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LakeQuality
F

Mt Maud Lake Mid Basin

Cook County, MinnesotaLimited DataEutrophic

Mt Maud Lake Mid Basin grades an F: water clarity, phosphorus, and chlorophyll-a all rate poorly, placing it among the most stressed lakes monitored in Minnesota. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

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. Mt Maud Lake Mid Basin ranks 111 of 128 in Cook County — at the lower end of the locally monitored distribution.

No invasive species are currently listed at Mt Maud Lake Mid Basin — the lake remains off the Minnesota infested-waters roster. The state fisheries records do not list documented species for Mt Maud Lake Mid Basin, which usually reflects a lack of formal fisheries survey work rather than an empty lake. 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 2021-09-21. 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 2.5 ft of visibility. Trophic State Index: 64.

MetricValueGrade
Water Clarity (Secchi Depth)2.5 ftF
PhosphorusNo data
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)64Eutrophic

High nutrients, frequent algae, reduced clarity

Water Quality Trend: Improving

Based on 3 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Improving+0.05 m/yr3
Phosphorus Improving-1.5 µg/L/yr2
Chlorophyll-a Improving-1.05 µg/L/yr2
See year-by-year chart →

Location

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County Ranking

Ranked #111 of 128 lakes in Cook County

Cleaner Lakes Within 30 Miles

Mt Maud Lake Mid Basin holds Grade F. 2 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in Cook County

Data Sources

Water quality data from the EPA Water Quality Portal

Grading methodology based on Metropolitan Council standards

Most recent sample: 2021-09-21

Monitoring stations: 1