Old River: toxic algae advisories
Old River, San Joaquin County. See all San Joaquin County waters.
What the state's records say
Caution advisory, last posted Sep 17, 2026. No all-clear recorded.
11 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 Old River
The state has an advisory on file for Old River (Caution advisory), last posted Sep 17, 2026, 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 |
|---|---|
| Downstream of the ORT Barrier (ODM) | Visual observation, last posted Sep 17, 2026. No all-clear recorded. |
| at Mountain House (ORM) | The state's latest record, from Sep 17, 2026, recommends no advisory. |
| near Doughty Cut (ORX) | Visual observation, last posted Aug 5, 2026. No all-clear recorded. |
| at Head of Old River (OH1) | Visual observation, last posted Aug 5, 2026. No all-clear recorded. |
| Old River at Tracy Wildlife Association (TWA) | The state's latest record, from Jul 24, 2026, recommends no advisory. |
| near Franks Tract near Terminous (OSJ) | Visual observation, last posted Nov 6, 2023. No all-clear recorded. |
| near Quimby Island (ORQ) | Visual observation, last posted Oct 26, 2023. No all-clear recorded. |
| Old River @ Rancho Del Rio | The state's latest record, from Sep 15, 2023, recommends no advisory. |
| at Downstream of the ORT Barrier (ODM) | Visual observation, last posted Sep 8, 2023. No all-clear recorded. |
| Upstream of Clifton Court Forebay intake (ORI) | The state's latest record, from Jun 29, 2023, recommends no advisory. |
| Old River at Grant Line Canal East of Temporary Barrier (GLE) | The state's latest record, from Jan 18, 2023, recommends no advisory. |
| near Quimby Island (ORQ) | The state's latest record, from Dec 30, 2022, recommends no advisory. |
| Downstream of the ORT Barrier (ODM) | The state's latest record, from Dec 20, 2022, recommends no advisory. |
| at Mountain House (ORM) | The state's latest record, from Dec 20, 2022, recommends no advisory. |
| at Tracy Wildlife Association (TWA) | The state's latest record, from Dec 8, 2022, recommends no advisory. |
| near Doughty Cut (ORX) | The state's latest record, from Dec 6, 2022, recommends no advisory. |
| Head of Old River (OH1) | The state's latest record, from Dec 6, 2022, recommends no advisory. |
| between Franks Tract and San Joaquin River (OSJ) | The state's latest record, from Nov 30, 2022, recommends no advisory. |
| East of Frank's Tract (FT) | Caution advisory, last posted Aug 24, 2022. No all-clear recorded. |
| East of Holland Riverside Marina (D28A) | Caution advisory, last posted Jul 22, 2022. No all-clear recorded. |
| near Quimby Island | The state's latest record, from Dec 9, 2021, recommends no advisory. |
| near Franks Tract near Terminus | The state's latest record, from Nov 18, 2021, recommends no advisory. |
| at Kings Island | Caution advisory, last posted Jul 8, 2021. No all-clear recorded. |
| at Rancho del Rio | Caution advisory, last posted Jun 17, 2021. No all-clear recorded. |
| Old River near Doughty Cut | The state's latest record, from Dec 4, 2018, recommends no advisory. |
| Old River at Head of Old River | The state's latest record, from Dec 4, 2018, recommends no advisory. |
| Old River near Franks Tract near Terminous | The state's latest record, from Dec 4, 2018, recommends no advisory. |
| Old River, upstream of Hammer Island | Caution advisory, last posted Dec 4, 2018. No all-clear recorded. |
| Old River at Mountain House Creek | The state's latest record, from Dec 4, 2018, recommends no advisory. |
| Doughty Cut above Grant Line Canal, near Old River Confluence | The state's latest record, from Dec 4, 2018, recommends no advisory. |
Advisory history
Every advisory record the state has published for Old 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 |
|---|---|---|---|
| Sep 17, 2026 | Downstream of the ORT Barrier (ODM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Sep 17, 2026 | at Mountain House (ORM) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Aug 6, 2026 | Downstream of the ORT Barrier (ODM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 6, 2026 | at Mountain House (ORM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 6, 2026 | Downstream of the ORT Barrier (ODM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 6, 2026 | at Mountain House (ORM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 5, 2026 | near Doughty Cut (ORX) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 5, 2026 | at Head of Old River (OH1) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Jul 24, 2026 | Old River at Tracy Wildlife Association (TWA) | None | Testing results below posting triggers; Updates from routine monitoring program-organization |
