Water resources - Management and Development - Victoria
Basin & Surface Water Management Area: Werribee River
Introduction
As resource demands and pressure increases so to do the requirements of both management and information needs. Outlined below are the key issues facing the region as determined by the State / Territory water management agency.
What is the estimated demand for surface water in Werribee River?
| Use and Sustainable Yield | |
|---|---|
Comment about sustainable yield figure: | While Victoria has a variety of programs under way aimed at identifying, improving and protecting environmental water requirements, the necessary investigations take considerable time and resources. Given the short time frame of the Audit, it was necessary to make some broad assumptions, and use a variety of approaches, to derive estimates of the sustainable yield for surface water management areas (SWMAs) in Victoria. Consideration was given to environmental water requirements (known and likely), existing user rights, and related social and economic impacts. The reported allocations to the environment represent the water that can currently be maintained or made available in an attempt to meet environmental water requirements. For surface water management areas in the southern part of Victoria where environmental values could potentially be threatened by further allocations, the sustainable yield was limited to the current allocation volume (or developed yield), pending the outcomes of further detailed investigations of environmental water requirements. For the Werribee River Basin the sustainable yield has been reported as equal to the developed yield. In the longer term, there may be further scope for freeing up additional water to improve environmental regimes by improving distribution and water use efficiencies (other options for improving environmental regimes will be considered as part of the Victorian River Health Strategy). In SWMAs where a significant portion of the available resource is committed to a downstream SWMA, there is also potential for trading of entitlements between the two SWMAs. This will result in a change to both the sustainable yield and the environmental allocation in both SWMAs. Trade out of a SWMA would decrease the sustainable yield of the SWMA and a trade of water rights into a SWMA would increase the sustainable yield. However, the sum of the sustainable yields for the two SWMAs would remain unchanged. |
Sustainable yield (ML/yr): | 35,900 |
Threshold year for sustainable year: | 2005 |
Diversion Volume 1996 (ML): | 32,250 |
Current resource development categorisation: | HIGH DEVELOPMENT |
| Estimated in 2020 | |
|---|---|
Estimated use in 2020(ML): | 35,900 |
% change from 1996: | -56 |
Resource development categorisation: | HIGH DEVELOPMENT |
| Estimated in 2050 | |
|---|---|
Estimated use in 2050(ML): | 35,900 |
% change from 1996: | -56 |
Resource development categorisation: | HIGH DEVELOPMENT |
How was this assessment undertaken in the Werribee River Surface Water Management Area?
Development Potential:
For the purposes of the Audit, an assessment of development potential in terms of the potential for increased use of water within each SWMA and GMA is required, together with estimates of developed yield and forecast use for the years 2020 and 2050. It should be noted that there is an important distinction to be made between this assessment of the volumetric development potential and the potential for further increases in water-based economic activity (the economic development potential), which also involves a consideration of the ability to acquire water via trading and via improvement in distribution and on-farm use efficiency. (See the State Overview Report (Table 8 and Maps 7 and 8 for rankings of each SWMA in terms of both the volumetric and economic development potential.) In the case of surface water, in some SWMAs increases in use can be accommodated without further development of infrastructure, but in others no further development is possible without new storage development. A state-wide investigation into potential dam sites for further surface water development was completed by the Rural Water Commission in 1986 (Alexander and Haydon, 1986). The sites identified in this study are still relevant today. Of the 143 potential dam sites identified, 73 were selected for detailed analysis. Site locations were restricted to high yielding streams with a salinity less than 1600 EC (1000 mg/L). Two different approaches were used to estimate the annual yield from the new storages - statistical equations and simulation modelling. Following a pilot study, the use of statistical equations was adopted as the preferred approach - in particular the Equivalent Storage Method (ESM). This method enabled storages in series to be accounted for. Annual yield for the various storages was estimated assuming:
- 95% supply security;
- an urban demand pattern;
- 20% storage capacity reserved for dead storage and drought security carryover.
Estimates of the annualised costs of supply from new storage sites were based on the capital costs estimated by Alexander and Haydon (1986), indexed to 1996, plus the estimated costs of water treatment (if required) and the necessary trunk mains and reticulation. It should be noted that Alexander and Haydons capital cost estimates (expressed in terms of $ per ML of incremental yield) were based on the volume of the dam embankment, catchment area and a parameter obtained from a relationship derived using existing dam embankment construction costs. Costs associated with spillway construction, road construction, and land purchase were not taken into account in the cost equation.
