WATER SUPPLY DEMAND STRATEGY

Transcription

1 WATER SUPPLY DEMAND STRATEGY Amphitheatre Water Supply System Strategic Plan

2 TABLE OF CONTENTS 1. INTRODUCTION CURRENT WATER RESOURCE REVIEW WATER DEMAND FORECASTING FUTURE WATER CHALLENGE DEMAND REDUCTION STRATEGIES SUPPLY ENHANCEMENT OPTIONS ALTERNATIVE WATER ATLAS WATER SECURITY OUTLOOK DEVELOPMENT OF PLANS MANAGEMENT OF RISK AND UNCERTAINTY STAKEHOLDER CONSULTATION GLOSSARY OF TERMS REFERENCES & RELEVANT INFORMATION Document Control Revision Document Approval Signed Date Draft Strategy V1 Written by M Jayasooriya (Planning Engineer) 9 Dec 2011 Draft Strategy V1 Endorsed by the Internal Review Panel 13 Dec 2011 Draft Strategy V1 Submitted to the Dept. of Sustainability & Environment 15 Dec 2011 Final Strategy V2 Submitted to the Minister for Water 30 March 2012 Electronic Copies Location of Report Draft Strategy V1 Trim Reference :BI/11/99308 Final Strategy V2 Trim Reference : Hard Copies Draft Strategy V1 Final Strategy V2 Location of Report Water Supply Demand Strategy Amphitheatre System 2

3 List Of Figures Figure 1.1 Policy Framework for Sustainable Urban Water Management... 4 Figure 1.2 Water Supply-Demand Strategy Objectives... 5 Figure 1.3 Water Supply Planning Framework in Victoria... 5 Figure 1.4 Regional Maps... 6 Figure 2.1 Schematic of Amphitheatre Water Supply System... 7 Figure 2.2 Amphitheatre Water Supply Catchment... 8 Figure 2.3 Historical Amphitheatre Catchment Rainfall... 9 Figure 2.4 Recent Storage Levels at Amphitheatre Reservoir... 9 Figure 2.5 Amphitheatre Recent Water Restriction History... 9 Figure 2.6 Summary of Security of Supply and System Yield Figure 2.7 Amphitheatre System Storage and Entitlement Figure 2.8 Amphitheatre Groundwater Licence Figure 2.9 Consumption by User Group Figure 2.10 Water Demand Trends Figure 2.11 Summary of proposed actions for short term planning as set out in the Amphitheatre WSDS Figure 2.12 Non-Revenue Water Amphitheatre water supply system Figure Current Demand Management Initiatives Figure 2.14 Future Demand Management Initiatives under Consideration in Figure 2.15 Amphitheatre 2006 Drought Response Plan Potential Supply Options Figure 3.1 Factors Influencing Water Demand Figure 3.2 Amphitheatre Projected Population and Connection Growth Rates Figure 3.3 Amphitheatre Current Water Demand Assumptions Figure 3.4 Amphitheatre - Projected Bulk Water Demand Figure 4.1 Projected Demand and Current System Yield Gradual Climate Change Figure 4.2 Water Requirement Projections Gradual Climate Change Figure 4.3 Projected Demand and Current System Yield Step Climate Change Scenario Figure 4.4 Water Requirement Projections Return to Dry Climate Change Figure 5.1 Proposed Water Consumption Targets Figure 5.2 Summary of Amphitheatre Non-revenue Water Performance and Targets Figure 7.1 Estimated Household Water Use Figure 7.2 Potential Water Savings from Potable Substitution Figure 9.1 Summary of Actions for Short, Medium and Long term Planning Figure 12.1 Glossary Central Highlands Region Water Authority 7 Learmonth Road Wendouree VIC 3353 Australia Telephone: Facsimile: Water Supply Demand Strategy Amphitheatre System 3

4 1. INTRODUCTION Background information The Victorian Government has outlined a sustainable vision for Victoria s future water supplies as a world leader in integrated urban water management, so that our cities become more sustainable and liveable. The purpose of Water Supply-Demand Strategies is to identify the best mix of measures to maintain a balance between the demand for water and available supply in urban supply systems now and into the future. Figure 1.1 Policy Framework for Sustainable Urban Water Management Balancing Water Supply & Demand Recycling & alternative water use Water Supply- Demand Strategy Reducing Water Demand Securing our urban water supplies The development of this Water Supply Demand Strategy (WSDS) details the commitment of Central Highlands Water (CHW) towards supporting more efficient urban water use and identifying supply options to maintain an appropriate balance between urban water supply and demand over the next 50 years. This long-term strategy is a key component of CHW s overall planning processes, which includes planning for drought response, financial expenditure, asset management, water quality and wastewater. Short-term actions presented in this strategy will inform the development of the Corporation s Water Plan ( ) This strategy follows on from the initial WSDS for this system, completed in This WSDS is to be reviewed every five years to take into account changes to the availability of water supplies and changes in consumer demand, as a requirement under the Statements of Obligations (SoO) issued to all water corporations by the Minister for Water under sections 4I and 8(1)(a) of the Water Industry Act Considering the effects of conditions faced and actions taken in the period of , this update outlines the integrated urban water use and supply options to maintain an appropriate balance between urban water supply and demand over the next 50 years. Key objectives The objective of WSDS is to facilitate efficient and effective urban water management in the medium and long term by adopting a range of measures that focuses on reducing water demand, securing water supplies, recycling and using alternative supplies, and balancing water supply and demand. Refer to Figure 1.2 for the key objectives. Water Supply Demand Strategy Amphitheatre System 4

