Birch Lake vs South Turtle Lake
Water quality, depth, fish species, and recreation comparison.
Birch Lake and South Turtle Lake read the same on nutrients and algae. Both are in Vilas County, Wisconsin.
Both Birch Lake and South Turtle Lake sit in Wisconsin. A same-state comparison strips out the state-level water-quality regime as a variable: any differences in the readings here are about the lakes themselves, not the agencies sampling them. The readings are close: Birch Lake and South Turtle Lake sit within a narrow band of each other on phosphorus, chlorophyll-a and clarity. The per-parameter table below shows where the small differences actually live.
With readings 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.
Birch Lake
Murky, only visible to about 6.5 ft.
South Turtle Lake
Moderate clarity, visible to about 8 ft.
Side-by-Side Metrics
| Metric | Birch Lake | South Turtle Lake |
|---|---|---|
| Water Clarity | 6.5 ft | 8 ft Better |
| Phosphorus | 16.3 µg/L Better | 17.3 µg/L |
| Chlorophyll-a (Algae) | No data | No data |
| Maximum Depth | 45 ft Better | 40 ft |
| Surface Area | 506 acres | 466 acres |
| Public Access | Yes | Yes |
| Fish Species | 6 | 6 |
| Trophic State | mesotrophic | mesotrophic |
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 Birch Lake or South Turtle Lake against a different lake.
Verdict
Both lakes earn the same Grade B. The tiebreakers come down to clarity (Birch Lake: 6.5 ft, South Turtle Lake: 8 ft) and what you want from the lake. Birch Lake matches its peer on species count.
Source: EPA National Aquatic Resource Surveys, 2026.