How Clean Is Jefferson Lake?
Jefferson Lake is algae-prone, with a higher bloom risk in warm months. It received a water quality grade of F (Algae-prone) based on EPA monitoring data. Water clarity (Secchi depth): 2 ft. Phosphorus: 86.5 µg/L. Chlorophyll-a (algae): 72 µg/L. Trophic State Index: 69.
Cleanliness Snapshot
| Metric | Jefferson Lake | Minnesota avg |
|---|---|---|
| Overall Grade | F | C |
| Water Clarity (Secchi) | 2 ft | — |
| Phosphorus | 86.5 µg/L | <30 = clean |
| Chlorophyll-a (Algae) | 72 µg/L | <10 = clean |
| Trophic State Index | 69 | <50 = clean |
How does Jefferson Lake compare?
Jefferson Lake's grade of F falls below the Minnesota state average of C. It ranks #10 of 13 lakes in Le Sueur County by water quality score. Multi-year monitoring data shows water quality is declining based on 6 years of records.
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