Trophic Assessment of Ten Publicly-owned Northeastern Ohio Lakes

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. OHIO J. SCI. 80(5): 223, 1980 Section 208 of the Federal Water Pollution Control Act (PI 92-500, 1972) provides for water quality management planning. The Governor of the State of Ohio designated the Northeast Ohio Areawide Coordinating Agency to carry out this planning in 7 northern Ohio counties. As part of the planning effort, the trophic status of 10 publicly owned lakes was determined. These lakes included Aquilla, Baldwin, Findley, Hinckley, Hodgson, Lower and Upper Shaker, (Horseshoe) Spencer, Virginia Kendall, and Wallace (fig. 1) where no previous comprehensive water quality information was available. Classification of water bodies according to trophic status has been a widely accepted practice among limnologists. Three major categories, oligo-, meso-, and eutrophic, describing the degree of enrichment have been recognized. These Manuscript received 2 January 1979 and in revised form 25 January 1980 (#79-1). This project was financed entirely with federal funds from U.S. EPA under grant P005221-01. The contents do not necessarily reflect the views and policies of U.S. EPA, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. terms, however, have come to be used in different ways by different investigators. For example, some investigators emphasize the relative nutrient flux available to aquatic plants, some refer to plant and animal production, and others emphasize the excess discharge of aquatic plant nutrients (Lee 1971). Reviews of the eutrophication process and its consequences include among others those of Sawyer (1966), AWWA (1966), Fruh et al (1966), Stewart and Rohlich (1967), Vollenweider (1968), National Academy of Science (1969), Rast and Lee (1978), and Likens (1972). In recent years, numerous systems have been devised to expand the number of trophic categories and to develop numerical indexes rather than to rely on nomenclatural schemes. More categories are desirable because of the need to distinguish between similar lakes and to detect slight changes in trophic status of lakes undergoing renovation or degradation, Leuschow et al (1970), Piwoni and Lee (1975), and Carlson (1977). Since differences in ranking among trophic indexes were regarded as relatively minor, the U.S. EPA trophic index system (TIN) was chosen for this study.