What is the Murray-Darling Basin?

The Murray-Darling Basin is the largest river system in Australia, draining about 1.06 million square kilometres or roughly one-seventh of the continent. It includes the Murray, Darling, Murrumbidgee, Goulburn, Lachlan, Macquarie, and many smaller rivers, and reaches across parts of Queensland, New South Wales, the ACT, Victoria, and South Australia.

The basin produces about 40 per cent of Australia's gross value of agricultural production, including most of the country's irrigated cotton, rice, dairy, wine grapes, and stone fruit. About 2.3 million people live in the basin and more than 40 First Nations are recognised as having rights and interests across the catchment.

Water in the basin has been allocated through licences for more than a century, but over-extraction caused the rivers to stop reaching the sea during the Millennium Drought of 1997 to 2009. The Murray-Darling Basin Plan, agreed by the Commonwealth and basin states in 2012 under the Water Act 2007, sets a Sustainable Diversion Limit on how much water can be taken for consumptive use, with the difference returned to the environment through buybacks and infrastructure efficiency projects. The plan committed to recovering 2,750 gigalitres of environmental water by 2024.

Implementation has been politically fraught. Reviews by the South Australian Royal Commission (2019) and the Productivity Commission have found mixed progress. The Restoring Our Rivers Act 2023 reinstated water buybacks as a tool to meet the remaining recovery target by 2027. The Murray-Darling Basin Authority, headquartered in Canberra, oversees implementation alongside state and federal water agencies, and a Water Minister sits in cabinet whenever basin policy is in dispute, reflecting how politically central river health has become.