Cyanobacteria are affecting waterways across Southern Oregon, with active state precautions or advisories now posted from Jackson and Douglas counties into the Klamath Basin as a striking bloom on Portland’s Willamette River adds another major waterway to Oregon’s expanding late-summer algae activity.
Agate Reservoir in Jackson County and Diamond Lake and Lemolo Lake in Douglas County were placed under precautions Aug. 21 following visible blooms. Odell Lake in Klamath County also remains under precaution after previously reaching advisory-level conditions, while Hyatt Lake in Jackson County, Siltcoos Lake in Douglas and Lane counties, Upper Klamath Lake, Agency Lake and the Upper Klamath National Wildlife Refuge remain among other Southern Oregon waters carrying active state designations.
Conditions are more serious at several locations. Agency Lake remains under a recreational health advisory after microcystin was detected at 16.9 micrograms per liter, while the Upper Klamath National Wildlife Refuge remains under an advisory following a microcystin measurement of 8.27 micrograms per liter. A permanent advisory also remains posted for the South Umpqua River and mainstream Umpqua River in Douglas County…