Estimated Use:
A computer model was developed to forecast annual water demands and water use and the likely sequencing of future yield developments (surface and groundwater) in each SWMA. The application of this simulation model enabled a consistent approach to be applied across all SWMAs.
Total demand was considered as comprising three principal sub-components - domestic, industrial/commercial and irrigation - with priority for supply being allocated in that order. In making predictions, a distinction was made between future demand and future use, with demand being considered to be the unrestricted demand for water, and use being the amount of water that could realistically be expected to be supplied to meet forecast demand, after various constraints on supply have been taken into account.
Initially, unrestricted demand was computed based upon an exponential growth curve, the derivation of which is described in detail in the State Technical Report. This was then restricted according to the estimated consumer response to price change associated with the costs of providing water from new system augmentations (in the case of surface water) or new groundwater sources. The price correction used to restrict demand varied according to the consumer group. It was assumed that water sources (surface and groundwater) would be sequentially exploited to meet demand according to the lowest economic cost, and taking into account specified acceptable salinity ranges for each type of use.
Where these forecast restricted demands in 2020 and 2050 exceeded current estimates of sustainable yield, forecast use was restricted to the sustainable yield. The developed yield at 2020 and 2050 was based on the estimated yield from the sources being exploited to meet forecast use for those years.
The estimates generated from this study should be used as indicative only. Limitations exist in the model conceptualisation and in the assumptions that were adopted. In particular, the model results only reflect potential increases in water use achieved through increased water diversion. No allowance is made for the future impacts of water trading, or improved distribution and on-farm water use efficiencies.
Developed Yield:
A computer model was developed to forecast annual water demands and water use and the likely sequencing of future yield developments (surface and groundwater) in each SWMA. The application of this simulation model enabled a consistent approach to be applied across all SWMAs.
Total demand was considered as comprising three principal sub-components - domestic, industrial/commercial and irrigation - with priority for supply being allocated in that order. In making predictions, a distinction was made between future demand and future use, with demand being considered to be the unrestricted demand for water, and use being the amount of water that could realistically be expected to be supplied to meet forecast demand, after various constraints on supply have been taken into account.
Initially, unrestricted demand was computed based upon an exponential growth curve, the derivation of which is described in detail in the State Technical Report. This was then restricted according to the estimated consumer response to price change associated with the costs of providing water from new system augmentations (in the case of surface water) or new groundwater sources. The price correction used to restrict demand varied according to the consumer group. It was assumed that water sources (surface and groundwater) would be sequentially exploited to meet demand according to the lowest economic cost, and taking into account specified acceptable salinity ranges for each type of use.
Where these forecast restricted demands in 2020 and 2050 exceeded current estimates of sustainable yield, forecast use was restricted to the sustainable yield. The developed yield at 2020 and 2050 was based on the estimated yield from the sources being exploited to meet forecast use for those years.
The estimates generated from this study should be used as indicative only. Limitations exist in the model conceptualisation and in the assumptions that were adopted. In particular, the model results only reflect potential increases in water use achieved through increased water diversion. No allowance is made for the future impacts of water trading, or improved distribution and on-farm water use efficiencies.
Management goals and objectives:
The Victorian Government is committed to ensuring the sustainable use of all water resources. The water reforms that have been undertaken to date in Victoria and the management initiatives currently underway (which are all consistent with the national water reform agenda) provide a sound foundation for ensuring the sustainable management of the States water resources into the future. Continued commitment and effort are required to complete these initiatives over the next five to ten years or so.
The Governments overall aims, broadly stated, are, by continuing to work within a consultative framework with all stakeholders, to maintain reliable supplies for water users, to improve the efficiency of use of the resource and the delivery of water services, and to ensure that the environmental values of rivers and wetlands are sustained and restored where necessary.
More specifically, management goals and objectives can be defined as follows:
- To fully implement an effective and equitable system of water allocation which recognises the sustainable limits of our water resources, provides adequately for both the environment and consumptive uses, and establishes clearly defined, tradeable property rights for water users which allow the movement of water to meet community needs.
- To improve the efficiency of water markets and facilitate water trading through full implementation of bulk entitlements, the refinement of trading rules, the development of more sophisticated water products, the development of inter-state trade, and further development of the regulatory framework as water markets grow.
- To protect and, where necessary restore, the condition of our rivers and catchments (recognising the strong interactions between land and water management) to balance the economic, social and environmental needs of current and future generations.
- To ensure efficient delivery of water supplies and efficient use of existing water resources in urban and rural areas.
- To promote opportunities for new sustainable water-based development where resources are currently under-utilised or where resources are made available via efficiency savings.
