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 Goulburn River?

How was this assessment undertaken in the Goulburn 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.

Comments on Management Responses in the Goulburn River Surface Water Management Area

Current Management Response:

Desired (Current) Management Response:

2020 Management Response:

The developed yield of the Goulburn River Basin has already reached the sustainable limits of the basins surface water resource. This means that any further surface water- based development in the SWMA 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 such as reclaimed water or groundwater.

With effective water resource management, the water resource development status of the basin 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:

The developed yield of the Goulburn River Basin has already reached the sustainable limits of the basins surface water resource. 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 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

Efficacy of the network:

Water Quantity Monitoring Network: The State resource assessment network currently consists of 239 river and stream sites where flows are continuously monitored, 7 unrated sites, 4 rainfall sites and 28 lake level sites. Some of these sites are part- funded by water authorities (primarily rural but some urban) and local councils. State-funded monitoring makes up about 35-40% of all surface quantity monitoring activities in the State.

Over the history of water data collection in Victoria, the aims of State-wide data collection programs have changed from being initially related to providing information for the planning of water resource development projects, to serving a much wider range of user needs.

With the advent of BEs and SMPs, water authorities have been required to undertake additional monitoring to ensure compliance with the provisions of their entitlements and relevant SMPs. This has resulted in some additional funding being made available to support relevant State resource assessment sites and a number of new sites being installed.

As resources become more fully utilised, the need for data and information to ensure their effective management and sustainable use increases. In particular, there is a clear need for long-term continuous records of water resource data at key locations. An important priority is therefore the maintenance and expansion, where necessary, of the surface water quantity monitoring network, in order to continue to improve our understanding of resource availability and guide future allocation and management decisions.

There are 52 gauging stations (including reservoir head gauges and flood warning gauges) in the Goulburn River Basin. A summary of the number of sites by catchment area and the number of sites by length of record is given below. This information was obtained from the Review of Victorias Hydrograph Network (SKM 1996). As this study was undertaken in 1995/1996, some of the figures will have changed, as another 5 years of data are available for most stations, and a limited number of stations ( <10 across the State) have closed.

Number of sites by catchment area (CA, km?) (not including reservoir head gauges and flood warning gauges):

- CA (100km?): 7

- CA (100 - 500)km?: 24

- CA (500 - 2000 km?): 6

- CA (>2000 km?): 12

Number of sites by length of record (LR):

- LR ( <10) 10

- LR (10-20) 9

- LR (20-30) 8

- LR (30-50) 16

- LR (>50) 9

Water Quality Monitoring: There are two major State-wide environmental water quality monitoring programs in Victoria. These are:

- The Victorian Water Quality Monitoring Network (VWQMN), managed by the Department of Natural Resources and Environment (NRE). The VWQMN is contracted out to WATER ECOscience, with funding provided by NRE, four regional water authorities and Melbourne Water.

- A network of fixed sites run and funded by the Environment Protection Authority (EPA).

Extensive water quality monitoring programs are also conducted by Melbourne Water, the Murray Darling Basin Commission (MDBC), various regional water authorities and the State-wide Salinity Monitoring program.

The following water quality issues are of concern in the Goulburn River Basin: nutrients, frequent eutrophication, salinity, turbidity.

The 1996 water quality monitoring review summarise the network in the Goulburn River Basin as follows: A total of 36 sites in the Goulburn catchment:

- 22 sites at which field parameters (EC, pH, temperature, DO and turbidity) are read

- 26 sites at which samples are taken for phosphorous, algal indicators, pesticides, colour and nitrates

- 15 biological monitoring sites.

Data management requirements:

Protective management:

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 Recommendations

Data Availability:

The availability of water use for Level One types of water use is generally good. Information for Level Two types of irrigation water use however, is generally not available. It was necessary to determine crop water use using irrigated crop area data and crop application rates. The crop area data was sourced from the Department of Natural Resources and Environment (Tatura) and the Goulburn Murray Water 1996/97 Annual Report.

The breakdown of the Level One urban/industrial use was generally only available for the following Level Two types of use: domestic, commercial/industrial, and system losses. In some instances system loss information was not available and it was necessary to estimate this as a percentage of the total water diversion. The percentage of loss to diversion was based on available system loss data for other urban water supply systems within the region.

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 were 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

• Victoria Water Resources Assessment 2000 Technical Report
• Link to data available for download on the Surface Water Management Areas
• Link to the Map Maker to make a map using this information.