HOME » Ramsar listed Wetlands of International Importance » The thirsty Coorong » Five years without river water
Five years without river water


 
Play  The very thirsty Coorong  website mike geddes.mp3  
To listen to soundfile: click on the headphones icon
To download soundfile: click on the mp3 file name

 

 
Dr Mike Geddes, a Visiting Research Fellow at the University of Adelaide, looks at one of Australia’s struggling Ramsar sites. Dr Geddes has spent many years researching The Coorong and this area is having ecological difficulties. The Coorong still meets the Ramsar criteria for international bird flyways, diversity of aquatic habitats and fish diversity. The Coorong was declared a Ramsar site in 1985, especially because the focus then was on migratory birds and the sight of thousands of stints and sandpipers migrating to The Coorong caught a lot of attention.
The area also has salt water lakes and fresh water streams and there is a gradient of water from fresh water to estuarine water to hyper marine water. When Dr Geddes was working with David Paton in the South Lagoon in the 1980s, the migratory bird numbers were between 100,000 and 3000,000 over the summer months. South Lagoon was also home for the Australian waders such as avocets, herons and banded stilts, along with ducks, swans, cormorants and pelicans.

 

 
The Coorong is struggling now. There has been no water added since 2005.
The barrages that separate the freshwater Lake Alexandrina and Lake Albert from The Murray (and which have been in place since 1940) have seen no water from the Murray pass into the lake and this lack of freshwater flow has meant that salinity levels in The Coorong are rising.
At the moment the salinity levels in the southern end of The Coorong are 3.5 times those of seawater. The Coorong is of course, open to the sea and this is maintained by dredging but there has been no freshwater flow from The Murray to counteract this.
The South Lagoon was once filled with diverse invertebrate fauna on which the birds fed but today it resembles a salt lake, like Lake Eyre. There is no marine fauna except for brine shrimps which are found in salt lakes. The invertebrates have moved elsewhere in the system. This change in ecological character was reported to Ramsar in 2009.

 

 
The future of The Coorong will depend on the plan for the Murray-Darling system and Dr Geddes hopes that end of system flows will be introduced, thus rejuvenating The Coorong. Lake Alexandrina has had dropping water levels due to the long drought and is also becoming saltier as the water evaporates. In fact in March this year the water level in the lake was one metre below sea level and that water was brackish at best. Ironically the barrages now serve to keep the sea water out of the lake (rather than holding back the flow of fresh water out from the lakes) so freshwater flows down the Murray are desperately needed.
Water levels are not as big an issue in The Coorong, as that is determined by the sea, however, the rising salinity is. Some 20 kilometres from the mouth of the Murray the salinity in The Coorong is higher than the sea itself and in the narrow waters that separate the North Lagoon from the South Lagoon the salinity is twice that of the sea. In the South Lagoon the salinity levels have been as high as five times that of the sea, highlighting the consequences of lack of flow.

 

 
Another problem for the lakes is the release of sulphuric acid. The soil contains sulphides which, when exposed to the air as a consequence of receding water, oxidises to sulphates. When wet these sulphates produce sulphuric acid, a problem the state government is trying to manage. Water is even now being pumped from Lake Alexandrina into Lake Albert to keep water levels up and limestone is also used to neutralise the acids in the soils. The SA Government is also aerial seeding to promote vegetation growth and hence bacterial growth which will ease the acid soil threat. Dr Geddes would like to see 40% of freshwater flows reaching the mouth of the Murray.

We should go with that flow.

Text: V.B. August 2010
Images from Michael Geddes are depictions of The Coorong from 2006 through to 2008.

For more information, please contact us
 
Ramsar conference wrap up with Ken Gosbell

Print Friendly Add to Favourites
Design & SEO by Image Traders Pty Ltd.  Copyright © A Question Of Balance 2017. All rights reserved.