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Alternative Water: Interstate Waters

The idea of turning coastal rivers inland and south instead of letting them run out into the sea has been proposed during almost every drought.

Moving water from one Australian state to another is complex and costly and would require formal arrangements to be in place in relation to the sharing of infrastructure and water access rights and entitlements. The cost to South Australia would also need to be low enough to be financially sound for South Australia and high enough to adequately compensate the state where the water came from, or the ‘source’ state.

Large water producing areas in northern and eastern Australia provide significant socio-economic and environmental assets for the people who live in those regions (and the state). It would be neither acceptable, nor legally possible, to divert water to South Australia unless there was considerable public support from the source state.

For South Australia to receive water from one of these schemes, the scheme would need to provide a benefit to the source state in the first instance. This information sheet briefly describes the proposals and the most recent viability assessments of the following:

‘Bradfield Scheme’ (Far North Queensland)
Clarence River (Northern New South Wales)
Ord River (Northern Western Australia)

Bradfield Scheme, Far North Queensland

Turning Queensland’s coastal rivers inland was first mooted in the 1800’s. The best-known proposal is the Bradfield scheme, conceived in 1938 by Dr J Bradfield, the designer of the Sydney Harbour Bridge. He envisaged diverting water from the Tully, Herbert, and Burdekin Rivers over the Great Dividing Range into rivers which would supply water for stock and other purposes in inland areas. To supply Adelaide, it was anticipated that water would be pumped approximately 800 km south from Cooper Creek.

The historic and modern variants of the Bradfield Scheme to deliver water for agriculture were most recently assessed in 2021 by CSIRO for the Commonwealth Government’s National Water Grid Fund and the Bradfield Regional Assessment and Development Panel (the Panel) for the Queensland Government.

Both the Panel and CSIRO found that Dr John Bradfield’s estimation of water flows were overestimated and had effectively doubled the amount of actual water in the system. Simply there is not enough consistently available water to make the proposals work. In addition, CSIRO found the cost of diversion infrastructure added such a premium to the cost of the water that future crop revenues would never pay off the cost of the water storage infrastructure.

With the additional requirement for 800km of pipeline to Adelaide, there is no evidence that pumping water overland from Far North Queensland would be a more economically attractive proposition for South Australia compared with other existing potential water supply options (such as seawater desalination).

The suite of reports is available on the CSIRO website and the Queensland Government’s Bradfield Scheme page.

Historic black-and-white map titled "Dr. J. J. C. Bradfield's Inland Drainage Scheme" showing proposed water diversion routes in northern Queensland. The map includes rivers, mountain ranges, and proposed dams (Tully, Herbert, and Burdekin Rivers) with white lines indicating engineered watercourses and arrows showing water flow direction. A large white circle highlights the primary catchment area and key infrastructure locations.

Clarence River, northern New South Wales

Various proposals have been made to divert eastward flowing rivers, such as the Clarence River in New South Wales, inland to supplement flows in the Murray-Darling River system. During public consultation on the Border Rivers Regional Water Strategy, the NSW Department of Planning and Environment was asked to undertake further analysis on inland diversion scheme options to consider the benefits to connectivity with the Barwon-Darling, coastal flood mitigation and energy generation. The analysis found that even with aspirational assumptions, inland diversion schemes are unlikely to be economically viable because:

the costs remain prohibitively expensive and would ultimately need to be recovered from water users;
an inland diversion scheme could reduce the impacts on Border River licence holders from the options presented in the draft Western Regional Water Strategy (if progressed), but would not remove all of the impacts or be capable of providing flows to the Barwon-Darling in the quantities needed at all times.
the scheme is unlikely to significantly reduce high flows in the Clarence Valley and so may not provide meaningful flood mitigation benefits but could significantly reduce low flows in the valley during droughts. There is strong opposition from coastal communities; and
hydropower energy potential was determined to be limited.

The reports are accessible at Border Rivers Regional Water Strategy engagement.

Ord River, northern Western Australia

The Ord River proposal, as envisaged in the 1980s, involved supplying water from the Ord River in the far north of Western Australia to Perth and Adelaide. A joint venture between the Western Australian and South Australian Governments was discussed to construct a pipeline through Western Australia to the junction of the Western Australian, Northern Territory and South Australian borders. One of the reasons it was supported by Western Australian authorities at that time was the realisation that it was not economically attractive without additional external financial backing which the diversion to South Australia was envisaged to facilitate.

In 2006, the Western Australian Government commissioned an independent study into options for bringing water to Perth from the Kimberley. This study found that bringing water down from the North wasn’t viable as:

much of the water in Lake Argyle is already allocated for use within the region and the demand for hydro-electric power in the Kimberley region to supply industry and towns is growing;
it was almost impossible to find a route from the north to the south of WA that wouldn’t impact endangered or protected flora and fauna; and
the pipeline would release about 0.6 million tonnes of carbon dioxide a year and that it would take between 70,000 and 250,000 hectares of actively growing forest to make up for that amount of carbon dioxide.

The report is accessible at Options for bringing water to Perth from the Kimberley.

In 2024, the Northern Territory Government commissioned a Preliminary Business Case for the Ord River Expansion to the Northern Territory. The report concluded that the elevated cost of water infrastructure expansion is not commercially viable if cost-recovery will come from irrigators alone. This necessitates government investment to harness the other benefits of the proposal. In July 2024, the Australian Government announced an investment of $2.3 million to develop a detailed business case for the Ord River expansion to the Northern Territory project, through the National Water Grid Fund.

The reports are accessible at Ord River expansion to the Northern Territory.

Would harvesting water from long distance sources be a viable option for supplying South Australia?

The South Australian Government has previously investigated long-distance water supply options, deeming them unattractive from social, economic and environmental perspectives. At this time there is no evidence that pumping water overland from interstate would be a more economically attractive proposition for South Australia compared with other existing potential water supply options (such as seawater desalination).

Additional reading

State Library of South Australia catalogue reference to Waterproofing Adelaide: Exploring the Issues, a 2004 report that included a brief summary of an assessment by SA Water of large-scale water supply options from interstate rivers for Adelaide. Options summary table on page 48 https://www.catalog.slsa.sa.gov.au/record=b1620223.