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LakeQuality

Charles Mill Reservoir vs Clear Fork Reservoir

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

Charles Mill Reservoir and Clear Fork Reservoir both received the same overall water quality grade of F (Very Poor). Both are in Wisconsin.

Both Charles Mill Reservoir and Clear Fork Reservoir sit in Ohio. 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. These two are within a letter of each other on the rubric — Charles Mill Reservoir (F) versus Clear Fork Reservoir (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

Charles Mill Reservoir

Ashland County, Wisconsin

Very murky, less than 0.9 ft of visibility.

F

Clear Fork Reservoir

Morrow County, Wisconsin

Very murky, less than 3.1 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.

MetricCharles Mill ReservoirClear Fork Reservoir
Overall GradeF (Very Poor)F (Very Poor)
Water Clarity0.9 ft3.1 ft
PhosphorusNo dataNo data
Chlorophyll-a (Algae)No dataNo data
Maximum Depth--
Surface Area1.4K acres1.0K acres
Public AccessUnknownUnknown
Fish Species00
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 (Charles Mill Reservoir: 0.9 ft, Clear Fork Reservoir: 3.1 ft) and what you want from the lake. Charles Mill Reservoir matches its peer on species count.