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Commonwealth environmental water in the Barwon-Darling catchment
Options for Commonwealth environmental water use in 2012-13
Annual Water Use Options 2012-13: Northern Murray-Darling Basin Unregulated Rivers identifies potential Commonwealth environmental watering actions for 2012-13.
Annual Water Use Options 2012-13: Northern Basin Unregulated Rivers – Fact Sheet summarises the approach and some of the options for using Commonwealth environmental water, as well as identifies how anyone may provide suggestions for use of environmental water.
Environmental watering in the catchment in 2011-12
There was no use of the Commonwealth's Barwon-Darling holdings in 2011-12 due to the development of water shepherding arrangements. Unused account balance has been carried over for use in 2012-13 or beyond. Under proposed Water Sharing Plan arrangements, there are no limits on carryover of unused account balances.
Environmental watering in the catchment in previous years
Darling River flows peaked in 2010-11 in late March following the third largest flood in the last 25 years. Commonwealth environmental water was used to complement these flows with 7.6 gigalitres used to provide river flows in the Darling River to Menindee Lakes and contribute to flows downstream of Menindee Lakes to the Darling Anabranch. The watering action in the Darling Anabranch was arranged in response to a proposal from an interested landholder and provided for environmental water from the Commonwealth, the Living Murray program and the New South Wales government to create a flow down the Great Darling Anabranch and connect to the Murray River. This was the first time that the Anabranch had received significant flows in over a decade. The Commonwealth's contribution to these flows were absorbed in the Anabranch by streams and wetlands.
For further information about the Commonwealth environmental watering in the Barwon-Darling and the outcomes achieved, please refer to the Commonwealth environmental water Outcomes Reports and Annual Reports.
Where is it?
The Barwon-Darling River flows in a south-westerly direction from the north-east region of the NSW-QLD border. The catchment includes the Barwon River from Mungindi to the confluence of the Culgoa River near Brewarrina (where the Barwon becomes the Darling River) and the Darling River to the Menindee Lakes. The Darling River drains Queensland's Darling Downs via the Condamine-Balonne and Warrego rivers. This catchment is representative of a large Australian dryland river system. Key characteristics include its low gradient and large floodplain, climatic variability and arid to semi-arid conditions.
Covering 45,510 km2 or 4.4 per cent of the total area of the MDB, the Barwon-Darling catchment is bounded to the west by the Bulloo catchment and receives flow from the Paroo, Warrego and Condamine-Balonne rivers in the north and west, and the Moonie, Border Rivers, Gwydir, Namoi and Macquarie-Castlereagh Rivers to the east. While the Barwon-Darling River itself is unregulated, many of its tributaries are regulated.
What makes this place so special?
The Barwon-Darling catchment is an ecologically significant area because it includes:
- wetlands along the river such as Wongalara Lake, Poopelloe Lake, Lake Woytchugga, Acres Billabong, Talyawalka Anabranch and Teryawynia Creek wetlands and several deflation basin wetlands (geological depressions formed by erosion when soil is shifted by the wind)
- major waterbird breeding habitat sites at lakes and other wetlands along the floodplain which are watered at a variety of flows
- the Barwon-Darling River channel and associated riparian habitats which support a wide variety of ecosystems and a number of fish species, including bony herring and golden perch
- a diverse range of flora species, including river red gum, black box, river cooba, coolabah and lignum
- fauna including species listed under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) such as Murray cod, Latham's snipe, rainbow bee-eater and superb parrot, and the NSW Threatened Species ACT 1995 (TSC Act) such as the blue-billed duck, the brolga and the grey falcon.
The Barwon-Darling River channel supports a wide variety of wetland types which vary along the river, and include anabranches, flood runners, billabongs, basins and swamps. The region also includes the significant environmental asset, Talyawalka Anabranch and Teryawynia Creek (listed as nationally important in the Directory of Important Wetlands in Australia). This site comprises the wetlands of the Talyawalka Anabranch of the Darling River and its tributary, Teryawynia Creek. These wetlands include numerous intermittent wet and dry lakebeds and are representative of a semi-arid inland floodplain wetland system. When inundated, the lakes provide habitat to more than 10,000 waterbirds.
What does the latest science say about the ecological health of the catchment?
The Murray-Darling Basin Commission Sustainable Rivers Audit (SRA) used several criteria to rate the overall health of river ecosystems in the Murray-Darling Basin. The Sustainable Rivers Audit reports the overall health of the Barwon-Darling Catchment as being poor.
The CSIRO Sustainable Yields report on the Barwon-Darling catchment provides information on the current and future water availability in the catchment. The report indicates that the current level of surface water extraction in the Darling Basin is high, with 39 per cent of average available water being diverted for use. Under the best estimate 2030 climate, average surface water availability (assessed at Bourke) would be reduced by 8 per cent and end-of-system flows would be reduced by 10 per cent.
Note that the boundaries of this catchment as defined by the Sustainable Rivers Audit and the Sustainable Yields report differ slightly to the boundaries used here.