High-Resolution Modeling of Infill Development Impact on Stormwater Dynamics in Denver, Colorado

AbstractGrowing cities require accurate knowledge of current and future hydrologic conditions to make effective stormwater management decisions. Yet, this information is lacking because cities are undergoing infill development/redevelopment, for which the hydrologic impacts are not adequately quantified. The current research studies the impacts of infill development on urban runoff in Denver, Colorado. A calibrated, high-resolution Stormwater Management Model for PC (PCSWMM) was used to simulate design storms and summer rainfall periods for multiple future redevelopment scenarios. Results predict that an increase of 1% in impervious area due to redevelopment will increase surface runoff volume by 1.63% for the 2-year, 24-h design storm and by 0.91% for the 100-year, 24-h design storm resulting in greater relative flood risks for smaller storm events. Flooding volumes will increase from 30,000 to 36,000 m3 for the 10-year, 24-h storm, which is 12% of the total storm rainfall volume. Results show the limitations of the existing storm sewer network, future flood potential, and the possibilities for stormwater beneficial use. Results will help inform current and future stormwater regulations regarding redevelopment.