How Clean Is Alder Lake?
Alder Lake is among the cleanest lakes in Minnesota. It received a water quality grade of A (Excellent) based on EPA monitoring data. Water clarity (Secchi depth): 13.8 ft. Phosphorus: 8 µg/L. Trophic State Index: 37.
Cleanliness Snapshot
| Metric | Alder Lake | Minnesota avg |
|---|---|---|
| Overall Grade | A | C |
| Water Clarity (Secchi) | 13.8 ft | — |
| Phosphorus | 8 µg/L | <30 = clean |
| Trophic State Index | 37 | <50 = clean |
How does Alder Lake compare?
Alder Lake's grade of A matches or beats the Minnesota state average of C. It ranks #38 of 128 lakes in Cook County by water quality score. Multi-year monitoring data shows water quality is stable based on 2 years of records.