| Jul 8, 2026 | Downstream of the ORT Barrier (ODM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Jul 8, 2026 | at Mountain House (ORM) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jul 8, 2026 | Old River at Tracy Wildlife Association (TWA) | None | Testing results below posting triggers; Updates from routine monitoring program-organization |
| Jun 18, 2026 | Downstream of the ORT Barrier (ODM) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jun 18, 2026 | at Mountain House (ORM) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| May 27, 2026 | Old River at Tracy Wildlife Association (TWA) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| May 27, 2026 | Downstream of the ORT Barrier (ODM) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| May 27, 2026 | at Mountain House (ORM) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Apr 29, 2026 | Old River at Tracy Wildlife Association (TWA) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Apr 29, 2026 | Downstream of the ORT Barrier (ODM) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Apr 29, 2026 | at Mountain House (ORM) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Feb 6, 2026 | Old River at Tracy Wildlife Association (TWA) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Feb 6, 2026 | at Head of Old River (OH1) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Feb 6, 2026 | Downstream of the ORT Barrier (ODM) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Feb 6, 2026 | at Mountain House (ORM) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Feb 6, 2026 | near Doughty Cut (ORX) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Feb 6, 2026 | at Head of Old River (OH1) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Feb 6, 2026 | Old River at Tracy Wildlife Association (TWA) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jan 15, 2026 | Downstream of the ORT Barrier (ODM) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jan 15, 2026 | at Mountain House (ORM) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Dec 12, 2025 | Downstream of the ORT Barrier (ODM) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Dec 12, 2025 | at Mountain House (ORM) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Nov 20, 2025 | Downstream of the ORT Barrier (ODM) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Nov 20, 2025 | at Mountain House (ORM) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Oct 30, 2025 | Downstream of the ORT Barrier (ODM) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Oct 30, 2025 | at Mountain House (ORM) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Sep 26, 2025 | Downstream of the ORT Barrier (ODM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Sep 26, 2025 | at Mountain House (ORM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Sep 24, 2025 | Old River at Tracy Wildlife Association (TWA) | None | Testing results below posting triggers; Updates from routine monitoring program-organization |
| Sep 24, 2025 | near Doughty Cut (ORX) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Sep 24, 2025 | at Head of Old River (OH1) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Aug 28, 2025 | at Mountain House (ORM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 28, 2025 | at Mountain House (ORM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 28, 2025 | Downstream of the ORT Barrier (ODM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 28, 2025 | at Mountain House (ORM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 18, 2025 | Old River at Tracy Wildlife Association (TWA) | None | Testing results below posting triggers; Updates from routine monitoring program-organization |
| Aug 11, 2025 | near Doughty Cut (ORX) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 11, 2025 | at Head of Old River (OH1) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 11, 2025 | at Mountain House (ORM) | Visual observation | Testing results below posting triggers; Updates from routine monitoring program-organization |
