THE Gillard government faces a fresh brawl with the eastern states over its Murray-Darling Basin plan after placating South Australia with a $1.7 billion pledge to inject extra water into the ailing river system.
Prime Minister Julia Gillard and Water Minister Tony Burke announced the new funding as a way to pump a further 450 billion litres back into the rivers - lifting the total amount returned through their basin rescue plan to 3200 billion litres.
The boost will come through infrastructure upgrades, such as improved channels and dams, which aim to save water while softening the blow to farming communities that depend on irrigation.
''It means that the river, the basin, will be more resilient for the future,'' Ms Gillard said.
South Australian Premier Jay Weatherill, who joined his federal Labor colleagues for yesterday's announcement, stepped back from previous threats to challenge the basin plan in the High Court.
But Victoria led the charge against the plan, with Water Minister Peter Walsh declaring emphatically he would not support a plan that returned 3200 billion litres of water to the river system. He labelled yesterday's announcement a stunt and a fantasy trip, and claimed it ''would cause substantial and sustained flooding of towns and private land, which is totally unacceptable to Victoria''.
New South Wales Deputy Premier Andrew Stoner said he would not be signing up to the plan unless the federal government proved it could ''actually deliver on that infrastructure and water-efficiency funding''.
Both Victoria and NSW argue that the baseline amount of water returned to the environment should be 2100 billion litres, with a possible 650 billion litres on top through savings from so-called ''environmental works and measures'', such as pumping water into wetlands.
Ms Gillard said $200 million would be spent raising bridges and extending dams - known as ''constraints'' - so more water can be flushed through the system without causing flooding.
Recent modelling by the independent Murray-Darling Basin Authority found that with river constraints removed, 3200 billion litres of water would greatly help the environment, especially river red gum and black box woodlands.
Coalition water spokesman Barnaby Joyce questioned how the government was going to deliver the extra water.
''Where are the calculations that add to $1.7 billion? Where's the hydrology study?'' he told ABC News 24. ''This is really into the never, never land stuff … we are $250 billion in debt at the moment … and now you are telling us that by 2024, magically, $1.7 billion will give us 450 [billion litres]. Prove it!''
The Australian Conservation Foundation's Paul Sinclair said buybacks of irrigators' water rights were the cheapest and most efficient way for the government to save water.
''This new funding must not become an ATM for irrigation companies,'' he said.