California
Toxic algae in Colusa County lakes
3 lakes and waterways in Colusa County have harmful algal bloom reports in California's official data. The most recent entry is for East Park Reservoir: There are no bloom reports for East Park Reservoir in the last 30 days of California's data. The most recent was a bloom report on 26 June 2025 at Coyote Cove Campground. East Park Reservoir has had blooms in three or more years.
Lakes with bloom history
Newest report first. Each lake has its own page with the full history and what the results mean.
Other waterbodies with a report
These have one or two reports in a single year, which isn't enough history for a page of their own yet.
- Little Stony Creek 2022
- Stoney Creek 2022
Source: California State Water Resources Control Board, official data, checked 24 October 2026. For today's conditions see the California HABs Portal map. No report doesn't mean a lake is safe: most water is only tested occasionally.