Wentworth Group of Concerned Scientists finds huge shortfalls in Murray-Darling Basin water flows
Independent analysis of Murray-Darling Basin water flows reveals one fifth has gone missing. It’s worse in the Coorong and Murray Mouth. So what is going on?
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Water that was expected to flow for the benefit of the environment has gone missing, top scientists say.
The Wentworth Group of Concerned Scientists checked how much water flowed past 27 river gauges across the Murray-Darling Basin compared to how much was expected from Basin Plan modelling.
They found that even after accounting for dry conditions, in the seven years since the Basin Plan came into effect, far less water was observed than expected.
More than 1200 billion litres failed to reach the South Australian border every year.
Co-author Professor Jamie Pittock from the Australian National University says South Australia is the big loser out of this” because we’re missing out on an enormous amount of water.
“Every South Australian should be concerned,” he said.
“It’s not just a portion of the water supplied to Adelaide, it’s also the health of the riverland, of the irrigation sector, of the red gum forests, the Coorong and the Lower Lakes that’s impacted by this poor management.”
The report released today reveals an estimated 5591GL of water was expected to flow across the South Australian border every year from 2012-13 to 2018-19, but only 78 per cent of this water arrived.
Downstream, 5081GL a year was expected to flow over Lock 1 into the Coorong and Lower Lakes, but only 70 per cent of this water arrived. (So almost a third went missing).
Flows through the barrages were insufficient to keep the Murray Mouth open without dredging.
The Wentworth Group says that Basin Governments must now investigate why river flows are 20 per cent less than expected and fix any shortfalls to progress towards the river health objectives listed in the Water Act and Basin Plan.
In response today, the Murray-Darling Basin Authority agreed there was a problem and blamed drought and climate change especially extreme temperatures causing evaporation.
Executive director of Basin Strategy and Knowledge, Vicki Woodburn, said the Assessment of river flows in the Murray-Darling Basin: Observed versus expected flows under the Basin Plan 2012-2019 was a valuable contribution to the science community’s views about improving the Basin Plan’s implementation to 2026.
“Our analysis also shows that the recent drought – that saw record high temperatures and low rainfall – meant that flows in the river system were inhibited,” she said.
However she suggested there was “more to the story” and promised to release an evaluation of the plan drawing on “other lines of evidence”.
“It’s important to measure not just flows, which in themselves are not targets within the Basin Plan,” Ms Woodburn said.
“We work with our state and federal colleagues to also measure bird and fish breeding, vegetation health and the health of complex ecosystems like the Gwydir wetlands and the Lower Lakes. We invest significant resources to check if the environment is responding to managed environmental water – and we know it is.”
SA’s peak environment body has called for the Murray-Darling Basin Plan water recovery targets to be urgently lifted in the wake of the report, which comes as concerning reports emerge interstate of attempts to scrap the extra 450GL of water recovery that SA negotiated when the Basin Plan was created.
Conservation SA chief executive Craig Wilkins says SA has the most to lose if water is missing.
“Alarm bells should be ringing in the offices of Water Ministers across the Murray-Darling
Basin – including SA Environment Minister David Speirs,” he said.
“With climate change, any shortfall in South Australia’s fair share will only increase.”
When the Murray-Darling Basin Plan was created, climate change loss was not factored in, but it was meant to be included later. The Wentworth Group has identified climate change as one of the major likely causes of the shortfall along with water theft, poor accounting, over-estimation of gains from efficiency projects and flood plain harvesting.