NSW Water Commissioner, David Harriss, has released a report summarising the management of the 2011-12 floods through the Barwon-Darling and Menindee Lakes systems.

 

Mr Harriss said that after nearly 10 years of drought throughout much of the Murray-Darling Basin, this was the third year in a row that the Office of Water and State Water Corporation had managed flood flows through the river systems in the west of the state.

 

“This is typical of the extreme variability of the Australian climate, and particularly in the Murray-Darling Basin,” Mr Harriss said.

 

Mr Harriss said that the floods in 2011-12 were the result of three separate rain events that included the wettest November in 133 years of records at Moree and the largest 8 day rainfall total at Wilcannia in 133 years of records.

 

“This led to record flooding in the Balonne River at St George and equalled the highest river level at Bourke since 1976.”

 

“In total, about 5,700,000 megalitres flowed past Wilcannia between mid-December 2011 and late May 2012 - over 11 times the volume of Sydney Harbour.”

 

Mr Harriss said that the Menindee Lakes, near Broken Hill in far-west NSW at the end of the Barwon Darling System, are surcharged above full supply levels.

 

“Flows from the Menindee Lakes into the Lower Darling River downstream of Menindee are now being increased to reduce the storage levels in the lakes to accommodate inflows expected after the mid July rainfall in upstream catchments reducing surcharge levels.”

 

Flows will increase to 4,000 megalitres per day to the Lower Darling River which will pass more water into the River Murray downstream and flows will also be released from Lake Cawndilla into the Great Darling Anabranch.”

 

The report into the Management of the Barwon-Darling floods of November 2011 – June 2012 is available on the Office of Waters website at www.water.nsw.gov.au.