Ml-Se Lake vs Outlet of Onamia Lake on the Rum River
Water quality, depth, fish species, and recreation comparison.
Outlet of Onamia Lake on the Rum River has a higher water quality grade (A, Excellent) than Ml-Se Lake (C, Fair). Both are in Mille Lacs County, Minnesota.
Ml-Se Lake and Outlet of Onamia Lake on the Rum River 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. Outlet of Onamia Lake on the Rum River (A) is materially cleaner than Ml-Se Lake (C). 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 — Outlet of Onamia Lake on the Rum River 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?
Ml-Se Lake
Moderate clarity, visible to about 7.4 ft.
Outlet of Onamia Lake on the Rum River
No clarity data.
Side-by-Side Metrics
| Metric | Ml-Se Lake | Outlet of Onamia Lake on the Rum River |
|---|---|---|
| Overall Grade | C (Fair) | A (Excellent) |
| Water Clarity | 7.4 ft | No data |
| Phosphorus | 25.8 µg/L | 21.8 µg/L |
| Chlorophyll-a (Algae) | 5.6 µg/L | 0.6 µg/L |
| Maximum Depth | 42 ft | 10 ft |
| Surface Area | 128,250 acres | 1,044 acres |
| Public Access | Yes | Yes |
| Fish Species | 21 | 0 |
| Trophic State | mesotrophic | oligotrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Outlet of Onamia Lake on the Rum River wins on overall water quality with a Grade A versus Ml-Se Lake's Grade C. For more fish-species variety, Ml-Se Lake edges ahead with 21 documented species.
Source: EPA National Aquatic Resource Surveys, 2026.