Science

Statement on the Guide to the Murray-Darling Basin Plan

Friday, 8 October, 2010
Richard Kingsford*

Australia has embarked on a historic path of returning the rivers of the Murray-Darling Basin to a more sustainable level. This decision of the Murray-Darling Basin Authority is historically significant and critical not only for the future of Australia’s internationally significant wetlands, such as the Coorong and the Lower Lakes, the Hattah-Kulkyne Lakes, Chowilla floodplain, Barmah-Millewa Forest and Macquarie Marshes but also the many thousands of smaller wetlands and the rivers that feed them. This decision will also help with the sustainability of the major wetlands which are equally important but not recognised internationally such as the Great Cumbung Swamp and the Lowbidgee wetlands. The release of the Guide to the Murray-Darling Basin Plan follows a considerable period of constructive work by the Murray-Darling Basin Authority on an initiative that commanded bipartisan political support. The rehabilitation was a key initiative of the previous Coalition Government. There are some key points relevant to the release of the Guide to the Murray-Darling Basin plan, relevant to the ongoing consultation processes.

  • This is one of Australia’s more important decisions on water and puts the nation at the forefront of international efforts to rehabilitate river systems degraded by overallocation of water.
  • This initiative culminates in a long period of Australia’s history where most Governments, communities and industries (including members of the irrigation industry) have acknowledged that the rivers of the Murray-Darling Basin are currently not sustainably managed.
  • Under current conditions, there is on average 11,000 GL of water extracted from the rivers of the Murray-Darling Basin each year (about 22 Sydney Harbour’s worth of water) which varies considerably depending on the dry and wet times. The Guide to the Basin Plan canvasses a range of cuts to extractions from rivers to deliver sustainability. These sustainable diversion limits will translate to cuts of 27-37% of current water use from the Murray-Darling Basin. The cuts are higher on the southern rivers of the Murray-Darling Basin.
  • The additional environmental water will be critical to avoid further loss of biodiversity and sustainability on international important wetlands, listed under the Ramsar Convention. In particular, the wetland affected by sustainable diversion limits include: Banrock station wetlands; Barmah-Millewa Forest; Coorong, Lake Alexandrina and Lake Albert; Chowilla floodplain; Gwydir wetlands; Hattah-Kulkyne Lakes; Gunbower Forest; Lake Albacutya; Macquarie Marshes and; Narran Lake.
  • The environmental water will also improve the functions of these wetlands and the many thousands of wetlands along the way that will also benefit. The environments of the main river channels are also likely to improve with increased environmental flows.
  • There will be broad environmental sustainability benefits for the economy. These include people who fish the river (recreational and professional), boating, bird watching, tourism, improved water quality for irrigation and floodplain grazing.
  • The best environmental outcomes will be delivered for the Murray-Darling Basin rivers if the Murray-Darling Basin Authority delivers final recommendations at the top of the range of cuts to extraction of water to ensure delivery of sustainable diversion limits.
  • The Environmental Watering Plan, part of the Basin Plan, will be a critical instrument in the delivery of environmental flows to the key wetland systems of the Murray-Darling Basin. It provides the link between sustainable diversion limits and environmental outcomes by focusing on the required flow regime for achieving sustainability in the key wetland systems.
  • The spread of potential cuts to deliver sustainable diversion limits falls unevenly across the Murray-Darling Basin, with higher cuts recommended for the southern river basins. This is a reflection of the history of water reform with lower adjustment on these rivers compared to some of the northern Darling tributaries.
  • Implementation of cuts to irrigation, which uses 95% of the water from Murray-Darling Basin Rivers, will be delayed until the water sharing plans of individual rivers are reviewed by the States, 2012-2017.
  • Implementation of the sustainable diversion limits will be the responsibility of the States and it is critical that these jurisdictions deliver on this historic initiative.
  • Enormous challenges remain if the community and their governments are to avoid the ecological problems that have faced us for the Murray-Darling Basin rivers and their wetlands. It will be particularly important to manage the rivers an environmental flow regime which recognises that it may be particularly important to guard against the potential vulnerability of ecosystems during dry periods (e.g. Lower Lakes and Coorong).
  • While the Murray-Darling Basin has focused all available resources in the development of the Murray-Darling Plan, it is clear that our current state of knowledge about the ecology of plants and animals dependent on our rivers is not well developed. We need to better understand how the different organisms are going to benefit with the increased environmental flows that are potentially promised under the Basin plan. The Australian government will have considerable amounts of water to manage but without good science and monitoring it will be difficult to demonstrate the effectiveness of this major initiative on the health of the Murray-Darling Basin Rivers.
  • Sustainable diversion limits are considerably less for groundwater systems than surface water systems, partly recognising that in some parts of the Murray-Darling Basin, these systems are not as overallocated as the rivers. Further, our current state of knowledge of groundwater systems, their supply to surface water, ecosystems and their sustainability remains particularly poor.
  • Some key wetlands, including wetlands listed under the Ramsar Convention, were excluded because there are no serious consequences of water resource development degrading these key wetland systems (e.g. Yantabulla Swamp, Paroo River wetlands, Currawinya Lakes). It will be critical to continue to recognise their importance in relation to state and Commonwealth conservation and river management programs.

* Professor Richard Kingsford is the Director of the Australian Wetlands and Rivers Centre, University of New South Wales.

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