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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: South Gippsland
Introduction
The South Gippsland Basin is the southern most Victorian basin, extending from Westernport Bay in the west to Lake Reeve in the east. It includes Wilsons Promontory National Park and Phillip Island. The Strzelecki and the Hoddle Ranges border it in the north. The basin covers 6,789 km2 (3% of the State). The topography is hilly in the north western and Wilsons Promontory regions; the western and eastern sections are mainly undulating; and there are plains near the eastern coast. The main stream networks are the Bass, Powlett, Tarwin, Franklin, Agnes and Tarra rivers. Within the South Gippsland Basin there are two major storages for domestic water supply:
- Candowie Reservoir is situated on Tennant Creek, a tributary of Bass River, and has a capacity of 2,270 ML. It supplies water to the towns around Western Port Bay and Phillip Island.
- Lance Creek Reservoir is situated on a tributary of the Powlett River, and has a capacity of 1,900 ML. The reservoir supplies the townships of Wonthaggi and Inverloch.
The average rainfall varies from 755 mm at Yarram to 970 mm at Leongatha and 1,083 mm at Tidal River, Wilsons Promontory. The Strzelecki Ranges receive up to 1,500 mm. The mean annual flow of the basin is 851,000 ML, which represents 4.2 % of the total runoff generated in the State.
Major land-uses in the basin include dairying, crops, pigs, cattle and sheep for wool. Tourism also plays an important role, with major tourist destinations including Wilsons Promontory and Phillip Island.
The average annual water use is 11,860 ML; 52 % for urban and industrial use, 35 % for irrigation and the remaining 13% for rural use.
(Note: The reported volume of water used does not account for the volume of reclaimed or returned water).
There are no surface water imports to or exports from the Basin.
Vital Statistics:
| Area: | 6,789 Km2 |
|---|---|
| Total storage volume: | 10,136 |
| Total surface water use: | 11,860 ML/yr |
| Development category: | LOW DEVELOPMENT |
| Mean annual run-off: | 851,000 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.
The sustainable yield of the South Gippsland Basin was determined by calculating the total volume of water that can be extracted from the river system (during May to November) such that the degree of change to the natural flow regime is not unacceptable, as defined by the achievement of a rating of 5 for the Hydrology sub-index of the Index of Stream Condition (ISC). This method is described in further detail in the Victorian Technical Report.
This approach is considered to be relatively conservative, and the estimate of the sustainable yield using this approach should therefore only be considered as an interim measure, pending the outcome of detailed environmental flow assessments.
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 South Gippsland Basin has been reported as low level of development (Category 1) with respect to allocation and diversion.
How saline are the surface water resources in the South Gippsland surface water management area?
Table: Surface water resource by salinity class.
| Total Volume, Divertible Yield (ML/Yr) | |
|---|---|
| Total volume (ML/yr), DIVERSION | 132,870 |
| <500 mg/l (ML/yr) | 132,870 |
| 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) |
|---|---|
| Bellview Creek Reservoir | 454 |
| Little Bass Reservoir | 250 |
| Ness Gully Creek | 105 |
| Hyland Reservoir (3) | 800 |
| Reservoir No 1 | 36 |
| Reservoir No 2 | 182 |
| Western Reservoir (No 4) | 1,137 |
| Battery Creek Storage | 96 |
| Deep Creek Reservoir | 46 |
| Candowie Reservoir | 2,430 |
| Lance Creek Reservoir | 4,600 |
| Total | 10,136 |
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.
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