Lower Pine Lake

Lower Pine Lake sits at the top of the Wisconsin DNR grading rubric with an A, a mark reached by the cleanest lakes in Wisconsin. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

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. Lower Pine Lake is unusually deep for Wisconsin at 102 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. The lake is compact at 96 acres, with partial shoreline records and little volume to buffer nutrient inputs. Among the 77 graded lakes in Polk County, Lower Pine Lake sits at rank 28, above the county median.

An invasive species record — Chinese Mystery Snail — has been logged at Lower Pine Lake; Wisconsin DNR maintains the official infested-waters list. Bass fishing is part of the appeal: the species list runs to 3, anchored by largemouth and/or smallmouth bass. A documented public access point at Lower Pine Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.