Delavan Lake vs Geneva Lake
Water quality, depth, fish species, and recreation comparison.
Geneva Lake reads lower on nutrients and algae than Delavan Lake. Both are in Walworth County, Wisconsin.
Delavan Lake and Geneva Lake are both in Wisconsin — 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 readings are meaningfully apart: Geneva Lake carries clearly lower phosphorus and chlorophyll-a readings than Delavan Lake. A spread that wide reflects real underlying differences, in watershed inputs, depth profiles, or monitoring rigor.
For a recreational visitor, the wider gap in the readings is decisive: Geneva Lake has the lower nutrient and algae numbers. For a researcher, the gap is the interesting part: what is different about the two watersheds, and which of those differences is mutable?
Delavan Lake
Moderate clarity, visible to about 8.9 ft.
Geneva Lake
Crystal clear, you can see 21 ft down.
Side-by-Side Metrics
| Metric | Delavan Lake | Geneva Lake |
|---|---|---|
| Water Clarity | 8.9 ft | 21 ft Better |
| Phosphorus | 52.5 µg/L | 13 µg/L Better |
| Chlorophyll-a (Algae) | 9.1 µg/L | 2.1 µg/L Better |
| Maximum Depth | 52 ft | 135 ft Better |
| Surface Area | 1,906 acres | 5,401 acres |
| Public Access | Yes | Yes |
| Fish Species | 6 | 6 |
| Trophic State | eutrophic | oligotrophic |
A green ✓ marks the better value for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better). Surface area and trophic state carry no tick — a bigger lake is not a better lake.
Swap a lake
Compare Delavan Lake or Geneva Lake against a different lake.
Verdict
Geneva Lake reads lower on nutrients and algae than Delavan Lake. Water clarity: 21 ft vs 8.9 ft. For fishing diversity, Geneva Lake also leads with 6 species.
Source: EPA National Aquatic Resource Surveys, 2026.