Big Round Deep Hole South Lake vs Deer Lake
Water quality, depth, fish species, and recreation comparison.
Deer Lake has a higher water quality grade (A, Excellent) than Big Round Deep Hole South Lake (D, Poor). Both are in Polk County, Wisconsin.
Big Round Deep Hole South Lake and Deer 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. Deer Lake (A) is materially cleaner than Big Round Deep Hole South Lake (D). A gap that wide is unlikely to close in a single year of remediation work; it reflects multi-decade differences in the lakes themselves.
For a recreational visitor, the wider grade gap is decisive — Deer Lake is the better water-quality choice. For a researcher, the gap is the interesting part: what is different about the two watersheds, and which of those differences is mutable?
Big Round Deep Hole South Lake
Murky, only visible to about 4.9 ft.
Deer Lake
Crystal clear, you can see 16 ft down.
Side-by-Side Metrics
| Metric | Big Round Deep Hole South Lake | Deer Lake |
|---|---|---|
| Overall Grade | D (Poor) | A (Excellent) |
| Water Clarity | 4.9 ft | 16 ft |
| Phosphorus | No data | 16.9 µg/L |
| Chlorophyll-a (Algae) | No data | No data |
| Maximum Depth | 17 ft | 46 ft |
| Surface Area | 1.0K acres | 786 acres |
| Public Access | Unknown | Unknown |
| Fish Species | 0 | 0 |
| Trophic State | eutrophic | mesotrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Deer Lake wins on overall water quality with a Grade A versus Big Round Deep Hole South Lake's Grade D. Water clarity: 16 ft vs 4.9 ft. For fishing diversity, Deer Lake also leads with 0 species.