Resilience and Vulnerability in Urban Drainage Systems: A Review

Abstract Urban drainage systems (UDS) are increasingly subjected to significant stress due to the intensification of extreme weather events driven by climate change and the densification of cities. These interrelated pressures, particularly the increased frequency and severity of rainfall events and the concentration of population and infrastructure, reveal critical vulnerabilities in both the structural integrity and operational reliability of sewer networks, hindering their ability to ensure service continuity and safeguard urban environments. In this context, the concept of resilience has emerged as a pivotal framework for assessing and enhancing the performance of drainage infrastructure under uncertain and adverse conditions. This review seeks to offer a comprehensive and systematic synthesis of the scientific literature on resilience and vulnerability in UDS, with a primary focus on pluvial networks, while incorporating references to potable water and other types of urban water systems to provide a broader contextual understanding. The scope of the analysis encompasses the conceptual evolution of resilience and vulnerability, the development and application of indices and modeling tools, as well as their implementation across diverse urban settings. A total of 109 articles are examined in detail and organized into thematic groups, which allow for the identification of prevailing methodological approaches, research gaps, and emerging trends. These findings indicate that while structural resilience (primarily related to physical infrastructure) is widely explored, functional and operational dimensions are comparatively underrepresented. Moreover, the lack of standardization and the frequent use of fragmented indicators limit the comparability of results and hinder the practical application of resilience assessments. These shortcomings highlight the necessity for more comprehensive and operationally focused frameworks that prioritize system functionality, adaptability, and continuity of service as core elements of resilience in UDS.