California / Reports /

Cyanobacteria advisory (harmful blue-green algae) reported, Aug 11, 2026

Advisory active · California State Water Resources Control Board (FHAB program)

Source: California State Water Resources Control Board (FHAB program) via Surface Water - Freshwater Harmful Algal Blooms, record 5289-3393, reported Aug 11, 2026, 12:00 AM PDT, retrieved 2026-11-06 03:07 UTC · Read the original notice

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1. Where the advisory applies

Issued by: California State Water Resources Control Board (FHAB program). Place named: “Northeast Black Creek Arm (upstream)”. Location: 37.92791, -120.61204; location source: given in the source record.

2. Waters named in the notice

The notice names: “Lake Tulloch”. DirtyWaterWatch links this report to Tulloch Reservoir, CA. Match basis: the report's location, matched to the nearest tracked water.

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When it happened and when it was reported

Event and notice times use Eastern Time (EST or EDT). Retrieval times use Coordinated Universal Time (UTC).

Started

Aug 11, 2026

Ended

not reported

Detail provided by the source

Times known to the day only

Reported to the source

Aug 11, 2026, 12:00 AM PDT

Published

not given

Source last updated

Aug 11, 2026, 12:00 AM PDT

Last retrieved by DirtyWaterWatch

2026-11-06 03:07 UTC

What was reported

Type

Cyanobacteria (harmful blue-green algae) can make water unfit for contact; the issuing authority decides when its advisory ends.

Status in the record

Advisory active

Advice from California State Water Resources Control Board (FHAB program)

“Caution advisory for cyanobacteria (harmful algal bloom), as recommended in the FHAB report”

Advice period

This report does not state a period. See the rule DirtyWaterWatch applies and its source.

Basis

not stated

Status history from this report

• Discharge or advisory reported Tulloch Reservoir: Official advisory in effect, Aug 10, 2026, 9:00 PM PDT to Aug 24, 2026, 9:00 PM PDT
• No current status shown Tulloch Reservoir: advisory not re-confirmed by its source recently, no map colour, Aug 24, 2026, 9:00 PM PDT to Nov 8, 2026, 8:00 PM PST (the end is scheduled: a new report can change it)

Source: DirtyWaterWatch calculations using this report and the published status rules. Updated 2026-11-06 09:03 UTC.

Source and versions

Source

Surface Water - Freshwater Harmful Algal Blooms

Source record number

5289-3393

Original notice

Read the original notice

Earlier version

None: this is the first record

Later versions

None

{
  "Bloom_Report_ID": 5289,
  "Report_Type": "Agency/Partner Reporting",
  "Bloom_Date_Created": "2026-08-11T10:00:12.000",
  "Water_Body_Name": "Lake Tulloch",
  "Official_Water_Body_Name": null,
  "Landmark": "Northeast Black Creek Arm (upstream)",
  "County": "Calaveras",
  "Regional_Water_Board": "Region 5 - Central Valley",
  "Bloom_Latitude": 37.9279098,
  "Bloom_Longitude": -120.61204,
  "Observation_Date": "2026-08-03",
  "Bloom_Texture": null,
  "Water_Body_Type": null,
  "Advisory_ID": 3393,
  "Advisory_Recommended": "Caution",
  "Advisory_Date": "2026-08-11",
  "AdvisoryStartDate": "2026-08-11",
  "AdvisoryEndDate": null,
  "AdvisoryDetail": "Lake-wide advisory; visual monitoring based advisory",
  "Advisory_Date_of_Recommendation": "2026-08-11",
  "Case_ID": 1744,
  "Case_Status": "Open",
  "Case_End_Date": null,
  "Last_Field_Result_Sample_Date": null,
  "advisory_level": "Caution"
}