Green Valley Lake vs Twelve Mile Lake
Water quality, depth, fish species, and recreation comparison.
Green Valley Lake and Twelve Mile Lake both received the same overall water quality grade of F (Very Poor). Both are in Union County, Wisconsin.
Both Green Valley Lake and Twelve Mile Lake sit in Iowa. A same-state comparison strips out the state-level water-quality regime as a variable: any grade differences here are about the lakes themselves, not the agencies grading them. These two are within a letter of each other on the rubric — Green Valley Lake (F) versus Twelve Mile Lake (F). The deciding factors for a recreational visitor are likely physical (depth, access, fish species) rather than water-quality differences.
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.
Twelve Mile Lake
Very murky, less than 2.4 ft of visibility.
Side-by-Side Metrics
| Metric | Green Valley Lake | Twelve Mile Lake |
|---|---|---|
| Overall Grade | F (Very Poor) | F (Very Poor) |
| Water Clarity | 1.5 ft | 2.4 ft |
| Phosphorus | No data | No data |
| Chlorophyll-a (Algae) | 61.7 µg/L | 45 µg/L |
| Maximum Depth | - | - |
| Surface Area | 336 acres | 633 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
Both lakes earn the same Grade F. The tiebreakers come down to clarity (Green Valley Lake: 1.5 ft, Twelve Mile Lake: 2.4 ft) and what you want from the lake. Green Valley Lake matches its peer on species count.