Prairie Lake

Prairie Lake earns an F: phosphorus readings still being added and clarity at 2.0 ft signal heavy nutrient loading from the surrounding watershed.

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. The lake bottoms out at 16 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. With 1,408 acres of surface and partial shoreline records, Prairie Lake is a large water by Wisconsin standards — recreational pressure is spread across a long shoreline. Within the 37 graded lakes of Barron County, Prairie Lake sits at rank 31, near the bottom of the county list.

An invasive species record — Banded Mystery Snail — has been logged at Prairie Lake; Wisconsin DNR maintains the official infested-waters list. The fishery includes walleye among the lake's 5 documented species — a notable draw for Wisconsin anglers. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.