A framework for characterizing the performance of urban drainage systems under multiple rainfall conditions

Urban drainage is typically assessed using a limited number of design storms or recorded events, offering only a partial understanding of system performance. This study proposes a framework for the systematic evaluation of urban drainage response at the basin scale across a broad rainfall intensity–duration domain using hydrologic–hydraulic simulations. Simulation results are synthesized into decision-support products, including both local and global indicators. Key outputs include intensity–duration (ID) diagrams, return period maps, and flood extent maps associated with extreme historical events. The framework is demonstrated in a 70% urbanized basin with approximately 460,000 inhabitants in the Buenos Aires Metropolitan Region (Argentina). The approach identified critical rainfall conditions, vulnerable areas, and patterns of hydraulic capacity exceedance. By linking rainfall characteristics, system response, and flood impacts, the framework provides a comprehensive perspective on drainage system behaviour and can support system diagnosis, infrastructure planning, climate change assessments, and urban water management.