Maple Lake vs Turtle Lake
Water quality, depth, fish species, and recreation comparison.
Maple Lake has a higher water quality grade (C, Fair) than Turtle Lake (D, Poor). Both are in Polk County, Minnesota.
Maple Lake and Turtle 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: Maple Lake (C) and Turtle Lake (D) 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.
Maple Lake
Very murky, less than 3.3 ft of visibility.
Turtle Lake
Very murky, less than 3 ft of visibility.
Side-by-Side Metrics
| Metric | Maple Lake | Turtle Lake |
|---|---|---|
| Overall Grade | C (Fair) | D (Poor) |
| Water Clarity | 3.3 ft | 3 ft |
| Phosphorus | 38.5 µg/L | 58.5 µg/L |
| Chlorophyll-a (Algae) | 17.8 µg/L | 25.4 µg/L |
| Maximum Depth | 14 ft | 12 ft |
| Surface Area | 1,641 acres | 525 acres |
| Public Access | Yes | Yes |
| Fish Species | 12 | 0 |
| Trophic State | eutrophic | eutrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Maple Lake wins on overall water quality with a Grade C versus Turtle Lake's Grade D. Water clarity: 3.3 ft vs 3 ft. For fishing diversity, Maple Lake also leads with 12 species.
Source: EPA National Aquatic Resource Surveys, 2026.