Fenner Lake

Fenner Lake earns an A — water clarity, phosphorus, and chlorophyll-a all rate among the best monitored waters in Marquette County. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

Trophically, Fenner Lake reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. At 41 acres, Fenner Lake sits below the Wisconsin median: a small water where shoreline activity has an outsized effect on water quality. Fenner Lake ranks 5 of 14 in Marquette County — solidly in the upper half of the local distribution.

Fenner Lake carries an invasive watermilfoil record — boat-launch decontamination and shoreline care matter more here than at uninfested lakes. Bass fishing is part of the appeal: the species list runs to 3, anchored by largemouth and/or smallmouth bass. Public access is available — the lake is on the Wisconsin DNR public-access list. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.