Big Twin Lake

On the LakeGrade rubric, Big Twin Lake pulls an A: clarity at 23.0 ft and phosphorus readings still being added put it in the top bracket for Wisconsin. 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.

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. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. The lake's surface area is not consistently recorded across state datasets — physical context remains partial. Among the 13 graded lakes in Green Lake County, Big Twin Lake ranks 1 — in the top quartile locally.

No invasive species are currently listed at Big Twin Lake — the lake remains off the Wisconsin infested-waters roster. The state fisheries records do not list documented species for Big Twin Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.