Trinity County: lake and river algae advisories

21 waters in Trinity County appear in the state's harmful algal bloom records. Waters whose latest record is an advisory come first.

Waters in Trinity County and what the state's latest record says
Water	Latest record
Anada Creek	Caution advisory, last posted Apr 26, 2021. No all-clear recorded.
Barry Creek	Algal mat alert sign, last posted Nov 13, 2020. No all-clear recorded.
Canyon Creek	Caution advisory, last posted Jul 23, 2021. No all-clear recorded.
Eagle Lakes	Caution advisory, last posted Apr 26, 2021. No all-clear recorded.
Ewing Reservoir	Caution advisory, last posted Nov 12, 2025. No all-clear recorded.
Lewiston Lake	Caution advisory, last posted Jul 7, 2021. No all-clear recorded.
Mad River	Caution advisory, last posted Apr 26, 2021. No all-clear recorded.
New River	Caution advisory, last posted Sep 1, 2021. No all-clear recorded.
Potato Creek	Caution advisory, last posted Oct 1, 2021. No all-clear recorded.
Ruth Lake	Caution advisory, last posted May 27, 2021. No all-clear recorded.
South Fork Trinity River	Algal mat alert sign, last posted Jul 15, 2021. No all-clear recorded.
Trinity River	Caution advisory, last posted Aug 9, 2021. No all-clear recorded.
Gant Gulch	The state's latest record, from May 22, 2026, recommends no advisory.
Little Browns Creek	Reports on file, with no advisory level the state has classified.
Little French Creek	The state's latest record, from Jul 17, 2024, recommends no advisory.
North Fork Middle Fork Eel River	The state's latest record, from Aug 13, 2025, recommends no advisory.
Queatchumpah Creek	The state's latest record, from May 29, 2026, recommends no advisory.
Tributary to Eel River	The state's latest record, from May 29, 2026, recommends no advisory.
Trinity Lake	The state's latest record, from Sep 2, 2026, recommends no advisory.
Trinity River South Fork	The state's latest record, from Aug 13, 2025, recommends no advisory.
Unnamed Creek	The state's latest record, from May 21, 2025, recommends no advisory.