The Murray-Darling basin is a large geographical area in the interior of southeastern Australia, whose name is derived from its two major rivers, the Murray River and the Darling River. It drains one-seventh of the Australian land mass,[1] and is currently by far the most significant agricultural area in Australia. It spans most of the states of New South Wales, Victoria, and the Australian Capital Territory, and parts of the states of Queensland (lower third) and South Australia (south-east corner). It is 3,375 kilometres (2,097 mi) in length (the Murray River is 2,589 km (1,609 mi) long).
Most of the 1,061,469 km2 (409,835 sq mi) basin is flat, low-lying and far inland, and receives little direct rainfall. The many rivers it contains tend to be long and slow-flowing, and carry a volume of water that is large only by Australian standards.
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The Murray Darling Basin is home for many native animal species. The true numbers are not known, but a fairly confident estimate has been made of these animals and the current status of their population. Among the indigenous fauna in the region, the study found that there were:
The Basin has also played host to a variety of introduced species. One of the most well known is the carp.
Introduced in around 1851, the four varieties of carp were used to stock up fish dams. Since then they have made their way into the river systems, where they spread quite quickly. These fish are very mobile, as they can travel easily on flood waters and their eggs can be transported by birds.
These fish are a problem because they feed by sucking gravel from the river bed and taking all the edible material off it, before returning the rest to the water. This stirs up all the sediment, reducing the quality of the water. When caught by a fisherman, it must be killed by law.
This area is one of the physiographic provinces of the larger East Australian Basins division, and encompasses the smaller Naracoorte Platform and Encounter Shelf physiographic sections.
Total water flow in the Murray-Darling basin 1885 to the present has averaged around 24,000 gigalitres per year. This is the lowest rate of the world's major river systems.[1] About 6% of Australia's total rainwater falls into the basin.[2] In most years only half of this quantity reaches the sea and in dry years much less. Estimated total annual flows for the basin have ranged from 5,000 gigalitres in 1902 to 57,000 gigalitres in 1956. Despite the magnitude of the basin, the hydrology of the streams within it is quite varied.
These waters are divided into three types:[3]
Of the approximately 13,000 gigalitres of flow in the basin, which studies have shown to be divertible, 11,500 gigalitres are removed for irrigation, industrial use, and domestic supply. Agricultural irrigation accounts for about 95% of the water removed,[1] including for the growing of rice and cotton. This extraction is highly controversial among scientists in Australia, regarding the agriculture industry's high water use in a region extremely short of water (as much due to exceptionally low run-off coefficients as to low rainfall).[5]
The basin covers five states and territory governments, who according to the Constitution, are responsible for managing water resources. The River Murray Commission was established in 1917.[1] Under the River Murray Waters Agreement, which never included Queensland despite the state containing about a quarter of the basin, the Commission's role was only as an advisory body with no authority for the enforcement of provisions. For a long time the Commission was only concerned with water quantity until salinity became a problem. This led to minor reforms in 1982 in which water quality became part of the Commission's responsibilities.[1] However, it was soon recognised that a new organisational structure which considered the national perspective was needed for effective management.
The Murray-Darling Basin Agreement was first adopted in 1985 but it wasn't until 1993 that its full legal status was in-acted.[1] The Agreement led to the creation of a number of new organisations under what is known as the Murray-Darling Basin Initiative. These included the Murray-Darling Basin Ministerial Council and the Murray Darling Basin Commission.
In October 2010, The Murray-Darling Basin Authority released a major document outlining its plan to secure the long-term ecological health of the Murray-Darling Basin. This entails cutting existing water allocations and increasing environmental flows.[6] The document is officially titled the Guide to the Proposed Murray-Darling Basin Plan. It is the first part of a three-stage process to address the problems of the Murray-Darling Basin.[7] MDBA is responsible for preparing and overseeing a legally-enforceable management plan—the Basin Plan.
The Basin Plan is designed to set and enforce environmentally sustainable limits on the quantities of water that may be taken from Basin water resources, to set Basin-wide environmental, water quality and salinity objectives, to develop efficient water trading regimes across the Basin, to set requirements for state water resource plans and to improve water security for all Basin users.[8] It also intends to optimise social and economic impacts once these environmental outcomes have been met.[9]
With the release of the Guide to the Proposed Murray-Darling Basin Plan there have been a number of protests and voiced concerns about the plan in rural towns that the MDBA have visited to present the plan to consultation meetings.[10] Over 5,000 people attended a MDBA meeting in Griffith where Griffith Mayor, Mike Neville, said the plan would "obliterate" Murrumbidgee valley communities.[11] Other groups also echo this feeling, such as the Victorian Farmers Federation[12] and Wine Group Growers' Australia.[13] Conversely, support for the Murray-Darling Basin plan has been received by various groups, including Australian Conservation Foundation,[14] and Environment Victoria.[15]
New legal advice from lawyers for the Federal Government is changing the plan. The Government's reading is that the plan must give equal weight to the environmental, social and economic impacts of proposed cuts to irrigation. Environmentalists and South Australian irrigators, at the end of the river in South Australia, say the authority should stick to its original figure.[16]
In October 2010, a parliamentary inquiry into the economic impacts of the plan was announced.[17]
In late October 2010 the Water Minister, Tony Burke, played down the prospect of a High Court challenge to the Murray-Darling Basin plan, as confusion continued over new legal advice released by the Government. In response to community concerns that the Murray-Darling Basin Authority had put environmental issues first over social and economic needs, Burke released new advice on the requirements of the Water Act. Burke stated that the Act does allow for the authority to 'optimise' the needs of all three areas, but constitutional lawyer, George Williams, had cast doubts over the interpretation of the laws, stating it could be subject to a legal challenge.[18]
The MDBA announced in November 2010 that it might be forced to push back the release of its final plan for the river system until early 2012.[19]
The MDBA chairman, Mike Taylor, reassured the public meeting that more work is being done to look at how the proposed cuts would affect regional communities. He stated; "Importantly, we want to make sure the social and economic impacts—which under any sort of scenario is very significant—were fully teased out".[20] Taylor resigned as he believed that the overriding principle should be the environmental outcome which was in conflict with the Gillard Government and following a period of sustained criticism of the Authority and the implementation of the proposed draft basin plan.[21] He was replaced by former New South Wales Planning Minister, Craig Knowles.[22][23][24]