Vulnerability Assessment of Sewer Networks

Abstract Urban storm water management faces significant challenges due to climate change, especially in cities with aging combined sewer systems. Many of these networks, which are over a century old, are increasingly strained by urban growth and changing climate patterns. This strain often results in capacity limitations and a heightened risk of surface overflow events. Although detailed sewer network data and occasional records of surface overflows exist, the lack of calibrated and regularly updated simulation models remains a significant hurdle in assessing network integrity. This study aims to address this challenge by introducing a methodology to evaluate sewer network vulnerability. Two distinct approaches are proposed for generating vulnerability indices for individual sewer sections. The first involves comparing theoretical capacity values among adjacent sewer segments, while the second establishes a probabilistic index for surface overflow occurrences in each section. Computational results from both approaches closely align with real surface runoff records, demonstrating their reliability in assessing network performance. By employing these methodologies, stakeholders are provided with a systematic framework to identify high-risk sewer segments and prioritize necessary network enhancements. These approaches support informed decision-making in urban infrastructure development and resilience planning, addressing the complex interplay of urbanization and climate change.