More fresh water, no weir: Coorong science review
About one-third of the Murray River's natural flow at its lower end is needed to sustain the
collapsing ecosystems in the wetlands of the Lower Lakes and Coorong, a new scientific review has
found.
The review's key recommendation is for a median target of 3,800 gigalitres (GL) a year - about 600
GL more than at present - to be measured at the tidal barrages built 60 years ago near the river
mouth.
This is the first time a volume of water has been identified to provide for the long-term health of the
wetlands, which were declared a Ramsar Wetland of International Importance in 1985.
As well, the scientists recommend shelving proposed engineering solutions to the crisis: building a
weir to separate the Murray from the Lower Lakes, allowing the lakes to fill with seawater and
building a channel between the Coorong and Lake Albert.
Professor Richard Kingsford from the University of NSW, who led the team, says: "History is
unfortunately finally catching up and we are seeing one of Australia’s iconic wetlands moving rapidly
towards a state of ecological collapse as a result of building dams and over-allocating this river."
Another author, Associate Professor Keith Walker of The University of Adelaide, says: “We support
some of the South Australian government’s initiatives. We believe that new weirs are not a solution,
and will hinder rather than help the prospects for recovery. The last thing we need is to repeat past
mistakes, disconnecting parts of the system with weirs, levees and other structures. It is one of the
reasons why the ecological health of the Murray has declined."
The report, Engineering a crisis in a Ramsar wetland: the Coorong, Lower Lakes and Murray Mouth
Australia, is critical of the long-term management of the wetlands. It was prepared as an
independent assessment of the best available scientific evidence. The team of six scientists from the
UNSW Australian Wetlands and Rivers Centre, the University of Adelaide and Flinders University
includes leading researchers on the river and its ecology and the report was reviewed in draft stage
by other experts in the field.
The report recognises important contributions made by current initiatives, particularly the Australian
Government, including the buyback of irrigation water and the new Murray-Darling Basin Authority,
and recognises also that current governments have largely inherited the problem. It finds that
declining river flows from upstream diversions, caused by drought and over-allocation, and seawater
incursions have combined to bring the ecosystem to a state of crisis.
For the first time in 7,000 years, Lake Alexandrina and Lake Albert are below sea level and drying
fast, and the habitats of many plants and animals are affected. Waterbirds are in sharp decline,
including migratory shorebirds for which Australia has international responsibilities.
“All our modelling of the system show that increased flows are really the only hope. None of the
engineering solutions proposed to date have anywhere near the same ecological benefits” says Dr
Rebecca Lester of Flinders University, another of the report’s authors.
Associate Professor Walker says: “Warnings by scientists over the past 25 years that this crisis was
inevitable have gone largely unheeded and we are now all being held to account. It is not a matter
for blame, but a call to action. If we are to keep what was once one of the world’s most magnificent,
we need to move very quickly. Quite simply, wetlands need water."
Media contacts:
Richard Kingsford 0419 634 215; Rebecca Lester 0400 828 000; Keith Walker (08) 8598 5362
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