How Clean Is Big Lake?
Big 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): 8.2 ft. Phosphorus: 14 µg/L. Chlorophyll-a (algae): 4.9 µg/L. Trophic State Index: 45.
Cleanliness Snapshot
| Metric | Big Lake | Minnesota avg |
|---|---|---|
| Overall Grade | A | C |
| Water Clarity (Secchi) | 8.2 ft | — |
| Phosphorus | 14 µg/L | <30 = clean |
| Chlorophyll-a (Algae) | 4.9 µg/L | <10 = clean |
| Trophic State Index | 45 | <50 = clean |
How does Big Lake compare?
Big Lake's grade of A matches or beats the Minnesota state average of C. It ranks #1 of 68 lakes in St. Louis County by water quality score.