The report forms part of the CSIRO Murray-Darling Basin Sustainable Yields project it's doing for the Federal Government and the Murray-Darling Basin States.

The project looks at the impacts of climate change and land use change across the basin's 18 regions.

The Barwon-Darling region stretches from northern NSW to Wilcannia on the Darling in the far south west and includes stream flow from a number of upstream regions.

The Barwon-Darling feeds into the nationally important Talyawalka wetlands. The region is home to 50,000 people. The major land use is dryland pasture for beef and sheep grazing. About 63,000ha of land are irrigated in 2000, mostly for cotton.

The report found:

* The current level of surface water use across the Darling Basin measured at Bourke is high at 39pc, which includes use in upstream regions. (Actual use within the Barwon-Darling region itself is much lower.)

* Groundwater use in the Barwon-Darling region is low but is projected to increase 24-fold to 240 gigalitres a year by 2030, taking groundwater use to over 50pc of total water use within the region.

CSIRO's median (or "best estimate") of climate change by 2030 indicates that, compared to historic climate:

* There would be a reduction in average surface water availability of 8pc and a reduction in end-of-system flows of 10pc.

* Total average surface water use would increase 2pc as a result of increased evaporation from on-farm irrigation dams, resulting in a very high relative use of surface water for the Darling Basin to Bourke of 41pc.

More information about the Sustainable Yields project can be found at www.environment.gov.au/water/mdb/ yields.html