Otter Creek Algal Bloom Monitoring 2018

Warning Advisory

  • Do not swim or water ski
  • 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.

Otter Creek State Park is located at the south end of Otter Creek Reservoir, a high-alpine waterbody located in Piute County near Antimony. It is a popular area for camping, boating, and fishing.

Update September 20, 2018

Otter Creek September 20, 2018

The Division of Water Quality (DWQ) visited Otter Creek Reservoir on September 12, 2018. While the monitoring crew did not observe visible cyanobacteria at the three sites on the reservoir, they collected a sample at the midshore site per follow-up sampling protocol.

Toxin-test results received by DWQ from the Utah Public Health Lab (UPHL) showed low anatoxin-a levels that exceeded the recreation health-based threshold for a Warning Advisory.

Due to elevated toxin levels in Mill Meadow Reservoir, the Utah Department of Agriculture and Food (UDAF) recommends that farmers and ranchers prevent livestock from drinking from the reservoir. UDAF advises producers to find alternative water sources until conditions improve.

Toxin Test Results

  • Surface sample collected at the midway shore of the reservoir.
  • Anatoxin-a: 0.15 micrograms per liter (µg/L)
  • Microcystin: 1.7 µg/L

The Warning Advisory for Otter Creek Reservoir remains in place.


Update September 4, 2018

Otter Creek Reservoir, August 16, 2018

Toxin test results and cyanobacteria cell-count concentrations for a surface sample collected midway in the reservoir by the Division of Water Quality (DWQ) on August 22, 2018, showed toxin levels and cyanobacteria cell counts continue to exceed the recreation health-based threshold for a Warning Advisory.

The Utah Public Health Lab (UPHL) found microcystin levels of 400 micrograms per liter (µg/L) after 500x dilution. Anatoxin-a levels were 0.14 µg/L. Toxigenic cyanobacteria cell-count densities were 115,989 cells per milliliter (cells/ml). All three measures exceed the threshold for a Warning Advisory.

The current Warning Advisory remains in place.


Update August 21, 2018

Cyanobacteria cell-count concentrations from a sample collected August 7, 2018, in Otter Creek Reservoir showed cell counts of 188,431 cells per milliliter (cells/ml). These cell densities exceed the recreation health-based threshold for a Warning Advisory. The reservoir remains under a Warning Advisory based on microcystin levels and cyanobacteria cell-count concentrations.

Warning Advisory for Manning Meadow Reservoir

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. Advisory actions:

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

Update August 17, 2018

Utah Public Health Lab (UPHL) toxin test results show high microcystin levels in the reservoir. The lab confirmed microcystin levels of 392 micrograms per liter (µg/L) after 300 times dilution. This result is well above the 50 µg/L reported yesterday pending further dilutions. The reservoir remains under a Warning Advisory.

Warning Advisory for Otter Creek Reservoir

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. Advisory actions:

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

Update August 16, 2018

The Central Utah Health Department has issued a Warning Advisory for Otter Creek Reservoir due to microcystin levels that exceed the recreation health-based threshold. Lab results show toxin levels in excess of 50 micrograms per liter (µg/L). These levels could go even higher with further dilutions by the lab. Health department officials are posting signs today to alert visitors of the advisory.

Warning Advisory for Otter Creek Reservoir

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. Advisory actions:

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

Update August 15, 2018

Lab results from the Utah Public Health Lab (UPHL) for the sample collected at Otter Creek Reservoir on August 7, 2018, showed microcystin levels >5 micrograms per liter (µg/L). Toxin levels will likely exceed 50 µg/L with further dilutions by the lab. These microcystin levels exceed the recreation health-based threshold for a Warning Advisory.


Update August 14, 2018

The Division of Water Quality visited Otter Creek State Park on August 7, 2018, and observed a bloom in the middle portion of the reservoir and along the shore. The monitoring crew collected a surface shoreline sample for anatoxin-a, microcystin, and phytoplankton. Toxin test strip results were non-detect for anatoxin-a but >10 µg/L for microcystin. The strip test result for microcystin exceeded the recreation health-based threshold for a Warning Advisory. The labs will validate these toxin screening results.

Toxin Test Strip Results

  • Anatoxin-a: non-detect
  • Microcystin: > 10 µg/L