Continuous Simulation of Integrated Bioretention-Infiltration Systems for Urban Retrofits

This paper presents the elements involved in the hydraulic and hydrologic analysis of bioretention systems as an integrated part of an urban retrofit project. The system was modeled using HydroCAD, a design storm (DS) event modeling software, as well as SWMM 5.0.013, a continuous simulation (CS) software. The resulting response to a series of design storms was computed by both of these models to provide a comparison between the methods. The resulting SWMM model was then run on the design year rainfall distribution. Even with an infiltration rate of less than half inch per hour, nearly 92% of all runoff was intercepted and infiltrated by the system with a surface area less than 2.5% of its contributory impervious area.