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LakeQuality
F

Mud Lake

Hennepin County, MinnesotaHypereutrophic

Mud Lake earns an F: 196 µg/L of phosphorus and clarity at 3.0 ft signal heavy nutrient loading from the surrounding watershed. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.

A TSI above 70 puts Mud Lake in hypereutrophic territory: visible blooms are common, and clarity rarely climbs even in early summer. 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 Hennepin County's 95 graded lakes, Mud Lake ranks 63 — below the local median, though not at the bottom.

Mud Lake has no invasive species recorded in Minnesota state databases as of 2022, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Mud 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 2022-10-04. 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 3 ft of visibility. Phosphorus level: 196 µg/L. Trophic State Index: 71.

MetricValueGrade
Water Clarity (Secchi Depth)3 ftF
Phosphorus196 µg/LF
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)71Hypereutrophic

Very high nutrients, dense algae, poor clarity

Water Quality Trend: Declining

Based on 2 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-0.15 m/yr2
Phosphorus Declining+6 µg/L/yr2

Location

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County Ranking

Ranked #63 of 95 lakes in Hennepin County

Nearby Lakes in Hennepin 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: 2022-10-04

Monitoring stations: 1