Photo 1. Exposed Lake bed, northern Lake Alexandrina, November 2009
Photo 2: Close up of lake bed in photo 1. Yellow crystals of indicate highly acidic soils
In its recent “Securing the Future” document released in December 2009, the Government has mentioned the possibility of ‘drying down the Lakes’ if the seawater option is not practical. This would be a disaster of immense proportions, and the possibility of recovery to any type of wetland, freshwater or marine, would be put off for hundreds of years.
Pre-germinated seed incorporated in November 2009 have been described as “successful”, but this is yet to be proved effective in the longer term over the summer period. Seeding of the large number of highly acidic areas such as Loveday Bay will also require vast amounts of limestone to be spread (hundreds of thousands of tonnes), since the lowest pH tolerance of the Pucinellia grass used is around pH 5. Levels of pH <3 have been measured in Loveday Bay.
Seeding and other bioremediation efforts have been concentrated around population centres where voters live or have large vineyards (eg Tolderol). There remain very large areas of exposed lake shores (see photos above) which are already highly acidic, and for which no immediate bioremediation can occur. These have low population densities, but will still contribute to the acidification of the lakes.
Although the possibility of seawater entering the Lower Lakes has been mooted by the State Government, we have yet to see any detailed plans of how this would occur. Valuable time for system development has been lost over the last two years with the unrealistic insistence on a fresh water solution. How is it that we could have allowed such a crisis to happen in our supposedly enlightened country? What is looming now is comparable with the Aral Sea problem which occurred many years ago in Soviet Russia, and has always been the source of derision of the bad management which led to this disaster. Lack of political will, too much attention to vested interest groups, and lack of balanced scientific input are all to blame.
If the concept of the Lower Lakes returning to their estuarine state were to be explored with open minds and scientific rigour with our best engineers assisting, we have no doubt that it is possible to accomplish this dramatic improvement towards a healthy estuarine system. By openly discussing this option, the public will in turn be able to come to grips with a new reality.
It is the only win-win, sustainable solution that South Australia has, given the change in our climate.
This report has been prepared in consultation with a number of people associated with the LakesNeedWater group and others with appropriate expertise.
Dr. Elizabeth Gordon-Mills is the primary contact person for enquiries arising from this report. Please contact her on firstname.lastname@example.org
Crosier, P. (2008). Water in a Changing Climate. Keynote address to the water policy summit. Conservation Council of South Australia.
CSIRO (2008). Water Availability in the Murray-Darling Basin. A Report from CSIRO to the Australian Government, October 2008. Pp. 1-67.
Department of Environment and Heritage (2009). The Future for Lake Albert. An adaptive management plan, October, 2009.
Fitzpatrick, R.W., P. Shand, and R.H.Merry (2009). Acid sulphate soils. In: Jennings, J.T. (Ed.) “Natural History of the Riverland and Murraylands”. Royal Society of South Australia (Inc.). Adelaide, South Australia, pp. 65-111.
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Johnston, S.G., R.T.Bush, L.A.Sullivan, E.d.Burton, D.Smith, M.A.Martens, A.E.McElnea, C.R.Ahern, B.Powell, L.P.Stephens, S.T. Wilbraham and S.van Heel (2009). Changes in water quality following tidal inundation of coastal lowland acid sulfate soil landscapes. Estuarine, Coastal and Shelf Science 81:257-266.
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