Monitoring is now underway in an effort to prevent an outbreak of blue-green algae in Adelaide’s Torrens Lake over summer.

Torrens Lake Popeye and paddle boats

The algae management program has been successfully implemented for the past 9 years to prevent Torrens Lake blue-green algae outbreaks and subsequent lake closures.

Green Adelaide Urban Water Team Leader Dr Nadine Kelly said that despite the low temperatures and heavy spring rainfall this year which lessen the risk of algae outbreaks in the lake, the project will continue to ensure we keep on top of changing conditions throughout summer.

“Since 2013, we have been monitoring algae levels and using flows of fresh water to successfully control blue-green algae in the lake.” Dr Kelly said.

“As the weather warms up over summer, Torrens Lake generally stops flowing and slowly heats up, which creates the ideal conditions for blue-green algae to grow.

“At high concentrations, toxins from some blue-green algae species can be harmful to people and wildlife. When that happens, the lake has to be closed for recreational use.

“While we haven’t yet had a very warm summer, meaning the risk of algal blooms is low, it’s still critical that we continue our monitoring and we’re prepared to implement our preventative control measure of releasing flows of fresh water into the lake.”

“Monitoring takes place twice a week in 7 locations, and if threshold levels of blue-green algae are reached, flows of fresh water from upstream storage will be used to freshen lake water quality and maintain algae at an acceptable level.”

“The need for fresh water to control algae in the lake will depend on rainfall and the persistence of high temperatures over summer.”

In preparation for the possible release of fresh water into the lake over summer, a small channel will be excavated across the narrow stretch of beach from the Torrens outlet to the sea at Henley Beach South, ensuring an easy passage for any water coming down the river. Channel excavation will take place in January and will ensure that the sand remains on the beach in the area.

The project is a collaboration between Green Adelaide, Department for Environment and Water, SA Water, Environment Protection Authority, City of Adelaide and the City of Charles Sturt.

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