Communities and agencies responsible for stormwater management (e.g., MS4 permit holders in United States) face new ever-increasing on-site stormwater runoff control regulations, while faced with funding limitations. Best Management Practices (BMPs) are employed to meet these challenges, which come with significant initial costs to install but to maintain in perpetuity. To examine the real long-term effectiveness and cost a one square mile urban catchment in the Denver region with mixed land uses was examined with the help of a recently developed spreadsheet model. Results will be described showing that BMPs capable of capturing runoff from larger areas are not only more cost-effective, but can compete in effectiveness with retention control measures.
The other challenge facing stormwater managers is what cost effective sizing of various types of BMPs are. A new model designed specifically for that purpose is described that has the potential of saving time and resources in pre-sizing BMP capture volumes for planning and design purposes.