Green Lake vs Willmar Lake
Water quality, depth, fish species, and recreation comparison.
Green Lake has a higher water quality grade (A, Excellent) than Willmar Lake (D, Poor). Both are in Kandiyohi County, Minnesota.
Green Lake and Willmar 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. Green Lake (A) is materially cleaner than Willmar Lake (D). A gap that wide is unlikely to close in a single year of remediation work; it reflects multi-decade differences in the lakes themselves.
For a recreational visitor, the wider grade gap is decisive — Green 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?
Green Lake
Good clarity, visible to about 13.1 ft.
Willmar Lake
Very murky, less than 2 ft of visibility.
Side-by-Side Metrics
| Metric | Green Lake | Willmar Lake |
|---|---|---|
| Overall Grade | A (Excellent) | D (Poor) |
| Water Clarity | 13.1 ft | 2 ft |
| Phosphorus | 14 µg/L | 72 µg/L |
| Chlorophyll-a (Algae) | No data | No data |
| Maximum Depth | 110 ft | 14 ft |
| Surface Area | 5.6K acres | 636.44 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
Green Lake wins on overall water quality with a Grade A versus Willmar Lake's Grade D. Water clarity: 13.1 ft vs 2 ft. For fishing diversity, Green Lake also leads with 1 species.