Green Valley Lake vs Three Mile Lake
Water quality, depth, fish species, and recreation comparison.
Three Mile Lake has a higher water quality grade (D, Poor) than Green Valley Lake (F, Very Poor). Both are in Union County, Wisconsin.
Green Valley Lake and Three Mile Lake are both in Iowa — 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: Green Valley Lake (F) and Three Mile 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.
Green Valley Lake
Very murky, less than 1.5 ft of visibility.
Three Mile Lake
Very murky, less than 2.7 ft of visibility.
Side-by-Side Metrics
| Metric | Green Valley Lake | Three Mile Lake |
|---|---|---|
| Overall Grade | F (Very Poor) | D (Poor) |
| Water Clarity | 1.5 ft | 2.7 ft |
| Phosphorus | No data | No data |
| Chlorophyll-a (Algae) | 61.7 µg/L | 28.4 µg/L |
| Maximum Depth | - | - |
| Surface Area | 336 acres | 880 acres |
| Public Access | Unknown | Unknown |
| Fish Species | 0 | 0 |
| Trophic State | hypereutrophic | eutrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Three Mile Lake wins on overall water quality with a Grade D versus Green Valley Lake's Grade F. Water clarity: 2.7 ft vs 1.5 ft. For fishing diversity, Three Mile Lake also leads with 0 species.