Upper Kimball Lake

Upper Kimball Lake earns an A — water clarity, phosphorus, and chlorophyll-a all rate among the best monitored waters in Washburn 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.

A TSI value of 37 puts Upper Kimball Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. The lake is compact at 42 acres, with partial shoreline records and little volume to buffer nutrient inputs. Within the 48 graded lakes of Washburn County, Upper Kimball Lake sits at rank 40, near the bottom of the county list.

No invasive species are currently listed at Upper Kimball Lake — the lake remains off the Wisconsin infested-waters roster. The fishery is bass-led, with 3 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.