County K Marsh Lake

County K Marsh Lake earns an F: 150 µg/L of phosphorus and clarity readings still being added signal heavy nutrient loading from the surrounding watershed.

A TSI above 70 puts County K Marsh Lake in hypereutrophic territory: visible blooms are common, and clarity rarely climbs even in early summer. 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 13 graded lakes of Green Lake County, County K Marsh Lake sits at rank 13, near the bottom of the county list.

County K Marsh Lake has no invasive species recorded in Wisconsin state databases as of 2025, though prevention practices still apply at all access points. The state fisheries records do not list documented species for County K Marsh 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.