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Jordanelle Reservoir Algal Bloom Monitoring 2019

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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.

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

Update November 27, 2019

Jordanell Reservoir, November 26, 2019

The Wasatch County Health Department removed the Warning Advisory on Jordanelle Reservoir on November 26, 2019, and took down the advisory signs.

The Division of Water Quality (DWQ) visited Jordanelle Reservoir on November 26, 2019. The monitoring crew did not observe signs of cyanobacteria at the reservoir, and sonde data also indicated the absence of cyanobacteria.

The close of the monitoring season and removal of advisories doesn’t mean HABs are no longer present, but rather that monitoring data won’t be collected during the colder months to verify their presence. HABs can persist throughout the fall and winter and can pose a potential threat to humans and pets. It’s important for recreators to recognize the signs of a bloom and take appropriate precautions.

Recreators are advised to stay out of the water and avoid any contact with water or scum if they suspect a harmful algal bloom. Hunters and fishers should clean waterfowl and fish well and discard all guts


Update November 19, 2019

Jordanelle Reservoir, November 12, 2019

Toxin test results received from the Utah Public Health Lab (UPHL) for samples collected on November 12, 2019, at Rock Cliff at Jordanelle Reservoir showed anatoxin-a levels in the surface samples that exceeded the recreation health-based threshold for a Warning Advisory. Microcystin levels in all samples were well below the advisory threshold.

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 Rock Cliff Area of Jordanelle Reservoir remains under a Warning Advisory.

Data Summary

Rock Cliff

  • Sample date: November 12, 2019
  • Sample type: Surface sample
  • Microcystin: <2.0 micrograms per liter (µg/L)
  • Anatoxin-a: 0.18 µg/L

Rock Cliff

  • Sample date: November 12, 2019
  • Sample type: Elbow-depth integrated composite sample
  • Microcystin: <0.10 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 µg/L

Update October 31, 2019

Jordanelle Reservoir, October 29, 2019

Jordanelle Reservoir, October 29, 2019

Toxin test results received from the Utah Public Health Lab (UPHL) for samples collected on October 22, 2019, at the Rock Cliff Area at Joranelle Reservoir showed anatoxin-a and microcystin levels well below the recreation health-based threshold for a Warning Advisory. Cyanobacteria cell-count concentration results are pending from PhycoTech.

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.

Jordanelle Reservoir remains under a Warning Advisory.

Data Summary

Rock Cliff Area

  • Sample date: October 22, 2019
  • Sample type: Elbow-depth integrated composite sample
  • Microcystin: 0.14 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 µg/L

Update October 18, 2019

Jordanelle Reservoir, Rock Cliff Boat Ramp, October 16, 2019

Cyanobacteria cell-count concentrations for the surface samples collected on October 16, 2019, at the Rock Cliff Area at Jordanelle Reservoir exceeded the recreation health-based threshold for a Danger Advisory. The primary taxon is Dolichospermum, a known producer of potent cyanotoxins such as microcystin and anatoxin-a.

The Wasatch County Health Department (WCHD) has determined that the Rock Cliff Area will remain under a Warning Advisory. WCHD is posting Danger signs in the area to warn recreationists to stay out of the water due to the high levels of cyanobacteria on the water surface.

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 Rock Cliff Area of Jordanelle Reservoir remains under a Warning Advisory.

Data Summary

Rock Cliff Boat Ramp

  • Sample date: October 16, 2019
  • Sample type: Surface sample
  • Microcystin: Pending
  • Anatoxin-a: 0.123 micrograms per liter (µg/L)
  • Cyanobacteria cell counts:12,682,424 cells per milliliter (cells/mL)

Rock Cliff Boat Ramp

  • Sample date: October 16, 2019
  • Sample type: Elbow-depth integrated composite sample
  • Microcystin: Pending
  • Anatoxin-a: <0.10 micrograms per liter (µg/L)
  • Cyanobacteria cell counts: 11,552 cells per milliliter (cells/mL)

Update October 17, 2019

The Wasatch County Health Department (WCHD) issued a Warning Advisory for the Rock Cliff Area of Jordanelle Reservoir after samples collected there by the Division of Water Quality (DWQ) on October 16, 2019, exceeded the recreation health-based threshold for a Warning Advisory for anatoxin-a. Toxin test results for microcystin and cyanobacteria cell-count concentrations are pending.

The DWQ monitoring crew visited Jordanelle Reservoir on October 16, 2019, and observed a significant accumulation of cyanobacteria near the Rock Cliff Area. There were visible cyanobacteria that resembled grass clippings and isolated clumps of cyanobacteria. The crew collected samples at the Rock Cliff Boat Ramp and submitted them to the Utah Public Health Lab for toxin testing and PhycoTech for cyanobacteria cell-count concentrations.

Jordanelle Reservoir remains open for recreation at this time. Recreationists are advised to not swim or waterski in areas of scum, avoid boating in areas of scum, keep animals away, and not ingest water. Visitors can still recreate in the reservoir but are cautioned to be mindful of water conditions, as blooms may move or disperse depending on temperature, wind, and weather.

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.

Data Summary

Rock Cliff Boat Ramp

  • Sample date: October 16, 2019
  • Sample type: Surface sample
  • Microcystin: Pending
  • Anatoxin-a: 0.123 micrograms per liter (µg/L)
  • Cyanobacteria cell counts: Pending

Rock Cliff Boat Ramp

  • Sample date: October 16, 2019
  • Sample type: Elbow-depth integrated composite sample
  • Microcystin: Pending
  • Anatoxin-a: <0.10 micrograms per liter (µg/L)
  • Cyanobacteria cell counts: Pending

Update October 17, 2019

Jordanelle Reservoir, Rock Cliff Boat Ramp, October 16, 2019

The Divison of Water Quality (DWQ) monitoring crew visited Jordanelle Reservoir on October 16, 2019, and observed a significant accumulation of cyanobacteria near the Rock Cliff Area. The crew collected samples at the Rock Cliff Boat Ramp and submitted them to the Utah Public Health Lab for toxin testing and PhycoTech for cyanobacteria cell-count concentrations.

The Wasatch County Health Department (WCHD) will wait for lab results before determining whether to issue an advisory. In the meantime, WCHD is visiting the reservoir today to run rapid toxin strip tests on the bloom to see if initial testing shows the presence of toxins.

Recreationists may wish to exercise caution in the area until test results are available.