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LakeQuality

Smithville Lake by Dam vs Watkins Mill Lake

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

Watkins Mill Lake has a higher water quality grade (D, Poor) than Smithville Lake by Dam (D, Poor). Both are in Clay County, Wisconsin.

Smithville Lake by Dam and Watkins Mill Lake are both in Missouri — 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 — Smithville Lake by Dam (D) versus Watkins Mill Lake (D). 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.

D

Smithville Lake by Dam

Clay County, Wisconsin

Very murky, less than 3.3 ft of visibility.

D

Watkins Mill Lake

Clay County, Wisconsin

Very murky, less than 3.2 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.

MetricSmithville Lake by DamWatkins Mill Lake
Overall GradeD (Poor)D (Poor)
Water Clarity3.3 ft3.2 ft
Phosphorus37 µg/L41 µg/L
Chlorophyll-a (Algae)25.3 µg/L18.2 µg/L
Maximum Depth--
Surface Area7.2K acres100 acres
Public AccessUnknownUnknown
Fish Species00
Trophic Stateeutrophiceutrophic

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

Verdict

Watkins Mill Lake wins on overall water quality with a Grade D versus Smithville Lake by Dam's Grade D. Water clarity: 3.2 ft vs 3.3 ft. For fishing diversity, Watkins Mill Lake also leads with 0 species.