Yuba Lake Algal Bloom Monitoring 2019

North Beach Shore: Danger

Danger Advisory

  • Waterbody closed
  • Keep out of the water

Remainder of Lake: Warning

Warning Advisory

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

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.

Visit the 2019 Photo Gallery

Get BloomWatch App

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

Update October 11, 2019

Yuba Lake, October 3, 2019

Toxin test results for samples collected by the Division of Water Quality (DWQ) at the North Shore of Yuba Lake on October 3, 2019, exceeded the recreation health-based threshold for a Warning Advisory for anatoxin-a. Toxin test levels at the West Boat Ramp were well below the advisory threshold for microcystin and anatoxin-a. Cyanobacteria cell-count concentration results are pending from PhycoTech.

The DWQ monitoring crew observed cyanobacteria that were clumped and dead along the shore. The predominant type of cyanobacteria observed resembled grass clippings. Overall, the bloom looked better than the previous visit.

A Danger Advisory indicates a high relative probability of acute health risk, cell-count density of >10 million cells per milliliter (cells/mL), microcystin levels >2,000 micrograms per liter (µg/L), or anatoxin-a levels >90 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 Danger Advisory for North Beach Shore and Warning Advisory for the rest of Yuba Lake remain in effect for now.

Data Summary

West Boat Ramp

  • Sample date: October 3, 2019
  • Sample type: Elbow-depth integrated composite sample
  • Microcystin: <2.0 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 µg/L

North Shore

  • Sample date: October 3, 2019
  • Sample type: Elbow-depth composite sample
  • Microcystin: <2.0 micrograms per liter (µg/L)
  • Anatoxin-a: 0.106 µg/L

Update September 25, 2019

Yuba Lake, September 18, 2019

Toxin test results for samples collected by the Division of Water Quality (DWQ) at the West Boat Ramp and North Shore of Yuba Lake on September 18, 2019, exceeded the recreation health-based threshold for a Warning Advisory for anatoxin-a. Cyanobacteria cell-count concentration results for samples collected on September 18, 2019, are pending from PhycoTech.

Cyanobacteria cell-count concentrations for samples collected at the West Boat Ramp and North Shore of Yuba Lake on September 10, 2019, exceeded the recreation health-based threshold for a Warning Advisory. The primary taxon in the sample was Aphanizomenon. Toxin test results for anatoxin-a and microcystin were well below the advisory threshold.

The DWQ monitoring crew observed bright green cyanobacteria in the water column that resembled grass clippings. Some of the cyanobacteria had clumped together to form mats on the surface. The water had a green hue.

A Danger Advisory indicates a high relative probability of acute health risk, cell-count density of >10 million cells per milliliter (cells/mL), microcystin levels >2,000 micrograms per liter (µg/L), or anatoxin-a levels >90 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 Danger Advisory for North Beach Shore and Warning Advisory for the rest of Yuba Lake remain in effect pending cyanobacteria cell-count data from PhycoTech.

Data Summary

West Boat Ramp

  • Sample date: September 18, 2019
  • Sample type: Surface sample
  • Microcystin: 2.6 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 µg/L
  • Cyanobacteria cell counts: Unavailable

West Boat Ramp

  • Sample date: September 18, 2019
  • Sample type: Elbow-depth composite sample
  • Microcystin: <2.0 micrograms per liter (µg/L)
  • Anatoxin-a: 0.122 µg/L
  • Cyanobacteria cell counts: Unavailable

North Shore

  • Sample date: September 18, 2019
  • Sample type: Elbow-depth composite sample
  • Microcystin: 0.148 micrograms per liter (µg/L)
  • Anatoxin-a: 0.129 µg/L
  • Cyanobacteria cell counts: Unavailable

West Boat Ramp

  • Sample date: September 10, 2019
  • Sample type: Surface sample
  • Microcystin: 2.8 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 µg/L
  • Cyanobacteria cell counts: 65,518 cells per milliliter (cells/mL)

