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LakeQuality

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.

Reviewed by LakeQuality Editorial Team · Updated

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?

C

Koronis Lake

Stearns County, Minnesota

Murky, only visible to about 6 ft.

F

Rice Lake

Stearns County, Minnesota

Very murky, less than 3 ft of visibility.

Side-by-Side Metrics

MetricKoronis LakeRice Lake
Overall GradeC (Fair)F (Very Poor)
Water Clarity6 ft3 ft
Phosphorus27 µg/L50 µg/L
Chlorophyll-a (Algae)13.8 µg/L39.5 µg/L
Maximum Depth132 ft41 ft
Surface Area2,968 acres1,513 acres
Public AccessYesYes
Fish Species2221
Trophic Stateeutrophiceutrophic

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.