Basin suffers through 9th dry autumn

10 June 2009

The Murray-Darling Basin has experienced its ninth consecutive autumn with below average rainfall, according to the latest Murray-Darling Basin Authority Drought Update.

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The latest Murray-Darling Basin Authority Drought Update reports that Murray system inflows for May were only 90 GL, slightly above the record low of 75 GL (in 1902), but well below the long term average of 390 GL.

Chief Executive Mr Rob Freeman said that for the June 2008 to May 2009 water year, Murray system inflows were the third driest in 118 years of records.

“This follows the seventh driest year in 2007-08 and the driest on record in 2006-07. Murray system inflows have been below average for nine out of the last ten years,” he said.

“Autumn is a critical time for wetting of the catchment before winter rainfall, but unfortunately, this did not eventuate.

“The prospects for irrigation allocations in 2009-10 will be highly dependent on future rainfall and system inflows,” Mr Freeman said. “Overall, the outlook for the 2009-10 water year remains grim, and is similar to the previous two years.”

He said the Bureau of Meteorology’s recent June to August rainfall outlook for south-eastern Australia indicated average rainfall, but also an increased risk of an El Niño developing during winter and spring.

MDBA active (useable water) storage for the Murray system at the end of May 2009 was 11 per cent of capacity (980 GL), which was well below the May long term average of 4,670 GL. The total volume of water in all Basin storages managed by the MDBA or by State governments, was about 3,940 GL, or 17 per cent of capacity.

Mr Freeman said the northern Basin had received some rain in May which resulted in only a small streamflow response and very little of that water was expected to reach Menindee Lakes. He said the prolonged and severe dry period continued to severely impact on wetlands and floodplain ecosystems across the southern half of the Basin.

“Small amounts of environmental water were made available during autumn to avoid critical loss of threatened species, reduce the risks of irretrievable damage and provide drought refuges at certain sites.

“Salinity along the Murray, upstream of Lock 1, remains relatively low due to the successful operation of salt interception schemes, a gradual reduction in saline groundwater levels during the prolonged drought, and a predominance of river flows originating from the fresher headwater storages in the Murray.

A copy of the MDBA Drought Update is available at www.mdba.gov.au/media_centre/drought_updates

Media contact: Sam Leone, phone (02) 6279 0141.

photo: Irene Dowdy