Manning Meadow Reservoir Algal Bloom Monitoring 2019

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 August 28, 2019

Manning Meadow, 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 on August 15, 2019, at the north shore of Manning Meadow Reservoir. Microcystin and anatoxin-a concentrations were well below the recreation health-based threshold for a Warning Advisory. Cyanobacteria cell-count concentrations are still pending from PhycoTech.

The advisory for Manning Meadow Reservoir can be lifted after two consecutive weeks of sampling fall below the recreation health-based threshold. DWQ will know more once it receives cell count densities. If cell counts fall below the threshold for the August 15, 2019, sample, and all parameters fall below the threshold in subsequent sampling, the advisory may be lifted. However, DWQ does not currently have the lab data to support that determination.

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 Manning Meadow Reservoir remains in place.

Surface sample

  • Sample Date: August 15, 2019
  • Microcystin: 0.54 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 µg/L

Elbow-depth integrated composite sample

  • Sample Date: August 15, 2019
  • Microcystin: 0.14 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 µg/L

Update August 14, 2019

Manning Meadow, August 9, 2019

Cyanobacteria cell-count concentrations from samples collected by the Division of Water Quality (DWQ) at the north shore of Manning Meadow Reservoir on August 9, 2019, were above the recreation health-based threshold for a Warning Advisory. Cell counts had decreased considerably from the previous week but remained above the advisory threshold in the surface sample. Gloeotrichia was the primary taxon in the samples.

Toxin test results from the Utah Public Health Lab for anatoxin-a and microcystin were well below recreation health-based thresholds for a health advisory.

The DWQ monitoring crew noted that the water column was clear with visible, dispersed nodules of cyanobacteria. The small green/yellow spherical nodules were dispersed throughout the lake and collected in the hoof prints of cattle along the shore. Cyanobacteria were seen at all sampling locations on the lake, but the highest concentrations were found at the northern end of the 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.

The Warning Advisory for Manning Meadow Reservoir remains in place.

Surface sample

  • Sample Date: August 9, 2019
  • Microcystin: <0.10 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 µg/L
  • Cell Counts: 112,645 cells per milliliter (cells/mL)

Elbow-depth integrated composite sample

  • Sample Date: August 9, 2019
  • Microcystin: <0.10 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 µg/L
  • Cell Counts: 5,089 cells per milliliter (cells/mL)

Update August 13, 2019

Manning Meadow, August 1, 2019

Manning Meadow, August 1, 2019

Cyanobacteria cell-count concentrations from samples collected by the Division of Water Quality (DWQ) at the south shore of Manning Meadow Reservoir on August 1, 2019, were above the recreation health-based threshold for a Warning Advisory. Cell-counts in the water column sample decreased from the previous week, but cell counts for the surface sample remained above 1 million cells per milliliter (cells/mL). Gloeotrichia was the primary taxon in the samples.

Toxin test results from the Utah Public Health Lab for anatoxin-a and microcystin were well below recreation health-based thresholds for a health advisory.

The DWQ monitoring crew observed visible yellowish/green nodules dispersed on the surface and through the water column. The cyanobacteria were primarily concentrated along the shore in small coves.

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 Manning Meadow Reservoir remains in place.

Surface sample

  • Sample Date: August 1, 2019
  • Microcystin: < 0.39 micrograms per liter (µg/L)
  • Anatoxin-a: < 0.10 µg/L
  • Cell Counts: 1,009,514 cells per milliliter (cells/mL)

Elbow-depth integrated composite sample

  • Sample Date: August 1, 2019
  • Microcystin: <0.10 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 µg/L
  • Cell Counts: 35,313 cells per milliliter (cells/mL)

Update August 5, 2019

Manning Meadow, July 26, 2019

Manning Meadow, July 26, 2019

Cyanobacteria cell-count concentrations from samples collected by the Division of Water Quality (DWQ) at the south shore of Manning Meadow Reservoir on July 26, 2019, were above the recreation health-based threshold for a Warning Advisory. Aphanizomenon was the primary taxon in the samples. Toxin test results from the Utah Public Health Lab were well below recreation health-based thresholds for a health advisory.

The DWQ monitoring crew observed small, cylindrical cyanobacteria throughout the water column. They also observed bright-green, isolated clumps of cyanobacteria resembling grass clippings concentrated along the 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.

Manning Meadow Reservoir remains under a Warning Advisory.

Cyanobacteria Cell Count Concentrations

  • Surface sample: 1,044,065 cells per milliliter (cells/mL)
  • Elbow-depth integrated composite sample: 173,557 cells/mL

Toxin Test Results

  • Microcystin: <0.10 micrograms per liter (µg/L)
  • Anatoxin-a: <0.10 µg/L

Update July 25, 2019

Manning Meadow, July 18, 2019

Manning Meadow, July 18, 2019

The Division of Water Quality (DWQ) collected both surface and elbow-depth integrated water samples at Manning Meadow Reservoir on July 18, 2019. The monitoring crew observed isolated clumps of cyanobacteria resembling grass clippings along the northern shore of the reservoir and throughout the water column.

DWQ received cyanobacterial cell-count concentration results from PhycoTech on July 24, 2019, of 5,946,097 cells per milliliter (cells/mL) on the surface and 182,774 cells/mL in the water column.

These cell-count densities exceed the recreation health-based threshold for a Warning Advisory. Based on these data, the Central Utah Public Health Department (CUPHD) has issued a Warning Advisory for Manning Meadow Reservoir. The CUPHD will be posting signs at the reservoir. The DWQ monitoring crew will collect follow-up samples this week.

Toxin samples were delivered to the Utah Public Health Lab (UPHL) for further analysis. UPHL testing showed anatoxin-a and microcystin levels of <0.10 micrograms per liter (µg/L), which are well below the recreation health-based threshold for a Warning Advisory.

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.