GIS Bathymetry Analysis Helps Protect Threatened Ramsar Wetland Site—Coorong Lower Lakes and Murray Mouth, Australia

Department of Environment and Natural Resources, Government of South Australia

Australia's Murray-Darling Basin exits to the Southern Ocean through the coastal region of South Australia known as the Coorong, Lower Lakes, and Murray Mouth. This 140,000-hectare (540-square-mile) area is recognized as a Ramsar Wetland of International Importance due to its abundant bird habitat and unique ecological values.

For seventy years, barrages installed near the River Murray mouth have maintained water levels in the Lower Lakes at around 0.7 of a meter above sea level. From 2007, the over allocation of water for human needs, combined with a deepening millennium drought, resulted in an unprecedented drop in freshwater inflows. This led to a decline in lake water levels, exposing vast areas of lakebed sediments. Acid sulfate soil became a real threat to nearby human communities and the wetland aquatic system, with the potential to radically change the ecological character of the area.

GIS bathymetry was used in conjunction with extensive biophysical monitoring to predict the location of acid sulfate soils. GIS-supported actions consisted of targeted water regulation, aerial limestone dosing to neutralize acid sulfate soils, and aerial seeding programs to stabilize exposed lake bed sediments. These measures helped to mitigate deterioration of the site for the benefit of the community and to protect its ecological character.

Courtesy of the Department of Environment and Natural Resources, Government of South Australia.

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