White Paper: Comparison Of Stormwater Quality Treatment Guidelines And Critical Structural Best Management Performance Factors And Parameters To Consider

Provisions to protect source water have become an important consideration in urban development in North America. In the United States, Phase I and Phase II of the U.S. Environmental Protection Agency's (EPA's) stormwater program require owner/operators to address stormwater runoff pollution issues. The program relies on National Pollutant Discharge Elimination System (NPDES) permits to implement programs and practices to control polluted stormwater runoff. To assist regional and local governments with meeting NPDES requirements, state governments developed stormwater quality and quantity management guidance manuals. The guidance manuals for stormwater quality management focused on traditional structural Best Management Practices (BMPs) such as swales, ponds and porous pavement. Due to lack of studies at the time, little or no guidance was provided for manufactured BMPs. As such regional and locals governments were left to use their best judgement to establish sizing guidelines for manufactured BMPs.

While climate, geology and hydrogeology change with location, the physical laws and considerations governing BMP effectiveness do not change. BMP performance is complex in nature and warrants more detailed consideration than most current guidelines provide. There exists a need for clear, concise, consistent and detailed stormwater guidelines to be adopted across the nation to facilitate proper BMP evaluation and design.

This paper examines stormwater quality treatment guidelines considered by regional and local governments. Sample design criteria are presented and discussed. Key BMP performance factors and parameters relevant to sizing manufactured devices are suggested.