Big Lake vs Medicine Lake
Water quality, depth, fish species, and recreation comparison.
Big Lake reads lower on nutrients and algae than Medicine Lake. Both are in Beltrami County, Minnesota.
Big Lake and Medicine 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 close: Big Lake and Medicine Lake sit within a narrow band of each other on phosphorus, chlorophyll-a and clarity. The per-parameter table below shows where the small differences actually live.
With readings this close, the choice between the two lakes turns on non-water-quality factors: depth, fish species, public access, distance from home. The per-lake pages below cover all of those.
Big Lake
Moderate clarity, visible to about 9.7 ft.
Medicine Lake
Moderate clarity, visible to about 7.9 ft.
Side-by-Side Metrics
| Metric | Big Lake | Medicine Lake |
|---|---|---|
| Water Clarity | 9.7 ft Better | 7.9 ft |
| Phosphorus | 15 µg/L Better | 23 µg/L |
| Chlorophyll-a (Algae) | 4.8 µg/L Better | 7.1 µg/L |
| Maximum Depth | 35 ft | 44 ft Better |
| Surface Area | 3,598 acres | 461 acres |
| Public Access | Yes | Yes |
| Fish Species | 17 Better | 12 |
| Trophic State | mesotrophic | mesotrophic |
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.
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Compare Big Lake or Medicine Lake against a different lake.
Verdict
Big Lake reads lower on nutrients and algae than Medicine Lake. Water clarity: 9.7 ft vs 7.9 ft. For fishing diversity, Big Lake also leads with 17 species.
Source: EPA National Aquatic Resource Surveys, 2026.