Not looking good for the Murray-Darling

Here is a rather worrying story from the Australian about the failing health of the Murray-Darling !

Hope dries with water in Murray's lower lakes
Jamie Walker and Pia Akerman
The Australian
August 08, 2008

WITH publicly controlled water reserves in the Murray-Darling plunging to a new low, the despondency of communities on the dying lower lakes deepened yesterday as river managers warned there was no chance of transferring water within the basin.

Meagre flows down the Murray have exposed mudflats near its mouth. Picture: Brett Hartwig

As this dramatic photograph of the Murray mouth and adjoining lakes shows, drought and over-pumping of the river water have wrought more destruction in the past three years than anyone could have imagined.

The fresh water on the right side of the barrage - which for more than 60 years has separated it from the salt water of the Coorong and, beyond the silt-ridden Murray mouth, the Southern Ocean - used to be a massive series of lakes.

In recent years, however, the meagre flows down the Murray have dramatically shrunk the lakes, exposing wide swaths of mudflats, and increasing salinity and the risk of acidification.

The Murray-Darling Basin Commission revealed yesterday that public dams and other reservoirs were barely one-fifth full, when they would normally be between half and two-thirds of capacity. Worse still for struggling farmers and townsfolk at the bottom of the river, the agency dashed any hope of an emergency injection of water from upstream.

"Given the current level of storage, it's not feasible to refill the lakes by transferring water from other parts of the basin without any significant rain," the commission's acting chief executive, Les Roberts, said yesterday.

"As little as 20 per cent of any water released in the north of the basin would reach the lower lakes in South Australia, meaning that four or five times the water needed at the lakes would have to be released from that far upstream."

To the dismay of locals, this will make more likely the controversial option of flooding the lower lakes with seawater and walling them off from the river with a new weir at Wellington, where the Murray meets the lakes about 35km from the existing barrages.

The South Australian Government has committed $30 million to site preparation for the project, and is negotiating to obtain land from fourth-generation farmer Jamie Withers, 37, who is torn by the prospect of the weir across the river. "It would completely change the way we operate," he told The Australian.

For others, it is already too late. Neil Shillabeer, 61, walked away from three generations of family history when he gave up the struggle and sold his farm near Narrung, a spit of land between Lake Alexandrina and Lake Albert. "It's a cancer that will work its way upriver," Mr Shillabeer said of the lakes' plight.

Clem Mason, 58, is clinging on at his mixed farm on nearby Poltalloch Peninsula. He can't irrigate and the grain crop that used to go to market to plump up his income is now reserved for his dairy herd.

"What we have down here is not a drought on the land ... it is a drought on the lakes," he said. "The water is simply not coming down."

Not only has the mouth of the river visibly narrowed since 2005, but the once-brimming expanses of Lake Alexandrina and Lake Albert have given way to lengthening mudflats, which threaten to turn acidic. The river mouth would be choked off entirely without constant dredging.

The grim comparison between what the lower lakes were just three years ago and their near-disastrous state today was underlined by data released to The Australian by the Murray-Darling Basin Commission. In July 2005, Lake Alexandrina contained 1600 gigalitres of water. Now, it holds just 940Gl.

Adjoining Lake Albert, at 100Gl, is down from 280Gl three years ago. The Coorong wetlands, opening onto the Southern Ocean, have tipped into crisis as the lakes dropped below sea level behind a series of barrages constructed in the 1930s. Currently, the level of Lake Albert is 0.3 of a metre below sealevel and requires water piped from Lake Alexandrina, which is at -0.4m.

Scientists fear that increasingly exposed soil beds will become acidic if the lakes fall to 1m below sealevel. SA Water Security Minister Karlene Maywald says this could happen by the middle of the next year if inflows to the river do not improve, forcing the state Government to start preparations to build the new weir upstream at Wellington.

The $120 million-plus project would allow the lakes to be flooded with seawater, protecting them from sulphate acid poisoning but ruining existing freshwater ecologies.

"Every river needs a delta, a wetland," Mr Mason said yesterday. "This is the wetland for the whole Murray River and they are going to cut it off. They are very responsible for their actions, and they are going to be remembered for them."

When full, the lower lakes hold a combined 2200Gl. But their extensive surface area and shallow depth means they lose up to 950Gl annually in evaporation and seepage.

The MDBC estimates that up to 1250Gl would be required to fill the lakes and maintain levels for a year. However, only 350Gl was forecast to flow into them in 2008-09.

http://www.theaustralian.news.com.au/story/0,25197,24146233-2702,00.html