Cass Lake 04-0030-00 Lake Water Quality

Cass Lake is located at the city of Cass Lake, MN, and spans both Cass and Beltrami Counties. It covers 15,958 acres and is the 8th largest lake in Minnesota in terms of surface area. Cass Lake has four inlets and one outlet, which classify it as a drainage lake. Water enters Cass Lake from the Mississippi River, Kitchi Lake, Pike Bay, and a ground-fed stream in the northeast. The Mississippi River enters and exits Cass Lake. Cass Lake water levels are affected by the operation of two dams on the Mississippi River. Otter Tail Power Company operates a dam upstream, just below Stump Lake. At the Cass Lake outlet is Knutson Dam, owned and operated by the U.S. Forest Service. A Superfund cleanup site exists on Pike Bay near the south side of Cass Lake. Water quality data have been collected on Cass Lake at various sites from 1979-2015 (Tables 2 & 3). These data show that the lake is mesotrophic (TSI = 44) with moderately clear water conditions most of the summer and excellent recreational opportunities. Cass Lake does not have an association. Its water quality is managed by the Leech Lake Band of Ojibwe Division of Resource Management.