Feasibility Study for Soda Bay Surface Water Treatment and Distribution Facility, Clear Lake, California

Engineering services were retained to provide a third-party review and feasibility analysis of the County Service Area #20, Soda Bay Water System Improvements. Potable water is supplied to the CSA#20 Soda Bay community by Lake County Special District (LCSD), which operates the Soda Bay Public Water System. This is a surface water distribution and treatment facility utilizing Clear Lake as the water source. The treatment facility consists of a raw water intake structure, raw water pumping station, pretreatment (ozonation), clarification/granular media filtration (GMF), granular activated carbon (GAC), and chlorine disinfection. Based on its inspections, the CDPH directed CSA#20 to submit an evaluation of plant and storage capacity upgrades to meet California Code of Regulations (CCR) Title 22 requirements.

Due to the seasonal algal blooms, three alternatives were identified for pretreatment: dissolved air floatation (DAF); inclined plate clarifier; and solids contact upflow clarifier. Based on the feasibility analysis, the use of shallow water wells installed along the shoreline of Clear Lake was recommended to improve quality of the surface water source. Additionally, recommendations were provided for improvements to the water storage and distribution system.