How Clean Is Big Deep Lake?
Big Deep 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): 19.4 ft. Phosphorus: 7 µg/L. Chlorophyll-a (algae): 1.9 µg/L. Trophic State Index: 35.
Cleanliness Snapshot
| Metric | Big Deep Lake | Minnesota avg |
|---|---|---|
| Overall Grade | A | C |
| Water Clarity (Secchi) | 19.4 ft | — |
| Phosphorus | 7 µg/L | <30 = clean |
| Chlorophyll-a (Algae) | 1.9 µg/L | <10 = clean |
| Trophic State Index | 35 | <50 = clean |
How does Big Deep Lake compare?
Big Deep Lake's grade of A matches or beats the Minnesota state average of C. It ranks #85 of 104 lakes in Cass County by water quality score. Multi-year monitoring data shows water quality is improving based on 4 years of records.