Minister for Water Penny Wong says there are no easy options, only hard choices when it comes to the crisis currently facing South Australia’s Storm Boy country.

But one of the options tabled by the Minister’s own Department in a submission to the ongoing Senate Inquiry I established into Water Management in the Lower Lakes and Coorong could carry with it costs too heavy to bear.

Opening the barrages to flood Lake Alexandrina with seawater is an option that the Australian Greens cannot support. The environmental, economic and social consequences of saltwater flooding of a freshwater ecosystem are numerous and devastating.

Both the South Australian and Federal Governments have put forward the idea of letting seawater into the lakes as a way of keeping in check the toxic acid sulphate soils that are being exposed as the lake beds dry out.

Ask the local people who live around the lakes what they think of that plan, and they’ll say freshwater flows are the only sustainable option. At the Senate Inquiry’s Adelaide hearing last week, Alexandrina Mayor Kym McHugh summed up the saltwater proposal simply as a “no-go” for his community, which was built on the back of irrigation, grazing and tourism. Coorong Mayor Roger Strother compared the spectre of a salty Lake Albert to the hypersaline Dead Sea. Sixth-generation fisherman Henry Jones said marine fauna are having a devastating effect on the creatures native to a formerly balanced estuarine environment.

Ask scientific experts their opinion on saltwater flooding, and they’ll point out that seawater contains sulphate ions, the precursor to sulphuric acid, and so the problem of acidification could actually worsen. The low tidal signal at the barrages means the seawater is unlikely to reach the parts of the lakes and Coorong that are most acidic. Low river inflows and rainfall will prevent effective flushing of the lakes, which will then progressively increase in salinity. The salt will foster more algae, mosquitoes and bacteria, and devastate freshwater species, like the Murrayhardy Head and Yarra Pygmy Perch, that cannot adapt quickly enough to survive. Serious measures, such as a weir, would have to be taken to attempt to stop the saltwater from creeping upstream into the Murray.

Perhaps most alarming is the risk of groundwater contamination by saltwater. The salinisation of underground aquifers that stretch far beyond the lakes’ surrounds could have disastrous consequences for Fleurieu Peninsula and its dairies, vineyards and family farms.

This week in the Senate I asked the Federal Minister for Water if she had commissioned a risk assessment of letting seawater flood into Lake Alexandrina. The answer was no, the Minister had not.  I then asked if the Minister would be commissioning such an assessment. The Senate was told that this would be a task for the South Australian Government. Whether the Federal Government does it or the South Australian Government does it, the lakes and Coorong communities deserve a risk assessment to know what the environment they rely on is facing. And no Minister should be putting forward such an option without knowing all the facts.

Once our lower lakes and Coorong turn to salt, they will never be fresh again. It will be game over for our Storm Boy country as we know it. These wetlands are of global significance, and so we cannot be surprised if flooding them with saltwater loses them their internationally recognised Ramsar status.

There are steps we can take to buy time for the lower lakes and Coorong, without the drastic move of saltwater flooding. South Australian ecologist Dr Kerri Muller told the Senate Inquiry last week about bioremediation, or using plants and mulch to cover the acid sulphate soils. This revegetation does not require water, and is a far preferable option to the irreversible measure of letting in the sea.

But freshwater flows are what the lower reaches of the Murray need, and what the Australian Greens will continue to fight for. A small improvement in rainfall over the lakes has been a small blessing. Ultimately, we must change business as usual, and rethink the overallocation that has gone on for decades. To rehabilitate our ailing river system, we must prioritise the environment and allocate water for the river itself. We must, or else we will simply watch our Storm Boy country fade away into history.

This is the unabridged version of an article that was published on page 18 of the Adelaide Advertiser on Tuesday 23/09/2008.