In high concentrations, blue-green algae can discolour water, form scums, produce unpleasant odours, and release toxins that can be harmful to both humans and wildlife. As a result, once blue-green algae concentrations reach a particular level, the Torrens Lake is temporarily closed to the public for health reasons. These lake closures can extend over weeks and months, causing significant social, economic and environmental impacts.
An algae management program was developed with the support of Green Adelaide, the Department for Environment and Water, SA Water, the Environment Protection Authority, the City of Adelaide and the City of Charles Sturt.
As part of the project, a variety of strategies have been tested to keep blue-green algae concentrations in the lake down over summer. The most successful strategy to date is to provide a controlled flow of fresh water down the river. This controlled flow dilutes nutrient levels, cools the lake water and keeps it well mixed.