Marion Lake vs Spring Lake
Water quality, depth, fish species, and recreation comparison.
Marion Lake has a higher water quality grade (C, Fair) than Spring Lake (F, Very Poor). Both are in Dakota County, Minnesota.
Marion Lake and Spring 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: Marion Lake grades a C while Spring Lake grades a F. 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 — Marion 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?
Marion Lake
Moderate clarity, visible to about 7 ft.
Spring Lake
Very murky, less than 2.1 ft of visibility.
Side-by-Side Metrics
| Metric | Marion Lake | Spring Lake |
|---|---|---|
| Overall Grade | C (Fair) | F (Very Poor) |
| Water Clarity | 7 ft | 2.1 ft |
| Phosphorus | No data | No data |
| Chlorophyll-a (Algae) | No data | No data |
| Maximum Depth | 21 ft | 17 ft |
| Surface Area | 530.3 acres | 1.5K acres |
| Public Access | Yes | Yes |
| Fish Species | 1 | 1 |
| Trophic State | mesotrophic | eutrophic |
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 C versus Spring Lake's Grade F. Water clarity: 7 ft vs 2.1 ft. For fishing diversity, Marion Lake also leads with 1 species.