Clara Lake-Deep Hole

Clara Lake-Deep Hole sits at the top of the Wisconsin DNR grading rubric with an A, a mark reached by the cleanest lakes in Wisconsin. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.

The lake's low TSI puts it in oligotrophic territory — the cleanest of the four trophic classes, but also the most vulnerable to nutrient-driven shifts. At 50 ft of maximum depth, Clara Lake-Deep Hole stratifies reliably through the summer — the hypolimnion stays cooler and clearer than the surface layer suggests. At 21 acres, Clara Lake-Deep Hole sits below the Wisconsin median: a small water where shoreline activity has an outsized effect on water quality. Clara Lake-Deep Hole ranks 3 of 19 in Lincoln County, putting it in the upper tier of locally monitored lakes.

Clara Lake-Deep Hole has no invasive species recorded in Wisconsin state databases as of 2022, though prevention practices still apply at all access points. The fishery is bass-led, with 2 documented species across the lake's records. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.