Acid Sulphate Soils
Acid Sulphate Soil problem and the reason for urgency. View the Catalyst show segments:
Catalyst: Drought Culprit, ABC TV Science, 28 May 2009
Catalyst, Fire, Flood and Acid Mud, ABC 1 May 2009
"Acid Mud" and "Coorong: The End of the LIne" are especially pertinent to the Lower Lakes region
A full scale weir at Pomanda (or other suitable location) would be necessary to prevent seawater from contaminating the fresh water in the River.
Regulator at Clayton would not be necessary if the lakes were returned to estuarine conditions.
Vegetation (not revegetation) of the exposed lakebed is a very unnatural activity.
In their natural (pre-barrage) state the lakes could never fall below sea level and the acid sulphate soil problem could not happen.
Severe drought has made freshwater unavailable, and so the choice becomes-either - no water - with exposed lakebeds, acid soils, erosion and corrosion, lime and bioremediation - or - seawater - with a thriving marine estuary.
While lime and bioremediation may neutralise acid soils on small areas of exposed lakebeds, - it is an unnatural alternative to having lake levels maintained as an estuary, and it is impossible to implement across the vast expanses of the lakes.
Proposed bioremediation is not likely to work, (20,000 hectares currently exposed according to the DEH). Climatic conditions, wind, no rain during summer, heat waves. Commonly sited example of bioremediation success is the East Trinity site in Qld which is only 700 hectares in an easy growing climate. see ASSAY, A Newsletter about ASS soils for details.
More from our website at http://www.lakesneedwater.org/remediationjournal
Trials to date have not been successful despite the claims.
Interesting Letters To the Editor:
Collection of favourite research reports:
A recap of our reasoning on this page http://www.lakesneedwater.org/case-for-seawater
There is not enough fresh water in the system to ameliorate the problem of keeping the acid sulphate soils covered. If the Lakes were returned to tidal estuaries, a rich and diverse ecosystem would ensue, thereby maintaining a Ramsar wetland as a marine system. Judicious opening and closing of the barrage gates according to the tides would allow for circulation, preventing hypersalinity.
The Lakes’ problems of 'no water' can be de-coupled from the overall problems of the River Murray water shortage, and should be separate given the Lakes previous history and proximity to the sea.
Ex: no other river is dammed up at the mouth (true?), barrages would never be built now knowing what we know about the environment.
The government is not preparing for the time when they will be forced to use seawater. The planning should be happening now in tandem to their other 'plans', and it should be public. To do otherwise is foolhardy.
The current Govt. ‘fixes’ are short term or too long term, and do not ‘fix’ the issue of 'no water' . ASS soil danger for all the regions around the LL still exists unless they use seawater.