North Shore

  • Sample date: September 10, 2019
  • Sample type: Elbow-depth composite sample
  • Microcystin: <2.0 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 µg/L
  • Cyanobacteria cell counts: 204,635 cells per milliliter (cells/mL)

Update September 16, 2019

Yuba Lake, North Shore, September 4, 2019

Yuba Lake, North Shore, September 4, 2019

Toxin test results received from the Utah Public Health Lab (UPHL) for samples collected by the Division of Water Quality (DWQ) at the North Beach Shore and Boat Ramp at Yuba Lake on September 4, 2019, showed anatoxin-a levels exceeding the recreation health-based threshold for a Warning Advisory in the water column sample at the North Beach Shore. Anatoxin-a and microcystin levels were well below the advisory threshold in all other samples. Cyanobacteria cell-count concentrations are pending from PhycoTech.

The North Beach Shore is the only location at Yuba Lake under a Danger Advisory. The North Beach Campground, including access to restrooms, is open. The remainder of Yuba Lake remains under a Warning Advisory.

The DWQ monitoring crew observed cyanobacteria particulates that resembled grass clipping particulates in the water column. The water had a green hue. The crew noted that the lake looked better than the previous visit.

A Danger Advisory indicates a high relative probability of acute health risk, cell-count density of >10 million cells per milliliter (cells/mL), microcystin levels >2,000 micrograms per liter (µg/L), or anatoxin-a levels >90 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 Danger Advisory for North Beach Shore and Warning Advisory for the rest of Yuba Lake remain in effect.

Data Summary

Surface sample: North Beach

  • Sample date: September 4, 2019
  • Microcystin: <2.0 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 µg/L

Elbow-depth integrated composite sample: North Beach

  • Sample date: September 4, 2019
  • Microcystin: < 2.0 micrograms per liter (µg/L)
  • Anatoxin-a: 0.12 µg/L

Elbow-depth integrated composite sample: Boat Ramp

  • Sample date: September 4, 2019
  • Microcystin: 0.11 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 µg/L

Update September 9, 2019

The Central Utah Health Department (CUHD) issued a Danger Advisory for the North Beach Shore after samples collected on August 27, 2019, showed cyanobacterial cell-count concentrations of approximately 10.1 cells per milliliter (cells/mL). These values exceed the recreation health-based threshold for a Danger Advisory.

The North Beach Shore is the only location at Yuba Lake under a Danger Advisory. The North Beach Campground, including access to restrooms, will be open. The remainder of Yuba Lake remains under a Warning Advisory.

A Danger Advisory indicates a high relative probability of acute health risk, cell-count density of >10 million cells per milliliter (cells/mL), microcystin levels >2,000 micrograms per liter (µg/L), or anatoxin-a levels >90 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.


Update September 6, 2019

Yuba Lake, August 27, 2019

Yuba Lake, August 27, 2019

Cyanobacteria cell-count results received by the Division of Water Quality (DWQ) for samples collected at Yuba Lake on August 27, 2019, exceeded the recreation health-based threshold for a Warning Advisory in three samples and the recreation health-based threshold for a Danger Advisory in one sample.

Cyanobacteria cell count concentrations in the surface sample for North Beach were over 10.1 million cells per milliliter (cells/mL). Cells counts in the other samples ranged from approximately 100,000 cells/mL to approximately 7.7 million cells/mL. Toxin test results were below the recreation health-based threshold for microcystin with the exception of microcystin levels of >5 µg/L in the surface sample at the Boat Ramp.

DWQ is now running new dilution curves for its enzyme-linked immunosorbent assay (ELISA) analysis for cyanotoxins. These different dilution ratios (1:1000 and 1:20) have changed the detection limit for microcystin from <0.10 micrograms per liter (µg/L) to <2.0 µg/L. The 1:20 dilution will detect toxin levels between 2 and 100 µg/L, and the 1:1000 dilution will detect toxin levels between 100 and 5,000 µg/L. These new dilution ratios should result in faster lab results. If further precision is needed, the lab will run additional dilutions.

