Superior Lake

Superior Lake earns an A — every scored parameter (phosphorus) rates among the best monitored waters in St. Louis County.

The lake's low TSI puts it in oligotrophic territory — the cleanest of the four trophic classes, but also the most vulnerable to nutrient-driven shifts. 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. Superior Lake ranks 24 of 187 in St. Louis County, putting it in the upper tier of locally monitored lakes.

Zebra mussels have been documented at Superior Lake, which alters the filter-feeding balance and can paradoxically increase water clarity while disrupting the food web. The state fisheries records do not list documented species for Superior Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. Public access is available — the lake is on the Minnesota PCA public-access list. 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.