How Clean Is Big Lake?
Big Lake is a clean lake by Minnesota standards. It received a water quality grade of B (Good) based on EPA monitoring data. Water clarity (Secchi depth): 9.1 ft. Phosphorus: 12 µg/L. Chlorophyll-a (algae): 3.2 µg/L. Trophic State Index: 42.
Cleanliness Snapshot
| Metric | Big Lake | Minnesota avg |
|---|---|---|
| Overall Grade | B | C |
| Water Clarity (Secchi) | 9.1 ft | — |
| Phosphorus | 12 µg/L | <30 = clean |
| Chlorophyll-a (Algae) | 3.2 µg/L | <10 = clean |
| Trophic State Index | 42 | <50 = clean |
How does Big Lake compare?
Big Lake's grade of B matches or beats the Minnesota state average of C. It ranks #1 of 33 lakes in Carlton County by water quality score. Multi-year monitoring data shows water quality is improving based on 5 years of records.