- To ensure the full implementation of a pro-active risk management approach for dealing with droughts in both the urban and rural water sectors.
- To ensure the continued development of our knowledge base and planning and management tools to support the sustainable management of a finite resource.
- To fully implement an effective Statewide policy, regulatory and institutional framework for the delivery of water services which ensures open and transparent decision making, clear accountabilities and responsibilities, customer focused and efficient service delivery, fair pricing, and community involvement in decision making.
See VIC Water Resources Assessment 2000 Report and Water Resources Assessment 2000 Technical Report for comment on methods and assumptions.
| Current 2000 | Desired 2000 | Desired 2020 | Desired 2050 | |
|---|---|---|---|---|
Management information | ||||
Scale of allocation planning | CATCHMENT | SUBCATCHMENT | SUBCATCHMENT | SUBCATCHMENT |
Inputs to allocation | MODELLING AND RESOURCE | DETAILED RESOURCE INVESTIGATION | DETAILED RESOURCE INVESTIGATION | DETAILED RESOURCE INVESTIGATION |
Type of monitoring - quantity | COMPREHENSIVE MONITORING | COMPREHENSIVE MONITORING | COMPREHENSIVE MONITORING | COMPREHENSIVE MONITORING |
Type of monitoring - quality | COMPREHENSIVE MONITORING | COMPREHENSIVE MONITORING | COMPREHENSIVE MONITORING | COMPREHENSIVE MONITORING |
Distribution efficiency (H,M,L) | HIGH | HIGH | HIGH | HIGH |
Use efficiency (H,M,L) | MEDIUM | HIGH | HIGH | HIGH |
Resource management efficiency (H,M,L) | NA | NA | NA | NA |
Degree of licensing | ALL MAJOR USES | ALL USES | ALL USES | ALL USES |
Water trading (None, Limited, Significant) | SIGNIFICANT | SIGNIFICANT | SIGNIFICANT | SIGNIFICANT |
Mechanism of trading | Permanent & Temporary | |||
Volume traded (ML/yr) | 0 | no data | no data | |
Number of transactions | 5 | |||
Inter-basin transfers | NONE | NONE | NONE | NONE |
Volume transferred (ML/yr) | 0 | no data | no data | |
Environmental allocation category:
| no data |
Comments on Management Responses in the Werribee River Surface Water Management Area
Current Management Response:
Desired (Current) Management Response:
2020 Management Response:
It has been forecast that by 2020 water use in the Werribee River Basin will have reached the sustainable limits of the basins surface water resources. This means that any further surface water-based development in the Basin can only be achieved via trading of water rights, via water savings achieved through improvements in distribution and water-use efficiency, or via use of alternative sources of water (e.g. reclaimed water).
With effective water resource management, the water resource development status of the Basin (with respect to surface water allocation) will remain as a Category 3* (fully developed) and will not move to an overdeveloped state.
The Victorian Government is committed to achieving a balance between extractive use and environmental requirements for all of the States rivers and streams. The Government intends, by continuing to work within a consultative framework with all stakeholders, to maintain reliable supplies for water users, ensure the environmental values of rivers and wetlands are sustained and restored where necessary, and to improve the efficiency of use of the resource. This will require operating smarter - using water more efficiently, cutting out waste and putting water to its most productive use. The sustainable management of surface water resources will also require all water users to be accountable for the impacts of ther use, providing for mitigation of any current (or future) adverse impacts on the environment or community.
The policies and actions for managing water resources will necessarily evolve and mature over time. An integrated planning and management approach will be required that covers all aspects of the water system including catchment management, water supply, use, and disposal of water, with a view to maximising the benefits of water use while maintaining healthy catchments, rivers and streams.
The key components of the likely future focus for resource management activities are described below:
Policies and mechanisms for water management. An integrated package of policies and mechanisms is required. Policies governing the allocation and use of water should strongly encourage efficient water use to meet agreed standards. Systems should be in place to facilitate the transfer of water rights, so that water can move to more efficient and productive uses.
Demand management. Water consumption patterns and the level of demand for water can be modified through a variety of demand management methods that include:
- Structural methods employed by the consumer or water authority, such as the use of water-efficient appliances, rainwater tanks, and leakage minimisation.
- Operational methods used by the water authority, such as pressure reduction, or changing the security of supply.
- Economic methods, including pricing policies, incentives and penalties.
- Socio-political methods, involving education, and improved building codes.
- Statutory methods, that can involve changes to policy affecting the allocation and use of water resources.
