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The Murray–Darling Basin is the catchment for Australia's largest river system. The Murray and the Darling rivers are Australia's longest rivers.

A map that shows the boundary of the Basin, including the northern and southern basins. Major towns and cities are listed on the map, as are the major rivers of the Basin.
The boundary of the Murray–Darling Basin, including the boundaries of the northern and southern basins.

The Basin covers an area of more than 1 million square kilometres, which is equal to 14% of mainland Australia. The Basin includes 75% of New South Wales, more than 50% of Victoria, 15% of Queensland, 8% of South Australia, and all of the Australian Capital Territory. The Basin area is the 20th largest river catchment in the world.

The Basin is bounded by the Great Dividing Range, including the Australia Alps, where snow lies for several months every winter. The north and west of the Basin is flat and semi-arid, taking in environments such as saltbush shrublands and mulga lands.

Most rivers rise in the Great Dividing Range but most of the river system is spread across riverine plains of low elevation and very low gradients. Compared with other rivers of the world, the rivers of the Basin have carved winding courses across the landscape and are slow flowing, in areas that are very dry, hot and receive little rainfall. The Basin is one of the flattest catchments in the world.

Basin geography 

  • An area of more than 1 million square kilometres — 14% of Australia's total surface area.
  • Australia's 3 longest rivers are found in the Basin: the Darling/Barwon river system (2,740 km), the Murray (2,530 km –Australia’s longest standalone river) and the Murrumbidgee (1,690 km).
  • At its widest, the Basin extends 1,200 km along the Murray valley in the southern Basin, from near Cooma in the east to the Murray Mouth in South Australia.
  • Much of the northern Basin is 800–900 km wide, from the Great Dividing Range in the east to the plains beyond the Darling River in western Queensland and New South Wales.
  • The length of Basin is almost 1,400 km, from the source of the Warrego River in Queensland, south to the headwaters of the Goulburn River in Victoria.

The region is called a Basin because all of the streams, creeks and rivers run to a common point. There are 22 major catchments (or sub-Basins) within the Murray–Darling Basin. The waters of the northern catchments run to the Darling River and the waters of the southern catchment run to the River Murray.

Most of the major rivers flow into either the Darling or the Murray. There are some rivers, like the Paroo, Lachlan and Wimmera rivers that terminate in wetlands or marshes, and their water only reaches the Darling or the Murray in the wettest of years, if at all.

For a more detailed description of the geography of each river catchment, see the Basin catchment profiles.

Updated: 23 Jan 2018