Big Pine Lake vs Marion Lake
Water quality, depth, fish species, and recreation comparison.
Marion Lake has a higher water quality grade (B, Good) than Big Pine Lake (C, Fair). Both are in Otter Tail County, Minnesota.
Big Pine Lake and Marion 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 close: Big Pine Lake (C) and Marion Lake (B) are within one letter of each other on the LakeGrade rubric. The per-parameter sub-grades below will show where the small differences actually live.
With grades this close, the choice between the two lakes turns on non-water-quality factors: depth, fish species, public access, distance from home. The per-lake pages below cover all of those.
Big Pine Lake
Moderate clarity, visible to about 8.7 ft.
Marion Lake
Good clarity, visible to about 11 ft.
Side-by-Side Metrics
| Metric | Big Pine Lake | Marion Lake |
|---|---|---|
| Overall Grade | C (Fair) | B (Good) |
| Water Clarity | 8.7 ft | 11 ft |
| Phosphorus | 26 µg/L | 18 µg/L |
| Chlorophyll-a (Algae) | 8 µg/L | 7.3 µg/L |
| Maximum Depth | 76 ft | 62 ft |
| Surface Area | 4,728 acres | 1,624 acres |
| Public Access | Yes | Yes |
| Fish Species | 20 | 17 |
| Trophic State | mesotrophic | mesotrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Marion Lake wins on overall water quality with a Grade B versus Big Pine Lake's Grade C. Water clarity: 11 ft vs 8.7 ft. For more fish-species variety, Big Pine Lake edges ahead with 20 documented species.
Source: EPA National Aquatic Resource Surveys, 2026.