Otter Lake

On the LakeGrade scale Otter Lake grades a B, with clarity at 8.0 ft and 18 µg/L of phosphorus placing it above the Wisconsin median. Clarity is the limiting factor — phosphorus is reasonable but suspended particles or algal cells keep water transparency below Wisconsin norms.

Mesotrophic conditions dominate at Otter Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. The lake bottoms out at 40 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. Otter Lake is small — 15 acres alongside partial shoreline records — which makes it sensitive to even modest changes in watershed runoff or recreational pressure. Within the 25 graded lakes of Waupaca County, Otter Lake sits at rank 21, near the bottom of the county list.

Eurasian watermilfoil is established at Otter Lake, which can dampen recreational access and pressure the native plant community. Walleye are documented at Otter Lake, one of 4 fish species on record for the lake. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.