How Clean Is Cottonwood Lake?
Cottonwood Lake has very poor water quality and a high algae bloom risk. It received a water quality grade of F (Very Poor) based on EPA monitoring data. Water clarity (Secchi depth): 1.8 ft. Phosphorus: 186 µg/L. Trophic State Index: 74.
Cleanliness Snapshot
| Metric | Cottonwood Lake | Minnesota avg |
|---|---|---|
| Overall Grade | F | C |
| Water Clarity (Secchi) | 1.8 ft | — |
| Phosphorus | 186 µg/L | <30 = clean |
| Trophic State Index | 74 | <50 = clean |
How does Cottonwood Lake compare?
Cottonwood Lake's grade of F falls below the Minnesota state average of C. It ranks #2 of 5 lakes in Lyon County by water quality score.