Knowledge Bank

Trophic assessments of 10 publicly-owned northeastern Ohio lakes including Aquilla, Baldwin, Findley, Hinckley, Hodgson (Muddy), Spencer, Lower Shaker, Upper Shaker, Virginia Kendall, and Wallace indicated that all were highly eutrophic. Criteria for these assessments were based on a Trophic State Index developed by the U.S. Environmental Protection Agency that incorporated epilimnetic levels of total phosphorus, dissolved phosphorus, inorganic nitrogen, dissolved oxygen, and chlorophyll a and Secchi disk water transparency into a single numerical index of trophic status (TIN). The most eutrophic lakes were Spencer, which had been purposely enriched to increase productivity, and the Shaker Lakes, which were enriched by storm water overflows of sanitary sewers. The least eutrophic lakes were Hodgson, Aquilla, Virginia Kendall, and Wallace reflecting relatively better watershed protection from soil erosion and domestic organic wastes.