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LakeQuality

Ada Lake vs Big Portage (E Bay Lake

Water quality, depth, fish species, and recreation comparison.

Ada Lake has a higher water quality grade (A, Excellent) than Big Portage (E Bay Lake (B, Good). 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 (B) 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.

A

Ada Lake

Cass County, Minnesota

Good clarity, visible to about 14 ft.

B

Big Portage (E Bay Lake

Cass County, Minnesota

Moderate clarity, visible to about 7.9 ft.

Side-by-Side Metrics

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

MetricAda LakeBig Portage (E Bay Lake
Overall GradeA (Excellent)B (Good)
Water Clarity14 ft7.9 ft
Phosphorus10 µg/L20 µg/L
Chlorophyll-a (Algae)No dataNo data
Maximum Depth60 ft23 ft
Surface Area963.31 acres902.34 acres
Public AccessYesYes
Fish Species11
Trophic Stateoligotrophicmesotrophic

Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).

Verdict

Ada Lake wins on overall water quality with a Grade A versus Big Portage (E Bay Lake's Grade B. Water clarity: 14 ft vs 7.9 ft. For fishing diversity, Ada Lake also leads with 1 species.