Marl Lake

On the LakeGrade rubric, Marl Lake pulls an A: clarity at 12.2 ft and 16 µg/L of phosphorus 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 near 42 places Marl Lake in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. The lake bottoms out at 35 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. Marl Lake is small — 28 acres alongside partial shoreline records — which makes it sensitive to even modest changes in watershed runoff or recreational pressure. Marl Lake ranks 11 of 32 in Waushara County — solidly in the upper half of the local distribution.

Eurasian watermilfoil has been documented at Marl Lake, requiring shoreline management to keep dense mats from crowding native vegetation. 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. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.