When population science meets urban sewer networks : decoding remaining life using life table analytics

Abstract

Global urban sewer infrastructure faces an unprecedented aging crisis, with cascading failures threatening public health, environmental protection, and urban resilience. The American Society of Civil Engineers estimates a $271 billion investment gap for US sewer systems alone, highlighting the urgent need for sewer aging analysis to prioritize maintenance needs and optimize resource allocation. Current analysis methodologies face a critical implementation barrier: their complex data type requirements limit practical adoption across diverse municipal contexts. This study is inspired by the recognition that sewer pipelines, like human populations, experience age-related deterioration and demographic life table can be applied to analyze dominant factors in this process. The methodology transforms traditional multi-parameter models into a two-input approach requiring only failure age and categorical factor classification, while maintaining statistical rigor through Wilcoxon signed-rank tests with Bonferroni correction. As one of Asia's leading metropolitan centers, Hong Kong presents an ideal case study for sewer aging analysis. Comprehensive empirical validation was conducted across 148,389 pipeline segments spanning four major regions, 18 districts, six soil types, and diverse environmental conditions. The research further contributes a quartile-based risk classification system integrated with GIS visualization for immediate spatial risk assessment. This streamlined approach enables immediate implementation across diverse municipal contexts and systematic transition from reactive repair strategies to predictive management approaches. Such accessibility supports sustainable urban development and resilient sewer systems globally, providing a viable solution to the contemporary infrastructure crisis. Graphical abstract: [Figure not available: see fulltext.]