Murray-Darling in poor state
Large parts of Australia's vital Murray-Darling Basin are in a critical condition, according to a report from a panel of independent experts.
Only one valley met the criteria for a good rating, while seven were judged to be poor and 13 were very poor.
The basin covers most of South Wales and Victoria, as well as parts of two other states, and is home to nearly half of Australia's farmland and food production.
The report was compiled by four ecologists using data gathered by state agencies from 2004-07.
Commission chief executive Dr Wendy Craik said: "While we have been aware of the degradation of our river system for some time, this sort of comprehensive study gives us the detailed data we need to plan for the future."
Alien species of fish rivalled or out-numbered native fish in nine of the 23 valleys and the most common alien species, the common carp, accounted for more than half of the fish biomass in the basin.
The Green Party called on the Federal Government to speed up action to save the river system.
"Under the government's current approach, their much vaunted basin plan doesn't come into effect until 2019," Senator Rachel Siewert said.
"It is obvious from the information we've received that the system will be gone by then. Instead of fiddling around the edges of the current system, the government should be requiring changes to be made now."
Water Minister Penny Wong admitted the report was a "sobering indicator" of the effects of climate change, drought and over-allocation of water.
But she claimed it was caused by the inaction by the previous government, and the Rudd administration is working to reverse the damage.
It has already committed $3.1bn to buying back water for the basin, and promised other investments in infrastructure.
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