CL fights algae with week-long alum treatment

The scheduled alum treatment is complete for the Main Lake, East Bay and the area north of the causeway. The clean-up concludes today as Aquatechnex, the company contracted by the Lake Elsinore & San Jacinto Watersheds Authority which oversees the project, wraps up the week-long task.

All went well, according to the watershed authority. The treatment is intended to reduce algae growth in the lake and has been successful in clearing up the water in past years. The lake remained open during the application of the alum.

Aquatechnex workers prepare the alum solution prior to heading out to the lake where it is sprayed out into the water. The alum attaches to algae-causing phosphorus and sinks to the bottom of the lake. Photo provided by Aquatechnex

Alum binds with phosphorus in the lake water, drops the nutrient to the lake bottom and thereby reduces algae growth in the lake, Mark Norton of the authority, said.

Canyon Lake water mostly comes from stormwater runoff from the upper watershed each year that has high levels of nutrients that hurt water quality and threaten aquatic life. This dose will be the 15th Canyon Lake alum application that has taken place over the years.

“Alum, the method selected to provide the best results for Canyon Lake, has a proven track record of success,” Mark said. “It is safe to both humans and aquatic life.”

In order to comply with water quality regulations enforced by the state, through the local Santa Ana Regional Water Quality Control Board, the Lake Elsinore & Canyon Lake Nutrient Total Maximum Daily Load Task Force utilizes local stakeholder funding to continue alum water treatments in Canyon Lake.

The task force evaluated several options during the CEQA process and determined that alum application provides the best option as a step to effectively treat the entire lake in a timely manner with minimal impact to Canyon Lake residents, Mark said.