Sugar Lake vs Third River Flowage Lake
Water quality, depth, fish species, and recreation comparison.
Sugar Lake and Third River Flowage Lake read the same on nutrients and algae. Both are in Itasca County, Minnesota.
Sugar Lake and Third River Flowage 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: Sugar Lake and Third River Flowage 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.
Sugar Lake
Moderate clarity, visible to about 8.4 ft.
Third River Flowage Lake
Moderate clarity, visible to about 6.9 ft.
Side-by-Side Metrics
| Metric | Sugar Lake | Third River Flowage Lake |
|---|---|---|
| Water Clarity | 8.4 ft Better | 6.9 ft |
| Phosphorus | 18 µg/L Better | 28.5 µg/L |
| Chlorophyll-a (Algae) | 4.9 µg/L Better | 5.5 µg/L |
| Maximum Depth | 22 ft | 69.8 ft Better |
| Surface Area | 1,509 acres | 56,471 acres |
| Public Access | Yes | Yes |
| Fish Species | 13 | 20 Better |
| 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.
Swap a lake
Compare Sugar Lake or Third River Flowage Lake against a different lake.
Verdict
Both lakes earn the same Grade C. The tiebreakers come down to clarity (Sugar Lake: 8.4 ft, Third River Flowage Lake: 6.9 ft) and what you want from the lake. Sugar Lake has fewer fish species than Third River Flowage Lake.
Source: EPA National Aquatic Resource Surveys, 2026.