Lake Assessment Program - Trout Lake Water Quality Update, Itasca County

Trout Lake is a 1,890-acre lake in Itasca County just south of Coleraine, Minnesota. The lake has a long history of water quality concerns going back to the early 1900s. The most apparent have been human impacts including received iron ore tailings from 1907-1940 and untreated waste water from 1910-1987. The Minnesota Pollution Control Agency (MPCA) conducted a Lake Assessment Program (LAP) of Trout Lake in 1987. That report showed the lake to be significantly impacted by waste water, driving the lake to a eutrophic status. Trophic indicators measurements from the 1970s and 1980s indicated eutrophic conditions, with summer mean TP values exceeding 50 ?g/L. In recent years the lake has shown significant improvements. The lake can now be categorized as mesotrophic with summer mean TP values around 15?g/L. Cl levels are high and are not showing signs of recovery, likely caused by continued input form city and road run off. The lake is well below the 303d impairment standards for NLF lakes.