Empirical Analysis and HEC-HMS Modeling of Green Stormwater Infrastructure: Capture, Ponding, and Infiltration in Urban Tucson

Abstract

Green Stormwater Infrastructure (GSI) has gained momentum in recent years for its dual ability to mitigate urban flooding through infiltration and enhance surface water quality by reducing runoff volumes and travel times. However, a gap remains in understanding the long-term performance and post-construction management of these systems. This study presents a detailed empirical analysis and hydrologic modeling effort for four GSI parks designed for stormwater harvesting in Tucson, Arizona. Results demonstrate that stormwater harvesting performance varies significantly across sites and is strongly influenced by local-scale heterogeneity. While some parks captured minimal runoff, others collected substantial volumes. Infiltration capacity did not appear to decline substantially over the less than two-year study period. HEC-HMS modeling and extreme event scenario analyses revealed that the flood mitigation potential of these systems is closely tied to rainfall intensity, with high-intensity storms overwhelming basin capacity and reducing effectiveness. These findings highlight the importance of continued monitoring and adaptive design improvements. Expanding research on GSI contributes to more resilient urban water management by supporting stormwater reuse strategies in the face of increasing climate and water resource variability.