Mud Lake

On the LakeGrade rubric Mud Lake fails the cutoffs — a TSI of 71 and persistent algal pressure put it in the bottom tier. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

Hypereutrophic conditions mean the lake is operating at the upper end of the productivity scale, with all the bloom risk that implies. Mud Lake reaches 19 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. At 182 acres, Mud Lake fits the Minnesota median for monitored lakes, with 2.2 miles of shoreline. Among the 14 graded lakes in Martin County, Mud Lake sits at rank 5, above the county median.

Mud Lake has no invasive species recorded in Minnesota state databases as of 2025, though prevention practices still apply at all access points. Walleye are documented at Mud Lake, one of 17 fish species on record for the lake. Public access is available — the lake is on the Minnesota PCA public-access list. Ice-out has been recorded 18 times at Mud Lake, with a median around Mar 25. The grade is supported by multiple sampling years from Minnesota PCA volunteers and partner agencies, giving the letter a reasonably stable foundation.