Surface water sustainable yield

Surface water sustainable yield volumes have been identified in this assessment for approximately one sixth of the surface water management areas in Australia .

For the remaining surface water management areas either:

• sustainable yield volumes have not been assessed, or
• they are considered an inappropriate method by which to assess sustainability of the resource.

Where the volumes have been identified, they are shown in the accompanying map. Where volumes have not been assessed, a qualitative assessment of the sustainability of the resource has been made relative to the caps (refer to Management of surface water caps section). The methods used to determine sustainable yield are detailed in the table below.

Method for determining surface water sustainable yield (where assessed)

Australian Capital Territory

The Australian Capital Territory has defined its sustainable yield volume on the basis of monitoring and modelling of long-term runoff and then setting aside environmental water in accordance with Environmental Flow Guidelines.

New South Wales

About 80 per cent (39 of 49) of New South Wales ' surface water management areas have had sustainable yields assessed. Eleven of the surface water management areas in New South Wales have sustainable yields greater than 100 gigalitres per year, eight of which have been assessed with the use of computer modelling (IQQM). These surface water management areas are all highly developed and have been investigated thoroughly. These modelled sustainable yield volumes are believed to have a high level of accuracy. The other 31 sustainable yield volumes are less accurate, having been derived from crop statistics and application rates.

Northern Territory and Western Australia

Sustainable yields have been determined for all surface water management areas in the Northern Territory (40 areas) and Western Australia (44 areas) using a provisional approach through state or territory-wide policy. Interestingly, these are two of the states and territories where water resource management is dominated by groundwater issues. Two thirds of the surface water management areas in the Northern Territory and 17 surface water management areas in Western Australia have sustainable yields in excess of 100 000 megalitres per year.

Queensland

Queensland has not assessed sustainable yield volumes for surface water management areas, but has advised that the resource is managed through the use of indicators and trigger levels to achieve sustainable allocation of the resource.

South Australia

Seven surface water management areas have defined a sustainable surface water yield in South Australia. This low number of sustainable yield volumes is a result of the planning process: South Australia has recently redefined its surface water management area boundaries and most surface water management areas have not been prescribed, nor has a water allocation plan been prepared. The State Water Plan provides a statewide default position for all unincorporated surface water areas, but more specific rules can apply in catchment water management plans. Catchment water management plans were in place in 200405 for most of the higher rainfall areas of the state (excluding Kangaroo Island ).

Tasmania

Thirty-two of Tasmania 's 48 surface water management areas have had sustainable yields assessed (16 have not). Fifteen of these surface water management areas have yields greater than 100 gigalitres per year. Sustainable yield estimates are not available for surface water management areas managed by Hydro Tasmania.

The sustainable yield volumes are mostly set through modelling or other analytical techniques. In 13 surface water management areas, a combination of digital elevation modelling and the Australian Water Balance Model were used to derive yields at catchment outlets. The resulting sustainable yield calculations can be seen on the water management plans. Sustainable yield in remaining surface water management areas where the Australian Water Balance Model has not been applied or a water management plan has not been completed is determined by basic hydrological modelling that estimates the sustainable yield of the surface water management area.

Victoria

Victoria has calculated sustainable yield volumes for 27 of its 29 surface water management areas. The Victorian Department of Sustainability and Environment does not consider the single sustainable yield figure as a meaningful measure of sustainable volumes for Victoria 's surface water management areas.

The accompanying map shows the volumes of those sustainable yields for each jurisdiction.

Sustainable yield - surface water July 2004 - June 2005

Download high resolution Map:

Sustainable yield - surface water July 2004 - June 2005 (1.6 Meg)

(this document requires the use of Adobe Acrobat Reader )

Interactive Maps:

Click on the links below to create and customise your own versions of the maps (e.g. add or remove layers) using the Map Maker tool on the Australian Natural Resource Atlas website:

• ANRA Map Maker Surface Water data

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