Thomas Lake

Thomas Lake sits at a C on the grading scale — not impaired, not pristine, with summer measurements that vary year to year. Clarity is the limiting factor — phosphorus is reasonable but suspended particles or algal cells keep water transparency below Minnesota norms.

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. A maximum depth of just 8 ft means sediment-bound phosphorus releases back into the water column whenever wind stirs the bottom — a classic shallow-lake dynamic. At 41 acres, Thomas Lake sits below the Minnesota median: a small water where shoreline activity has an outsized effect on water quality. Among the 36 graded lakes in Dakota County, Thomas Lake sits at rank 15, above the county median.

Eurasian watermilfoil is established at Thomas Lake, which can dampen recreational access and pressure the native plant community. Bass fishing is part of the appeal: the species list runs to 6, anchored by largemouth and/or smallmouth bass. A documented public access point at Thomas Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. The lake has a partial ice record — 7 observed ice-outs, centered near Apr 4. 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.