How Clean Is Upper South Long Lake?
Upper South Long Lake has fair water quality — typical of lakes with moderate nutrient enrichment. It received a water quality grade of C (Fair) based on EPA monitoring data. Water clarity (Secchi depth): 6 ft. Phosphorus: 16 µg/L. Chlorophyll-a (algae): 8.5 µg/L. Trophic State Index: 49.
Cleanliness Snapshot
| Metric | Upper South Long Lake | Minnesota avg |
|---|---|---|
| Overall Grade | C | C |
| Water Clarity (Secchi) | 6 ft | — |
| Phosphorus | 16 µg/L | <30 = clean |
| Chlorophyll-a (Algae) | 8.5 µg/L | <10 = clean |
| Trophic State Index | 49 | <50 = clean |
How does Upper South Long Lake compare?
Upper South Long Lake's grade of C matches or beats the Minnesota state average of C. It ranks #68 of 85 lakes in Crow Wing County by water quality score. Multi-year monitoring data shows water quality is improving based on 6 years of records.
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