5 Figure 1.2 Water Supply-Demand Strategy Objectives Key Objectives: 1. Ensure safe, secure, reliable and affordable water supplies that meet society s needs; 2. Enable customers to have access to desired water products and services, and to choose to use water for activities they value highly; 3. Encourage all water resources including rainwater, stormwater and recycled water to be utilised in ways that are efficient and fit-for-purpose, whilst ensuring that public and environmental health are protected wherever possible; 4. Encourage water projects to also enhance the liveability, productivity, prosperity and environment of our cities and towns wherever possible; 5. Ensure that water needs of environmental assets are transparently considered and delivered; and 6. Ensure that water planning is subject to a transparent and rigorous decision-making process, with clear roles and responsibilities and accountabilities, which can adapt to the changing environment. The WSDS is a key component of the framework of plans and processes that governs the management of water for urban consumption in the state of Victoria. Figure 1.3 depicts the Victorian water supply planning framework and highlights the importance of the WSDS in developing strategies to achieve sustainable management of water resources to ensure that they meet the current and future water needs of the community. Figure 1.3 Water Supply Planning Framework in Victoria Source: Guidelines for the Development of a Water Supply-Demand Strategy (Version 2) Previous long-term planning Long-term water supply planning is an ongoing process that requires regular review. As part of this process, Water Supply-Demand Strategies shall be reviewed every five years. Some of the previous long-term planning studies undertaken by CHW include: Amphitheatre Water Supply-Demand Strategy 2006 Regulatory documents governing water management in the Amphitheatre system The Victorian Liberal Nationals Coalition Plan For Water Central Highlands Region Water Authority Water Plan Western Region Sustainable Water Strategy 2011 Water Supply Demand Strategy Amphitheatre System 5

6 Plan development CHW has developed this plan in accordance with the Guidelines for the Development of a Water Supply Demand Strategy (Version 2) prepared and issued in October 2011 by the Department of Sustainability and Environment (DSE), with the assistance of representatives of all metropolitan and urban water corporations and the Department of Treasury and Finance. Figure 1.4 Regional Maps Source: National Water Planning Report Card 2011 AMPHITHEATRE Source: CHW GIS System Water Supply Demand Strategy Amphitheatre System 6

7 2. CURRENT WATER RESOURCE REVIEW Distribution network Amphitheatre is located between Avoca and Ararat along the Pyrenees Highway. The Amphitheatre water supply system provides non-potable water to 76 connections and serves a permanent population of approximately 120 people as at 30 June Raw Water Supply System The water supply system consists of Amphitheatre reservoir with a capacity of 67 ML, located on Forest Creek, approximately 2km north west of the township. The reservoir receives water from springs within the catchment. The water supply has been a reliable resource and water restrictions have rarely been required, before the Millennium Drought. Amphitheatre water supply system is primarily supplied from the Amphitheatre Reservoir, however in periods of low storage levels, a drought relief bore can be utilised, which can supply up to 20 ML/year. In the past this bore water has been mixed with reservoir water, using the three 22kL inline storage tanks as mixing tanks, before being pressure injected into the system through a 3 L/s pressure pump. The quality of the water can be variable and tends to be highly coloured. High levels of turbidity and E. coli counts are also seasonal concerns. Community members tend to use private rainwater tanks to supplement the domestic supply. A schematic diagram of the Amphitheatre water supply system is displayed in Figure 2.1. Figure 2.1 Schematic of Amphitheatre Water Supply System Water supply catchment Amphitheatre Reservoir is located in the Pyrenees Ranges along Forest Creek and forms part of the Upper Avoca River (upstream of Charlton). The Forest Creek catchment area is approximately 300 Ha, and the land is predominantly used for grazing and contains some native forest. CHW owns 9 Ha around the Amphitheatre Reservoir, which has no public access. The Forest Creek (Amphitheatre) catchment area was declared and gazetted a Designated Catchment in CHW is actively involved in catchment management activities to protect source water quality and maximise the harvest of water resources. The details of the Amphitheatre catchment are given in Figure 2.2. Water Supply Demand Strategy Amphitheatre System 7

8 Figure 2.2 Amphitheatre Water Supply Catchment Reservoir Catchment Area Land Use Amphitheatre Reservoir 300 ha Predominantly used for grazing with some native forest CHW is actively involved in catchment management activities to protect source water quality and maximise the harvest of water resources. Some of the most important activities include catchment inspections, river health works, creating buffer zones around streams, biodiversity management, fire prevention, property management, and the ability to respond emergency incidents. River health The official manager of the broader Avoca River Catchment is the North Central Catchment Management Authority (NCCMA). The NCCMA develops key strategies to maintain and restore river health and environmental values. The streams situated within the Upper Avoca catchment (Number 2 Creek- Reach 18 and Avoca River-Reach 7) are classified as poor and moderate using the Index of Stream Condition (ISC) in obtained from the Victorian Water Resources Data Warehouse. The area contains many important environmental assets including species of native fish, significant flora and fauna, aquatic invertebrate communities and areas of wetland rarity. High economic value is also placed on this area as it provides urban water for several towns, rural water for stock and domestic purposes, irrigated crops and lifestyle properties. Whilst, social values of significance include areas used for fishing, swimming, sight seeing, and passive recreation. CHW recognises the importance of improving river health and will continue to undertake catchment protection activities within the water supply catchment. It will also work with the NCCMA to identify opportunities and implement programs to maintain environmental values and improve river health, while securing the water future of Amphitheatre. CHW is committed to maintaining compliance with current and future environmental water obligations as reflected in the Environmental Water Reserve and in the regional Sustainable Water Strategy. Drought conditions The extensive drought during the past decade has placed significant stress on water supply systems across the region. Figure 2.3 displays the below average rainfall over the period. Water Supply Demand Strategy Amphitheatre System 8

