Environmental vandalism?

Seawater flooding likely for Murray

"It's the writing on the wall, that's for sure," water scientist Stephen Beare said.

Ms Maywald, who has been fronting public meetings this week in the lower lakes communities, said there was a "70 to 80 per cent chance" that the weir would proceed.

But she admitted that the cost of site preparations was at least 20 per cent of the budgeted cost of the weir, estimated at between $120 million and $150 million.

Asked if the controversial project was now inevitable, Ms Maywald said a final decision would not be made until next month. She insisted that building the weir remained an option of last resort to insulate Adelaide's domestic water supply from opening the barrages currently sealing off the lower lakes from the sea.

"We do not want to do this," she said. "If it happens, our hand has been forced."

Gee. I'm sure there was never a drought before, since time began, which caused the Murray/Darling such a terrible problem. It's a good thing that mankind has the technology to save the river and the lower lakes by pumping sea water into it.

I'm pretty sure that it will change the ecology of the area and introduce a whole raft of new problems to the mix.

However, on current indications, the tipping point for acidification of the lower lakes would be reached in June next year. Construction of the weir would take nine months, meaning preparatory work had to begin now.

Currently, the level of Lake Alexandrina is 35cm below sea level. Ms Maywald said acidification would be triggered at negative 1m, occurring next June unless NSW and Victoria reversed decisions to release reserves into the parched river or rains flushed out the system.

Fourth-generation Lake Alexandrina fisherman Henry Jones, 65, reacted with dismay to the move yesterday.

"It is devastating to people down here. You can see it in their eyes ... we have been living in dread of this."