Developing alternative water resources. In some cases, the use of reclaimed municipal effluent, stormwater, irrigation drainage or desalinated water may be more economical than developing new raw water sources. Their use is also likely to provide environmental and social benefits.
Community education. All of the previous initiatives should be underpinned by community education aimed at raising the awareness of water consumers of the need for improved water use efficiency. Improvements generally will
not occur unless people recognise the need for, and benefits of, change. While improving water use efficiency is very important in the irrigation industry, there is also considerable scope for improvements in the urban and industrial sectors. Education on the technologies and methods available for improving efficiency should be coupled with the provision of information on security of water supply, drought risks and property management planning.
2050 Management Response:
It has been forecast that by 2050 water use in the Werribee River Basin will have reached the sustainable limits of the basins surface water resources. This means that any further surface water-based development in the Basin can only be achieved via trading of water rights, via water savings achieved through improvements in distribution and water-use efficiency, or via use of alternative sources of water (e.g. reclaimed water).
With effective water resource management, the water resource development status of the Basin (with respect to surface water allocation) will remain as a Category 3* (fully developed) and will not move to an overdeveloped state.
The key components of sustainable surface water management into the future is described under the management response for the Year 2020.
See VIC Water Resources Assessment 2000 Report for comment on management responses.
Assessment of Monitoring
Data management requirements: Data management requirements for water quantity and quality data include: - Easy access to data and information (interpreted data); - Rapid access to information for management purposes for stakeholders and resource managers; - User friendly interfaces to databases; - Fast interpretation and reporting of results; - Consistent sampling and analytical methodology and records of past changes to these. Historically, data from the States stream gauging network has been managed by the various incarnations of the former Rural Water Corporations hydrographic section and stored on a HYDSYS data base. Data and information from the various water quality networks throughout the State were managed and reported more or less independently with only a limited amount of interaction between networks. In the review of the Victorian Water Quality Network, conducted in 1996 (NRE, 1996), the following conclusions on network information management were listed: 1. A consistent compatible approach to future data management, through a common database or well-defined links between databases is important. To facilitate the use of the data other features could include: - electronic availability of, and access (via the internet) to data, summaries and reports for all clients; and - links to other databases on landuse, catchment characteristics, and demographics. 2. Improved reporting is required. Reporting needs to be more informative and current, incorporate comprehensive analysis of data, and provide more graphic presentation of information in a format that is readily interpretable by the broader community. 3. A standard site numbering systems needs to be introduced so that all contributors to the network use the same system. 4. Linking the database with a Geographic Information System would be desirable to enable easy interpretation of data. 5. Double-handling of data needs to be minimised and quality assurance procedures for data management maintained, monitored and reported on. Following this review, the Victorian Government acted to improve data management and the accessibility of data and information by developing and launching the Victorian Water Resources Data Warehouse on-line, which provides access to water quality and quantity data. (Web site address: http://www.vicwaterdata.net/). The data is accessible in an interactive, easy to use form over the internet, providing for direct queries of the monitoring data, along with a range of interpreted reports and summary information. The site will be maintained and expanded to incorporate marine, biological, groundwater and community monitoring information over the next year, effectively providing a one-stop-shop for access to all the water resource monitoring data collected in the State. Regional Monitoring Partnerships There is scope to improve the efficiency and service delivery of the current monitoring programs through greater coordination of the various monitoring activities undertaken around the State by different Government departments and agencies (State and Commonwealth), water authorities, and Catchment Management Authorities. A process to ensure such coordination has been initiated and involves the development of monitoring partnerships in specific regions of the State. These monitoring partnerships entail all parties currently undertaking any monitoring of water quantity and water quality in a region clarifying and coordinating their monitoring requirements and developing a single monitoring contract. This partnership process has been initiated in the Gippsland region and it is intended to develop three or four further partnerships to cover the entire State. All data collected as part of a monitoring partnership will be stored and managed as part of the State Water Resources Data Warehouse Protective management: The Heritage Rivers Act 1992 (Vic.) provides for the protection and management of all nominated heritage rivers (HAs) and natural catchment areas (CAs). Administration of the Act is the responsibility of the Minister for Environment and Conservation. The Act: ? identifies 18 heritage river and 26 natural catchment areas; ? specifies management principles for heritage river and natural catchment areas; ? requires management plans to be prepared for all heritage rivers and natural catchment areas; ? identifies activities not permitted in nominated heritage river and natural catchment areas; ? overlays but does not