Urbanization has increased the impervious surface which has increased the likelihood of flash floods, and water logging by producing more runoff. An effective sustainable and resilient solution to this problem is to install Green Stormwater Infrastructure (GSI). The benefits of GSI at the per site scale have been proven, as well as demonstrated across a city in models. In this study, the performance of an interconnected system made up of ten raingardens, two cisterns, a detention basin, three infiltration systems, and a bioswale was assessed, which is more indicative of a middle-scale, such as the block level. The 16 GSI were recently constructed alongside multiple new residence halls at Villanova University, which was formerly nine acres of impervious parking lot. The performance of the post-construction phase was compared to the pre-construction phase, and it was found that the total runoff volume has decreased by 45% percent for individual events like Hurricane IDA and Tropical Storm Fred, and approximately 70% for frequent rainfall events (e.g., the 25 mm event). Additionally, it was noted that the peak flow has decreased from the pre-construction period. Further, monitoring of each component within the GSI system allows for a quantitative understanding of which GSI components are contributing most to the reductions observed, which can be used to inform future GSI and system designs.
