Clearwater Lake vs Upper South Long Lake
Water quality, depth, fish species, and recreation comparison.
Clearwater Lake has a higher water quality grade (A, Excellent) than Upper South Long Lake (C, Fair). Both are in Crow Wing County, Minnesota.
Both Clearwater Lake and Upper South Long Lake sit in Minnesota. A same-state comparison strips out the state-level water-quality regime as a variable: any grade differences here are about the lakes themselves, not the agencies grading them. The grades are meaningfully apart: Clearwater Lake grades a A while Upper South Long Lake grades a C. That two-letter spread reflects real underlying differences — different watershed inputs, different depth profiles, or different monitoring rigor.
For a recreational visitor, the wider grade gap is decisive — Clearwater Lake is the better water-quality choice. For a researcher, the gap is the interesting part: what is different about the two watersheds, and which of those differences is mutable?
Clearwater Lake
Good clarity, visible to about 13 ft.
Upper South Long Lake
Murky, only visible to about 6 ft.
Side-by-Side Metrics
| Metric | Clearwater Lake | Upper South Long Lake |
|---|---|---|
| Overall Grade | A (Excellent) | C (Fair) |
| Water Clarity | 13 ft | 6 ft |
| Phosphorus | 12 µg/L | 16 µg/L |
| Chlorophyll-a (Algae) | 3.7 µg/L | 8.5 µg/L |
| Maximum Depth | 54 ft | 47 ft |
| Surface Area | 905 acres | 804 acres |
| Public Access | Yes | Yes |
| Fish Species | 16 | 16 |
| Trophic State | mesotrophic | mesotrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Clearwater Lake wins on overall water quality with a Grade A versus Upper South Long Lake's Grade C. Water clarity: 13 ft vs 6 ft. For fishing diversity, Clearwater Lake also leads with 16 species.
Source: EPA National Aquatic Resource Surveys, 2026.