Green Castle Lake vs Otter Creek Lake
Water quality, depth, fish species, and recreation comparison.
Green Castle Lake has a higher water quality grade (C, Fair) than Otter Creek Lake (D, Poor). Both are in Wisconsin.
Green Castle Lake and Otter Creek 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 Castle Lake (C) and Otter Creek 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 Castle Lake
Murky, only visible to about 4.6 ft.
Otter Creek Lake
Very murky, less than 1.3 ft of visibility.
Side-by-Side Metrics
| Metric | Green Castle Lake | Otter Creek Lake |
|---|---|---|
| Overall Grade | C (Fair) | D (Poor) |
| Water Clarity | 4.6 ft | 1.3 ft |
| Phosphorus | No data | No data |
| Chlorophyll-a (Algae) | 6.9 µg/L | 24 µg/L |
| Maximum Depth | - | - |
| Surface Area | 17 acres | 60 acres |
| Public Access | Unknown | Unknown |
| Fish Species | 0 | 0 |
| Trophic State | eutrophic | eutrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Green Castle Lake wins on overall water quality with a Grade C versus Otter Creek Lake's Grade D. Water clarity: 4.6 ft vs 1.3 ft. For fishing diversity, Green Castle Lake also leads with 0 species.