Are best-management-practice criteria really environmentally friendly?

In the 1990s, a number of best management practices (BMPs) manuals have been developed that address the control of urban runoff to protect receiving water quality. More recently, several papers have investigated the effectiveness of these BMPs in protecting small urban watercourses, and have concluded that they do not. Investigations of both design practices and effectiveness reveal that there is a lot of ignorance in the scientific and engineering community about what constitutes a properly designed BMP and what it really achieves, with respect to environmental protection. This paper discusses the state-of-practice in BMP design in the United States and points out its strengths and weaknesses with respect to real protection of the downstream receiving water environment. The paper recommends an approach to design criteria development that can be applied over a wide variety of climatologic, topologic, and geologic conditions to protect receiving waters systems.