Beltrami Lake vs Turtle River Lake
Water quality, depth, fish species, and recreation comparison.
Beltrami Lake has a higher water quality grade (A, Excellent) than Turtle River Lake (C, Fair). Both are in Beltrami County, Minnesota.
Both Beltrami Lake and Turtle River 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: Beltrami Lake grades a A while Turtle River 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 — Beltrami 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?
Beltrami Lake
Good clarity, visible to about 11.2 ft.
Turtle River Lake
Moderate clarity, visible to about 8.5 ft.
Side-by-Side Metrics
| Metric | Beltrami Lake | Turtle River Lake |
|---|---|---|
| Overall Grade | A (Excellent) | C (Fair) |
| Water Clarity | 11.2 ft | 8.5 ft |
| Phosphorus | 15 µg/L | 18.5 µg/L |
| Chlorophyll-a (Algae) | 4.3 µg/L | 7.5 µg/L |
| Maximum Depth | 50 ft | 63 ft |
| Surface Area | 726 acres | 1,740 acres |
| Public Access | Yes | Yes |
| Fish Species | 16 | 20 |
| Trophic State | mesotrophic | mesotrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Beltrami Lake wins on overall water quality with a Grade A versus Turtle River Lake's Grade C. Water clarity: 11.2 ft vs 8.5 ft. For more fish-species variety, Turtle River Lake edges ahead with 20 documented species.
Source: EPA National Aquatic Resource Surveys, 2026.