DEPARTMENT OF PRIMARY INDUSTRIES
Groundwater Management
| Groundwater Management Areas have been established as part of a framework for managing groundwater reserves in Victoria. In 1998, new groundwater management arrangements were put in place to maximise development opportunities, yet ensure that groundwater resources are managed in a sustainable way. These management arrangements included: |
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See also Statewide Groundwater Management and Statewide Groundwater Areas (external link).
Related Links on the Statewide VRO Website
Groundwater Information Notes are available on the DSE website (external link) |
For each GMA, a Permissible Annual Volume (PAV) has been determined. This is the volume of groundwater available for allocation and is based on ensuring the long-term sustainability of the resource. Some GMAs may be divided into a number of zones and a PAV may be set for each one. What's a Megalitre? |
Water Resources Availability and Use
The principal groundwater resources in Victoria lie south of the Great Dividing Range and are contained in Tertiary or younger unconsolidated sediments. Groundwater is highly used within the Gippsland Province. There is extensive extraction for mine de-watering and gas and oil production in the basin, along with intensive agriculture and irrigation.
As part of the National Land and Water Resources Audit (NLWRA), Sinclair Knight Merz (SKM) undertook an analysis of water resources availability and use, on behalf of DSE, for 29 Australian Water Resource Council (AWRC) basins in Victoria. An analysis was undertaken for Groundwater Management Areas (GMAs) and Unincorporated Areas (UAs). GMAs are defined as areas where groundwater development has already occurred or where there is potential for groundwater development. Groundwater Provinces are based on a combination of the principal hydrogeological basins and geological zones within Victoria. The UAs comprise the areas between the GMAs and the Province boundaries. The Rural Water Authorities have the responsibility of licensing all extractions and monitoring use in the GMAs.
The key components of the NLWRA study were:
- Definition of Groundwater Management Units (GMAs). This involved the definition of Groundwater Management Areas in each State and within each groundwater province. Boundaries were defined spatially and according to depth limits based on aquifer extents in each province. Representative bores were also identified for each GMA. Areas lying outside of GMAs within a Province were identified and reported on as Unincorporated Areas (UAs).
- Determination of the sustainable yield. The sustainable yield was determined for each GMA and UA. The working definition for sustainable yield adopted for the project was "the volume of water to be allocated to consumptive users which does not result in long term falling groundwater levels or pressures". This does not include the volume of groundwater set aside for Groundwater Dependent Ecosystems, or any other environmental allocations.
- Determination of allocation volumes and use type. Using licensing information held by the Water Authorities, allocation volumes were determined for each GMA and UA. Information was obtained for different levels of use. Level One types of use included four categories: Urban/ Industrial, Rural, Irrigation, In-Situ (eg. recreational, environmental). Level Two types included the breakdown of each of these categories into further sub-categories, such as irrigation for cereals, grapes, fruits, vegetables, crops, pasture, etc.
- Estimation of the current abstraction of groundwater. This information was obtained from various sources depending on availability of information. Typical sources of information included bore metering, field surveys, local knowledge from water authorities and licensing information.
- Groundwater trend level assessment. Representative monitoring bores were selected for trend analysis of the groundwater levels. This was analysed and comments were provided along with the hydrographic data for the representative bores for each GMA.
- Major abstraction bores. For each GMA major abstraction bores were identified and reported on for average abstractions and 1996/97 abstractions. The use type for the bore was also identified.
- Groundwater salinity assessment. Groundwater salinity levels were reported for each GMA, reporting on the minimum, maximum and median groundwater salinity value in mg/L. Salinity is an important consideration when assessing groundwater resources, much of which is highly saline and has reduced use options because of its quality.
- Categorisation of the resource. Each GMA was categorised into one of four categories that define the current level of water resource development with respect to existing allocation and abstraction.
Category 1: Low level resource development.
Developed Use between 0% and 30% of Sustainable Yield.
Category 2: Minimum level resource development.
Developed Use between 31% and 70% of Sustainable Yield.
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Category 3: High level resource development.
Developed Use between 71% and 100% of Sustainable Yield.
Category 4: Over developed resource.
Developed Use greater than 100% Sustainable Yield.
The Table below summarises the GMA's in East Gippsland in each development category for both abstraction and allocation.
East Gippsland Groundwater Management Area (GMA) Development Categories
GMA | Development Category | |
Abstraction | Allocation | |
Wy-Yung | 2 | 3 |
Seacombe | 4 | 4 |
Sale | 3 | 4 |
Groundwater resources outside the GMAs are referred to as Unincorporated Areas (UAs). These are often inaccessible, or located in State or National Parks and cover large parts of the East Gippsland region. In general, water resources in UAs are often highly saline and of little beneficial use. It is currently unclear whether the UAs in the East Gippsland region are saline or what their potential is for development.
© The State of Victoria, 1996 - 2008.
This document was last reviewed on 25/09/2008