Merced River: toxic algae advisories
Merced River, Mariposa County. See all Mariposa County waters.
What the state's records say
Caution advisory, last posted Nov 4, 2022. No all-clear recorded.
7 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 Merced River
The state has an advisory on file for Merced River (Caution advisory), last posted Nov 4, 2022, 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 |
|---|---|
| El Portal | Algal mat alert sign, last posted Nov 4, 2022. No all-clear recorded. |
| Happy Isles Bridge | Algal mat general awareness sign, last posted Nov 4, 2022. No all-clear recorded. |
| Pohono Bridge | Algal mat general awareness sign, last posted Nov 4, 2022. No all-clear recorded. |
| Superintendents bridge | Algal mat alert sign, last posted Sep 27, 2022. No all-clear recorded. |
| at top of Nevada Falls | Reports on file, with no advisory level the state has classified. |
| at Saxon Creek | The state's latest record, from Nov 10, 2021, recommends no advisory. |
| SF ~2.6mi above main stem | Caution advisory, last posted Sep 8, 2021. No all-clear recorded. |
| NF below Bean Cr. | Caution advisory, last posted Jul 1, 2021. No all-clear recorded. |
| SF ~2.6mi above main stem | Caution advisory, last posted Jul 1, 2021. No all-clear recorded. |
| Merced River, at Briceburg | The state's latest record, from Sep 1, 2020, recommends no advisory. |
Advisory history
Every advisory record the state has published for Merced 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 |
|---|---|---|---|
| Nov 4, 2022 | El Portal | Algal mat alert sign | Advisory based on visual and toxins; Bottom/benthic bloom observed |
| Nov 4, 2022 | Happy Isles Bridge | Algal mat general awareness sign | Rec algal mat general awareness |
| Nov 4, 2022 | Pohono Bridge | Algal mat general awareness sign | Rec algal mat general awareness |
| Sep 27, 2022 | Superintendents bridge | Algal mat alert sign | Bottom/benthic bloom observed |
| Sep 23, 2022 | El Portal | Algal mat alert sign | Advisory based on visual and toxins; Bottom/benthic bloom observed |
| Sep 23, 2022 | Pohono Bridge | Algal mat alert sign | Advisory based on visual and toxins; Bottom/benthic bloom observed |
| Sep 23, 2022 | Happy Isles Bridge | Algal mat alert sign | Advisory based on visual and toxins; Bottom/benthic bloom observed |
| Nov 10, 2021 | at top of Nevada Falls | NA - refer to Report Details | Suspected bloom, investigation ongoing |
| Nov 10, 2021 | at Saxon Creek | None | Testing results below posting triggers |
| Sep 8, 2021 | SF ~2.6mi above main stem | Caution | Advisory based on visual and toxins |
| Jul 1, 2021 | NF below Bean Cr. | Caution | Advisory based on visual and toxins |
| Jul 1, 2021 | SF ~2.6mi above main stem | Caution | Advisory based on visual and toxins |
| Sep 1, 2020 | Merced River, at Briceburg | None | De-posting 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.