| Aug 11, 2025 | at Head of Old River (OH1) | None | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 11, 2025 | at Head of Old River (OH1) | None | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 7, 2025 | near Doughty Cut (ORX) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 7, 2025 | Downstream of the ORT Barrier (ODM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 7, 2025 | at Mountain House (ORM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 7, 2025 | near Doughty Cut (ORX) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Aug 7, 2025 | at Head of Old River (OH1) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jul 30, 2025 | Old River at Tracy Wildlife Association (TWA) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jul 30, 2025 | near Doughty Cut (ORX) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jul 30, 2025 | at Head of Old River (OH1) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jul 9, 2025 | Downstream of the ORT Barrier (ODM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Jul 9, 2025 | at Mountain House (ORM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Jun 23, 2025 | Old River at Tracy Wildlife Association (TWA) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jun 12, 2025 | Downstream of the ORT Barrier (ODM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Jun 12, 2025 | at Mountain House (ORM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Jun 12, 2025 | near Doughty Cut (ORX) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jun 12, 2025 | at Head of Old River (OH1) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jun 12, 2025 | Old River at Tracy Wildlife Association (TWA) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jun 3, 2025 | near Doughty Cut (ORX) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jun 3, 2025 | at Head of Old River (OH1) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jun 3, 2025 | Old River at Tracy Wildlife Association (TWA) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| May 29, 2025 | at Mountain House (ORM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| May 29, 2025 | Downstream of the ORT Barrier (ODM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Apr 18, 2025 | Downstream of the ORT Barrier (ODM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Apr 18, 2025 | at Mountain House (ORM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Apr 18, 2025 | near Doughty Cut (ORX) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Apr 18, 2025 | at Head of Old River (OH1) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Mar 25, 2025 | Downstream of the ORT Barrier (ODM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Mar 25, 2025 | at Mountain House (ORM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Mar 25, 2025 | Old River at Tracy Wildlife Association (TWA) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Mar 25, 2025 | near Doughty Cut (ORX) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Mar 25, 2025 | at Head of Old River (OH1) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Feb 26, 2025 | Old River at Tracy Wildlife Association (TWA) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Feb 19, 2025 | Downstream of the ORT Barrier (ODM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Feb 19, 2025 | at Mountain House (ORM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Feb 19, 2025 | near Doughty Cut (ORX) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Feb 19, 2025 | at Head of Old River (OH1) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Feb 19, 2025 | Old River at Tracy Wildlife Association (TWA) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Dec 17, 2024 | Downstream of the ORT Barrier (ODM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Dec 17, 2024 | Downstream of the ORT Barrier (ODM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Dec 17, 2024 | at Mountain House (ORM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Dec 17, 2024 | near Doughty Cut (ORX) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Dec 17, 2024 | at Head of Old River (OH1) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Dec 17, 2024 | Old River at Tracy Wildlife Association (TWA) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Nov 13, 2024 | Downstream of the ORT Barrier (ODM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Nov 13, 2024 | near Doughty Cut (ORX) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Nov 13, 2024 | at Head of Old River (OH1) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Nov 13, 2024 | at Mountain House (ORM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Nov 13, 2024 | Old River at Tracy Wildlife Association (TWA) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Oct 11, 2024 | Downstream of the ORT Barrier (ODM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Oct 11, 2024 | Old River at Tracy Wildlife Association (TWA) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Oct 11, 2024 | Downstream of the ORT Barrier (ODM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Oct 11, 2024 | at Mountain House (ORM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Oct 11, 2024 | near Doughty Cut (ORX) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Oct 