Water management

Bill McCormick, Science, Technology, Environment and Resources

Key Issue
Under the Murray-Darling Basin Plan, the Minister will make adjustments to limits on water use in the Murray-Darling Basin during the next year.
The Commonwealth will be contributing to the construction of new dams around Australia through grants and concessional loans.

Water use in Australia varies year by year. In 2013–14, 23,500 gigalitres (GL) were used, principally for irrigation (13,400 GL or 57%) and urban use (3,900 GL or 17%).

Australia’s annual rainfall is highly variable, both in volume and geographic distribution. This variability affects runoff, streamflow, groundwater recharge and water availability for human use. There is high rainfall in parts of the northern tropics, the east coast and western Tasmania. However, 40% of Australia has rainfall of less than 300 millimetres (mm) per year. Rainfall has also declined in some areas due to the failure of autumn and early winter rains, with a decrease since 1950 of 15–40 mm per decade in south-western Western Australia (WA) and 20–50 mm per decade in eastern Australia and Tasmania.

While 72% of Australia’s water runoff occurs in northern Australia, coastal Queensland and Tasmania, only 7% is generated in the Murray–Darling Basin (MDB) where more than two-thirds of Australia’s irrigation water is used.

Water harvesting, storage and distribution have therefore been a vital factor in urban and regional development in Australia. The building of dams and associated irrigation areas has increased water availability but has also damaged the environment, causing the long-term ecological decline of rivers, wetlands and floodplains. The community and industry has suffered from the adverse environmental effects and poor water quality.

Murray-Darling Basin

The decline in river health in the Murray‑Darling Basin (MDB) triggered the development of the Basin Plan 2012, which sets environmentally sustainable limits for the consumptive use of water. The Murray-Darling Basin Authority (MDBA) is implementing the Basin Plan in concert with the Basin states (Queensland, New South Wales, the Australian Capital Territory, Victoria and South Australia) and other stakeholders.

A fundamental challenge for the Basin Plan will be achieving the long-term average sustainable diversion limit (SDL) of surface water of 10,873 GL per year for urban, industrial and agricultural use in the MDB. To reach the SDL, the Australian Government has committed to recovering 2,750 GL of water for the environment by 2019. This recovery will be achieved through both investment in infrastructure efficiency (for at least 600 GL of the water) and water buybacks. By 30 June 2016, 1,981.4 GL, or 72% of this water target, had been recovered.

The Basin Plan contains a SDL Adjustment Mechanism which allows the Minister for Agriculture and Water Resources, on the advice of the MDBA, to change the SDL up or down by up to five per cent (544 GL) as long as environmental and socio-economic outcomes are not compromised.

The 2,750 GL of environmental water can be decreased by up to 650 GL through ‘supply measures’ that increase the quantity of water available to the environment (for example, by reducing evaporation losses at storages). Alternatively, it can be increased by up to 450 GL through ‘efficiency measures’ that recover additional water for the environment by making water delivery systems for irrigation more efficient. There are also ‘constraints measures’ that ease or remove structures or rules that constrain the delivery of environmental water.

Basin states provided an agreed package of supply, efficiency and constraint measures under the SDL adjustment mechanism to the MDBA in May 2016. The MDBA will publish a draft of the proposed SDL adjustment in late 2016 or early 2017. The Minister will then table the final SDL adjustments, which will be disallowable by Parliament.

Dams and water infrastructure projects

Over the past twenty years the construction of significant dams has been limited for a variety of reasons. These include lack of economic viability and environmental impact.

A 2014 CSIRO study of potential dams in northern Australia found that the best sites had been already developed and the next best sites have limited areas of soils suitable for irrigated agriculture. It did identify other potential dam locations, including up- and downstream of the existing Burdekin Dam, in the Herbert River Gorge in Queensland and in the Fitzroy catchment in WA. The report estimated that if 15 of the ‘most promising large dams’ outside of national parks and other protected areas were developed, they could irrigate 350,000 hectares.

In 2013 the Coalition committed to plan for new dams. The 2014 Water Infrastructure Options Paper identified 31 water infrastructure projects with potential for Commonwealth involvement, including those already funded by the Commonwealth.

The Commonwealth has established the National Water Infrastructure Development Fund, with $59.5 million allocated to 40 feasibility studies. Funding of $450 million will be available from 2017–18 for water infrastructure projects, including $170 million for northern Australian projects.

In addition, the $2 billion National Water Infrastructure Loan Facility, announced in the 2016 Budget, will support major water infrastructure projects proposed by states and territories with private sector partners over 10 years. Concessional loans aim to stimulate and accelerate economically viable dams, weirs, pipelines and managed aquifer recharge schemes. The first five years of the loans will be interest only, with the principal and interest repaid over the next ten years.

The 2016 Coalition election policy also commits the Commonwealth to providing funding for other water infrastructure projects, including up to $130 million for the Rookwood Weir in Queensland (if economically viable).

Further reading

Bureau of Meteorology, Water in Australia 2013-14, December 2015.

C Petheram et al, Northern rivers and dams: a preliminary assessment of surface water storage potential for northern Australia, CSIRO Technical Report, Australia, December 2014.

 

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