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Kerbs Lake

Otter Tail County, MinnesotaOligotrophic

Kerbs Lake sits at the top of the Minnesota PCA grading rubric with an A, a mark reached by the cleanest lakes in Minnesota. The two scored sub-grades — clarity and phosphorus — track close together, so neither one is dragging the average down.

A TSI value of 31 puts Kerbs Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. The lake's surface area is not consistently recorded across state datasets — physical context remains partial. Among the 97 graded lakes in Otter Tail County, Kerbs Lake ranks 19 — in the top quartile locally.

Kerbs Lake is on the Minnesota infested-waters list for zebra mussels — boaters should follow clean-drain-dry protocols when moving gear to or from the lake. The state fisheries records do not list documented species for Kerbs Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. The lake lacks a documented public access point, so visitor use is limited. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-09-15. Grade methodology: LakeGrade methodology.

Reviewed by LakeQuality Editorial Team · Updated

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Swimming Safety

Excellent for swimming, crystal clear water with minimal algae

Water Quality Grade: A, Excellent

Crystal clear, you can see 27.7 ft down. Phosphorus level: 7 µg/L. Trophic State Index: 31.

MetricValueGrade
Water Clarity (Secchi Depth)27.7 ftA
Phosphorus7 µg/LA
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)31Oligotrophic

Low nutrients, clear water, excellent for swimming

Invasive & Introduced Species

Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.

zebra mussel

Water Quality Trend: Improving

Based on 5 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Improving+0.201 m/yr5
Phosphorus Stable+0.05 µg/L/yr5
See year-by-year chart →

Location

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County Ranking

Ranked #19 of 97 lakes in Otter Tail County

Nearby Lakes in Otter Tail County

EPA Impairment Status

Kerbs Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).

Causes of impairment

Impaired biota (cause unknown)Mercury

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit MN56-0328-00 · Official waterbody report · Matched by proximity (1.67 km)

Data Sources

Water quality data from the EPA Water Quality Portal

Impairment status from EPA ATTAINS 303(d) database

Grading methodology based on Metropolitan Council standards

Most recent sample: 2024-09-15

Monitoring stations: 1