How Clean Is Blackduck Lake?
Blackduck Lake has poor water quality, with elevated phosphorus and algae. It received a water quality grade of D (Poor) based on EPA monitoring data. Water clarity (Secchi depth): 6.8 ft. Phosphorus: 43 µg/L. Chlorophyll-a (algae): 23.3 µg/L. Trophic State Index: 56.
Cleanliness Snapshot
| Metric | Blackduck Lake | Minnesota avg |
|---|---|---|
| Overall Grade | D | C |
| Water Clarity (Secchi) | 6.8 ft | — |
| Phosphorus | 43 µg/L | <30 = clean |
| Chlorophyll-a (Algae) | 23.3 µg/L | <10 = clean |
| Trophic State Index | 56 | <50 = clean |
How does Blackduck Lake compare?
Blackduck Lake's grade of D falls below the Minnesota state average of C. It ranks #66 of 68 lakes in St. Louis County by water quality score. Multi-year monitoring data shows water quality is stable based on 6 years of records.