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LakeQuality
F

Unnamed Lake

Grant County, MinnesotaHypereutrophic

Unnamed Lake earns an F: 269 µg/L of phosphorus and clarity at 0.7 ft signal heavy nutrient loading from the surrounding watershed. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

Hypereutrophic conditions mean the lake is operating at the upper end of the productivity scale, with all the bloom risk that implies. 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 10 graded lakes of Grant County, Unnamed Lake sits at rank 8, near the bottom of the county list.

No invasive species are currently listed at Unnamed Lake — the lake remains off the Minnesota infested-waters roster. The state fisheries records do not list documented species for Unnamed 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 2023-08-10. Grade methodology: LakeGrade methodology.

Swimming Safety

Avoid swimming, very poor water quality, potential algae toxins

Water Quality Grade: F, Very Poor

Very murky, less than 0.7 ft of visibility. Phosphorus level: 269 µg/L. Trophic State Index: 84.

MetricValueGrade
Water Clarity (Secchi Depth)0.7 ftF
Phosphorus269 µg/LF
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)84Hypereutrophic

Very high nutrients, dense algae, poor clarity

Location

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County Ranking

Ranked #8 of 10 lakes in Grant County

Nearby Lakes in Grant County

Hypereutrophic Lakes in Minnesota

Data Sources

Water quality data from the EPA Water Quality Portal

Grading methodology based on Metropolitan Council standards

Most recent sample: 2023-08-10

Monitoring stations: 1