Upper Gull Lake

On the LakeGrade rubric, Upper Gull Lake pulls an A: clarity at 10.0 ft and 19 µg/L of phosphorus put it in the top bracket for Minnesota. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

Mesotrophic conditions dominate at Upper Gull Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. At 54 ft of maximum depth, Upper Gull Lake stratifies reliably through the summer — the hypolimnion stays cooler and clearer than the surface layer suggests. The lake's 422 acres and 8.6 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Upper Gull Lake ranks 56 of 133 in Cass County — solidly in the upper half of the local distribution.

Zebra mussel presence at Upper Gull Lake means the lake's clarity numbers carry an asterisk — filtered water is not the same as nutrient-poor water. Walleye are documented at Upper Gull Lake, one of 20 fish species on record for the lake. The lake lacks a documented public access point, so visitor use is limited. The lake has a partial ice record — 6 observed ice-outs, centered near Apr 25. 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.