The DWQ monitoring crew observed cyanobacteria that resembled grass clippings that had formed clumps and concentrated along the shoreline. The cyanobacteria were persistent in high concentrations to the end of the boat ramp. The crew saw a large number of dead carp along the shoreline.

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. A Danger Advisory indicates a high relative probability of acute health risk, cell-count density of >10 million cells per milliliter (cells/mL), microcystin levels >2,000 micrograms per liter (µg/L), or anatoxin-a levels >90 µg/L.

The Warning Advisory for Yuba Lake remains in place.

Data Summary

Yuba Lake Boat Ramp

  • Sample date: August 27, 2019
  • Sample type: Surface sample
  • Microcystin: >5 micrograms per liter (µg/L)
  • Cyanobacteria cell counts: 815,066 cells per milliliter (cells/mL)

Yuba Lake Boat Ramp

  • Sample date: August 27, 2019
  • Sample type: Elbow-depth integrated composite sample
  • Microcystin: no test results yet
  • Cyanobacteria cell counts: 96,639 cells per milliliter (cells/mL)

Yuba Lake North Beach

  • Sample date: August 27, 2019
  • Sample type: Surface sample
  • Microcystin: <2.0 micrograms per liter (µg/L)
  • Cyanobacteria cell counts: 10,176,262 cells per milliliter (cells/mL)

Yuba Lake North Beach

  • Sample date: August 27, 2019
  • Sample type: Elbow-depth integrated composite sample
  • Microcystin: <2.0 micrograms per liter (µg/L)
  • Cyanobacteria cell counts: 7,651,688 cells per milliliter (cells/mL)

Update August 30, 2019

Yuba Lake, North Beach, August 22, 2019

Cyanobacteria cell-count concentrations for samples collected by the Division of Water Quality (DWQ) at the West Beach and North Beach of Yuba Lake on August 22, 2019, exceeded the recreation health-based threshold for a Warning Advisory. Cell-count densities were 235,013 cells per milliliter (cells/mL) at the North Beach, and 28,784 cells/mL at the West Beach. The primary taxa in the samples was Aphanizomenon.

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 place.

Data Summary

  • Sample date: August 22, 2019
  • Sample type: Elbow-depth integrated composite sample
  • Sample locations: North Beach and West Beach
  • Cell counts: North Beach: 235,013 cells per milliliter (cells/mL), West Beach: 28,784 cells/mL

Update August 28, 2019

Yuba Lake, August 15, 2019

The Division of Water Quality (DWQ) received toxin test results from the Utah Public Health Lab (UPHL) on August 27, 2019, for samples collected August 15, 2019, at the north shore and boat ramp at Yuba Lake. Microcystin concentrations were well below the recreation health-based threshold for a Warning Advisory. Anatoxin-a was detected at the boat ramp. Cyanobacteria cell-count concentrations are still pending from PhycoTech.

The DWQ Monitoring crew observed cyanobacteria that resembled grass clippings and isolated clumps pushed up against the shore. Some of the cyanobacteria collected on the lake bed and were visible throughout the water column and at all sampling sites. There was evidence of dried cyanobacteria on the beach, surrounding vegetation, and the boat ramp.

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.

Due to the detection of anatoxin-a, the Warning Advisory for Yuba Lake remains in place.

Data Summary

North Shore

Elbow-depth integrated composite sample
  • Sample Date: August 15, 2019
  • Microcystin: 0.43 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 µg/L

Boat Ramp

Surface sample
  • Sample Date: August 15, 2019
  • Microcystin: 2.4 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 µg/L
Elbow-depth integrated composite sample
  • Sample Date: August 15, 2019
  • Microcystin: 0.16 micrograms per liter (µg/L)
  • Anatoxin-a: 0.13 µg/L

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.

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.