Current Cyanobacteria Advisories

The table below is continually updated with the most current information on recreational use health advisories issued and lifted throughout the season for monitored and sampled water bodies.

Remember: Only a fraction of all water bodies in Oregon are visually monitored or sampled due to limited physical and monetary resources. A water body with no recreational health advisory is not an indication that a bloom is not present. You are your own best advocate when ensuring your safety, and that of your family and pets. Be aware and "when in doubt, stay out."

= Advisory in effect lifted = Advisory has been lifted = Permanent advisory

Waterbody	Status	Link	County	Toxin	Data (ppb)
Lake Ewauna	Advisory in effect	September 22, 2023	Klamath	Microcystin	8
Willow Creek Reservoir	Advisory in effect	September 19, 2023	Morrow	Microcystin	46
Hells Canyon Reservoir	Advisory in effect	August 3, 2023	Wallowa and Baker (issued by State of Idaho)	Microcystin	>50
Brownlee Reservoir	Advisory in effect	August 3, 2023	Baker (issued by State of Idaho)	Microcystin	>50
Agency Lake	Advisory in effect	July 25, 2023	Klamath	Microcystin	16
Upper Klamath Lake	Advisory in effect	July 25, 2023	Klamath	Microcystin	41
Willamette River in Portland	Advisory has been lifted	September 28, 2023	Multnomah	Microcystin
Aarons Lake	Advisory has been lifted	September 14, 2023	Columbia	Microcystin
Pete's Slough & Sturgeon Lake	Advisory has been lifted	August 25, 2023	Columbia & Multnomah	Microcystin
Cullaby Lake	Advisory has been lifted	August 21, 2023	Clatsop	Cyanobacteria
Galesville Reservoir	Advisory has been lifted	June 30, 2023	Douglas	Cyanobacteria
South Umpqua River and mainstream Umpqua River	Permanent Recreational Use Advisory	Posted Sign	Douglas

Douglas County Permanent Recreational Use Advisory: South Umpqua River and mainstem Umpqua River

The advisory covers the South Umpqua River from Canyonville downstream to the confluence with the mainstem Umpqua River, and the mainstem Umpqua River downstream past Elkton to Sawyers Rapids. Pools in the bedrock along the rivers edge are known to develop cyanobacteria (blue-green algae) blooms that can be harmful to pets and people if accidental ingestion occurs. Signs have been posted at several access areas along the river.