Sylvan Lake

On the LakeGrade rubric, Sylvan Lake pulls an A: clarity at 19.8 ft and 7 µg/L of phosphorus put it in the top bracket for Minnesota. clarity and phosphorus rate similarly, so there is no obvious single lever to pull on watershed management.

Trophically, Sylvan Lake reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. At 1,280 acres, Sylvan Lake is one of the larger lakes in Cass County, with partial shoreline records supporting multiple distinct use patterns. Among the 132 graded lakes in Cass County, Sylvan Lake ranks 23 — in the top quartile locally.

Zebra mussel presence at Sylvan Lake means the lake's clarity numbers carry an asterisk — filtered water is not the same as nutrient-poor water. The state fisheries records do not list documented species for Sylvan Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. The lake lacks a documented public access point, so visitor use is limited. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.