Lake Koshkonong vs Rock Lake
Water quality, depth, fish species, and recreation comparison.
Rock Lake has a higher water quality grade (A, Excellent) than Lake Koshkonong (D, Poor). Both are in Jefferson County, Wisconsin.
D
Lake Koshkonong
Jefferson County, Wisconsin
Murky, only visible to about 5.7 ft.
A
Rock Lake
Jefferson County, Wisconsin
Crystal clear, you can see 39.4 ft down.
Side-by-Side Metrics
| Metric | Lake Koshkonong | Rock Lake |
|---|---|---|
| Overall Grade | D (Poor) | A (Excellent) |
| Water Clarity | 5.7 ft | 39.4 ft |
| Phosphorus | 287 µg/L | 17.9 µg/L |
| Chlorophyll-a (Algae) | No data | No data |
| Maximum Depth | 7 ft | 60 ft |
| Surface Area | 10.6K acres | 1.4K acres |
| Public Access | Yes | Yes |
| Fish Species | 7 | 5 |
| Trophic State | eutrophic | oligotrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Rock Lake wins on overall water quality with a Grade A versus Lake Koshkonong's Grade D. Water clarity: 39.4 ft vs 5.7 ft. For more fish-species variety, Lake Koshkonong edges ahead with 7 documented species.