Green Infrastructure Opportunities in Gray Wet Weather Plans

Low Impact Development (LID) and Green Infrastructure (GI) Best Management Practices (BMPs) have been widely utilized as a method of erosion/sedimentation and water pollution control predominantly for land development programs and, to a lesser degree, urban storm water runoff. Recently the focus is shifting from “green field” development practices to application of GI BMPs in mature urban neighborhoods. Whether retrofit projects aimed at reducing flow into Combined Sewer Systems or neighborhood redevelopment programs responsive to LID regulations, interest in application of GI in urban settings is growing. With the emergence of integrated watershed based Long Term Control Plans (LTCPs), and, Municipal Separate Storm Sewer Systems (MS4) permit requirements and Total Maximum Daily Load (TMDL) limits for specific pollutant constituents on local streams, inclusion of GI, particularly for retrofit applications in urban stormwater/wet-weather and CSO facilities planning, has gained the interest of the regulatory agencies, permittees and diverse environmental interest groups. This paper addresses application of a GIS-based BMP siting approach to identifying, at a planning level, potential sites for retrofit GI projects intended to minimize runoff to drainage systems.