Environment SA News

Torrens Lake algae control trial underway

An annual project to control blue-green algae in the Torrens Lake during Adelaide’s summer months is underway with a release of fresh water from upstream storages.

Torrens Lake algae control trial underway
The iconic Torrens Lake has received a flow of fresh water to prevent build-up of blue-green algae

The flow of water over a two day period helps dilute any blue-green algae in the lake, with the aim of preventing a build-up in the lead up to Christmas.

Natural Resources Adelaide and Mount Lofty Ranges Senior Water Projects Officer Dr Nadine Kilsby said 2018-19 will be the eighth year of the River Torrens Water Quality Improvement Project, which has been successful in preventing lake closures for the past five years.

“Torrens Lake is an iconic landmark and one of Adelaide’s premier public spaces,” Dr Kilsby said.

“With less rainfall over summer, water stops flowing into the lake and it slowly heats up, making conditions ideal for the growth of blue-green algae, which can discolour the water, produce unpleasant odours and at high concentrations, release toxins that can be harmful to both humans and wildlife.

“Understandably, those conditions could potentially result in the closure of the lake for recreational use.

“However, each summer since 2011-12 we have implemented a range of measures to combat the algae problem.

“Since 2013, flows of fresh water into the lake have had the greatest impact in successfully controlling the growth of blue-green algae.”

Dr Kilsby said the first release of water this season will help ensure the lake is in good condition through the Christmas-New Year period and has been deliberately timed to follow recent rain, to reduce the volume of fresh water required from upstream storages.

Following the release of the water, higher than usual flows are noticeable in the River Torrens for around two days as water makes its way from the hills, through the city to the Torrens outlet at Henley Beach South, where a channel will be maintained to ensure the water heads directly to the sea.

Water resulting from the flows will be of a better quality than stormwater.

However, as with all flows into the sea from urban areas, beach goers are encouraged to avoid swimming in turbid or discoloured water.

The River Torrens Water Quality Improvement Project has been developed with the support of the Adelaide and Mount Lofty Ranges Natural Resources Management Board, the Department for Environment and Water, SA Water, the Environment Protection Authority and the City of Adelaide.

Click here for updates about the River Torrens project during the summer months.