Clear Lake is one of California’s most important natural resources, supporting recreation, local businesses, wildlife, and surrounding communities. For decades, the lake has experienced some of the nation’s most severe harmful algal blooms, driven by excessive phosphorus loading from both watershed sources and nutrient-rich lake sediments.

These recurring blooms have degraded water quality, threatened ecosystem health, and reduced recreational and economic opportunities throughout the region. Long-term recovery requires addressing both external nutrient sources and the phosphorus already stored within the lake’s sediments.

Lake County, with approval from the Clear Lake Blue Ribbon Committee, partnered with EutroPHIX to evaluate a targeted phosphorus management strategy. The project will apply EutroSORB® G, a phosphorus-binding material with an established environmental safety record, to sediments in the Upper Arm where phosphorus concentrations are especially high.

The demonstration project is intentionally limited in scale to evaluate effectiveness, collect monitoring data through 2028, and provide scientific information to guide future restoration planning while allowing normal lake activities to continue uninterrupted.