Big Lake vs W Two Rivers Reservoir
Water quality, depth, fish species, and recreation comparison.
Big Lake reads lower on nutrients and algae than W Two Rivers Reservoir. Both are in St. Louis County, Minnesota.
Both Big Lake and W Two Rivers Reservoir sit in Minnesota. A same-state comparison strips out the state-level water-quality regime as a variable: any differences in the readings here are about the lakes themselves, not the agencies sampling them. The readings are meaningfully apart: Big Lake carries clearly lower phosphorus and chlorophyll-a readings than W Two Rivers Reservoir. 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: Big 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?
Big Lake
Moderate clarity, visible to about 8.2 ft.
W Two Rivers Reservoir
Murky, only visible to about 6.4 ft.
Side-by-Side Metrics
| Metric | Big Lake | W Two Rivers Reservoir |
|---|---|---|
| Water Clarity | 8.2 ft Better | 6.4 ft |
| Phosphorus | 14 µg/L Better | 29 µg/L |
| Chlorophyll-a (Algae) | 4.9 µg/L Better | 5.5 µg/L |
| Maximum Depth | 22 ft | 27 ft Better |
| Surface Area | 1,904 acres | 967 acres |
| Public Access | Yes | Yes |
| Fish Species | 8 Better | 0 |
| Trophic State | mesotrophic | eutrophic |
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.
Swap a lake
Compare Big Lake or W Two Rivers Reservoir against a different lake.
Verdict
Big Lake reads lower on nutrients and algae than W Two Rivers Reservoir. Water clarity: 8.2 ft vs 6.4 ft. For fishing diversity, Big Lake also leads with 8 species.
Source: EPA National Aquatic Resource Surveys, 2026.