Little Birch Lake vs Osakis Lake
Water quality, depth, fish species, and recreation comparison.
Little Birch Lake has a higher water quality grade (A, Excellent) than Osakis Lake (D, Poor). Both are in Todd County, Minnesota.
Little Birch Lake and Osakis Lake are both in Minnesota — 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 grades are meaningfully apart: Little Birch Lake grades a A while Osakis Lake grades a D. That two-letter spread reflects real underlying differences — different watershed inputs, different depth profiles, or different monitoring rigor.
For a recreational visitor, the wider grade gap is decisive — Little Birch 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?
Little Birch Lake
Good clarity, visible to about 13 ft.
Osakis Lake
Good clarity, visible to about 10.5 ft.
Side-by-Side Metrics
| Metric | Little Birch Lake | Osakis Lake |
|---|---|---|
| Overall Grade | A (Excellent) | D (Poor) |
| Water Clarity | 13 ft | 10.5 ft |
| Phosphorus | 19 µg/L | 75 µg/L |
| Chlorophyll-a (Algae) | 3.1 µg/L | 9.6 µg/L |
| Maximum Depth | 89 ft | 73 ft |
| Surface Area | 839 acres | 6,389 acres |
| Public Access | Yes | Yes |
| Fish Species | 20 | 18 |
| Trophic State | mesotrophic | eutrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Little Birch Lake wins on overall water quality with a Grade A versus Osakis Lake's Grade D. Water clarity: 13 ft vs 10.5 ft. For fishing diversity, Little Birch Lake also leads with 20 species.
Source: EPA National Aquatic Resource Surveys, 2026.