Carstens Lake

On the scoring rubric Carstens Lake grades a D: clarity at 5.2 ft and 93 µg/L of phosphorus keep it in the lower bracket for Manitowoc County. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

Eutrophic conditions are the baseline here: clarity drops noticeably in late summer, and dissolved oxygen near the bottom can become a concern. 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. Within the 19 graded lakes of Manitowoc County, Carstens Lake sits at rank 17, near the bottom of the county list.

Carstens Lake has no invasive species recorded in Wisconsin state databases as of 2026, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Carstens Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.