SA releases findings on environmental flow requirements
The South Australian Government has released a series of internationally peer-revied scientific reports that determine the environmental flow requirements for the Coorong, Lower Lakes and Murray Mouth areas.
State Minister for the River Murray Paul Caica said the reports will be crucial in assisting the State Government determine a response to the forthcoming Murray Darling Basin Authority’s final determination of environmental flow requirements.
“The Environmental Water Requirements of the Coorong, Lower Lakes and Murray Mouth reports identify the flow regime needed from the Murray-Darling Basin to maintain the site as a healthy and resilient wetland of international importance,’’ Mr Caica said.
The main findings of the reports are as follows:
- The River Murray should flow out to sea every year, without the need for dredging at the Murray Mouth
- Sufficient water should flow through the barrages and out of the Murray Mouth to export salt and maintain salinity in Lake Alexandrina below 1000 EC 95 per cent of the time
- Water levels in the Lakes should vary seasonally and between years • Higher flows should be delivered regularly to keep the south lagoon of the Coorong.
“The Environmental Water Requirements reports show that to achieve these outcomes, a range of flows, rather than a fixed volume of water, should be delivered from year to year, reflecting the nature of the river as one that experiences periods of low flow and floods,’’ Mr Caica said.
“It shows at least 6000 gigalitres of water should flow through the barrages within every three year period.
“In addition high flows of 6000 and 10000 gigalitres a year every three and seven years should occur to maintain a healthy Coorong.”
Mr Caica said the reports have undergone an international peer review coordinated by the Goyder Institute for Water Research which found that the science underpinning the flow regime recommended for the Coorong and Lower Lakes is accurate and defensible.
“They were also part of a broader set of technical documents used by the Goyder Institute for Water Research in the recent science review of the Guide to the proposed Basin Plan undertaken for the State Government,’’ he said.The Goyder Institute science review indicated that Basin water recovery scenarios of 3500 GL and 4000 GL are most likely to achieve the environmental objectives for the Riverland-Chowilla floodplain and the Coorong, Lower Lakes and Murray Mouth.”
Mr Caica said the Federal Government and Basin State Governments have a responsibility to conserve and protect the ecological character of the Coorong and Lower Lakes.