Lake Pacawa

Lake Pacawa earns a D — measurements through 2024 show persistent nutrient pressure that limits clarity through the summer. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

A TSI in the eutrophic range signals a lake doing what nutrient-loaded waters do — supporting an active algal community at the cost of clear water. At only 12 ft deep, Lake Pacawa is shallow — wind keeps the water column mixed and sediment resuspension drives phosphorus levels harder to manage. The lake is compact at 23 acres, with partial shoreline records and little volume to buffer nutrient inputs. Lake Pacawa ranks 27 of 28 in Portage County — at the lower end of the locally monitored distribution.

Eurasian watermilfoil has been documented at Lake Pacawa, requiring shoreline management to keep dense mats from crowding native vegetation. The state fisheries records do not list documented species for Lake Pacawa, which usually reflects a lack of formal fisheries survey work rather than an empty lake. 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.