Ada Lake vs Big Portage (E Bay Lake
Water quality, depth, fish species, and recreation comparison.
Ada Lake and Big Portage (E Bay Lake both received the same overall water quality grade of A (Excellent). Both are in Cass County, Minnesota.
Both Ada Lake and Big Portage (E Bay Lake sit in Minnesota. A same-state comparison strips out the state-level water-quality regime as a variable: any grade differences here are about the lakes themselves, not the agencies grading them. The grades are close: Ada Lake (A) and Big Portage (E Bay Lake (A) are within one letter of each other on the LakeGrade rubric. The per-parameter sub-grades below will show where the small differences actually live.
With grades 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.
Ada Lake
Good clarity, visible to about 14 ft.
Big Portage (E Bay Lake
Moderate clarity, visible to about 8.9 ft.
Side-by-Side Metrics
| Metric | Ada Lake | Big Portage (E Bay Lake |
|---|---|---|
| Overall Grade | A (Excellent) | A (Excellent) |
| Water Clarity | 14 ft | 8.9 ft |
| Phosphorus | 10 µg/L | 19 µg/L |
| Chlorophyll-a (Algae) | 2.7 µg/L | 6.4 µg/L |
| Maximum Depth | 60 ft | 23 ft |
| Surface Area | 963 acres | 902 acres |
| Public Access | Yes | Yes |
| Fish Species | 16 | 13 |
| Trophic State | oligotrophic | mesotrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Both lakes earn the same Grade A. The tiebreakers come down to clarity (Ada Lake: 14 ft, Big Portage (E Bay Lake: 8.9 ft) and what you want from the lake. Ada Lake supports more documented fish species.
Source: EPA National Aquatic Resource Surveys, 2026.