County staff outline 14‑buoy pilot to fight Clear Lake harmful algal blooms

Lake County water resources staff on June 9 described a 24‑month pilot to place 14 LG Sonic ultrasonic buoys in the lower arm of Clear Lake to mitigate harmful algal blooms, outlining safety protections and monitoring plans and saying the project is contingent on release of grant funds.

Water Resources Director Pawan explained the technology and pilot design and said the buoys "would be placed on the lake" and that each "emits ultrasonic waveforms which prevents the algae from rising in the water column which starves them from sunlight and photosynthesis." He said two of the buoys will also collect real‑time water‑quality data and that the county will monitor and tune the emitters to local conditions.

Staff described navigational safety measures: reflective markings, hazard buoys adjacent to LG Sonic units, a marked navigation channel (with red/green markers and solar lights), ramp signage and outreach to fishing‑tournament organizers and ramp users. Pawan said the buoys will be anchored (225‑lb anchors and additional anchoring methods), inspected visually every two weeks and after major weather events, and maintained through a combination of HUD funding (approximately $981,000) and a local blue‑ribbon contribution (about $400,000) for monitoring and maintenance.

Supervisors asked about comparators and coordination with other pilots (UC Davis oxygenation in the Oaks arm and phosphorus mitigation in the upper arm) and about how the county will evaluate effectiveness. Staff said the deployments are pilot scale and intended to identify solutions that could be scaled if successful.

The board did not take formal action; staff said the project will move forward once funding is released and the county completes required NEPA and CEQA steps.