Clear Lake

The lake stretches roughly 19 miles through three connected arms—Upper, Oaks, and Lower—with about 100 miles of shoreline, an average depth near 27 feet, and a maximum depth of about 60 feet. Broad, relatively shallow basins, tule-lined coves, rocky points, and a few small islands create a productive warmwater environment that is also prone to seasonal algae and turbidity swings.

Clear Lake is a major Northern California destination for bass fishing, boating, and lakeside recreation centered on communities such as Lakeport, Clearlake, and Clearlake Oaks. Fisheries are managed by the California Department of Fish and Wildlife, and public ramps, marinas, and parks ring much of the shore.

Water levels are reported on the historic Rumsey gauge at Lakeport, where zero Rumsey equals about 1,318.26 feet above mean sea level and a full lake is defined as 7.56 feet Rumsey (about 1,325.8 feet MSL). Court rules generally keep the lake between zero and 7.56 feet Rumsey, with limited flood exceptions up to about 9.0 feet Rumsey. Because summer irrigation releases and winter storms can move the pool quickly, monitoring current lake levels matters for docks, flooding risk, and fishing access.