Summary of the Lower Lakes Crisis

24 January 2010

Very Low Inflows 

The Barrages and Evaporation

Lake Levels below Sea Level 

Acid Sulphate Soils 

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. 

Bioremediation 

Trials by the government have been only partly successful, and these presently cover a small proportion of the exposed sediments (about one quarter, not including what will be exposed this summer) 

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. 

Salinity Problems 

Dredging the Mouth 

Lower River Murray Problems 

Returning the Lower Lakes to an Estuary 

This idea has been met with much opposition about its supposed deleterious effects, and continues to be called ‘last resort’ or a ‘temporary measure’, despite the fact that tidal inundation has been successful in remediation of acid sulphate soils in other Australian states. There has been no evidence published in the public realm to support claims made by government consultants and public servants as to why this proposal could not work. The main objections could be overcome with engineering solutions. They are as follows: 

Use of the Tides 

Modify Barrage Gates 

Seawater Does Not Make Sulphidic Soils Worse 

Estuaries Are Natural 

Conclusion 

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 egordon-mills@lakesneedwater.org 

Sources 

Cresswell, R.G. and A.L. Herczeg (2004). Angus-Bremer Plains. Groundwater Recharge, Mixing and Salinity across the Angus-Bremer Plains, South Australia: Geochemical and Isotopic Constraints. CSIRO Land and Technical Report 29/04. pp.vi+64. 

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. 

Gippsland Coastal Board (2002). What Controls Water Level in the Lakes? Gippsland Lakes Environmental Study. Fact Sheet number 4. Jan. 24, 2002. 

Government of South Australia (2009). Public Health: Acid Sulphate Soils and Dust. Pamphlet March 4, 2009. 

Government of South Australia (2009). Murray Futures Lower Lakes Pipelines. Irrigation water to Langhorne Creek and Currency Creek. Fact Sheet, April 16, 2009. 

Government of South Australia (2009). Acidic water found in Lake Alexandrina region. Dept Environment and Heritage. August 28, 2009. 

Government of South Australia (2009). Murray Futures. Lower Lakes and Coorong Recovery. The Coorong, Lower Lakes and Murray Mouth: Managing for a Healthy Future. Pp.iv+33. August 2009. 

Government of South Australia (2009). River Murray Water Resources Report. Issue 51. Dec. 8, 2009. 

Government of South Australia (2009). Riverbank Collapse Update—Caloote and Sturt Reserve. Dept Water, Land and Biodiversity, December 11, 2009. 

Government of South Australia (2009). Murray Futures. Lower Lakes and Coorong Recovery. Securing the Future. A Long Term Plan for the Coorong, Lower Lakes and Murray Mouth. Draft for Public Comment. Pp. ix+110. 

Indraratna, B., W.C. Glamore, and G.A. Tularam (2002). Effects of tidal buffering on acid sulphate soil environments in coastal areas of New South Wales. Geotechnical and Geological Engineering 20:181-199. 

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. 

Kingsford, R.T., P.G. Fairweather, M.C. Geddes, R.E. Lester, J. Sammut, and K.F.Walker (2009). Engineering a Crisis in a Ramsar Wetland: the Coorong, Lower Lakes and Murray Mouth. Pp. 1-56. Australian Wetlands and Rivers Centre. University of New South Wales 

Walker, D.J. (2002). The Behaviour and Future of the River Murray Mouth. Centre for Applied Modelling in Water Engineering, University of Adelaide. Pp.iii+22.