The Murrumbidgee Catchment covers 84,000 square kilometres of southern New South Wales. It is bordered by the Great Dividing Range to the east, the Lachlan Catchment to the north and the Murray Catchment to the south.
The river originates in the alpine area of Kosciuszko National Park and flows through the Monaro High Plains and the low-lying plains of the western Riverina, joining the Murray River south of Balranald.
Supporting a complex range of natural ecosystems, the Murrumbidgee Catchment contains many significant in-channel and wetland habitats including the mid-Murrumbidgee and Lowbidgee wetlands, which provide important habitat for a range of aquatic and terrestrial species including frogs, fish and waterbirds.
The primary users of water in the region are the two major irrigation districts in the catchment – Murrumbidgee and Coleambally Irrigation Areas. Irrigation also occurs around Hay and Balranald in the west and in eastern parts of the catchment, including around Wagga Wagga.
Regulated water is provided by two major headwater storages, Burrinjuck Dam on the Murrumbidgee River and Blowering Dam on the Tumut River. Collectively these storages have a capacity of 2,654 GL.
Most of the flow in the Murrumbidgee River comes from the upper portion of the catchment, and is delivered by the main tributary rivers: Cotter, Yass, Molonglo, Queanbeyan, Bredbo, Numerall, Goodradigbee and Tumut. Several tributaries located immediately downstream of the dams contribute significant inflows, including Adelong, Adjungbilly, Gilmore, Hillas, Tarcutta, Kyeamba, Jugiong, Muttama, Billabong and Houlghans Creeks, and Goobarragandra River. The middle and lower portions of the catchment do not contribute significant inflows.
The Murrumbidgee catchment is an ecologically significant area because it includes:
- a diverse range of flora and fauna species, including river red gum forests and woodlands, black box and lignum
- species listed as threatened under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act), such as the vulnerable southern bell frog
- wetlands of international significance listed under the Ramsar Convention (Fivebough and Tuckerbil Swamps in the Murrumbidgee Irrigation Area)
- colonial bird breeding sites
Two large-scale environmental assets in the Murrumbidgee include the Lower Murrumbidgee River Floodplain and the Mid-Murrumbidgee-River Wetlands.
The Lower Murrumbidgee River Floodplain, which is listed under the Directory of Important Wetlands in Australia, is a wetland of national significance. It covers approximately 200,000 hectares and includes some of the largest lignum wetlands in NSW. It is one of the most important breeding sites in eastern Australia for the straw-necked ibis. The wetland provides critical breeding habitat for waterbirds, including the Australian white ibis, glossy ibis, royal spoonbill, and great egret.
The Mid-Murrumbidgee-River Wetlands consist of several nationally significant wetlands. They support vegetation communities including river red gum forests and woodlands and black box woodlands that provide vital habitat to threatened species including the Australasian bittern.