Oregon Health Authority has lifted the recreational use health advisory for Thief Valley Reservoir in Baker and Union Counties.
The advisory, originally issued July 2, was lifted after water monitoring confirmed that water levels are now too low for regular recreational use.
Despite the lifted advisory, OHA advised recreational visitors to remain alert for signs of cyanobacteria blooms, which can develop at any time when conditions are favorable. Only a fraction of Oregon's water bodies are monitored for blooms and toxins.
Warning signs include water that is foamy, scummy, thick like paint, pea-green or blue-green, or areas with thick brownish-red mats or bright green clumps suspended in the water. When recreating, people should avoid swallowing water or inhaling droplets in areas showing bloom signs and keep pets out of affected areas.
Even in clear water, cyanotoxins can persist. Toxins released when blooms die can spread into surrounding clear water, and certain species of cyanobacteria that anchor at the bottom or in sediment can release toxins without visible discoloration.