Sprite Lake

Sprite Lake earns an F: phosphorus readings still being added and clarity at 3.0 ft signal heavy nutrient loading from the surrounding watershed.

Eutrophic conditions are the baseline here: clarity drops noticeably in late summer, and dissolved oxygen near the bottom can become a concern. A maximum depth of 16 ft puts Sprite Lake in the middle of Minnesota's depth distribution. Sprite Lake is small — 12 acres alongside 0.7 miles of shoreline — which makes it sensitive to even modest changes in watershed runoff or recreational pressure. Within the 187 graded lakes of St. Louis County, Sprite Lake sits at rank 185, near the bottom of the county list.

Sprite Lake has no invasive species recorded in Minnesota state databases as of 2021, though prevention practices still apply at all access points. The lake's fish records list 1 species — a varied community without one dominant gamefish. 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.