The Murray Darling Basin covers an area of 1,061,469 km² and includes three of Australia’s biggest and longest rivers (including the Murray River and the Darling River).
The Basin is a diverse area encompassing forested mountains and valleys to the east, through to arid rangelands and Mallee scrub to the North and East. This diversity is reflected in the rich cultures of more than 40 Aboriginal First Nations.
The Murray River, Australia’s biggest river, captures the flows from this vast Basin and empties into the Southern Ocean at Goolwa, near Adelaide in South Australia.
The rivers flowing into the Murray also nourish more than 30 000 lakes and wetlands, including 11 classified as Internationally significant under the Ramsar Convention on Wetlands.
The Basin spans four States and one Territory, making management of the river systems complex.
Over 2 million people live in the Basin and over four million people are reliant on water sourced from its catchment.
The Basin has always been a heartland for Aboriginal culture in South Eastern Australia. The rich resources supplied by its river systems support dense populations, with sophisticated economic, cultural and spiritual practices. Water is the key driver for these productive cultural and ecological landscapes.
The natural variability of the river systems (including periods of flooding and drought) drives diverse and productive ecosystems. Many plants and animals are adapted to flourish through different parts of the wetting and drying cycle.
The World’s largest River Redgum Forests have flourished for millennia along the floodplains of the major rivers of the Basin. These iconic forests require periodic floods to establish, grow and regenerate. Redgums and other floodplain forests support an abundance of culturally significant plant and animal species. Lakes and billabongs provide breeding and feeding grounds for native fish including the endangered Murray Cod.
It was the water resources and productive landscapes, which had been managed by Aboriginal people for millennia, which first drew Europeans to investigate Australia’s inland waterways for pastoral and industrial exploitation.
Over 150 years of land clearing, water extraction, physical disruption of waterways and devaluing of Indigenous knowledge have seen the environment of the Basin severely degraded. Recent research highlights the critical condition of many Basin ecosystems and threatened species.
The Basin waterways are impacted by high levels of salinity, poor water quality, toxic blue-green algae outbreaks and infestations of invasive European carp.
Iconic native fish such as the Murray Cod and Macquarie Perch suffer from reduced river connectivity, cold water pollution from dam-releases and altered flow patterns.
In 2012, the Australian Government implemented The Murray Darling Basin Plan to address some of these issues. The Basin Plan is supposed to return the equivalent of 3200 gigalitres (GL) of water back to the river, as environmental flows.
The Murray-Darling Basin has also undergone a significant loss in the surface of land occupied by wetlands.
Below are some of the major environmental and ecological issues (mostly water-related) in the Murray-Darling Basin :