Water flows at key sites in Murray-Darling are worse than before basin plan, report says | Australia news

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Water flows at key environmental sites in the Murray-Darling Basin are unimproved or worse than before the basin plan was implemented, a scientific report has found, raising serious questions about where the $8.5bn of environmental water purchased by taxpayers is going.

The Wentworth Group of Concerned Scientists, a group of eminent environmental scientists formed a decade ago to advocate for the river system, have looked at two key sites which they identified when the plan was put in place in 2010.

They have found that environmental flows are not meeting the government’s own objectives for improving the health of the river at these sites.

At one site flows have actually declined, compared to pre-plan days.

The work, the first time anyone – including the Murray-Darling Basin Authority – has tried to look in detail at progress against the plan’s own environmental objectives, paints a worrying picture of whether the plan is working.

In coming up with the environmental water recovery targets in the plan, the federal government identified 122 indicator sites – sites that needed more flows to ensure biodiversity was preserved or restored.

These included wetlands and other sensitive or degraded parts of the river. They then identified the sorts of flows that were needed to mimic nature to restore the ecology. These included overall volumes as well as small pulse flows and occasional floods.

The fish kills at Menindee in January on an unprecedented scale have sounded alarm bells about whether the plan is actually working to restore the health of Australia’s most important river system.

In recent weeks, the Wentworth group has analysed in detail two sites – one at Wilcannia in the Lower Darling, 200km above Menindee and another at Chowilla on the Murray in South Australia – to see what is happening.

It found that in the case of the Wilcannia site, two out of three of the desired flow outcomes had failed to be achieved. “Only small flows have passed the target, with base flows and large flows failing to achieve hydrological conditions assumed necessary for ecological restoration,” the report said.

In the case of the floodplains at Chowilla, none of the indicators met the five targets and the flows were failing to achieve requirements for ecological restoration.

A spokesman for the Wentworth group, Prof Jamie Pittock from Australian National University, said that despite 2,016GL of water being recovered for the environment (63% of that envisaged under the basin plan) at a cost of $8.5bn, the environmental flow targets had failed to be achieved. And this was during the relatively wet period from 2010-2018.

The report says that “in general annual average flows can be up to 40% and 60% smaller than expected under the Basin Plan. Observed flows are similar to or less than the baseline (pre-Basin Plan) model results, revealing that instead of an increase, there has actually been no improvement or even a decline in water flows since the implementation of the Basin Plan.”

Pittock said that the results were disastrous for the environmental health of the river.

He said the result at Wilcannia, where two of three indicators were not met – including the overall flows – suggested the plan was going the wrong way.

“The failure to meet the targets is likely due to low flows being pumped by irrigators upstream under the NSW government’s dodgy water sharing plan,” he said.

The Chowilla site was picked because it is a sensitive floodplain which needs to be regularly inundated to ensure that wetlands and river red gums survive.

Pittock said the watering was just not occurring because both the NSW and Victorian governments had failed to deal with constraints as promised along the river that meant insufficient water could be assembled to ensure the Murray overflowed its banks and watered the floodplain.

These constraints include bridges and roads that might get flooded, or town levies that need to be raised to allow the big flows to be released for the environment.

Asked what would happen to the Chowilla floodplains if the environmental watering targets were not achieved, Pittock said wetlands could die in a couple of years, and river red gum forests over the next few decades.

“It’s an awful trajectory and the government must change course,” he said.

The Murray–Darling Basin Authority said it acknowledged the report contained useful pieces of analysis.

“We would not expect flows across the Basin to fully reflect Basin Plan modelling at this stage of implementation. Eight seasons in the context of a highly variable climate is not long enough to draw statistically significant conclusions in comparison to a 114-year modelled period,” it said.

The Wentworth group was also highly critical of the authority’s lack of monitoring, saying it looked at overall flows but not the all-important pulse flows that the plan itself identifies as needed.

The group has called for the authority to urgently evaluate the success of its water recovery efforts using an approach which takes into account variable climate.



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