A Continuous-Simulation Approach for the Design and Long-Term Performance Assessment of Infiltration Basins for Sustainable Urban Water Management

This study proposes a comprehensive methodology for the design and performance assessment of infiltration ponds integrated within hybrid grey–green urban drainage systems. The scope of the ponds is twofold: (i) increase infiltration of rainwater, and hence groundwater recharge, and (ii) decrease pluvial discharge downstream. The framework is applied to the Rome Technopole district, which serves as a pilot case for testing and demonstrating the procedure. Through 30-year continuous simulations performed with the EPA Storm Water Management Model and forced with a 5 min historical rainfall, the approach enables a performance-based evaluation that captures the full hydrological variability and the hydraulic performances of urban drainage systems. The methodology relies on physically based models for both the grey stormwater drainage network and the infiltration ponds, combined with a long-term simulation and functional analysis under transient conditions. The approach explicitly represents the main hydrological processes, including runoff generation, flow routing, storage dynamics, infiltration, and soil moisture variability, enabling a quantitative evaluation of peak-flow attenuation, infiltration efficiency, groundwater recharge volumes, seasonal variability, and wet–dry cycle behaviour. The latter is used to assess the long-term evolution of pond performance and its implications for maintenance activities, including clogging development and removal. Scenario analyses explore the influence of pond geometry and storage volumes, highlighting the trade-offs between hydrological efficiency, evaporation losses, and drawdown times. Beyond the specific application to the Rome Technopole developed in this study, we propose a generalizable, practitioner-oriented design procedure suited to contexts where infiltration-based solutions are desirable but regulatory guidance is fragmented. The proposed design workflow identifies critical parameters for both the hydraulic design and the operational management of infiltration ponds, enabling a statistical evaluation of their performance. The analysis of peak-flow reduction, infiltrated volumes, and the timing and frequency of wet–dry cycles provides a robust technical basis for the proper sizing, integration, and long-term assessment of infiltration ponds within urban drainage planning.