THE Federal Government cannot buy water to revive the Murray River's Lower Lakes without jeopardising $5 billion of vines, citrus and other permanent plantings.

That's one of the key messages from the Federal Department of Environment, Water, Heritage and the Arts' submission to the Senate Inquiry into Water Management in the Coorong and Lower Lakes.

The department told the inquiry there was enough water in the southern basin's storages to save the lakes from acidification.

But DEWHA warned diverting water to Lakes Alexandrina and Albert would slash the southern basin's horticultural production by $750 million to $1 billion, as well as risk ruining $5 billion of permanent plantings.

Federal Water Minister Penny Wong has dismissed the option, saying permanent plantings have to be protected.

DEWHA's submission also makes it clear buying water from northern Darling irrigators to revive the Lower Lakes is doomed to fail.

The report found even if the Government bought and released all 810 gigalitres held in the northern Darling system's public (210 gigalitres) and private (600 gigalitres) storages, only 160 gigalitres to 240 gigalitres would reach the Lower Lakes.

The report states: "transmission losses are likely to be very high . . . in the vicinity of 70-80 per cent."

"Purchasing water from smaller storages would be a large logistical challenge, with 500 gigalitres held in 2000 dams. Much of the water would likely have to be pumped to return it to river systems."

DEWHA also dismissed the option of releasing water from the Menindee Lakes to raise the levels of the Lower Lakes.

It said the Menindee Lakes held 512 gigalitres, part of which needed to be set aside to meet critical human needs, including Adelaide's water supplies, for 2009-10.

Of the 512 gigalitres in the Menindee Lakes, about 200 gigalitres was underpinning current critical human needs, 200 gigalitres more was needed to cover evaporation losses, 34 gigalitres was dead storage and 50 gigalitres would be lost getting the water to the South Australia's Lower Lakes.

As for squeezing any more water out of the southern Murray Darling Basin, the DEWHA submission simply stated there was only 3949 gigalitres in storage.

Yet the Murray Darling Basin Commission is already committed to delivering 4292 gigalitres to meet town, stock, irrigation carryover, loss and dilution flow commitments.

One of these commitments is to deliver 350 gigalitres in dilution flows across the South Australian border and into the Lower Lakes to maintain Adelaide's water quality.

The inquiry was formed to determine if a rescue package could be developed to "save" the lower lakes and Coorong.

University of Adelaide and CSIRO scientists have found the Lower Lakes are suffering as water recedes, exposing acid sulphate soils that are releasing toxic aluminium into the water.