Long Trade Lake

On the scoring rubric Long Trade Lake grades a D: clarity at 3.0 ft and 88 µg/L of phosphorus keep it in the lower bracket for Polk County. 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.

At a TSI of 65, Long Trade Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. At only 13 ft deep, Long Trade Lake is shallow — wind keeps the water column mixed and sediment resuspension drives phosphorus levels harder to manage. The lake's 150 acres and partial shoreline records put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Long Trade Lake ranks 68 of 74 in Polk County — at the lower end of the locally monitored distribution.

Eurasian watermilfoil is established at Long Trade 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.