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LakeQuality

Crystal Lake vs Lake Diane South Basin; Amboy Township

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

Crystal Lake has a higher water quality grade (B, Good) than Lake Diane South Basin; Amboy Township (D, Poor). Both are in Hillsdale County, Wisconsin.

Both Crystal Lake and Lake Diane South Basin; Amboy Township sit in Michigan. 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. The grades are meaningfully apart: Crystal Lake grades a B while Lake Diane South Basin; Amboy Township grades a D. 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 — Crystal 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?

B

Crystal Lake

Hillsdale County, Wisconsin

Moderate clarity, visible to about 9.5 ft.

D

Lake Diane South Basin; Amboy Township

Hillsdale County, Wisconsin

Very murky, less than 2.5 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.

MetricCrystal LakeLake Diane South Basin; Amboy Township
Overall GradeB (Good)D (Poor)
Water Clarity9.5 ft2.5 ft
PhosphorusNo dataNo data
Chlorophyll-a (Algae)4 µg/L29 µg/L
Maximum Depth--
Surface Area125 acres290 acres
Public AccessUnknownUnknown
Fish Species160
Trophic Statemesotrophiceutrophic

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

Verdict

Crystal Lake wins on overall water quality with a Grade B versus Lake Diane South Basin; Amboy Township's Grade D. Water clarity: 9.5 ft vs 2.5 ft. For fishing diversity, Crystal Lake also leads with 16 species.