alter existing land tenure, although it may require changed management goals for maximum protection of special values; ? prevents the disposal of unalienated Crown land without the approval of the Minister. Heritage river areas are defined as being a substantial part of a river system with outstanding nature conservation, recreational, scenic and/or cultural heritage values. The heritage river area includes the stream-bed and banks and a 200 m wide strip beside each stream bank, or the public land water frontage, or as otherwise mapped. Seventeen heritage rivers have been defined under the Act, the total length of these rivers being 2000 km, which is just over 3% of the length of the named streams in Victoria. These defined segments of rivers vary from those with particularly high natural values, to regulated systems with high cultural, scenic and recreational values. The 26 natural catchments all lie either within State forest or national park. They have remained effectively free from disturbance and, consequently, physical and biological processes are essentially unimpaired in these catchments. The aim of management for these catchments is to retain them in their essentially natural condition. For each of the HAs the Act prescribes a variety of general restrictions on land and water uses tailored to the particular circumstances. These can include: - no impoundments, artificial barriers or structures are to be constructed; - no new water diversions; - new water diversions not to significantly impair attributes of area; - no timber harvesting. For CAs the following land and water uses are not permitted: - clearing of indigenous flora - harvesting of timber - establishment of plantations - mining - mineral exploration (except in accordance with recommendations of the Land Conservation Council (LCC)) - extractive industries - construction of new water storages or new water diversions - carrying out of waterway management - grazing of domestic animals - making of new roads or the upgrading of existing roads - discharging of effluent - introduction of non-indigenous species of fauna - stocking of the area with indigenous fauna, except for the purpose of conserving an indigenous species of fauna which would otherwise be at risk - use of powered water craft More specifically tailored requirements for land and water management are also prescribed in the Act for some HAs and CAs. Section 8 of the Heritage Rivers Act requires management plans to be prepared for each heritage river and natural catchment area. These plans provide a framework for the long-term management of these areas and set out a process to meet the requirements of the Heritage Rivers Act. One Heritage Rivers is located within the Werribee River Basin - Lerderderg River HA The restricted land and water uses in the Lerderderg River HA include: - new water diversions not to significantly impair attributes of area. - no timber harvesting. In addition, the following specific land and water uses are also specified in the Act: - New impoundments, artificial barriers, or structures that impede the passage of in-stream fauna, or diversions of water from the river only be permitted if their volumes, timing, construction, and release regime do not significantly impair riparian vegetation quality or scenic landscape value. There are no natural catchments listed under the Act that are located within the Werribee River Basin. Options for monitoring: On a national scale, there is currently: - no systematic approach for water resource data collection, analysis, comparibility, storage and reporting; - no national system that links surface water and groundwater information and water quality and quantity information; and - limited comparibility of definitions and approaches for resource management concepts such as environmental water provisions and sustainable flow regime; - limited understanding of the impact of land use practices, such as farm dams and afforestation, on catchment yield; and - limited knowledge of surface water/groundwater interaction and conjunctive use potential. To address these issues, activities required at a national level include: - Implementing an effective national reporting system for water resource data that will enable the status and trends in water resource development and management to be tracked and reported; - Developing a consistent Australia-wide approach to determining sustainable flow regimes for surface water and sustainable yields for groundwater; - Developing a consistent approach for integrating groundwater management with surface water management; - Establishing systems for the benchmarking and continued monitoring of stream condition and environmental flow outcomes; - Establishing a science capacity which will enable the development of innovative and effective land and water management systems. At a State scale, priority activities include: - Maintenance and expansion, where necessary, of surface and groundwater monitoring networks to improve our understanding of the quantity and quality of our water resources to to ensure that allocation and management decisions are soundly based; - Continued development of the State Data Warehouse to ensure that all water related data and associated information products are readily available to water and catchment managers and the wider community; - Improved understanding of environmental water requirements so that recommendation s can be made for environmental flow regimes which will sustain river health with a high degree of certainty; - Improved understanding of the linkages between surface and groundwater systems, with a view to developing management regimes that allow for the conjunctive use of these resources; - Improved ability to predict the impacts of land use change and management practices on surface water and groundwater availability and quality at a catchment scale. See VIC Water Resources Assessment 2000 Technical Report for an assessment of monitoring Data Availability, Gaps and RecommendationsData Availability: The availability of water use and water resource data for Level One types of water use is generally good. Non-Metropolitan Urban Water Authorities were able to provide a breakdown of the Level One urban/industrial use for the following Level Two types of use: domestic and industrial/commercial and