9 Figure 2.3 Historical Amphitheatre Catchment Rainfall 1 Annual Rainfall Totals Rainfall (mm) Annual Rainfall Average Rainfall Source: Data obtained from the Bureau of Meteorology website, Recent storage levels at Amphitheatre reservoir are shown in Figure 2.4. Figure 2.4 Recent Storage Levels at Amphitheatre Reservoir Amphitheatre Reservoir - Water Storage 100% % Full Capacity 80% 60% 40% 20% 0% Jan-1997 Jan-1998 Jan-1999 Jan-2000 Jan-2001 Jan-2002 Jan-2003 Jan-2004 Jan-2005 Jan-2006 Jan-2007 Jan-2008 Jan-2009 Jan-2010 Jan-2011 Amphitheatre has remained largely unaffected during most years, due to persistent spring-fed inflows. However, it has been placed under stress during the extremely dry seasons of 2002/03, 2006/07 and 2008/09 when rapid reservoir drawdown has occurred due to limited inflow, high evaporation rates and seepage. As a result, water restrictions were introduced in December See Figure 2.5 below for details on recent restriction levels. Figure 2.5 Amphitheatre Recent Water Restriction History Period February November 2006 Water Restriction Level PWSR 1 Rainfall data taken from the Natte Yalloak rain gauge site, as the Amphitheatre data was less reliable Water Supply Demand Strategy Amphitheatre System 9

10 Period December February 2007 Stage 2 March 2007 April 2007 Stage 3 May October 2007 Stage 4 November December 2008 Stage 2 January September 2009 Stage 3 October 2009 to present Water Restriction Level PWSR As of August 2011, Permanent Water Saving Rules (PWSR) were in force and the volume of water available for the Amphitheatre water supply system was at full capacity. In addition, CHW has access to a further 20 ML/year from the Amphitheatre drought relief bore. Despite a full recovery of water supplies in the Amphitheatre system, CHW remain focused on implementing water saving and leakage detection initiatives to help conserve existing water supplies. Water resource modelling The assessment of current surface water supplies and the investigation of the Amphitheatre system s ability to cope with different supply and demand scenarios have been carried out previously, during the development of the 2006 WSDS, using the Resource Allocation Model (REALM) software Package. The model was not updated for this WSDS due to data inaccuracies, which meant that it was not possible to provide any improvement over current yield estimates. A spreadsheet-based calculation was performed in order to assess the future yield assuming that the current yield reduces pro-rata with estimated stream flow reductions. The basic assumptions used for the calculations are discussed below: It was assumed that the current yield of the Amphitheatre water supply system is the equivalent of the bulk entitlement of 25 ML/year. Historical CHW data suggests that it is reasonable to adopt the current bulk entitlement as the current yield. In the case of a return to dry scenario, it was assumed that the current yield would be reduced to 18 ML/ annum, which was adopted in the 2006 WSDS. The three gradual climate change scenarios adopted were based on the current bulk entitlement, gradually reducing in the future due to wet, dry, and medium climate change as outlined in the Guidelines for the Development of a Water Supply Demand Strategy (Version 2). Standard of service CHW has adopted supply reliability as its level of service (LOS) measure. The measures include both the frequency of key restriction levels and the frequency of reaching critical storage levels. CHW s adopted standard of service for the Amphitheatre water supply system is to achieve supply outcomes such that water restrictions are not expected to occur more often than one year in every ten on average (i.e. 90% standard of service). In addition, the system must have the capacity to provide a base level of supply during the worst drought years. This approach provides a statistically sound and repeatable basis for identifying the timing for an upgrade of assets. It also allows a number of criteria to be applied in a system and the critical criteria for the system to be determined, providing a planning focus on the weakest point of the system. Water Supply Demand Strategy Amphitheatre System 10

