Sweeney Lake

Sweeney Lake earns a D — measurements through 2025 show persistent nutrient pressure that limits clarity through the summer. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

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. A maximum depth of 18 ft puts Sweeney Lake in the middle of Wisconsin's depth distribution. The lake's 191 acres and partial shoreline records put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Within the 134 graded lakes of Oneida County, Sweeney Lake sits at rank 125, near the bottom of the county list.

An invasive species record — Chinese Mystery Snail — has been logged at Sweeney Lake; Wisconsin DNR maintains the official infested-waters list. Walleye are documented at Sweeney Lake, one of 5 fish species on record for the lake. A documented public access point at Sweeney Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.