Barrages Block Sense

Let's be honest:  a dry river is not necessarily an environmental catastrophe.  Last week we were warned that a leaked government report claims there is only six months to save the Murray-Darling Basin.

In response, the Federal Opposition leader, Brendan Nelson, called on the Prime Minister, Kelvin Rudd, to make a joint tour of the River Murray's lower lakes region.

Mr Nelson said he thought it was "very important that the leaders of this nation have a first-hand look at the environmental, economic and human catastrophe which is unfolding in the Lower Murray lakes".

The leaked report focused on the lower lakes, and as I have previously written (Acid Sulfate Blame Floating Upstream, The Land, May 15), a solution to many of the environmental problems at the Murray's mouth is to simply open the barrages and let the area flood with saltwater.

The barrages were built from the 1920s to keep the Southern Ocean out and to raise the lake level, including for boating.

These same barrages also facilitated the development of irrigated farming in this area, but they are unnatural.

If the barrages were now opened, irrigators dependent on freshwater from the lower lakes would need to be compensated.

But the alternative, continuing to send large quantities of water from the drought-drained reserves in the Hume and Dartmouth dams during this protracted big dry, is less viable.

Some argue that if a permanent weir was constructed just upstream of the lakes at Wellington and the barrages used under "an adaptive management regime", there could be water savings in the order of 750,000 megalitres a year.

Opening the barrages would take some pressure off the system, because less water would need to be allocated to South Australia, but the river could still run dry.

Indeed, it doesn't matter how many leaked government reports call for more water for environmental flows, if there's ongoing drought and the upstream dams runs dry, there will be simply no water for the river.

It would be an economic and human catastrophe for the many towns now dependent on the river for their water supply, but it would not necessarily be a catastrophe for the environment.

The River Murray in its natural state could be reduced to a chain of saline ponds.

Indeed, the idea that a river should be always brimming with freshwater is a very European concept -- in reality, alien to a land of drought and flooding rains.

So, let's be honest, many South Australians want to keep the barrages shut to the Southern Ocean and many Victorians and New South Welshmen want to keep the river full of water -- not to save the environment, but to avoid what Mr Nelson has described as a potential economic and social catastrophe.

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