Mount Gambier City Council will activate ultrasonic wave technology to remove harmful blue and green algae in the city’s valley.
Key points:
- Harmful blue and green algae has been found in the Valley Lake following water testing
- The ultrasonic waves used to control algae levels will not impact any other aquatic life
- Algae levels are higher during the warmer months
This follows months of testing in the lake, which is a popular spot for waterskiing and recreational boating activities.
Two floats were installed on the Valley Lake in January with one monitoring the water quality and the other emitting ultrasonic waves.
The council has worked with a water-testing company to collect physical samples as well as measure water quality at different depths.
The results of the testing has found the presence of harmful blue and green algae and cyanobacteria.
Council environmental sustainability officer Aaron Izzard said algae would be controlled through ultrasonic technology.
“[The float] sends out an ultrasonic signal through the water, which only targets algae and bacteria,
“[It] disrupts the components within those organisms that allow them to float. So they sink to the bottom and die.”
Testing of the ultrasonic waves was conducted during the cooler months.
The council is now waiting to see how effective the technology is during summer where the algae is more prevalent and will consider using it long-term.
The ultrasonic float will be activated in September and will run until autumn.
Algae can trigger illness
Mr Izzard says it is important to control algae levels.
“There’s lots of different species of algae, and most of them are benign, but there are some that can have a negative impact on on people,” he said.
“There’s certain species of algae that can make people sick — not super sick but a bit nauseous.
“We want the lake to be able to be used for aquatic recreation so ideally you want to manage those harmful algae and bacteria that are there.”
The technology specifically targets algae and will not harmful to other aquatic life, Mr Izzard says.
“It has been tested and it hasn’t been found to be harmful to any other kind of aquatic organisms, it just targets of bacteria and algae,” he said.
“It doesn’t affect any kind of insects, animals or fish.”
Boating unlikely to be affected
The floats are clearly marked and Mr Izzard says they are unlikely to affect recreational users of the Valley Lake during summer.
“We’ve tried to make them quite visible. They’re not very big in the grand scheme of the lake,” he said.
“People can still jet ski or boat and do loops around the lake. There’s still plenty of room to be able to utilise the lake for aquatic sports.”
Mr Izzard said the ultrasonic wave technology was a cost-effective way to control algae levels.
“If you’re looking at the annual cost it’s not a big investment — particularly if we’re enabling the lake to be used in the greater capacity for aquatic sports,” he said.
“We went out to tender for this project and there was all sorts of proposals, but some were more costly, but this one’s quite cost effective.”