Karth Lake

The LakeGrade rubric puts Karth Lake at a C: clarity at 6.6 ft, 30 µg/L of phosphorus, and a TSI of 52 signal an intermediate trophic state. The lake's weakest score is on Secchi depth — the water looks more turbid than its phosphorus number alone would predict.

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. 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. Among the 51 graded lakes in Ramsey County, Karth Lake sits at rank 20, above the county median.

Karth Lake has no invasive species recorded in Minnesota state databases as of 2024, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Karth 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. Multiple sampling years from Minnesota PCA volunteers and partner agencies back the grade, so the letter should hold steady absent a major watershed shift.