Mike Hutchison shows off Sonic Solutions, a sonar machine used to kill algae in ponds.
Gaithersburg city officials are considering using an ultrasonic algae control device to kill the filamentous algae growing in the lake at the entrance to the Lakelands community. The battle against the algae in that lake has been ongoing with city officials trying solutions such as hay bales to keep it under control.
This new sonar-emitting device is one of the only solutions left before trying an aerator in the lake.
“Lake Varuna is the entry feature for this large community and that is the reason we are looking at it,” said Gaithersburg Public Works Director James Arnoult. While other lakes in the city have a similar issue with algae, Arnoult said Lake Varuna is a high visibility lake.
In Kentlands, Inspiration Lake suffers from a similar algae situation; however, Arnoult said he believes that lake includes a mix of filamentous algae and pondweed. The SonicSolutions will not kill pondweed, he said. Filamentous algae are quickly reproducing algae that cling to the surface of the pond.
Mike Hutchison, president of SportsAggregates (the seller of the sonar device), met with city officials lakeside September 3. Hutchison took water and an algae sample from the lake to test to be sure the algae was treatable by the device. The test cost $150.
The SonicSolutions works by emitting ultrasonic waves that fan out and inhibit the growth and spread of algae by destroying the algae’s cellular structure. It is safe for plants and fish operating on a floating platform just below the surface of the water. Results can be seen within two weeks of installation, according to SonicSolutions.
City officials are considering using a version powered by solar panels to avoid the added cost of running power into the lake.
The SonicSolutions device costs about $4,000 each, and Lake Varuna would require two of them. The solar panels to run them will cost about $4,000.
In comparison, an aerator used in Lake Lynette costs about $10,000 but another $30,000 to power, according to Gaithersburg Environmental Specialist Gary Dyson. Hutchison said the solar power sonar devices would cost in one year what a fountain would cost to run for half of a day.
SonicSolutions has been in business since 2003 and has sold the majority of its units to golf courses.
In June, city officials seemed ready to try a copper sulfate spray used to mitigate algae blooms in Lake Varuna. Dyson said while the spray can work in many lakes, Lake Varuna’s water level most likely would make the spray ineffective.
“We are starting to think that it is not going to work,” Dyson said.
To be effective the spray must remain in the water for seven days. Getting the water to remain in that pond for that period of time isn’t possible, he said.
“When you apply it you have to make sure the water doesn’t leave the pond for a certain number of days. We must drop the pond to have storage space for seven days and that would almost drain the pond,” he said.
Dyson said the city is looking to explore the sonar option before moving forward with aerators in that lake.
“This seems like the best solution to kill the algae. The aerators just push it to the sides of the lake,” he said, adding that cleaning up the trash at Lake Varuna is a priority whenever he has volunteers looking for community service hours.
Lake Lynette already has an aerator; however, Lake Helene does not. Neither of those lakes has filamentous algae, according to Laura Sarno, project manager for the Department of Public Works. Lake Nirvana has an aerator and “looks fine,” Sarno said.
All three of those lakes feed the larger Inspiration Lake.
“Algae by no means means the lake is not healthy, but people don’t see it quite that way,” Sarno said. “It is difficult to change people’s minds. It is good that they are concerned about their community.”