URBAN STORMWATER BMP PERFORMANCE: APPLICATION OF RECENT FINDINGS FROM THE NATIONAL STORMWATER BEST MANAGEMENT PRACTICES DATABASE PROJECT

Over the last year the National Stormwater Best Management Practices (BMP) Database Project team has completed a revised analysis of water quality and quantity data collected. The current database contains nearly 200 BMP studies. The findings of the reanalysis have significant implications for the implementation, modeling, and management of runoff to Total Maximum Daily Load (TMDL) affected watersheds. Based on the results of the analysis we now have (for some BMP types that are well represented in the Database) sufficient information to begin to not only statistically quantify water quality performance of BMPs, but to better understand some relationships between design and performance. This understanding has been extended, with the addition of the newer data, to include hydrologic characteristics of various BMPs types showing their ability to provide volume reduction. Project findings have become the basis for a number of ongoing BMP research projects which are discussed in this paper. In addition, the analysis results have proven to be a useful tool for implementation of TMDL driven non-point pollution control projects. Specifically the results of the statistical analysis conducted as part of the project are useful as the basis for probabilistic modeling of BMP effluent concentrations and loads. This paper provides specific examples from the results of the analysis of the database and presents a discussion of the application of those results in practice for watershed modeling, BMP selection, and potential stormwater design.