Doomed Planet

Murray facts & fictions

False story told to save the Murray

The one issue that has received very little public scrutiny in the contentious debate on the Murray Darling basin water reform is the false premise that the Murray River’s terminal Lower Lakes must be maintained as a freshwater environment when the historical record, empirical evidence and much of the peer-reviewed scientific literature demonstrates an estuarine history. 

This issue is central to the credibility of the current Murray Darling Basin Authority draft plan because of the large amount of water required from the basin to maintain the lakes as a freshwater system.

Massive concrete sea dykes (barrages) 7.6km in length were completed in 1940 separating the Lower Lakes from the Murray mouth and the Southern Ocean forever, changing a flourishing and biologically diverse estuarine environment to an artificial man-made freshwater lake system full of European carp.

During times of plenty, this system now totally dependent on Murray River inflows could be maintained at a constant and artificially high level, but as the last drought has shown there simply is not enough water storage available in the basin during extended drought to maintain this unsustainable environment.

This false premise that the Lower Lakes be kept fresh underpins the major focus of the current draft plan of scavenging water from anywhere in the basin to achieve this end. The worst aspect of this egregious situation is that water is denied to emblematic natural environments, such as the Ramsar listed Barmah-Millewa forest to foolishly maintain an artificial and unsustainable environment in the Lower Lakes. 

Former MDBA CEO Rob Freeman was clear on this subject in an interview on October 9 2010 saying “If the Coorong, Lower Lakes and Murray mouth were chosen as a priority in this particular example, then insufficient water will be available in the median-to-wet years to meet targets at floodplain sites like Barmah-Millewa forest.” What a perverse outcome, where artificial environments are prioritised over natural environments.

How did we get to this, where a false premise based on junk science, is accepted as the starting point for major water reform?

A clue can be found by examining the populist narrative that has been established over the last decade by environment groups, South Australian and some federal politicians, the media in general and people who genuinely care about the Murray. This is expressed as: fresh water is good, estuarine bad; the environment is good – even if it is man-made, irrigated agriculture is bad; city water use is frugal, rural water use is wasteful.

 This is an easy narrative to establish, particularly during the worst drought that many of us have ever seen, but like many concocted narratives it can be unravelled by anyone who cares to probe.

Professor John Briscoe from Harvard University a globally recognised water expert who was appointed to the MDBA High-Level Expert review panel, in a submission to the senate inquiry into the Water Act 2007 said,

The environmental vote was important in the election of 2007.  After seven years of drought environmental conditions were poor, not least in the Murray Darling Basin.  The electoral arithmetic of Australia is such that most of the electorate live in the coastal cities. Most city dwellers have both little knowledge of the land and water environment of the world’s driest continent, and a paternalistic and dim view of farmers and agriculture. He who could capture the environmental vote would strongly improve his chances in the election. Most environmental minded voters were Labor. If the Liberal Party were to woo some away it had to do something dramatic. The Water Act of 2007 was one of the dramatic efforts.

The Water Act is the legislative framework for any MDBA plan and was adroitly conceived and framed for political advantage, while at the same time conforming to the populist narrative.

The stark fact that the Lower Lakes were a naturally healthy estuarine environment when the massive sea dykes were constructed is denied or glossed over in the current narrative. This is reinforced via scientific reports to the South Australian government, which rather than portray the established scientific literature chose to conform to government policy, which is to maintain a freshwater lake system.

This conveniently allows the South Australian and federal governments, as well as the MDBA, to point to a scientific basis for maintaining the status quo at enormous cost to basin environments and communities.

Digressing for just a moment: If the Lower Lakes was a freshwater system as many vigorously maintain – why were the sea dykes built in the first place?

This dubious science that so conveniently conforms to government policy; is now called into question with the release of a peer-reviewed report by the Australian Environment Foundation written by biologist Dr Jennifer Marohasy.

This report shows that water minister Tony Burke could buy back all the water in the basin and still fail to keep the Murray mouth open despite his assertions that more water would keep the mouth open nine years out of ten. 

The report also shows, as do other reports, the interrupted evolution of the estuary and Lower Lakes through the construction of the sea dykes has had a degrading impact on the environment.

Bird Island immediately behind the sea mouth of the Murray never existed prior to the construction of the sea dykes; it is now a kilometre in diameter with dunes four metres high and is increasing in size each year. It is likely Bird Island will permanently plug the mouth of the Murray River while the sea dykes stay closed.

The MDBA and the Water Minister can continue to develop the plan based on a false premise and junk science, but the next drought will lead to drying Lower Lakes once again, as there is not enough water storage during extended drought to offset the 800 -1000 gigalitres of freshwater evaporated every year from a large shallow lake system. To put this massive evaporation loss in some context, Adelaide draws on average 200 gigalitres each year from the Murray. 

It seems too self-evident to state, but we would all rather evaporate sea water than precious fresh water when “insufficient water will be available in the median-to-wet years”, let alone dry years for all of the basin’s environments.

The other alternative to the current plan is to accept the science and the historical record; open the dykes and let the tide in to restore a natural biologically diverse estuarine environment at no cost to the taxpayer, basin communities or the environment.

Max Rheese is Executive Director of the Australian Environment Foundation

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