The Oregon Health Authority downgraded its recreational use advisory for Prineville Reservoir in Crook County to a precaution, the agency announced. Water monitoring confirmed that cyanotoxin levels have dropped below recreational guideline values for people.
However, levels remain above the authority's educational guideline values for dogs. Pet owners should keep their pets away from areas that appear to have algae blooms.
The agency advises recreational visitors to remain alert to signs of cyanobacteria blooms, which can develop and disappear at any time when conditions are favorable. Visitors should avoid areas where water is foamy, scummy, thick like paint, pea-green or blue-green, or where thick brownish-red mats or bright green clumps are visible.
People, especially small children and pets, should avoid swimming or boating activities that involve swallowing water or inhaling droplets in these areas. Cyanotoxins can exist in clear water around the bloom as toxins are released when a bloom dies, the authority said.
The original advisory was issued on July 27.