The Big Darby Accord - A Model for TMDL Implementation in an Urbanizing Watershed

Big Darby Creek is a Midwestern stream on the western edge of a large metropolitan area, Columbus, Ohio. Big Darby Creek is a national and state scenic river, and contains populations of state and federal endangered species, as well as being a stream of overall high quality. The State of Ohio conducted detailed water quality surveys (Ohio EPA, 2004b) and used the results of those surveys to prepare Total Maximum Daily Loads (TMDLs) for the protection and restoration of Big Darby Creek. Planning for TMDL implementation was occurring as these documents were being finalized, culminating in the Big Darby Accord, a local government driven multi- jurisdictional effort to balance development interests with conservation interests in the Franklin County portion of the Big Darby watershed. The Big Darby Accord provides a framework for the successful implementation of a land use plan prepared to achieve the TMDL targets. Big Darby Creek - Ecological Background Big Darby Creek is a high quality stream in central Ohio designated a National and State Scenic River because of its outstanding aquatic biodiversity. It harbors a nationally-recognized diverse population of mussels, fish, and macroinvertebrates, with many state and federally endangered species. It is a prime source for water recreation and natural resource education in Ohio. The watershed is located in central Ohio and covers an area of about 555 square miles (388,000 acres). A biologically important portion is in close proximity to the City of Columbus and surrounding suburbs, making it very attractive for commercial and residential development. Big Darby Creek flows over 80 miles from its source near Bellefontaine in Logan County to the Scioto River near Circleville in Pickaway County. The Big Darby and tributaries flow over gravel and clay-based glacial till underlain by the limestone bedrock, forming a mostly flat landscape along with gravel substrates along streams and hydric soils in much of the uplands.