Manning Meadow Reservoir is located on Monroe Mountain in the Fishlake National Forest. It is a fairly remote reservoir popular for fishing.
Update July 30, 2018
Lab results for the sample collected July 19, 2018, showed anatoxin-a levels of 0.81 micrograms per liter (µg/L) and toxigenic cyanobacteria cell counts of 5,763,310 cells per milliliter (cells/ml). Toxin levels and cell-count densities exceed recreation health-based thresholds for primary contact such as swimming and ingestion of reservoir water by pets or livestock.
The phycology lab noted that the bloom appeared to be decaying, so it may not pose a threat at this time. Visitors should still exercise caution in areas of the reservoir that appear to be experiencing blooms.
Update July 25, 2018
The Central Utah Health Department received a report on July 17, 2018, of a possible bloom on Manning Meadow Reservoir. Microscope investigation of a sample indicates a possibility of gloeotrichia, a genus of cyanobacteria that generally doesn’t produce high toxin levels (e.g., microcystin), but which can produce high toxin levels if cell-count concentrations reach into the millions. Potential cyanotoxins microcystin and anatoxin-a were not detected when analyzed using strip tests.