Chippewa Flowage -Winter Dam Lake vs Lac Courte Oreilles Lake
Water quality, depth, fish species, and recreation comparison.
Lac Courte Oreilles Lake has a higher water quality grade (A, Excellent) than Chippewa Flowage -Winter Dam Lake (D, Poor). Both are in Sawyer County, Wisconsin.
Both Chippewa Flowage -Winter Dam Lake and Lac Courte Oreilles Lake sit in Wisconsin. A same-state comparison strips out the state-level water-quality regime as a variable: any grade differences here are about the lakes themselves, not the agencies grading them. Lac Courte Oreilles Lake (A) is materially cleaner than Chippewa Flowage -Winter Dam 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 — Lac Courte Oreilles 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?
Chippewa Flowage -Winter Dam Lake
Murky, only visible to about 4.4 ft.
Lac Courte Oreilles Lake
Good clarity, visible to about 12.2 ft.
Side-by-Side Metrics
| Metric | Chippewa Flowage -Winter Dam Lake | Lac Courte Oreilles Lake |
|---|---|---|
| Overall Grade | D (Poor) | A (Excellent) |
| Water Clarity | 4.4 ft | 12.2 ft |
| Phosphorus | 42 µg/L | 15 µg/L |
| Chlorophyll-a (Algae) | 8.6 µg/L | 1.7 µg/L |
| Maximum Depth | 92 ft | 90 ft |
| Surface Area | 14,593 acres | 5,139 acres |
| Public Access | Yes | Yes |
| Fish Species | 8 | 6 |
| Trophic State | eutrophic | mesotrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Lac Courte Oreilles Lake wins on overall water quality with a Grade A versus Chippewa Flowage -Winter Dam Lake's Grade D. Water clarity: 12.2 ft vs 4.4 ft. For more fish-species variety, Chippewa Flowage -Winter Dam Lake edges ahead with 8 documented species.
Source: EPA National Aquatic Resource Surveys, 2026.