11 Security of supply The actual likelihood of water restrictions occurring is known as the security of supply. CHW has calculated the security of supply under two modelling scenarios. Assuming the current yield is equivalent to the bulk entitlement, the security of supply in the Amphitheatre system is greater than 1 in 10 years (90% security of supply) at the current level of demand. While using a return to dry scenario (18 ML/year from 2006 WSDS) the likelihood of water restrictions in the Amphitheatre system is greater than 1 in 10 years (90% security of supply) at the current level of demand. System yield The system yield is a term used to describe the volume of water that can be harvested in order to achieve the adopted standard of service. System yield is always associated with a standard of service and reduces if the standard of service increases. In practical terms, this means that a water supply system may be acceptable to one community, which is willing to accept more frequent restrictions. However, the same system may be unacceptable for another community who are less tolerant of frequent restrictions. Using the 90% standard of service and following the revision of stream flow data, it was assumed that Amphitheatre water supply system has a system yield of 25 ML/year. Under a continued low inflow scenario the system yield using the 90% standard of service is estimated only 18 ML/year, which was the figure used in the previous WSDS. Figure 2.6 provides a summary of the current level of demand, adopted standard of service, security of supply and system yield for the Amphitheatre water supply system using the two modelling scenarios. Figure 2.6 Summary of Security of Supply and System Yield Item Scenario based on long Scenario based on a term average inflows continuation of low inflows Adopted standard of service (water restriction target) 1 in 10 years (90%) Current level of unrestricted demand 9 ML/year Current security of supply Greater than 90% Greater than 90% Current system yield 25 ML/year 18 ML/year Current augmentation required to meet adopted standard of service Bulk Entitlement and Groundwater Licences CHW s entitlement to utilise surface water from the Amphitheatre system is specified in the Bulk Entitlement (Amphitheatre) Conversion Order 2003 made under sections 43 and 47 of the Water Act Refer to Figure 2.7 for details. Figure 2.7 Amphitheatre System Storage and Entitlement Source Storage Entitlement Amphitheatre Res 67 ML 25 ML/year (at a rate not exceeding 1.5 ML per day) CHW s licence to extract groundwater for the Amphitheatre system is specified in the Groundwater Licence No made under sections 51, 67 and 145 of the Water Act Refer to Figure 2.8 for details. Nil Nil Water Supply Demand Strategy Amphitheatre System 11

12 Figure 2.8 Amphitheatre Groundwater Licence Source Annual Volume Daily Volume Amphitheatre Bore Water demand trends 20 ML/year Max volume extracted per day must not exceed 0.5 ML The 2010/11 bulk demand for the Amphitheatre water supply system was recorded as 9 ML. Figure 2.9 depicts the comparative usage of different consumer groups for the 2010/11 financial year. There has been a significant decline in per capita demands, as a result of restrictions, demand initiatives and other factors, from those experienced in the pre-restriction period as shown in Figure The current level of demand is approximately the estimated level of unrestrictable demand, indicating that further demand management initiatives are unlikely to provide significant further reductions in unit demands. Figure 2.9 Consumption by User Group Non-Revenue Water, 28% Concessional, 5% Non-Residential, 0% Residential, 68% The lifting of restrictions and the adoption of Permanent Water Saving Rules (PWSR) has not led to any significant rebound in demand to date. There has been a modest increase in demand in the 2010/11 demands over those of the previous year. It should be noted that NRW shown in Figure 2.9 has been measured from the outlets of the bore and reservoir, and will include losses associated with raw water transfer to the tanks, as well as distribution system losses. This is known as Total Losses. Water Supply Demand Strategy Amphitheatre System 12

13 Figure 2.10 Water Demand Trends 2 Amphitheatre Per Capita Usage 's Average /11 Recorded Demand 50 0 Total per capita usage (litres/head/day) Residential per capita usage (litres/head/day) Amphitheatre was not affected by water restrictions during 2010/11, including the critical summer period, and therefore CHW has assumed that recorded demand for the 2010/11 financial year is equivalent to unrestricted demand The current total per capita water usage and current residential per capita water usage is significantly lower than 1990 water usage. This is due to the impact of long term water restrictions which have resulted in behavioural changes in water use by the wider community. Extensive customer awareness programs initiated by CHW also contributed to the reduction of per capita water usage. Review of previous WSDS Actions The previous WSDS for the Amphitheatre system was completed in Short-term actions recommended in that strategy are included in figure Figure 2.11 Summary of proposed actions for short term planning as set out in the Amphitheatre WSDS 2006 Timeframe Action required Status Short term (next 5 years) Commission drought relief bore Commissioned in 2008 Develop detailed leakage prevention and reduction Ongoing plans Work towards achieving water savings of 0.2 Significant water savings ML/year by 2010 achieved to-date In progress, engaged Further investigations into contingency options GHD and a draft report submitted Commission drought relief bore The Amphitheatre drought relief bore was commissioned in 2008, and now provides Amphitheatre with a reliable back up water source albeit at high TDS in the event of reduced available water supply from the Amphitheatre reservoir. As part of this work, tanks, additional pipework and valving were installed to allow blending of reservoir and bore water for increased operational flexibility. Non-Revenue Water CHW has had a strong focus on reducing non-revenue water throughout the region, setting an overall target of 10% non-revenue water by The performance of the Amphitheatre system can be seen in Figure Note that total per capita usage is derived from bulk water usage, and will therefore include a non-revenue water component. Water Supply Demand Strategy Amphitheatre System 13

