Black Brook Flowage Lake vs North Twin Lake
Water quality, depth, fish species, and recreation comparison.
North Twin Lake has a higher water quality grade (A, Excellent) than Black Brook Flowage Lake (B, Good). Both are in Polk County, Wisconsin.
Black Brook Flowage Lake and North Twin 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. These two are within a letter of each other on the rubric — Black Brook Flowage Lake (B) versus North Twin Lake (A). 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.
Black Brook Flowage Lake
Good clarity, visible to about 10.5 ft.
North Twin Lake
No clarity data.
Side-by-Side Metrics
| Metric | Black Brook Flowage Lake | North Twin Lake |
|---|---|---|
| Overall Grade | B (Good) | A (Excellent) |
| Water Clarity | 10.5 ft | No data |
| Phosphorus | 46.6 µg/L | 10.1 µg/L |
| Chlorophyll-a (Algae) | No data | No data |
| Maximum Depth | - | - |
| Surface Area | 98 acres | 639 acres |
| Public Access | Unknown | Unknown |
| Fish Species | 0 | 0 |
| Trophic State | eutrophic | oligotrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
North Twin Lake wins on overall water quality with a Grade A versus Black Brook Flowage Lake's Grade B. For fishing diversity, North Twin Lake also leads with 0 species.