Koronis Lake vs Rice Lake
Water quality, depth, fish species, and recreation comparison.
Koronis Lake has a higher water quality grade (C, Fair) than Rice Lake (F, Very Poor). Both are in Stearns County, Minnesota.
Koronis Lake and Rice 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: Koronis Lake grades a C while Rice Lake grades a F. 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 — Koronis 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?
Koronis Lake
Murky, only visible to about 6 ft.
Rice Lake
Very murky, less than 3 ft of visibility.
Side-by-Side Metrics
| Metric | Koronis Lake | Rice Lake |
|---|---|---|
| Overall Grade | C (Fair) | F (Very Poor) |
| Water Clarity | 6 ft | 3 ft |
| Phosphorus | 27 µg/L | 50 µg/L |
| Chlorophyll-a (Algae) | 13.8 µg/L | 39.5 µg/L |
| Maximum Depth | 132 ft | 41 ft |
| Surface Area | 2,968 acres | 1,513 acres |
| Public Access | Yes | Yes |
| Fish Species | 22 | 21 |
| Trophic State | eutrophic | eutrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Koronis Lake wins on overall water quality with a Grade C versus Rice Lake's Grade F. Water clarity: 6 ft vs 3 ft. For fishing diversity, Koronis Lake also leads with 22 species.
Source: EPA National Aquatic Resource Surveys, 2026.