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LakeQuality

Hat Rapids Flowage Lake vs Maple Lake

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

Maple Lake has a higher water quality grade (A, Excellent) than Hat Rapids Flowage Lake (D, Poor). Both are in Oneida County, Wisconsin.

Hat Rapids Flowage Lake and Maple 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. Maple Lake (A) is materially cleaner than Hat Rapids Flowage Lake (D). A gap that wide is unlikely to close in a single year of remediation work; it reflects multi-decade differences in the lakes themselves.

For a recreational visitor, the wider grade gap is decisive — Maple 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?

D

Hat Rapids Flowage Lake

Oneida County, Wisconsin

Murky, only visible to about 3.5 ft.

A

Maple Lake

Oneida County, Wisconsin

Good clarity, visible to about 12.5 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.

MetricHat Rapids Flowage LakeMaple Lake
Overall GradeD (Poor)A (Excellent)
Water Clarity3.5 ft12.5 ft
PhosphorusNo data15.8 µg/L
Chlorophyll-a (Algae)No dataNo data
Maximum Depth--
Surface Area640 acres144 acres
Public AccessUnknownUnknown
Fish Species00
Trophic Stateeutrophicmesotrophic

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

Verdict

Maple Lake wins on overall water quality with a Grade A versus Hat Rapids Flowage Lake's Grade D. Water clarity: 12.5 ft vs 3.5 ft. For fishing diversity, Maple Lake also leads with 0 species.