Lakes With Algae Problems in Oregon
21 lakes in Oregon report elevated algae levels (chlorophyll-a above 20 µg/L). These lakes are most likely to develop blue-green algae blooms during warm, calm summer weather. Avoid swimming during visible blooms and rinse pets after contact.
Ranked List
| # | Lake | County | Grade | Clarity | Phosphorus | Algae |
|---|---|---|---|---|---|---|
| 1 | Brownlee Reservoir | Baker | F | - | - | 198 µg/L |
| 2 | Shoalwater Bay Lake | Klamath | F | - | 220 µg/L | 147 µg/L |
| 3 | Cold Springs Reservoir | Umatilla | F | - | - | 126 µg/L |
| 4 | Rattlesnake Point Lake | Klamath | F | - | 185 µg/L | 124.5 µg/L |
| 5 | Upper Klamath Lake | Klamath | F | - | 195 µg/L | 117 µg/L |
| 6 | Lake Billy Chinook | Jefferson | F | - | - | 93.5 µg/L |
| 7 | Mid-North Lake | Klamath | F | - | 180 µg/L | 82.7 µg/L |
| 8 | Mid-Trench Lake | Klamath | F | - | 240 µg/L | 80.6 µg/L |
| 9 | Upper Klamath Lake | Klamath | F | - | - | 71.6 µg/L |
| 10 | Williamson River Outlet Lake | Klamath | F | - | 165 µg/L | 70.5 µg/L |
| 11 | Agency Lake South | Klamath | F | - | 110 µg/L | 61.6 µg/L |
| 12 | Lake Billy Chinook | Jefferson | F | - | - | 59.6 µg/L |
| 13 | Lake Billy Chinook | Jefferson | F | - | - | 52.3 µg/L |
| 14 | Thief Valley Reservoir | Union | F | - | - | 51.2 µg/L |
| 15 | Malheur Lake | Harney | F | - | 807.5 µg/L | 45.5 µg/L |
| 16 | Diamond Lake | Douglas | F | - | - | 42.6 µg/L |
| 17 | Cullaby Lake | Clatsop | F | - | - | 36.8 µg/L |
| 18 | Deschutes River Arm Lake | Jefferson | F | - | - | 33.1 µg/L |
| 19 | Tenmile Lake | Coos | F | - | - | 30.6 µg/L |
| 20 | Lake Billy Chinook | Jefferson | D | - | - | 24.6 µg/L |
| 21 | Crooked River Arm Lake | Jefferson | D | - | - | 24.6 µg/L |