Grossman Slough Lake

Grossman Slough Lake earns an F: 708 µg/L of phosphorus and clarity at 2.3 ft signal heavy nutrient loading from the surrounding watershed. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

The hypereutrophic status — TSI 82 — reflects sustained heavy nutrient loading from the surrounding watershed and frequent algal pressure. 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 6 graded lakes of Stevens County, Grossman Slough Lake sits at rank 6, near the bottom of the county list.

Grossman Slough Lake has no invasive species recorded in Minnesota state databases as of 2023, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Grossman Slough 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.