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Achieving Long-Term Protection of Water Quality of Grand Lake St. Marys Through Implementation of Conservation Practices and Control of Phosphorus Input from Agricultural Drainage
Citation:
Yuan, Y., R. Bingner, AND D. Wilcox. Achieving Long-Term Protection of Water Quality of Grand Lake St. Marys Through Implementation of Conservation Practices and Control of Phosphorus Input from Agricultural Drainage. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-14/266, 2015.
Impact/Purpose:
This report provides information to address the overall goal of improving water quality of Grand Lake St. Marys in a long run. Thus, it provides information useful to watershed managers in developing an overall management plan.
Description:
Grand Lake St. Marys (GLSM), a 13,000 acre lake in northwestern Ohio, is experiencing toxic levels of algal blooms resulting primarily from phosphorus input from agricultural runoff. The algal blooms are so severe that the Ohio Department of Natural Resources advised against any and all contact with the lake water, including the launching of watercraft in 2010. The algal blooms have impacted biota, curtailed recreational and economic activities, and decreased overall quality of life for residents. As part of its agricultural activities, the GLSM watershed includes a limited number of large Concentrated Animal Feeding Operations (CAFOs) which are regulated by the US Environmental Protection Agency (USEPA) through the Ohio EPA, and medium-sized CAFOs regulated by the Ohio Department of Agriculture (ODA). In addition to these regulated operations, there are many Animal Feeding Operations (AFOs) which house animals in numbers that fall below CAFO thresholds. Questions concerning the longer term restoration of water quality for GLSM include: 1) if AFO/CAFO production is sustainable in terms of the amount of animal manure produced; 2) if point source discharges contribute to the algal bloom significantly; 3) if conservation practices can be adopted to limit nutrient loadings to the lake; 4) if existing drainage entering the lake from the contributing watershed can be controlled or altered to improve the lake’s water quality; 5) if the 2008 draft (currently unadopted by the State of Ohio) water quality criteria of 32 ppb for phosphorus for large impoundments is sufficient to protect the lake; and 6) if Manure Treatment Technologies including anaerobic digestion, nutrient removal, composting and converting animal manure to biofuel are practical solutions to remove excess animal manure from the watershed?