14 It should be noted that NRW shown in Figure 2.12 does not include losses associated with raw water transfer to the tanks. Associated NRW targets relate to Distribution Losses only Figure 2.12 Non-Revenue Water Amphitheatre water supply system System Losses - Amphitheatre % 40.0% % Volume (ML ) Oct-02 Feb-03 Jun-03 Oct-03 Feb-04 Jun-04 Oct-04 Feb-05 Jun-05 Oct-05 Feb-06 Jun-06 Oct-06 Feb-07 Jun-07 Oct-07 Feb-08 Jun-08 Oct-08 Feb-09 Jun-09 Oct-09 Feb-10 Jun-10 Oct-10 Feb-11 Jun-11 Oct-11 Feb-12 Jun-12 Oct-12 Feb-13 Jun-13 Volume Actual Proportion Tri-Cycle Target ending Rolling 12 month Actual Proportion Since the release of the initial Amphitheatre WSDS in 2006, CHW has reduced non-revenue water in the Amphitheatre water supply system by approximately 1.1 ML/year. Leakage rates have been reduced from a rate of 0.15 L/s in 2006, to a current leakage rate of 0.05 L/s. Work completed and ongoing in the Amphitheatre water supply system to minimise non-revenue water losses include the following: - Monitoring bulk flows on a weekly basis. - Measuring unaccounted water at the end of each property meter tricycle (three times per year). - Quantify losses associated with water mains scouring activities, undertaken for water quality purposes. - Prompt service response times to burst water mains (within travel limitations). - Determine minimum nightly flow level, by the use of data loggers. - Viewing all pipeline alignments in Amphitheatre for visible signs of leakage, including leak detection on a yearly basis - Relocation of all private service meters closer to the water main - Maintaining bulk meter accuracy through regular verification and meter replacements. - Replace flow meter at Reservoir. Demand Management Demand for CHW supplied potable water has changed greatly over the last five years. The protracted dry climatic conditions and resulting shortages of surface water resources created a major change in attitudes and behaviours of CHW customers and CHW strategy and actions. CHW was prompted to accelerate demand management plans and develop new strategies for rapidly improving customer water efficiency and maintaining the improvements. Through CHW initiatives and the general severity of the supply situation, customer research indicates that customers developed an appreciation of how precious water resources are and now firmly believe that water is a resource that should be used sustainably. The research also indicates 30.0% 25.0% 20.0% 15.0% 10.0% 5.0% 0.0% Proportion Lost Water Supply Demand Strategy Amphitheatre System 14

15 that the current attitudes and behaviours towards water conservation are strongly held and are unlikely to weaken significantly in the short term. Almost all of the Demand Management Initiatives, current and future considered, in the 2006 WSDS, have been successfully implemented already, with some still continuing. New initiatives not considered in the previous review have also been implemented. The main initiative that was proposed but did not proceed was the Washing Machine Rebate Scheme. A washing machine rebate is however now available through the Victorian Government s new Living Victoria Rebate Program and is being promoted by CHW to its customers. With the combination of restrictions and a large variety of demand management activities it is challenging to separate out the impacts of individual initiatives. Estimated impacts of some major programs are given below and on-going end use analysis will allow the impact of device adoption and behaviour change (both temporary and in-grained) to become clearer as more detailed data collection and surveys are undertaken. Figures 2.13 and 2.14 show the initiatives listed in the 2006 WSDS. Figure Current Demand Management Initiatives Current Initiative Permanent Water Saving Rules Community Education program Supporting community events Media releases and advertising Customer newsletters Water saving information listed on the CHW website Retrofitting and rebates scheme National Water Week events and promotions Consumption reduction strategies for major consumers Large (non-residential) consumer efficiency program Five Star House Description Statewide regulations that conserve water usage Ongoing primary school education program CHW provide sponsorship and displays to promote water saving awareness Ongoing campaign to keep raise community awareness of water issues Household water saving information for customers Water saving information for household and commercial customers State Government s Water Smart Gardens and Homes Rebates Scheme to encourage installation of water efficient appliances Local events that raise awareness during National Water Week CHW liaise with the local shire, community groups, major customers and key stakeholders to explore demand reduction options and alternative water sources (such as wastewater reuse). Provision of assistance to large consumers to improve efficiency Energy and water efficiency legislation for new homes Figure 2.14 Future Demand Management Initiatives under Consideration in 2006 Future Initiative Washing machine rebate scheme Exchange/Giveaway program Description A rebate scheme for CHW customers who purchase water efficient washing machines Program where CHW customers could exchange old showerheads for new water efficient showerheads (free of charge) or receive a free do-it-yourself water efficiency kit for home installation. Review of Drought Response Plan Actions The Amphitheatre Drought Response Plan (DRP) was first developed in 2006, and is currently undergoing a review. See Figure 2.15 for a list of potential actions specified in the Amphitheatre DRP. Water Supply Demand Strategy Amphitheatre System 15

16 Figure 2.15 Amphitheatre 2006 Drought Response Plan Potential Supply Options Potential supply augmentation options during extreme drought conditions Option Current Status Key considerations Drought relief bore A production bore has been drilled, and commissioned at this stage. Yield of the bore requires verification Some lead-time required to connect to the water supply Water cartage Water cartage could be used for short term relief in extreme circumstances system Highly impractical Low yield, high cost The drought relief bore has now been commissioned and is part of the supply system. The bore water can be blended with reservoir water, via tank setup, for operational flexibility. Water cartage is an ongoing option during low flow periods and the tanks can be used as a carting point. However water carting has not been required to-date. Water Supply Demand Strategy Amphitheatre System 16

