and the Darling. It is defined by the catchment areas of the Murray and Darling Rivers and their many tributaries.

The Murray-Darling Basin lies to the west of the Great Dividing Range which runs the length of the east coast of Australia. The Basin extends across much of southeastern Australia, with the mouth of the Murray River on the southern coast of Australia near Adelaide. It includes over one million square kilometers, and about oneseventh of the land area of Australia. The Basin extends to over three-quarters of the State of New South Wales (NSW), more than half of State of Victoria, significant portions of the States of Queensland and South Australia and includes the whole of the Australian Capital Territory. Well over half of the Basin is in NSW and almost a quarter is in Queensland.

The Basin contains more than 20 major rivers as well as important groundwater systems. It is also an important source of freshwater for domestic consumption, agricultural production and industry.

The rivers of the Murray-Darling Basin are characterized by flat gradients (much of the basin is less than 200 meters above sea level), highly variable flows, and limited runoff. Average annual runoff is some 24 million cubic meters (m<sup>3</sup> ) of which around half is lost to natural processes. Total runoff is the lowest of any of the world’s major basins and average annual flow to the sea is a mere 400 m<sup>3</sup> per second. Much of the Basin is semi-arid and some 86% of the area contributes no runoff. The Basin covers 14% of Australia but receives only 6.1% of Australia’s mean annual runoff (Goss 2003: 1).

Wetlands systems play an important role for rivers in the Basin. There are about 30,000 wetlands in the Basin, with 11 being listed for their internationally significant environmental values. The wetlands are major considerations in environmental management of the rivers.

The water resources of the Basin are now highly developed. Annual diversions from the river system are 11.43 million m<sup>3</sup> , 96% of which is for irrigation (Goss 2003: 1). Total water storage capacity in the Basin is 34.7 million m<sup>3</sup> , which supports some 1,470,000 hectares of irrigated crops and pastures in the Basin (representing 71 percent of Australia’s total area of irrigated crops and pastures).

In 1996 the Basin was home to nearly 2 million people (or about 11% of the total Australian population) and another million people outside the Basin were heavily dependent upon the Basin’s water resources. The Basin boasts a gross value of production of over A$23 billion, of which approximately A$4.5 billion is generated by irrigated agriculture. Around 40 percent of Australia’s gross value of agricultural production originates from the Murray-Darling Basin.

# **5. Basin Management Issues and Stakeholders**

In light of the high degree of development of water use in the Basin, the dominant basin management issues of the 20<sup>th</sup> century were water scarcity, over-allocation of water supplies,<sup>4</sup> and drought exposure. These issues stimulated the development of institutional arrangements in the Basin from the beginning of the 20<sup>th</sup> century to the 1990s. Those

> 4 Almost half of the Basin’s surface water management areas are over-appropriated, i.e., authorized uses exceed mean annual flows.

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