11, 2024 | at Head of Old River (OH1) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Sep 13, 2024 | Downstream of the ORT Barrier (ODM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Sep 13, 2024 | at Mountain House (ORM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Aug 27, 2024 | Downstream of the ORT Barrier (ODM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 16, 2024 | Downstream of the ORT Barrier (ODM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 16, 2024 | at Mountain House (ORM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 16, 2024 | near Doughty Cut (ORX) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Aug 16, 2024 | at Head of Old River (OH1) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Aug 8, 2024 | Old River at Tracy Wildlife Association (TWA) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jul 12, 2024 | Downstream of the ORT Barrier (ODM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Jul 12, 2024 | at Mountain House (ORM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Jun 18, 2024 | near Doughty Cut (ORX) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jun 18, 2024 | at Head of Old River (OH1) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jun 18, 2024 | Downstream of the ORT Barrier (ODM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Jun 18, 2024 | at Mountain House (ORM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| May 3, 2024 | Old River at Tracy Wildlife Association (TWA) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| May 3, 2024 | Downstream of the ORT Barrier (ODM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| May 3, 2024 | at Mountain House (ORM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Mar 22, 2024 | Old River at Tracy Wildlife Association (TWA) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Mar 8, 2024 | Downstream of the ORT Barrier (ODM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Mar 8, 2024 | at Mountain House (ORM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Feb 27, 2024 | Old River at Tracy Wildlife Association (TWA) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Feb 12, 2024 | Downstream of the ORT Barrier (ODM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Feb 12, 2024 | at Mountain House (ORM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jan 25, 2024 | near Doughty Cut (ORX) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jan 25, 2024 | at Head of Old River (OH1) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jan 25, 2024 | Old River at Tracy Wildlife Association (TWA) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jan 22, 2024 | Downstream of the ORT Barrier (ODM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jan 22, 2024 | at Mountain House (ORM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Dec 21, 2023 | Old River at Tracy Wildlife Association (TWA) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Dec 21, 2023 | near Doughty Cut (ORX) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Dec 21, 2023 | at Head of Old River (OH1) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Dec 8, 2023 | at Mountain House (ORM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Dec 8, 2023 | Downstream of the ORT Barrier (ODM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Dec 8, 2023 | at Mountain House (ORM) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Dec 1, 2023 | Old River at Tracy Wildlife Association (TWA) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Nov 14, 2023 | near Doughty Cut (ORX) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Nov 14, 2023 | at Head of Old River (OH1) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Nov 6, 2023 | near Franks Tract near Terminous (OSJ) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Oct 26, 2023 | near Quimby Island (ORQ) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Oct 17, 2023 | near Franks Tract near Terminous (OSJ) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Oct 11, 2023 | near Doughty Cut (ORX) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Oct 11, 2023 | at Head of Old River (OH1) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Sep 27, 2023 | Old River at Tracy Wildlife Association (TWA) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Sep 15, 2023 | Old River @ Rancho Del Rio | None | Testing results below posting triggers; Updates from routine monitoring program-organization |
