Long Lake vs St. Clair Lake
Water quality, depth, fish species, and recreation comparison.
Long Lake has a higher water quality grade (A, Excellent) than St. Clair Lake (C, Fair). Both are in Becker County, Minnesota.
Long Lake and St. Clair Lake are both in Minnesota — a same-state head-to-head where the comparison comes down to lake-specific differences in depth, watershed, and monitoring history rather than the broader state-level water-quality regime. The grades are meaningfully apart: Long Lake grades a A while St. Clair 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 — Long 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?
Long Lake
Crystal clear, you can see 20 ft down.
St. Clair Lake
Murky, only visible to about 4.6 ft.
Side-by-Side Metrics
| Metric | Long Lake | St. Clair Lake |
|---|---|---|
| Overall Grade | A (Excellent) | C (Fair) |
| Water Clarity | 20 ft | 4.6 ft |
| Phosphorus | 8 µg/L | 50 µg/L |
| Chlorophyll-a (Algae) | No data | No data |
| Maximum Depth | - | - |
| Surface Area | 45 acres | 45 acres |
| Public Access | Unknown | Unknown |
| Fish Species | 1 | 0 |
| Trophic State | oligotrophic | eutrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Long Lake wins on overall water quality with a Grade A versus St. Clair Lake's Grade C. Water clarity: 20 ft vs 4.6 ft. For fishing diversity, Long Lake also leads with 1 species.