More water for Murray-Darling, says report

By Joanna Egan 7 June 2010
Reading Time: 3 Minutes Print this page
Climate change experts warn that more water needs to be diverted into the Murray-Darling Basin to sustain future agriculture.

CLIMATE CHANGE EXPERTS warn that more water needs to be diverted into the Murray-Darling River system to be able to sustain Australia’s future agriculture.

In its report, released last week, the Wentworth Group of Concerned Scientists’ (WG) conclude that, in addition to existing caps on river diversion, 4,400 gigalitres of water needs to be diverted back to the system to restore the flow to two-thirds of its natural rate.

“We need a major change in the way we manage the river system,” says WG agricultural scientist Dr John Williams. “It’s about [restoring] the flow into the wetland and the flow back into the river so that we get the food chain being built up … it’s about putting the river system back together again so it’s healthy and functioning, so we can have sustainable irrigation into the long term.”   

One third of Australia’s food

Twenty major rivers flow through the Murray-Darling Basin, which stretches over about one seventh of Australia’s total land mass. They support the production of over one third of Australia’s food supply and provide water to about three quarters of Australia’s irrigated crops and pastures.

But the precious resource is being stretched too far and too much water is being diverted for irrigation and too little is being left to sustain the river system. As a result there is a real risk the ecosystems supporting them will collapse, which will have a devastating effect on the economies and communities that rely on it.

The Federal Government has allocated $8.9 billion as part of its Water for the Future program to facilitate the reduction of extractions from the Murray-Darling Basin. In the coming months, the Murray-Darling Basin Authority is set to release a Basin Plan that will set caps, known as sustainable diversion limits, on the total amount of water that can be taken from the system and used for irrigation.

The WG report makes its own recommendations for caps on 18 water catchments. “First we looked at the how much water we needed in each catchment,” says WG environmental engineer, Tim Stubbs. “Then we moved to the economics and said, ‘If we want to take this out of the Basin at the lowest economic cost we need to take it from the catchments where we’re getting the lowest dollars per megalitre in return’.”

Major reductions

Their approach suggests that each catchment needs to reduce its water extraction from the river system by less than 10 per cent. Two catchments, however, will be more drastically affected, Tim says, with the Murray likely seeing a 39 per cent reduction in how much the catchment can take from the system and the Murrumbidgee set for a 65 per cent reduction.

The new report criticises the Government’s Water for the Future program and offers its approach as a more viable alternative. “Today’s policy is focussed too much on those within the Basin communities that are in water dependent industries and much less attention is given to rural residents of Australia who work elsewhere but whose communities will be just as much affected by having to live with less water,” says Professor Chris Miller from Flinders University, who helped compile the report.

Under current policy, only those with water to sell will receive financial compensation and little support will be provided to help the broader community adjust to a future with less water. WG’s approach hopes to invest $5 billion of the Federal Government funding in public infrastructure to “assist the communities most affected by reductions in diversions to restructure their economies,” it states in the report.

“The impacts on communities are going to flow beyond irrigators and to all people within those communities,” says Tim. “[Our approach] is a supported change as opposed to just investing in irrigation infrastructure and taking water out of communities.”