THE parched and vanishing Lower Lakes have won a death-row reprieve, thanks to a life-giving inflow of floodwaters secured from NSW.

The State Government announced late yesterday it had secured 148 billion litres of the estimated 800 billion flowing into Menindee Lakes following heavy rains late last month, Adelaide Now reports.

The extra water will be enough to "significantly" stave off plans to build a weir at Wellington, halt acidification and rising salinity levels in the lakes and mitigate the risk of riverbank collapses.

The amount - which Premier Mike Rann said was the "first slice" of water and hinted there might be more to come - is more than some commentators had expected but still a small portion of the total.

NSW can only store up to 610 gigalitres (billion litres) in the Menindee Lakes system and would have to hand control of the water to a federal authority if storages exceeded 640 gigalitres.

The announcement follows a sustained campaign by The Advertiser and AdelaideNow, which included a petition signed by more than 6200 people.

The news comes as the Bureau of Meteorology predicts a cooler end to summer, more rain and a low chance of future heatwaves.

On the back of global warming concerns, the Bureau's latest seasonal forecast, released yesterday, shows the state is due for a drop in temperature and above average rainfall.

The prediction means:

  • A likely drop in water consumption;
  • Lower rates of evaporation
  • Less pressure on the state's power supply and;
  • Less chance of a repeat of last January's sweltering two-week heatwave, where more than 700 people were admitted to hospital and at least 75 died.

Images of NSW awash with floodwaters, published in The Advertiser on January 6, caught the government on the hop and sparked negotiations.

The total amount secured was closer to 200 gigalitres but between 30 and 50 gigalitres is expected to be lost to evaporation, seepage and recharging groundwater storages.

Environment Minister Jay Weatherill said the water will be stored in Lake Victoria, near the state border, and released into the Lower Lakes as needed.

It would take about 15 days for the water to reach Lake Victoria and another seven to 12 days to reach the Lower Lakes.

Mr Weatherill labelled it a "massive win" for the lakes.

"We've had to fight for every drop of this water," he said.

The River, Lakes and Coorong Action Group welcomed the water which it said would make an "enormous difference" to the quality and ecology of the lakes.

It also would delay the possibility of opening the barrages to let seawater into the lakes, spokeswoman Professor Diane Bell said.

"However, it illustrates we need a federal independent body managing the river because more water was available," she said.

"There was somewhere between 200 and 300 gigalitres that could have come down."

Mr Rann stressed NSW was under no legal obligation to release any water to NSW.

"Together with the State Government's 170 billion litre environmental reserve, this means that an extra 320 billion litres will flow into the Lower Lakes this year," he said.

The government has secured 104 gigalitres of this 170-gigalitre target and has until March 31 to secure the rest.

Under yesterday's agreement, 48 gigalitres has been allocated under the Living Murray Initiative's Darling Anabranch water supply project.

While the government says this is all new water, the Opposition claims SA was already entitled to that water.

"We were already going to get that," Liberal Water Security spokesman Mitch Williams said, labelling the explanation "spin".

"NSW is working overtime to divert the water every which way to ensure bugger all is left for SA. They are obviously trying to keep everything they can.

"All we're getting is the crumbs that fall off the table."

Adelaide University water expert Mike Young said Adelaide used about 200 gigalitres of water in a typical year without water restrictions while 250 gigalitres would be enough to cater for all SA irrigators, currently on 48 per cent allocations, for a year.

Meanwhile, Country Fire Service assistant chief officer Rob Sandford said, despite the Bureau of Meteorology's forecast of cooler weather yesterday, there would have to be a dramatic change in weather patterns to decrease the state's bushfire risk.

"We're not going to reduce our risk of fire based on a small amount of rain that we may or may not receive," he said.

"And from a temperature perspective, we would need to significantly lower our maximum temperatures for it to make any difference."

Read more on Adelaide Now.