Latest study on Bradfield scheme in Queensland again concludes proposal doesn’t hold water

<span>Photograph: Phil Copp/Getty Images</span>
Photograph: Phil Copp/Getty Images

A Queensland government study into the feasibility of the Bradfield water scheme has reached the same conclusion as previous studies from 1947, 1982, 2004 and 2020 – that diverting flood waters inland is not viable.

John Bradfield, the engineer who built the Sydney Harbour Bridge, devised the scheme in 1938. Bradfield thought he could irrigate the interior and change the arid climate of central Australia by building a series of dams and diverting northern flood waters to the west of the Great Dividing Range.

Every few years – usually after prolonged droughts – public debate returns to Bradfield’s long-discredited idea, with politicians pitching themselves as nation-builders who can succeed where others have failed.

The Queensland Liberal National party promised to build a new version of the Bradfield scheme before the 2020 state election. The Palaszczuk government responded by promising a study.

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That study – led by Prof Ross Garnaut – was released on Thursday and found that “such a scheme would not be feasible”.

“The panel concluded that the Bradfield scheme and similar proposals fall at the first hurdle: there is not enough water available on a consistent basis to support them, while doing all of the other valuable things that water does in the relevant catchments,” Garnaut said.

“The idea of using the immense water resources of northern and central Queensland to promote regional development is sound.

“In today’s circumstances, using the water productively, closer to where it falls, will make a far bigger and more valuable contribution to regional development.”

The CSIRO in 2020 found that while the scheme was “physically plausible” it was not economically viable. A 2004 study debunked the notion that diverting water inland would change the arid interior climate.

In 1982, it was concluded that the water delivered to inland rivers from a modified version of the Bradfield Scheme would cost more than 20 times as much for each hectare irrigated as water from the Burdekin Dam. It found that building the scheme was “unjustifiable expenditure”.

Those reports followed the first detailed assessment of the Bradfield scheme from 1947 which found Bradfield had overestimated the potential water supply for the scheme and that it would probably cost significantly more than first thought.

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In 2022, the same conclusion was reached: there is not enough water.

“Both the panel and CSIRO found that Dr John Bradfield’s estimation of water flows were overestimates, effectively doubling the amount of actual water in the system,” the report said.

“Without enough water, no Bradfield scheme would work.

“On paper, the idea – now more than 80 years old – held great nation-building promise. The heavy rains and large river flows of northern and central Queensland are major regional, state and national assets.”

The study found there was “no economic, environmental, social or cultural heritage case for immense storage of water in northern Queensland with a view to its movement over long distances west and south for irrigation”.