subsequently drive efficiency measures. Social. The upward trend on customer water bills and infrastructure costs pressing on costof-living concerns for many consumers is a significant factor for a customer service driven industry such as water supply. Economic. The increasing price to service providers for bulk water as well as their own operational cost increases from energy, fuel, etc., together with a cap on their ability to pass these costs on to customers has a strong influence.

8 Conversely (and similarly) there are several factors that can detract focus from a sustained leakage management policy: Regulatory. Political and machinery of government changes can have a profound impact on the clarity, efficiency, scrutiny and longevity of adequate legislation. Environmental. Heavy rainfall patterns and flooding can shift the focus away from the 'unseen' issues of leakage to the more visible wastewater overflows and property inundations. Limited or stretched operational resources have to react to the priority issues. Social. Customers may be unconvinced on the efficacy of significant expenditure on infrastructure and monitoring to find 'invisible' leaks. Economic. Many of the benefits of both leakage and pressure management programs have been difficult to demonstrate and cost. Case studies from international projects with initially high leakage (>60%) lack local context. Predicted savings and benefits have often fallen short (including Logan's pilot project). Balancing the significant upfront capital expenditure against long term operational savings can also be difficult. CONCLUSIONS At each stage of a leakage management program sustainability issues should be identified and addressed. The water industry is a dynamic environment and project drivers can often change frequently and sometimes dramatically. Environmental drivers primarily play both a direct and indirect role. The constantly evolving and increasing extremes in weather patterns will continue to drive more sustainable and efficient water supply networks. The cost of water supply to service providers and subsequently to customers will continue to increase as the significant cost of securing supplies against drought and other environmental factors is met. As these costs increase, the social drivers and community expectations around the efficiency of service providers and management of water loss will continue to increase. Active monitoring of pressure and flow in each DMA is essential to sustain the benefits of implementing a leakage management program. The business must commit the resources (people, processes, software and hardware systems) to the program or risk losing the benefits. A sustainable program needs a driver to maintain the business commitment. This driver can be environmental, social or economic. The economic level of leakage can provide an effective driver for a sustainable leakage management program. ACKNOWLEDGMENTS The authors of this paper would like to acknowledge Logan City Council and the members of the Infrastructure Planning, Network Operations, Customer Service and others in the water branch for their support throughout the period covered by this case study. The support of Parsons Brinkerhoff and the Logan Water Alliance is also acknowledged. REFERENCES Australian Government National Water Commission National Performance Report Urban Water Utilities. Lambert, A Leakage and Pressure Management Evaluation & Targeting Software (LAPMET). LGIS Guidelines for implementing Pressure and Leakage Management in Areas Containing Buildings with Fire Protection and other Hydraulic Systems. Local Government Infrastructure Services Pty Ltd. QLD Australia. Riolo S (2007). Snapshot ILI: a KPI-based tool to complement goal achievement. Volume 3, Proceedings of IWA Water Loss 2007 Conference, Bucharest, Romania. SEQ Water Institutional Arrangements Queensland Water Directorate website (qldwater.com.au) Stapely, S Unravelling NRW levels in Australia. International Water Assocation Water 21 article. Thomas, J. Grimley, K. Prenzler, T Logan Water Pressure and Leakage Management Program - DMA Design Report. MWH Australia Pty Ltd, QLD. Australia. UK Water Industry, Managing Leakage Report E, Interpreting Measured Night Flows (1994).