17 3. WATER DEMAND FORECASTING General Water demand forecasts are a key component of developing effective water supply-demand strategies as they drive the need to implement measures that moderate demand, or investigate the provision of alternative and additional water supplies. CHW recognise the difficulty in establishing statistically accurate projections beyond a five-year period due to the wide range of factors that influence water demand and have used rigorous analysis of historical trends and developed forecasts using local and regional information. Figure 3.1 Factors Influencing Water Demand Source: Guidelines for the Development of a Water Supply-Demand Strategy (Version 2) Methodology CHW have based the water demand forecast on a demand model incorporating end use analysis of key demand sectors. This has allowed the impacts of water device adoption rates and changes in customer water use behaviours to be tracked. The model incorporates a weather correction module to allow differentiation between the impacts of annual variation in demand due to changes in temperature and rainfall, and changes in underlying demand caused by device adoption and customer behaviour in reaction to restrictions, supply issues and other external factors. The model also incorporates impacts of pricing and economic conditions. Water Supply Demand Strategy Amphitheatre System 17

18 The model forecasts have been based on forecast trends in the adoption rates and assessments of the possible range of customer behaviours in reaction to the climate scenarios. It should be noted that, due to the permanent impacts of device adoption rates the model has demonstrated that unit demand rates are likely to remain low even assuming a return to customer behaviours (e.g. shower times, garden watering times) from pre-restriction drought conditions. In particular, the advent of rainwater and greywater systems, the adoption of water efficient devices (such as drip systems), the conversion to drought tolerant gardens and the increasing stock of smaller house blocks with reduced garden space, has reduced the potential rebound in outdoor potable water reuse even if garden watering behaviours are relaxed. Due to the large uncertainties regarding demand factor trends beyond the next water plan period, unit demands have been held constant beyond 2017/18. The future climate trends and changes in water device technologies will have an unpredictable impact on demand. CHW will continue to monitor these trends and update forecasts. It is planned that, if any signs of a demand re-bound appear, CHW will continue to design focused demand management initiatives to encourage customer behaviours that promote efficient water usage. The model has been used to generate a range of scenarios providing reasonable upper and lower bounds to future demand. The end use modeling for this system has initially been based on that for Ballarat due to data limitations. A separate end use model will be developed for this system as more local data is collected. Adopted growth rates Through the release of Victoria In Future 2008 (VIF) statistics, the Department of Sustainability and Environment (DSE) developed population projections for Statistical Local Areas across Victoria. The Amphitheatre water supply system lies within the Statistical Local Area (SLA) of Pyrenees (S) North. The SLA also incorporates the rural areas surrounding Amphitheatre, small rural communities and the larger townships of Avoca, Amphitheatre and Amphitheatre. In developing forecasts, VIF growth statistics have been used as the baseline for CHW forecasts, along with sensitivity tests against historic CHW water data and other local information. The Victoria In Future (VIF) projected statistics suggest that minimal growth is likely to occur for the Statistical Local Area (SLA). CHW has elected to adopt a population growth rate consistent with those projected by the VIF statistics for the Amphitheatre Township. Figure 3.2 Amphitheatre Projected Population and Connection Growth Rates Adopted Victoria In Future Period Population Adopted Connection Growth Projections Growth Non- Decade Pyrenees (S) North Amphitheatre Residential Residential Concessional % 0.13% 0.13% 0.25% 0.25% % 0.00% 0.00% 0.10% 0.10% % 0.00% 0.00% 0.05% 0.05% % 0.00% 0.00% 0.02% 0.02% % 0.00% 0.00% 0.00% 0.00% The projections shown in Figure 3.2 form the base demand figures for future water demand in the Amphitheatre system and provide the basis of CHW s short, medium and long term planning to achieve an appropriate balance between supply and demand. Water Supply Demand Strategy Amphitheatre System 18

19 The base demand figures used for Amphitheatre s water demand projections also include water savings due to strategies that CHW already have in place. These savings include reductions due to existing demand management initiatives and the current non-revenue water strategy (details of which are listed in Figure 3.3). The introduction of Permanent Water Saving Rules (PWSR) in 2006 was a significant factor in reducing demand, and in changing community behaviour in relation to responsible water usage. However, CHW believe that PWSR s have a negligible ongoing effect on actual water savings, and any savings will now be part of the existing baseline demand. Figure 3.3 Amphitheatre Current Water Demand Assumptions Water Demand Savings Item Permanent Water Saving Rules Existing Demand Management Strategy Unaccounted Water Strategy 3 Residential Non- Residential Concessional Comments 0% 0% 0% Now form part of baseline demand 0% 0% 0% Target of 20% Bulk water demand projections Target of 20% Target of 20% Figure 3.4 gives the forecast bulk water demands for the planning period. Figure 3.4 Amphitheatre - Projected Bulk Water Demand Committed to maintaining current estimated per capita consumption over the next 50 years. 50 year target as per CHW s draft Nonrevenue Water Strategy for Amphitheatre October 2011 The demand forecast adopted is based on a conservative selection of a scenario near the upper limit, making some provision for the uncertainties involved in whether there will be a return to pre-restriction customer behaviours. This provides a bias towards an early date for reaching the system yield. Anticipated bulk demand projections include a non-revenue water component. Non-revenue water projections are based on long-term average non-revenue water information, which for Amphitheatre is approximately 8% less than 2010/11 Total Losses figure. The result is a significantly reduced first year projection. 3 CHW has proposed an overall NRW target of 10%, and a target specific to Amphitheatre of 20%. See Chapter 5 for details. Water Supply Demand Strategy Amphitheatre System 19

