Yuba Lake Algal Bloom Monitoring 2019

Warning Advisory

  • Do not swim or water ski in this area
  • Do not ingest the water
  • Keep pets and livestock away
  • Clean fish well and discard guts
  • Avoid areas of scum when boating

Report a Bloom

24-Hour DEQ Environment Incidents Line: (801) 536-4123

Call Utah Poison Control Center

If you believe you or your pet have been exposed to a harmful algal bloom, call (800) 222-1222.

Get BloomWatch App

Help us track cyanobacteria blooms with your smartphone. Go to cyanos.org for more info.

Update August 16, 2019

Yuba Lake

Yuba Lake, August 9, 2019

Toxin test results from the Utah Public Health Lab (UPHL) for samples collected on Yuba Lake on August 9, 2019, continued to exceed the recreation health-based threshold for a Warning Advisory. Microcystin values for the surface sample after dilutions were 7.5 micrograms per liter (µg/L).

A Warning Advisory indicates a moderate relative probability of acute health risk, cell-count density of 20,000 – 10 million cells per milliliter (cells/ml), microcystin levels of 4-2,000 micrograms per liter (µg/L), or anatoxin-a levels above non-detect.

The Warning Advisory for Yuba Lake remains in effect.


Update August 14, 2019

Yuba Lake, August 9, 2019

Toxin test results and cyanobacteria cell-count concentrations for samples collected by the Division of Water Quality (DWQ) on the North Shore of Yuba Lake on August 9, 2019, exceeded the recreation health-based threshold for a Warning Advisory.

Microcystin values in the surface sample were between 5 micrograms per liter (µg/L) and 2000 µg/L. Further dilutions by the Utah Public Health Lab will be necessary to quantify microcystin concentrations. Cyanobacteria cell-count concentrations in the surface sample at the North Shore were more than 3 million cells per milliliter (cells/mL). Aphanizomenon was the primary taxon in both samples.

The DWQ monitoring crew observed a high concentration of decaying cyanobacteria resembling “spilled paint” along the North Shore. They also observed a large number of visible cyanobacteria resembling grass clippings throughout the water column and in clumps along the shore. The water column was very turbid. There were similar concentrations of cyanobacteria at the Northwest Boat Ramp. Based on the ephemeral nature of cyanobacteria blooms and composite satellite imagery showing the bloom to be present lakewide, the Warning Advisory applies to the entire lake. The Department of Natural Resources advises recreators to avoid areas of visible scum or decaying cyanobacteria.

A Warning Advisory indicates a moderate relative probability of acute health risk, cell-count density of 20,000 – 10 million cells per milliliter (cells/ml), microcystin levels of 4-2,000 micrograms per liter (µg/L), or anatoxin-a levels above non-detect.

The Warning Advisory for Yuba Lake remains in effect.

Data Summary

North Shore

  • Sample Type: Surface sample
  • Sample Date: August 9, 2019
  • Microcystin: Between 5 and 2000 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 µg/L
  • Cyanobacteria cell count concentrations: 3,061,104 cells per milliliter (cells/mL)

North Shore

  • Sample Type: Elbow-depth integrated composite sample
  • Sample Date: August 9, 2019
  • Microcystin: 1.652 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 µg/L
  • Cyanobacteria cell count concentrations: 38,584 cells per milliliter (cells/mL)

Update August 12, 2019

The Division of Water Quality (DWQ) received cyanobacteria cell-count concentrations from PhycoTech for samples collected at the North Beach of Yuba Lake on August 1, 2019. Cell-count densities were 100,072 cells per milliliter (cells/mL), which exceeds the recreation health-based threshold for a Warning Advisory. The primary cyanobacteria taxon found in the samples was Microcytis, although Aphanizomenon and Dolichospermum were also present.

DWQ returned to the lake on August 9, 2019, to collect additional samples for lab analysis of toxins and cell counts. Results are pending.

A Warning Advisory indicates a moderate relative probability of acute health risk, cell-count density of 20,000 – 10 million cells per milliliter (cells/ml), microcystin levels of 4-2,000 micrograms per liter (µg/L), or anatoxin-a levels above non-detect.

The Warning Advisory for Yuba Lake remains in effect.


Update August 7, 2019

Yuba Lake, August 1, 2019

Yuba Lake, August 1, 2019

The Central Utah Health Department (CUHD) issued a Warning Advisory for Yuba Lake after toxin test results from water column samples collected by the Division of Water Quality (DWQ) at the north shore of Yuba Lake on August 1, 2019, showed microcystin levels of 128 micrograms per liter (µg/L). These values are well above the recreation health-based advisory threshold for a Warning Advisory.

Anatoxin-a was non-detect, and cell-count concentrations are still pending from PhycoTech. DWQ will return to the lake on August 9, 2019, to collect additional samples for lab analysis

The DWQ monitoring crew saw visible cyanobacteria along the northern shore of the lake, from North Beach to the State Park boat launch. The water column had a green hue and the cyanobacteria resembled grass clippings. There was also evidence of past blooms on the lakeshore. The crew observed high recreation use, both motorized and non-motorized, in the area where the bloom was observed and samples were taken.

Yuba Lake, August 1, 2019

Yuba Lake, August 1, 2019

A Warning Advisory indicates a moderate relative probability of acute health risk, cell-count density of 20,000 – 10 million cells per milliliter (cells/ml), microcystin levels of 4-2,000 micrograms per liter (µg/L), or anatoxin-a levels above non-detect.