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LakeQuality

Cottonwood Lake vs Timm Lake

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

Cottonwood Lake and Timm Lake both received the same overall water quality grade of F (Very Poor). Both are in Minnesota.

Cottonwood Lake and Timm 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. These two are within a letter of each other on the rubric — Cottonwood Lake (F) versus Timm Lake (F). The deciding factors for a recreational visitor are likely physical (depth, access, fish species) rather than water-quality differences.

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

Cottonwood Lake

Lyon County, Minnesota

Very murky, less than 1.8 ft of visibility.

F

Timm Lake

Yellow Medicine County, Minnesota

Very murky, less than 2 ft of visibility.

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.

MetricCottonwood LakeTimm Lake
Overall GradeF (Very Poor)F (Very Poor)
Water Clarity1.8 ft2 ft
Phosphorus186 µg/LNo data
Chlorophyll-a (Algae)No dataNo data
Maximum Depth--
Surface Area378 acres260 acres
Public AccessUnknownUnknown
Fish Species10
Trophic Statehypereutrophiceutrophic

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

Verdict

Both lakes earn the same Grade F. The tiebreakers come down to clarity (Cottonwood Lake: 1.8 ft, Timm Lake: 2 ft) and what you want from the lake. Cottonwood Lake supports more documented fish species.