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In this section you will find detailed information, including national overviews and state and regional level assessments, from the 2000-2002 National Land and Water Resources Audit theme assessments.
Water resources - Overview - Victoria
Basin & Surface Water Management Area: Ovens River
Introduction
The Ovens River Basin is located in north-east Victoria and covers an area of 7,985 km2, representing 3.5 % of the State. The area extends from the Murray River in the north, to the Great Dividing Range in the south and is bordered by the Broken River Basin in the west and the Kiewa River Basin in the east. The topography of the Basin is diverse ranging from riverine plains near the Murray River and broad alluvial valleys around Myrtleford, to rugged alpine peaks and plateaux around the Great Dividing Range. Mt Buffalo, a large granite massif in the south of the basin, is an important landscape feature.
The main stream network is the Ovens/King River. The Ovens River and its upstream tributaries - the Buckland, Catherine, Dandongadale, Buffalo and Rose rivers - have their headwaters in the great dividing range, in the section extending between Mt Cobbler and Mt Hotham. The King River, situated west of the Ovens River, has it's headwaters on the Great Divide east of Mt Buller. The Ovens and the King Rivers meet on the riverine plain at Wangaratta. The main storages in the basin are Lake Buffalo on the Buffalo River and Lake William Hovel on the King River.
The climate is temperate and average annual rainfall in the Basin ranges from 630mm Wangaratta to 1500mm and 1890mm at Mt Hotham and Mt Buffalo respectively.
The mean annual flow of the basin is 1,692,000 ML, which represents 8.4 % of the total runoff generated within the State.
Major land uses in the Basin include forestry, tobacco growing, viticulture,sheep grazing for meat and wool and beef cattle.
Average annual surface water use is 39,340 ML with urban/industrial representing 23% of total use, irrigation 67%, and rural 10%.
(Note: The reported volume of water used represents the total water consumed within the basin. This estimate of water use does not account for the volume of reclaimed or returned water and does not include water that is allocated for use in other management areas).
Approximately 66% (26,000 ML) of the water consumed in the basin each year is harvested from the Ovens River and its tributaries. The remaining 34% (13,340 ML) is diverted from the Murray River, with private diversions for irrigation and rural water use extending from Hume Dam to Yarrawonga.
There are no water exports from the basin.
Vital Statistics:
| Area: | 7,985 Km2 |
|---|---|
| Total storage volume: | 38,400 |
| Total surface water use: | 39,340 ML/yr |
| Development category: | FULL DEVELOPMENT |
| Mean annual run-off: | 1,692,000 ML/yr |
A four-class classification system was developed to provide a simple method to communicate the status of the use and allocation of Australia's water resources in relation to sustainable water management.
It is important to recognise that adequately quantifying a sustainable flow regime or sustainable yield and consequent operating rules is a complex matter. State, Territory and scientific agencies continue to develop and apply methods and measures for determining sustainable flow regimes and sustainable yields.
This categorisation provides a general guide only. Please refer to the State and Territory Overview and Technical reports for detail on the analysis methods used.
| Category | Development status | ||
|---|---|---|---|
| 1 | <30% | Low development | |
| 2 | 30 - 70% | Moderate development | |
| 3 | 70 - 100% | Highly developed | |
| 4 | 100% | Overdeveloped |
* Water use as a percentage of sustainable flow regime (surface water) and sustainable yield (groundwater)
PLEASE NOTE:
Sustainable Yield:
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.
Within the Murray Darling Basin, sustainable yields were determined in the context of the 1996 agreement to cap diversions within the Basin at 1993/94 levels of development. By ensuring that diversions in the Murray-Darling Basin will not increase, the Cap protects the security of supply of existing users at a regional scale while, in effect, defining the remaining water as an environmental allocation. The sustainable yields for the SWMAs located within the Basin were reported as the average annual diversions from each SWMA with the Cap in place. The average annual diversions were estimated using water resource allocation models (REALM) of the relevant water supply systems. It should be noted that the Cap is a critical first step in countering ecological degradation. To halt degradation fully it may need to be lowered (and therefore sustainable yields may need to be redefined), but it is too early to tell whether this is the case.
This approach assumes that the current environmental water provisions represent the maximum volume of water that can currently be made available to the environment after consideration is given to the rights of existing users, and related social and economic impacts. In some situations these provisions may not fully meet the environments requirements.
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.
PLEASE NOTE:
Categorisation:
The categorisation of SWMAs in terms of the current level of water resource development has been determined with consideration given to the level of allocation and actual diversion of the resource relative to the assessed sustainable yield.
Five development categories have been defined:
Category 1: Low level of development: 0-30% Category 2: Medium level of development: 31-70% Category 3: High level of development: 71-99% Category 3*: Fully developed: 100% Category 4: Over allocated/used resource: >100%
The development category for the Ovens River Basin been reported as fully developed (Category 3*) with respect to both allocation and diversion. This is consistent with the Murray-Darling Basin Cap, which sets the average allocation to equal the volume of water that would have been diverted under 1993/94 levels of development. 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).
How saline are the surface water resources in the Ovens River surface water management area?
Table: Surface water resource by salinity class.
| Total Volume, Divertible Yield (ML/Yr) | |
|---|---|
| Total volume (ML/yr), DIVERSION | 664,000 |
| <500 mg/l (ML/yr) | 664,000 |
| 500 mg/l (ML/yr) - 1500 mg/l (ML/yr) | no data |
| 1500 mg/l (ML/yr) - 5000 mg/l (ML/yr) | no data |
| 5000 mg/l (ML/yr) - 14000 mg/l (ML/yr) | no data |
| > 14000 mg/l (ML/yr) | no data |
Major water storages
Table: Major water storage areas:
| Storage name: | Capacity (ML) |
|---|---|
| Kerferd | 900 |
| Buffalo | 24,000 |
| William Hovell | 13,500 |
| Total | 38,400 |
Further Information
- View the Victoria Water Resources Assessment 2000 Report
- View the Victoria Water Resources Assessment 2000 Technical Report
- Link to data available for download on the:
- Surface Water Management Areas
- Data from the 1985 Review of Australia's Water Resources and Water Use
- Link to the Map Maker to make a map using this information.
- For more information about water and other natural resource issues link to www.dse.vic.gov.au