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LakeQuality

Lake Nehai Tonkayea vs Thomas Hill Res. Nr. Dam Lake

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

Lake Nehai Tonkayea has a higher water quality grade (B, Good) than Thomas Hill Res. Nr. Dam Lake (D, Poor). Both are in Wisconsin.

Lake Nehai Tonkayea and Thomas Hill Res. Nr. Dam 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. Lake Nehai Tonkayea (B) is materially cleaner than Thomas Hill Res. Nr. Dam 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 — Lake Nehai Tonkayea 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?

B

Lake Nehai Tonkayea

Chariton County, Wisconsin

Moderate clarity, visible to about 8 ft.

D

Thomas Hill Res. Nr. Dam Lake

Randolph County, Wisconsin

Very murky, less than 2.3 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.

MetricLake Nehai TonkayeaThomas Hill Res. Nr. Dam Lake
Overall GradeB (Good)D (Poor)
Water Clarity8 ft2.3 ft
Phosphorus10 µg/L61 µg/L
Chlorophyll-a (Algae)1.3 µg/L14.2 µg/L
Maximum Depth--
Surface Area250 acres3.5K acres
Public AccessUnknownUnknown
Fish Species00
Trophic Stateoligotrophiceutrophic

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

Verdict

Lake Nehai Tonkayea wins on overall water quality with a Grade B versus Thomas Hill Res. Nr. Dam Lake's Grade D. Water clarity: 8 ft vs 2.3 ft. For fishing diversity, Lake Nehai Tonkayea also leads with 0 species.