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LakeQuality

Beaver Lake vs Greenfield Lake

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

Beaver Lake and Greenfield Lake both received the same overall water quality grade of F (Very Poor). Both are in Wisconsin.

Beaver Lake and Greenfield Lake are both in Iowa — 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: Beaver Lake (F) and Greenfield Lake (F) 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

Beaver Lake

Dallas County, Wisconsin

Very murky, less than 1.9 ft of visibility.

F

Greenfield Lake

Adair County, Wisconsin

Very murky, less than 2.1 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.

MetricBeaver LakeGreenfield Lake
Overall GradeF (Very Poor)F (Very Poor)
Water Clarity1.9 ft2.1 ft
PhosphorusNo dataNo data
Chlorophyll-a (Algae)62.2 µg/L53.8 µg/L
Maximum Depth--
Surface Area34 acres49.6 acres
Public AccessUnknownUnknown
Fish Species00
Trophic Stateeutrophiceutrophic

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 (Beaver Lake: 1.9 ft, Greenfield Lake: 2.1 ft) and what you want from the lake. Beaver Lake matches its peer on species count.