Comparison of BMP Performance Using the International BMP Database

This paper explores the performance and relative pollutant removal of several common best management practices (BMPs) using data contained in the International Stormwater BMP Database. These BMPs include retention (wet) ponds, extended detention basins, vegetated swales, and sand filters. Although the database contains numerous studies with varying amounts of detail, this comparison is based on the performance of only those sites with reported basic design characteristics and water quality data (event mean concentrations) so that constituent concentrations can be accurately determined and related to the design of the individual BMP. The use of selected BMPs has a number of advantages. Some of the variability in performance observed for facilities of a specific type can be explained by differences in design and/or watershed characteristics; consequently, the expected performance for a given set of conditions can be predicted more accurately. In addition, the differences in performance among BMP types for a given set of conditions can also be established with a higher degree of certainty. The principle measure for comparing the performance between the selected BMPs is their discharge quality, which was found to be a function of the influent concentrations for many constituents. A comparison of the discharge quality as a function of the concentration in untreated runoff demonstrates substantial differences in performance among these BMPs for many constituents.