20 4. FUTURE WATER CHALLENGE Climate change The greatest uncertainty in assessing the future water demand against water yield is the potential impact of climate change. Although uncertainty exists, CHW can still undertake effective planning by considering a range of plausible scenarios that may eventuate, and developing plans to take the most appropriate action to deal with these circumstances. Yield estimates for the Amphitheatre system have been made based on the DSE Guidelines. These figures show that Amphitheatre has sufficient yield to service demand for at least the next few decades, including under the Return to Dry (Millennium Drought) scenario. Figure 4.1 Projected Demand and Current System Yield Gradual Climate Change Figure 4.2 Water Requirement Projections Gradual Climate Change Projected Demand Wet Climate Change Dry Climate Change Year Forecast Water Yield Shortfall Water Yield Shortfall ML 25 ML Nil 25 ML Nil ML 25 ML Nil 23 ML Nil ML 23 ML Nil 17 ML Nil ML 22 ML Nil 13 ML 1 ML Return to Dry climate change Following the severity of the dry conditions experienced during the past decade the DSE subsequently made the decision to consider a step climate change scenario. This strategic government decision and the severity of the drought necessitated the development of plans for a resumption of low inflows in CHW s water supply demand strategies. Under this scenario, historical data sets were adjusted to mirror the low inflow trends of the past decade. The approach assumes that a sudden shift or downward step is effective immediately and is equivalent to a step climate change scenario. Water Supply Demand Strategy Amphitheatre System 20

21 Figure 4.3 and 4.4 depict the water supply and demand situation under a return to dry climate change scenario. This scenario also depicts an adequate buffer between water yield and water demand for at least the next 50 years, so there is little need for short-term future options under this scenario. Figure 4.3 Projected Demand and Current System Yield Step Climate Change Scenario Figure 4.4 Water Requirement Projections Return to Dry Climate Change Projected Demand Return to Dry (Step Climate Change) Year Forecast Water Yield Shortfall ML 18 ML Nil ML 18 ML Nil ML 18 ML Nil ML 18 ML Nil Planning approach Through the development of this water supply demand strategy, CHW has adopted the most appropriate course of action, timing of options, and contingency plans to deal with the uncertainty and risk associated with drought and climate change. Annual reviews of the water resource situation will be undertaken, as well as a five yearly comprehensive review of the strategy, and future options will be implemented earlier than anticipated, if necessary. Water Supply Demand Strategy Amphitheatre System 21

22 5. DEMAND REDUCTION STRATEGIES CHW s current and future demand management strategies have and will continue to help to reduce the amount of additional water supplies that need to be used in the future. Demand reduction initiatives look towards improving water conservation through the achievement of greater efficiency, technological improvements and behavioural change. Current and future demand management initiatives The demand management initiatives outlined in Section 2 have achieved significant reductions in water demand for both residential and non-residential customers. Residential indoor demand has declined and is forecast to continue to decline as customers adopt, both consciously and through growth and natural replacement, water efficient devices. Residential outdoor demand has largely been supplied through alternative water sources (primarily rainwater tanks) and changes to community behaviours. Whilst there is expected to be some bounce-back in outdoor usage, it is expected that an increasing percentage of this will be serviced by alternative water. The non-residential and concessional demand is expected to remain low due to the impact of demand initiatives such as Water MAP which have reduced both process water demand, predominately through alternative water sources, and employee related demand. CHW will continue with a number of the current demand initiatives during the near future, however, given the very low demands currently being experienced, it is too early to identify new initiatives that may be able to have a significant impact. It is likely that there will be some increase in water usage if there is a return to dry hot summers and CHW will continue to monitor water demand patterns to identify any particular usages that are increasing and develop focused demand initiatives (or modify existing initiatives) to suit. The future savings that can be achieved will heavily depend on the balance between demand reductions with continued adoption rates and demand increases due to customer behavior bounce-back. Figure 5.1 Proposed Water Consumption Targets Water consumption Total water usage (per capita) Residential water usage (per capita) Amphitheatre System Litres/person/day Litres/person/day Current Unrestricted Demand and 2060 Target Demand Future water efficiency initiatives are expected to continue to focus on leading the community in water efficiency and sustainable use of our precious water resources, specifically aiming at maintaining customers good behaviours and high levels of water efficiency. CHW will continue to support Government initiatives such as rebates for water efficient devices and assistance to non-residential customers with their water efficiency efforts. These targets and initiatives are driven by the community s intention of being water efficient and environmentally responsible, which CHW fully supports and encourages. There is no projected supply demand imbalance in the short to medium-term. In the short-term CHW will continue to support the current initiatives listed above. CHW will continue to monitor the situation and remain ready to respond to changes. The medium to longterm outlook will depend on a number of factors, especially the effects of Climate Variability and the availability of water supply, Government direction and community consultation. There is also an expectation that technology improvements over the next 50 years will create natural improvements in the efficiency of water-use applications. Water Supply Demand Strategy Amphitheatre System 22

23 Non-revenue water CHW is currently reviewing the non-revenue water strategy for all water supply systems and a key component of this review is likely to be the announcement of an 10% overall target for nonrevenue water by To achieve this, a target of 20% non-revenue water is likely to be set for the Amphitheatre system. See Figure 5.2 for details on non-revenue water targets and performance for Amphitheatre, note that all figures relate to Distribution Losses, which corresponds to information shown in Figure Figure 5.2 Summary of Amphitheatre Non-revenue Water Performance and Targets Amphitheatre NRW (FY2010/11) Amphitheatre Long-term Average NRW Proposed Amphitheatre System NRW Target Overall CHW NRW Target 22% 20% 20% 10% Future non-revenue water initiatives for Amphitheatre will not only include a renewed commitment to current initiatives, but will also include: The installation of a new flow meter and pressure sensor linked to CHW s SCADA system, to ensure an increased capability to promptly detect and locate bursts and leaks within the system. The installation of extra valves on private services to ensure more effective isolation of bursts and leaks. Water Supply Demand Strategy Amphitheatre System 23

