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Koronis Lake reads lower on nutrients and algae than Rice Lake. 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 readings are meaningfully apart: Koronis Lake carries clearly lower phosphorus and chlorophyll-a readings than Rice Lake. A spread that wide reflects real underlying differences, in watershed inputs, depth profiles, or monitoring rigor.

For a recreational visitor, the wider gap in the readings is decisive: Koronis Lake has the lower nutrient and algae numbers. 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

Stearns County, Minnesota

Murky, only visible to about 6 ft.

Rice Lake

Stearns County, Minnesota

Very murky, less than 3 ft of visibility.

Side-by-Side Metrics

MetricKoronis LakeRice Lake
Water Clarity6 ft Better3 ft
Phosphorus27 µg/L Better50 µg/L
Chlorophyll-a (Algae)13.8 µg/L Better39.5 µg/L
Maximum Depth132 ft Better41 ft
Surface Area2,968 acres1,513 acres
Public AccessYesYes
Fish Species22 Better21
Trophic Stateeutrophiceutrophic

A green ✓ marks the better value for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better). Surface area and trophic state carry no tick — a bigger lake is not a better lake.

Verdict

Koronis Lake reads lower on nutrients and algae than Rice Lake. Water clarity: 6 ft vs 3 ft. For fishing diversity, Koronis Lake also leads with 22 species.

Source: EPA National Aquatic Resource Surveys, 2026.