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LakeQuality
D

Vermilion Lake

St. Louis County, MinnesotaLimited DataEutrophic

Vermilion Lake earns a D — measurements through 2024 show persistent nutrient pressure that limits clarity through the summer. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

A TSI in the eutrophic range signals a lake doing what nutrient-loaded waters do — supporting an active algal community at the cost of clear water. 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. Within the 187 graded lakes of St. Louis County, Vermilion Lake sits at rank 168, near the bottom of the county list.

Vermilion Lake has at least one documented invasive species (spiny waterflea), so boaters and anglers should observe clean-drain-dry steps when leaving the lake. The state fisheries records do not list documented species for Vermilion Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. Public access is available — the lake is on the Minnesota PCA public-access list. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-07. Grade methodology: LakeGrade methodology.

Swimming Safety

Swimming not recommended, poor water quality with high algae risk

Water Quality Grade: D, Poor

Murky, only visible to about 4 ft. Trophic State Index: 57.

MetricValueGrade
Water Clarity (Secchi Depth)4 ftD
PhosphorusNo data
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)57Eutrophic

High nutrients, frequent algae, reduced clarity

Invasive Species

spiny waterflea

Water Quality Trend: Declining

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

MetricTrendChange/YearYears
Water Clarity Declining-0.181 m/yr5

Location

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County Ranking

Ranked #168 of 187 lakes in St. Louis County

Nearby Lakes in St. Louis County

Eutrophic Lakes in Minnesota

DNR Reports & Resources

Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Vermilion Lake. 1 report on file.

Data Sources

Water quality data from the EPA Water Quality Portal

Grading methodology based on Metropolitan Council standards

Most recent sample: 2024-10-07

Monitoring stations: 1