Deer Creek Reservoir Algal Bloom Monitoring 2019

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

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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 7, 2019

Deer Creek, October 22, 2019

The Wasatch County Health Department (WCHD) has removed the Warning Advisory on Deer Creek Reservoir. Toxin test results received from the Utah Public Health Lab (UPHL) for samples collected by the Division of Water Quality (DWQ) at the Charleston Day Use Area on October 22, 2019, and in the open water on October 28, 2019, showed anatoxin-a and microcystin levels well below the recreation health-based threshold for a Warning Advisory.

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.

Data Summary

Open Water

  • Sample date: October 28, 2019
  • Sample type: Elbow-depth integrated composite sample
  • Microcystin: <2.0 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 µg/L

Charleston Day Use Area

  • Sample date: October 22, 2019
  • Sample type: Elbow-depth integrated composite sample
  • Microcystin: 0.13 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 µg/L

Update October 31, 2019

Deer Creek Reservoir, October 17, 2019

Deer Creek Reservoir, October 17, 2019

Toxin test results received from the Utah Public Health Lab (UPHL) for samples collected by the Division of Water Quality (DWQ) on October 17, 2019, at the Charleston Day Use Area at Deer Creek Reservoir showed anatoxin-a and microcystin levels well below the recreation health-based threshold for a Warning Advisory. Cyanobacteria cell-count concentrations 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.

Deer Creek Reservoir remains under a Warning Advisory.

Data Summary

Access

  • Sample date: October 17, 2019
  • Sample type: Elbow-depth integrated composite sample
  • Microcystin: <2.0 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 mg/L

Update October 15, 2019

Charleston Day Use Area at Deer Creek Reservoir, October 1, 2019

Charleston Day Use Area at Deer Creek Reservoir, October 1, 2019

Toxin test results received from the Utah Public Health Lab (UPHL) for samples collected by the Division of Water Quality (DWQ) at several locations at Deer Creek Reservoir on September 17, 2019, September 27, 2019, October 1, 2019, and October 7, 2019, showed anatoxin-a and microcystin exceeding the recreation health-based threshold for a Warning Advisory in the October samples. Cyanobacteria cell-count concentrations are pending for two of the samples.

The DWQ monitoring crew observed cyanobacteria in the water column that resembled grass clippings and spherical nodules. The particles were well dispersed in the water column, and the water had a green hue. The cyanobacteria were concentrated along the eastern shore.

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 remains in place.

Data Summary

Island Day Use Area

  • Sample date: October 7, 2019
  • Sample type: Elbow-depth integrated composite sample
  • Microcystin: 17.14 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 µg/L
  • Cyanobacteria cell counts: Pending

Charleston Day Use Area

  • Sample date: October 1, 2019
  • Sample type: Elbow-depth integrated composite sample
  • Microcystin: 3.0 micrograms per liter (µg/L)
  • Anatoxin-a: 0.102 µg/L
  • Cyanobacteria cell counts: Pending

Access

  • Sample date: September 27, 2019
  • Sample type: Elbow-depth integrated composite sample
  • Microcystin: <2.0 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 µg/L
  • Cyanobacteria cell counts: 2,635 cells per milliliter (cells/mL)

Charleston Day Use Area

  • Sample date: September 17, 2019
  • Sample type: Elbow-depth integrated composite sample
  • Microcystin: < 2.0 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 µg/L
  • Cyanobacteria cell counts: 282 cells per milliliter (cells/mL)
Charleston Day Use Area at Deer Creek Reservoir, October 1, 2019

Charleston Day Use Area at Deer Creek Reservoir, October 1, 2019

Deer Creek Reservoir, September 17, 2019

Deer Creek Reservoir, September 17, 2019


Update August 30, 2019

Deer Creek Reservoir, North End of Reservoir (Looking East to West), Drone footage, Week of August 26, 2019.

Deer Creek Reservoir, North End of Reservoir (Looking East to West), Drone footage, Week of August 26, 2019.

The Wasatch County Health Department (WCHD) posted Warning Advisory signs at access points on Deer Creek Reservoir on August 30, 2019, to alert the public about areas of the reservoir that are experiencing harmful algal blooms.

Deer Creek 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.

The Division of Water Quality (DWQ) and WCHD visited the reservoir multiple times between August 26 and August 29, 2019, and observed cyanobacteria accumulations at the Charleston Day Use area and the northern portion of the reservoir. Cyanobacteria were also observed at other areas of the reservoir. Satellite imagery and drone footage confirm the extent of the bloom.

DWQ and WCHD collected samples at a variety of locations on the reservoir on August 29, 2019. These samples have been submitted to the lab, and results should be available early next week.

Test results received on August 28, 2019, for samples collected on August 27, 2019, at the Charleston Day Use Area showed cyanobacteria cell-count concentrations of approximately 728,000 cells per milliliter (cells/mL), which exceeds the recreation health-based threshold for a Warning Advisory. The primary taxon in the samples was Dolichospermum, a species that can produce both microcystin and anatoxin-a. Toxin test results received to date, however, were well below the health 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.

Data Summary

Surface Sample

  • Sample date: August 27, 2019
  • Microcystin: 0.24 micrograms per liter (µg/)
  • Anatoxin-a: <0.10 µg/L
  • Cell counts: 727,167 cells per milliliter (cells/mL)

Elbow-depth Integrated Composite Sample

  • Sample date: August 27, 2019
  • Microcystin: <0.10 micrograms per liter (µg/)
  • Anatoxin-a: <0.10 µg/L