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The Forum > Article Comments > Restoring the Murray River's estuary > Comments

Restoring the Murray River's estuary : Comments

By Jennifer Marohasy, published 26/3/2012

Something Barnaby Joyce and Sarah Hanson-Young should agree on.

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A good article. As a former Crow eater I am ashamed to say that not only does this article hit the nail on the metaphorical head, it exposes much current thinking in Nanny State South Australia.

Lets cut to the chase. There is nothing either the Federal or state governments can do about the Murray. It's in full flood now which will give it a flush but even with taking the barges away, there simply is not enough water (in lean years) to irrigate the southern reaches.

The best thing farmers can do in SA is make a rational decision to save their families and that is to sell up.
Posted by Cheryl, Monday, 26 March 2012 9:51:32 AM
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I agree also. SA people have a fairly major sense of entitlement. They not only want to 'save' the lakes but draw water from the Murray upstream so they can crack 2m population. How about this proposition? Either; save the lakes and reduce population or go for 2m but open the barrages.

Some greens have outed themselves as closet conservatives. The geological destiny of the lakes is to become permanently saline only prevented by the barrages and taking water from upstream users. The fresh water should be held in by a weir near Wellington with a channel kept open to the sea. Yes that means at low tide in dry years Lakes Albert and Alexandrina and the western Coorong will get hypersaline and perhaps even smell bad at times. That or reduce population; can't have it both ways.
Posted by Taswegian, Monday, 26 March 2012 10:06:19 AM
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The Vasse-Wonnerup Estuaries in SW WA cover 2000 hectares of Ramsar listed wetlands. Since the 1920s, two sets of floodgates have prevented seawater from entering the estuaries, protecting farmland from saltwater and providing flood protection to the Busselton townsite.
In the 1980s, the Busselton Naturalists Club (of which I'm the president)successfully campaigned to allow controlled amounts of seawater to enter the estuaries to prevent summer fish kills and to provide water and associated food resources for up to 30,000 waterbirds. The state environmental agency opposed this move on the grounds that impacts were unknown, but they have since relented somewhat when a survey in the 2000s showed 37,000 birds still using the estuaries.
The Club is now trying to have more fresh seawater enter the estuaries each summer to more closely mimic pre-European hydrological regimes. The state environmental agency is opposing this, publicly saying that this change will kill the small area of freshwater-dependent vegetation which has established around the edge of one estuary in the years since the floodgates were installed. The more likely reason for their opposition is that they will have to better manage water levels in the estuaries and take some flak if any agricultural pastured land is affected by seawater.
The wetlands behind the barrages at the mouth of the Murray River are many times larger than the Vasse-Wonnerup but the technical and environmental issues seem to be identical: a denial by scientists and others that they got it wrong when the barrages were first installed; and a reluctance to expose themselves to criticism should they return the system to natural hydrological regimes, should something go wrong.
In the 1980s, the statement which finally achieved the desired change of management of the Vasse-Wonnerup estuaries was that this would be a trial which could be easily reversed if it didn't work. Management of the Murray's mouth could be subject to a 5 or 10 year trial of allowing seawater through the barrage, after which a science-based review assesses impacts and recommends what should be done in the future.
Posted by Bernie Masters, Monday, 26 March 2012 11:01:19 AM
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Interesting points Bernie. How about writing us an artcle?
Posted by GrahamY, Monday, 26 March 2012 8:23:30 PM
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The barrages on the lower Murray are a folly and with rising sea levels the barrages will eventually be confined to history. Water management in South Australia has always been in conflict with water quality. Evaporation from the storages such as Lake Victoria increases the salt content and reduces the volume. The weirs and the barrage raise the river level and this in turn raises the groundwater levels. As much of the lower Murray is incised into lacustrine sediments the flow in and out of the groundwater system is rapid. During times of low river level this groundwater returns to the river with lots of mobilised salt and this has a disastrous effect on water quality.
Posted by SILLER, Sunday, 1 April 2012 11:58:20 AM
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