The Torrens Lake is an important community asset and tourism icon for Adelaide, but for much of its recent history it has suffered from frequent and repeated blue-green algae (cyanobacteria) blooms.
These microscopic blue-green algae are naturally occurring, but can reach high concentrations (or 'bloom') in situations where warm temperatures, stagnant water and high nutrient levels combine.
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. Lake closure can extend over weeks or even months, and the social, economic and environmental impact is significant.
What is being done?
The River Torrens Water Quality Improvement Project was developed with the support of the then Adelaide and Mount Lofty Ranges NRM Board (now Green Adelaide), the Department for Environment and Water, SA Water, the Environment Protection Authority, and the City of Adelaide.
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 tool we have at the moment is to provide a controlled flow of fresh water down the river. The controlled flow event dilutes nutrient levels, cools the lake water, and keeps the lake water well mixed.
Water flow data
Department for Environment and Water, SA Water, the Environment Protection Authority and the City of Adelaide.