Modeled Flow Duration Variations and Costs for Pollutant Removal Associated with Different Stormwater Control Practices

Abstract

Runoff volume and pollutant discharges increase with development, with associated detrimental receiving water effects. These increases can be partially controlled by installing stormwater control practices, such as wet detention pond at outfalls, using conservation design controls such as grass swales and bioretention devices. The runoff volume and the pollutants associated with the different source areas within a watershed can be used to identify the most likely suitable stormwater control practices for the area. This paper presents the reductions in runoff volume and pollutant discharged, and the costs associated with installing these control practices in an example 228 acre watershed located in Jefferson County, AL with 75% commercial lands and 25% residential lands. The Source Loading and Management Model for Windows (WinSLAMM) was used to calculate the reduction of these pollutants and runoff volume, the associated variations in flow durations, and the costs involved in retrofitting different combinations of a wet detention pond, grass swales, and bioretention devices in the example watershed.