Underwood Lake

On the LakeGrade rubric, Underwood Lake pulls an A: clarity at 59.9 ft and phosphorus readings still being added put it in the top bracket for Wisconsin. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

A TSI value of 18 puts Underwood Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. Underwood Lake reaches 37 ft at its deepest point — typical for Wisconsin mid-sized lakes, with seasonal stratification but limited cold-water refuge. Underwood Lake is small — 45 acres alongside partial shoreline records — which makes it sensitive to even modest changes in watershed runoff or recreational pressure. Underwood Lake ranks 23 of 66 in Oconto County — solidly in the upper half of the local distribution.

Eurasian watermilfoil is established at Underwood Lake, which can dampen recreational access and pressure the native plant community. 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.