| Sep 13, 2023 | near Doughty Cut (ORX) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Sep 13, 2023 | at Head of Old River (OH1) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Sep 13, 2023 | near Quimby Island (ORQ) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Sep 8, 2023 | at Downstream of the ORT Barrier (ODM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Sep 8, 2023 | at Mountain House (ORM) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 25, 2023 | near Franks Tract near Terminous (OSJ) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 25, 2023 | near Franks Tract near Terminous (OSJ) | Visual observation | Updates from routine monitoring program-organization; Visual monitoring only-present bloom |
| Aug 23, 2023 | Old River @ Rancho Del Rio | None | Testing results below posting triggers; Updates from routine monitoring program-organization |
| Aug 22, 2023 | Old River at Tracy Wildlife Association (TWA) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Aug 14, 2023 | at Head of Old River (OH1) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Aug 7, 2023 | Downstream of the ORT Barrier (ODM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Aug 7, 2023 | at Mountain House (ORM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Aug 7, 2023 | Old River @ Rancho Del Rio | None | Testing results below posting triggers; Updates from routine monitoring program-organization |
| Aug 1, 2023 | near Quimby Island (ORQ) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Aug 1, 2023 | at Mountain House (ORM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Aug 1, 2023 | Downstream of the ORT Barrier (ODM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jul 28, 2023 | Old River at Tracy Wildlife Association (TWA) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jul 28, 2023 | at Head of Old River (OH1) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jul 24, 2023 | near Franks Tract near Terminous (OSJ) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jun 29, 2023 | Upstream of Clifton Court Forebay intake (ORI) | None | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-absent bloom |
| Jun 22, 2023 | Old River @ Rancho Del Rio | None | No cyano bloom w/testing; Updates from routine monitoring program-organization |
| Jun 20, 2023 | Old River at Tracy Wildlife Association (TWA) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jun 9, 2023 | near Quimby Island (ORQ) | NA - refer to Report Details | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-absent bloom |
| Jun 9, 2023 | near Quimby Island (ORQ) | None | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-absent bloom |
| Jun 8, 2023 | at Mountain House (ORM) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jun 8, 2023 | Downstream of the ORT Barrier (ODM) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jun 8, 2023 | at Mountain House (ORM) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| Jun 8, 2023 | Upstream of Clifton Court Forebay intake (ORI) | None | Updates from routine monitoring program-organization; visual monitoring based advisory; Visual monitoring only-absent bloom |
| May 26, 2023 | Old River at Tracy Wildlife Association (TWA) | NA - refer to Report Details | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| May 26, 2023 | Old River at Tracy Wildlife Association (TWA) | None | Updates from routine monitoring program-organization; Visual monitoring only-absent bloom |
| May 26, 2023 | Old River at Tracy Wildlife Association (TWA) | None | Updates from routine monitoring program-organization; visual monitoring based advisory |
| May 23, 2023 | Old River @ Rancho Del Rio | None | No cyano bloom w/testing; Updates from routine monitoring program-organization |
| May 22, 2023 | at Downstream of the ORT Barrier (ODM) | None | Updates from routine monitoring program-organization |
| May 22, 2023 | at Mountain House (ORM) | None | Updates from routine monitoring program-organization |
| May 17, 2023 | Downstream of the ORT Barrier (ODM) | None | Updates from routine monitoring program-organization |
| Apr 20, 2023 | near Quimby Island (ORQ) | None | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Apr 20, 2023 | near Franks Tract near Terminous (OSJ) | None | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Apr 18, 2023 | Downstream of the ORT Barrier (ODM) | None | Updates from routine monitoring program-organization |
| Apr 18, 2023 | at Mountain House (ORM) | None | Updates from routine monitoring program-organization |
| Apr 11, 2023 | Old River at Tracy Wildlife Association (TWA) | None | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Mar 20, 2023 | Old River at Tracy Wildlife Association (TWA) | None | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Mar 16, 2023 | Upstream of Clifton Court Forebay intake (ORI) | None | Updates from routine monitoring program-organization |
