Durphee Lake

Durphee Lake sits at the top of the Wisconsin DNR grading rubric with an A, a mark reached by the cleanest lakes in Wisconsin. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

A TSI value of 40 puts Durphee Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. 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 Sawyer County's 52 graded lakes, Durphee Lake ranks 34 — below the local median, though not at the bottom.

Durphee Lake has no invasive species recorded in Wisconsin state databases as of 2024, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Durphee Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. Multiple sampling years from the Wisconsin DNR Citizen Lake Monitoring Network back the grade, so the letter should hold steady absent a major watershed shift.