Mad River: toxic algae advisories
Mad River, Trinity County. See all Trinity County waters.
What the state's records say
Caution advisory, last posted Apr 26, 2021. No all-clear recorded.
4 reported spots here have an advisory with no all-clear recorded.
Reporting is voluntary, so the state may not have recorded an end even if conditions changed. Check posted signs and the official map.
What this level asks: Algae that can make toxins may be present. Keep people, children and pets away from algae and scum, and do not let pets drink the water.
Before you go, check the state's official algae page and any signs posted at the water.
Dogs at Mad River
The state has an advisory on file for Mad River (Caution advisory), last posted Apr 26, 2021, and no all-clear recorded. Keep your dog out of the water and away from scum on the shore until the state records an end.
Reported spots
The state records each report at a spot, such as a beach or a boat ramp. Each spot's latest deciding record:
| Spot | Status |
|---|---|
| tributary below Ruth Lake near Humboldt & Trinity County line | The state's latest record, from Apr 11, 2022, recommends no advisory. |
| near Tule Divide Rd | Caution advisory, last posted Apr 26, 2021. No all-clear recorded. |
| near Rush-Zenia Rd | Caution advisory, last posted Apr 26, 2021. No all-clear recorded. |
| near Mad River Rd Bridge | Caution advisory, last posted Apr 26, 2021. No all-clear recorded. |
| near Lost Bridge Rd | Caution advisory, last posted Apr 26, 2021. No all-clear recorded. |
Advisory history
Every advisory record the state has published for Mad River, newest first. "None" is the state's record that no advisory was recommended on that date. "NA" records do not change a status.
| Date | Spot | State's level | Notes |
|---|---|---|---|
| Apr 11, 2022 | tributary below Ruth Lake near Humboldt & Trinity County line | None | No cyano bloom w/photos |
| Apr 26, 2021 | near Tule Divide Rd | Caution | visual monitoring based advisory |
| Apr 26, 2021 | near Rush-Zenia Rd | Caution | visual monitoring based advisory |
| Apr 26, 2021 | near Mad River Rd Bridge | Caution | visual monitoring based advisory |
| Apr 26, 2021 | near Lost Bridge Rd | Caution | visual monitoring based advisory |
Source
Advisory data: California State Water Resources Control Board, Freshwater Harmful Algal Bloom Program, via data.ca.gov (public domain). Advisories are recommendations; reporting is voluntary and incomplete. The state's data. An advisory ends only when the state records a later "None" (no advisory recommended) at the same spot, or an end date. A blank end date is unknown.