| Mar 7, 2023 | Downstream of the ORT Barrier (ODM) | None | Updates from routine monitoring program-organization |
| Mar 2, 2023 | near Quimby Island (ORQ) | None | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Feb 21, 2023 | Upstream of Clifton Court Forebay intake (ORI) | None | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Jan 31, 2023 | near Quimby Island (ORQ) | None | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Jan 31, 2023 | near Quimby Island (ORQ) | Blank in the state's file | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Jan 30, 2023 | near Franks Tract near Terminous (OSJ) | None | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Jan 18, 2023 | at Mountain House (ORM) | None | Updates from routine monitoring program-organization |
| Jan 18, 2023 | Upstream of Clifton Court Forebay intake (ORI) | None | Updates from routine monitoring program-organization |
| Jan 18, 2023 | Old River at Tracy Wildlife Association (TWA) | None | Updates from routine monitoring program-organization |
| Jan 18, 2023 | at Downstream of the ORT Barrier (ODM) | None | Updates from routine monitoring program-organization |
| Jan 18, 2023 | at Mountain House (ORM) | None | Updates from routine monitoring program-organization |
| Jan 18, 2023 | Old River at Grant Line Canal East of Temporary Barrier (GLE) | None | Bottom/benthic bloom observed |
| Jan 17, 2023 | at Head of Old River (OH1) | None | visual monitoring based advisory |
| Jan 1, 2023 | near Quimby Island (ORQ) | Blank in the state's file | Updates from routine monitoring program-organization |
| Jan 1, 2023 | at Downstream of the ORT Barrier (ODM) | None | Updates from routine monitoring program-organization |
| Jan 1, 2023 | at Mountain House (ORM) | None | Updates from routine monitoring program-organization |
| Dec 30, 2022 | near Quimby Island (ORQ) | None | Updates from routine monitoring program-organization |
| Dec 20, 2022 | Downstream of the ORT Barrier (ODM) | None | Updates from routine monitoring program-organization |
| Dec 20, 2022 | at Mountain House (ORM) | None | Updates from routine monitoring program-organization |
| Dec 8, 2022 | at Tracy Wildlife Association (TWA) | None | End date recorded: Oct 25, 2022. Updates from routine monitoring program-organization; visual monitoring based advisory |
| Dec 6, 2022 | near Doughty Cut (ORX) | None | End date recorded: Dec 6, 2022. visual monitoring based advisory |
| Dec 6, 2022 | Head of Old River (OH1) | None | End date recorded: Dec 6, 2022. visual monitoring based advisory |
| Nov 30, 2022 | between Franks Tract and San Joaquin River (OSJ) | None | Updates from routine monitoring program-organization |
| Nov 16, 2022 | at Tracy Wildlife Association (TWA) | None | End date recorded: Oct 25, 2022. Updates from routine monitoring program-organization; visual monitoring based advisory |
| Nov 9, 2022 | Downstream of the ORT Barrier (ODM) | Caution | Updates from routine monitoring program-organization |
| Nov 9, 2022 | at Mountain House (ORM) | None | Updates from routine monitoring program-organization |
| Nov 1, 2022 | between Franks Tract and San Joaquin River (OSJ) | Caution | Updates from routine monitoring program-organization |
| Oct 25, 2022 | at Tracy Wildlife Association (TWA) | None | End date recorded: Oct 25, 2022. Updates from routine monitoring program-organization; visual monitoring based advisory |
| Oct 25, 2022 | near Doughty Cut (ORX) | Caution | visual monitoring based advisory |
| Oct 25, 2022 | Head of Old River (OH1) | Caution | visual monitoring based advisory |
| Oct 21, 2022 | near Quimby Island (ORQ) | None | Updates from routine monitoring program-organization |
| Sep 30, 2022 | between Franks Tract and San Joaquin River (OSJ) | Caution | Updates from routine monitoring program-organization |
| Sep 19, 2022 | Downstream of the ORT Barrier (ODM) | Caution | Updates from routine monitoring program-organization |
| Sep 19, 2022 | at Mountain House (ORM) | Caution | Updates from routine monitoring program-organization |
| Sep 19, 2022 | between Franks Tract and San Joaquin River (OSJ) | Caution | Updates from routine monitoring program-organization |
| Sep 19, 2022 | between Franks Tract and San Joaquin River (OSJ) | Caution | Updates from routine monitoring program-organization |
| Sep 15, 2022 | at Tracy Wildlife Association (TWA) | Caution | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Sep 15, 2022 | Head of Old River (OH1) | Caution | visual monitoring based advisory |
| Sep 15, 2022 | near Doughty Cut (ORX) | Caution | visual monitoring based advisory |
