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LakeQuality

North Turtle Lake vs South Turtle Lake

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

South Turtle Lake has a higher water quality grade (B, Good) than North Turtle Lake (D, Poor). Both are in Otter Tail County, Minnesota.

Both North Turtle Lake and South Turtle Lake sit in Minnesota. 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: South Turtle Lake grades a B while North Turtle Lake 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 — South Turtle 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

North Turtle Lake

Otter Tail County, Minnesota

Murky, only visible to about 3.8 ft.

B

South Turtle Lake

Otter Tail County, Minnesota

Good clarity, visible to about 14.1 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.

MetricNorth Turtle LakeSouth Turtle Lake
Overall GradeD (Poor)B (Good)
Water Clarity3.8 ft14.1 ft
Phosphorus63 µg/L20 µg/L
Chlorophyll-a (Algae)No dataNo data
Maximum Depth19 ft35 ft
Surface Area1.8K acres836.57 acres
Public AccessYesYes
Fish Species11
Trophic Stateeutrophicmesotrophic

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

Verdict

South Turtle Lake wins on overall water quality with a Grade B versus North Turtle Lake's Grade D. Water clarity: 14.1 ft vs 3.8 ft. For fishing diversity, South Turtle Lake also leads with 1 species.