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LakeQuality

Clam River Flowage Lake vs Minerva Lake

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

Minerva Lake has a higher water quality grade (A, Excellent) than Clam River Flowage Lake (F, Very Poor). Both are in Burnett County, Wisconsin.

Clam River Flowage Lake and Minerva Lake are both in Wisconsin — 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 meaningfully apart: Minerva Lake grades a A while Clam River Flowage Lake grades a F. That two-letter spread reflects real underlying differences — different watershed inputs, different depth profiles, or different monitoring rigor.

For a recreational visitor, the wider grade gap is decisive — Minerva Lake is the better water-quality choice. For a researcher, the gap is the interesting part: what is different about the two watersheds, and which of those differences is mutable?

F

Clam River Flowage Lake

Burnett County, Wisconsin

Very murky, less than 2.2 ft of visibility.

A

Minerva Lake

Burnett County, Wisconsin

Good clarity, visible to about 10.5 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.

MetricClam River Flowage LakeMinerva Lake
Overall GradeF (Very Poor)A (Excellent)
Water Clarity2.2 ft10.5 ft
PhosphorusNo data16.3 µg/L
Chlorophyll-a (Algae)No dataNo data
Maximum Depth--
Surface Area360 acres245 acres
Public AccessUnknownUnknown
Fish Species00
Trophic Stateeutrophicmesotrophic

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

Verdict

Minerva Lake wins on overall water quality with a Grade A versus Clam River Flowage Lake's Grade F. Water clarity: 10.5 ft vs 2.2 ft. For fishing diversity, Minerva Lake also leads with 0 species.