| Sep 8, 2022 | Head of Old River (OH1) | Caution | visual monitoring based advisory |
| Sep 8, 2022 | near Doughty Cut (ORX) | Caution | visual monitoring based advisory |
| Sep 8, 2022 | near Doughty Cut (ORX) | Caution | visual monitoring based advisory |
| Aug 24, 2022 | East of Frank's Tract (FT) | Caution | Advisory based on visual and toxins; Bottom/benthic bloom observed |
| Aug 18, 2022 | at Tracy Wildlife Association (TWA) | None | Updates from routine monitoring program-organization; visual monitoring based advisory |
| Aug 4, 2022 | Head of Old River (OH1) | Caution | visual monitoring based advisory |
| Aug 4, 2022 | near Doughty Cut (ORX) | Caution | visual monitoring based advisory |
| Aug 3, 2022 | between Franks Tract and San Joaquin River (OSJ) | Caution | Updates from routine monitoring program-organization |
| Aug 1, 2022 | at Tracy Wildlife Association (TWA) | Caution | Updates from routine monitoring program-organization |
| Jul 22, 2022 | East of Holland Riverside Marina (D28A) | Caution | visual monitoring based advisory |
| Jul 20, 2022 | at Tracy Wildlife Association (TWA) | None | Updates from routine monitoring program-organization |
| Jul 6, 2022 | Downstream of the ORT Barrier (ODM) | Caution | Updates from routine monitoring program-organization |
| Jul 6, 2022 | at Mountain House (ORM) | Caution | Updates from routine monitoring program-organization |
| Jul 6, 2022 | between Franks Tract and San Joaquin River (OSJ) | Caution | Updates from routine monitoring program-organization |
| Jun 23, 2022 | at Tracy Wildlife Association (TWA) | None | Updates from routine monitoring program-organization |
| Jun 23, 2022 | between Franks Tract and San Joaquin River (OSJ) | None | Updates from routine monitoring program-organization |
| Jun 21, 2022 | at Tracy Wildlife Association (TWA) | Caution | Updates from routine monitoring program-organization |
| Jun 16, 2022 | between Franks Tract and San Joaquin River (OSJ) | Caution | Updates from routine monitoring program-organization |
| Jun 16, 2022 | between Franks Tract and San Joaquin River (OSJ) | Caution | Updates from routine monitoring program-organization |
| Jun 3, 2022 | Downstream of the ORT Barrier (ODM) | Caution | Updates from routine monitoring program-organization |
| Jun 3, 2022 | at Mountain House (ORM) | Caution | Updates from routine monitoring program-organization |
| Jun 2, 2022 | between Franks Tract and San Joaquin River (OSJ) | None | Updates from routine monitoring program-organization |
| Jun 1, 2022 | Head of Old River (OH1) | None | |
| Jun 1, 2022 | near Doughty Cut (ORX) | None | |
| May 25, 2022 | at Tracy Wildlife Association (TWA) | None | Updates from routine monitoring program-organization |
| May 18, 2022 | near Quimby Island (ORQ) | None | Updates from routine monitoring program-organization |
| May 4, 2022 | between Franks Tract and San Joaquin River (OSJ) | None | Updates from routine monitoring program-organization |
| May 4, 2022 | near Quimby Island (ORQ) | None | Updates from routine monitoring program-organization |
| May 3, 2022 | Head of Old River (OH1) | None | |
| May 3, 2022 | near Doughty Cut (ORX) | None | |
| Apr 19, 2022 | at Tracy Wildlife Association (TWA) | None | Updates from routine monitoring program-organization |
| Apr 13, 2022 | Downstream of the ORT Barrier (ODM) | None | Updates from routine monitoring program-organization |
| Apr 13, 2022 | at Mountain House (ORM) | None | Updates from routine monitoring program-organization |
| Apr 1, 2022 | between Franks Tract and San Joaquin River (OSJ) | None | Updates from routine monitoring program-organization |
| Mar 30, 2022 | at Tracy Wildlife Association (TWA) | None | Updates from routine monitoring program-organization |
| Mar 4, 2022 | near Quimby Island (ORQ) | None | Updates from routine monitoring program-organization |
| Dec 9, 2021 | near Quimby Island | None | Testing results below posting triggers |
| Nov 18, 2021 | near Franks Tract near Terminus | None | Testing results below posting triggers |
| Jul 8, 2021 | at Kings Island | Caution | Advisory based on visual and toxins |
| Jun 17, 2021 | at Rancho del Rio | Caution | visual monitoring based advisory |
| Dec 4, 2018 | Old River near Doughty Cut | None | |
| Dec 4, 2018 | Old River at Head of Old River | None | |
| Dec 4, 2018 | Old River near Franks Tract near Terminous | None | |
| Dec 4, 2018 | Old River, upstream of Hammer Island | Caution | |
| Dec 4, 2018 | Old River at Mountain House Creek | None | |
| Dec 4, 2018 | Doughty Cut above Grant Line Canal, near Old River Confluence | None |
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.