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LakeQuality

Mountain Lake vs Wellner-Hageman Reservoir

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

Wellner-Hageman Reservoir has a higher water quality grade (D, Poor) than Mountain Lake (F, Very Poor). Both are in Minnesota.

Mountain Lake and Wellner-Hageman Reservoir 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 grades are close: Mountain Lake (F) and Wellner-Hageman Reservoir (D) 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.

F

Mountain Lake

Cottonwood County, Minnesota

Very murky, less than 1.2 ft of visibility.

D

Wellner-Hageman Reservoir

Brown County, Minnesota

Murky, only visible to about 3.7 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.

MetricMountain LakeWellner-Hageman Reservoir
Overall GradeF (Very Poor)D (Poor)
Water Clarity1.2 ft3.7 ft
Phosphorus148.5 µg/L45 µg/L
Chlorophyll-a (Algae)No data38.5 µg/L
Maximum Depth--
Surface Area230 acres71 acres
Public AccessUnknownUnknown
Fish Species11
Trophic Statehypereutrophiceutrophic

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

Verdict

Wellner-Hageman Reservoir wins on overall water quality with a Grade D versus Mountain Lake's Grade F. Water clarity: 3.7 ft vs 1.2 ft. For fishing diversity, Wellner-Hageman Reservoir also leads with 1 species.