system losses. Irrigation use data was not available from Southern Rural Water for the Werribee River Basin. An estimate of the total volume of water used was produced by using irrigated crop area data, sourced from the Australian Bureau of Statistics 1996/97 census information, and crop application rates. The breakdown to Level Two types of irrigation use was also determined using irrigated crop area data and crop application rates. Metered records of usage by private rural water diverters are not available. In all SWMAs it was assumed that rural water use represents 90% of the license volume. Water allocation data, water quality information and gauged flow data at key sites within the basin are all available. Current Gaps and Recommendations: Data Gaps: - Rural and irrigation (Level Two) water use. - Accurate assessments of system distribution losses. - Adequate understanding of the relationship between flows and river ecosystems. - Adequate assessment of environmental flow requirements. - Adequate information regarding surface/groundwater interaction. - Adequate knowledge of the impact of farm dams and climate change on catchment yield and hydrology. - Adequate stream gauging information to enable the assessment of the streamflow regime under natural flow conditions. Recommendations: - Maintenance and expansion, where necessary, of surface water monitoring networks to improve our understanding of the quantity and quality of our water resources to guide future allocation and management decisions. - Improved data on the components of surface water use, including crop types, irrigated areas, and related user management decisions. - Improved understanding of environmental water requirements so that recommendations can be made for environmental flow regimes which will sustain river health with some degree of certainty. - Development of a consistent methodology for the assessment of environmental flow requirements for use in all water allocation processes. - Improved understanding of the linkages between surface and groundwater systems, with a view to developing management regimes that allow for the conjunctive use of these resources where a high degree of linkage is present. - Improved understanding of the risks associated with climate change and the implications for sustainable yields and the security of surface water supplies (particularly during droughts) and the viability of irrigated agriculture on a regional basis. - Improved understanding of the cumulative impacts of farm dams on streamflows. - Improved ability to estimate surface water flows in ungauged catchments. Future Gaps: Annual forecasts of surface water use over the next 50 years were generated using a simulation model that considered the available water resources, their quality, and the economics of their development. Limitations associated with a modelling approach exist in the accuracy and reliability of the input data, as well as the model conceptualisation itself. The majority of the model inputs were derived as part of Project One, and for the purpose of this modelling exercise, were considered generally reliable. However, this study would have benefited from more detailed data for estimation of the consumer price elasticity of demand (in all sectors). In regards to model conceptualisation, two key limitations are recognised. Firstly, the model is resource development orientated. That is, it satisfies continued growth in demand by developing additional resources. This has been the traditional approach to water resource management. However, it is anticipated that with higher costs associated with developing new water resources and generally fewer resources available to be developed, the approach is increasingly shifting to demand orientated solutions; that is, demand management. These solutions revolve around more efficient use of existing water resources, particularly in water intensive agriculture where large savings can be achieved by improving distribution and irrigation efficiencies. Alternative pricing structures can be used to provide rational incentives to increase investment in water saving technologies that cost less than the development of new supplies. It is difficult, however, to account for such factors in a regionally based model that is driven by demand projections, particularly over a 50 year period. Secondly, the model is spatially inexplicit. This means that water demands can be supplied from anywhere within the study SWMA, irrespective of the location of the source relative to the demand centre. The model allows water resources to be preferentially developed on the basis of water quality and cost (i.e. the cheapest source having the required quality is developed first. Consequently, it is possible that the model may develop an inexpensive groundwater resource for distant consumers that have a local, but conceptually more expensive, surface water resource. This limitation may be overcome by modelling portions of the SWMA that are fragmented in line with smaller regional demand areas. Nonetheless, while the simulated process of resource selection may not always be realistic, importantly the forecasts of overall water use are considered reliable. Despite the limitations acknowledged above, the model provides a useful insight into the opportunities that remain for system augmentation, as well as forecasts of the likely upper limit to water use. It is considered that limited value would be gained by making further improvements to the model conceptualisation. Given the highly developed status of most of Victorias water resources, the key to meeting future demands is more efficient and productive use of existing resources. As described in the State Overview Report, in addition to water trading, the Victorian Government has a number of initiatives underway to promote the more efficient use of existing resources. See VIC Water Resources Assessment 2000 Technical Report for a review of data availability,gaps and recommendations. Further information
NewsletterWhat's newNew 'Land Use of Australia, Version 3' data showing irrigation, agriculture and landuse for the years 1992, 1993, 1996, 1998, 2000 and 2001 have been added to the Map Maker. Australian Water Resources 2005 data has been added to the Map Maker. Key
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