24 6. SUPPLY ENHANCEMENT OPTIONS The Amphitheatre water supply system has sufficient capacity to service the forecast demand until at least 2055, as discussed in Section 4, based on conservative demand scenarios and adopting the worst cast Return to Dry scenario. CHW will continue to assess Amphitheatre s water demand growth and the effects of climate change to ensure that an appropriate balance between supply and demand is maintained. CHW is also reviewing opportunities to modify existing system strategies to address the reform principles provided in the Living Melbourne, Living Victoria Roadmap. Potable Water Initiatives Any further augmentations to the Amphitheatre water supply system are expected to be driven from a quality rather than a quantity perspective. Enhancement of raw water quality by minor system improvements including reservoir aeration and coarse treatment at the distribution tanks will be considered. These minor system improvements are the recommendations of a study to investigate future water quality enhancement options in Amphitheatre. Alternative Water Initiatives CHW is currently undertaking a review of its re-use strategy for wastewater to identify any further opportunities for re-use. Demand Initiatives Demand is currently at the estimated non-restrictable level of demand, limiting the options for new demand initiatives. Continual monitoring of demand levels will be undertaken to identify any signs of bounce-back. Current demand initiatives will be modified or new initiatives will be undertaken to provide a focused response to the identified nature of the bounce-back. Contingency options CHW will continue to assess Amphitheatre s water demand growth and the effects of climate change to ensure that an appropriate balance between supply and demand is maintained. Supply augmentation options have been outlined as contingencies to deal with future uncertainty. Two potential contingency options are listed below: 1. use the ground water bore 2. water carting CHW will conduct further investigations into these options over the next two years, and consider implementing the most appropriate option, if necessary. Water Supply Demand Strategy Amphitheatre System 24

25 7. ALTERNATIVE WATER ATLAS The Guidelines for the Development of a Water Supply Demand Strategy (Version 2) advise that a Water Supply Demand Strategy should provide information on specific opportunities for increasing the supply of alternative water services within the geographical bounds of their service areas. This Alternative Water Atlas aims to: - Identify the volumes of storm water, recycled water and other alternative water sources available within the works of the water corporation and local council. - Inform future opportunities for the use of these identified sources of alternative water for the benefit of the community. The guidelines further states that for systems where no imbalance between supply and demand has been identified, it is reasonable to expect that only high level information about alternative water sources will be provided in the Alternative Water Atlas. As there is no supply and demand imbalance in the Amphitheatre water supply system, high level information about alternative water resources is provided. End use analysis of demands for the Ballarat system, which has similar demand characteristics, has estimated current water usage by residential customers. These are given in Figure 7.1 along with current industry estimates of water usage in new developments (5 star). Potential water savings from potable substitution initiatives are provided in Figure 7.2 Figure 7.1 Estimated Household Water Use Scenario Kitchen Bathroom Toilet Laundry Outdoor Total Household water use ( l/household/day) Existing Development Existing Development New development ( 5 star demand) Accordingly, a range of reuse scenarios can be considered and the details of these scenarios are given in Figure 7.2: Figure 7.2 Potential Water Savings from Potable Substitution Reuse Scenario Household water use ( l/household/day) Existing Development Toilet Flushing Toilet Flushing and laundry Toilet Flushing, laundry and hot water Toilet Flushing, laundry, irrigation* and hot water The following options will be considered where appropriate: Recycled water At present, Amphitheatre does not have a sewerage service. Storm water Harvesting New development CHW may explore the possibility of storm water harvesting as a possible future supply option to Amphitheatre Township. Water Supply Demand Strategy Amphitheatre System 25

26 CHW is expecting to gather further information in relation to storm water harvesting, in collaboration with the Pyrenees Shire Council, to inform detailed cost benefit analysis of the storm water options. Rainwater Tanks Substitution of potable supplies with fit-for-purpose water such as rainwater for toilet flushing, laundry, hot water and garden use is a potential alternative supply arrangement. CHW acknowledges the important role that using rainwater tanks have in conserving urban water supplies. CHW continues to support the use of rainwater tanks through the State Government Water Smart Gardens and Homes Rebates & 5 Star Building Standard requirements. A study carried out for the City of Ballarat, Benefits of rainwater tanks in Ballarat, has revealed that installation of rainwater tanks can potentially reduce household water demand by 20-40%. CHW will continue to work with Council to assess what additional initiatives would encourage existing property owners to retrofit rainwater tanks and the cost benefit compared to other alternative water initiatives. Additional Groundwater Resources Where smaller systems are being totally or partially supplied from groundwater, CHW will continue to monitor localised groundwater opportunities, where water quality is improved or in greater supply. Any additional or revised applications will be managed via the appropriate licenses from Goulburn Murray Water (GMW), Southern Rural Water (SRW) or Grampians Wimmera Mallee Water (GWMW) as the licensing authorities. Water Supply Demand Strategy Amphitheatre System 26