Evaluating Rain Garden Efficacy for Sustainable Urban Stormwater Management

The expansion of impervious surfaces, combined with ongoing climate change, has led to significant environmental impacts, most notably urban flooding. The rising frequency of these events underlines the inadequacy of conventional urban drainage systems, necessitating a strategic transition toward sustainable and resilient stormwater management. Within this framework, Nature-based Solutions (NbS) represent a key strategy, offering multifunctional and regenerative methods to strengthen urban resilience against intensifying environmental hazards. Among the several types of NbS, the Rain Garden (RG) is a bio-retention system designed to intercept, temporarily store, and treat stormwater runoff generated by surrounding impervious surfaces. However, despite a broad consensus on the advantages of RGs, their large-scale implementation remains limited. Thus, this study evaluates the hydrological efficiency of a rain garden proposed for a specific site in Cerisano, Southern Italy. By utilizing EPA-SWMM software to develop a predictive model across different RG configurations, the research explores how varying design parameters influence system performance. The findings confirm that RGs are a reliable strategy for urban stormwater control, highlighting that their hydrological performance is highly dependent on specific design variables. The demonstrated efficacy of this sustainable approach supports its widespread adoption as a tool for addressing the environmental pressures of modern urbanization.
Acknowledgements: This work was funded by the Next Generation EU - Italian NRRP, Mission 4, Component 2, Investment 1.5, call for the creation and strengthening of 'Innovation Ecosystems', building 'Territorial R&D Leaders' (Directorial Decree n. 2021/3277) - project Tech4You - Technologies for climate change adaptation and quality of life improvement, n. ECS0000009. This work reflects only the authors' views and opinions, neither the Ministry for University and Research nor the European Commission can be considered responsible for them. We would like to thank the Municipality of Cerisano for supporting these project activities as a stakeholder.