Making waves: a call for the resilient design imperative of urban drinking water systems

Evaluating and enhancing the resilience of urban drinking water systems is a prerequisite for sustaining essential services under climate and infrastructure uncertainty. Drawing on the destructive 2021 "7·20" Zhengzhou rainstorm flood as a critical case study, this paper advocates that resilience should be established as a core design requirement for urban drinking water systems. It first analyses the cascading failures of Zhengzhou's urban water supply triggered by the flood, including water treatment plant outages, widespread service suspensions, emergency water supply arrangements and post-disaster recovery operations. Resilience-centered design needs to transcend traditional reliability-oriented or hazard-specific risk assessment frameworks, with greater focus on failure modes, systematic stress testing and multi-layered redundancy. Against this backdrop, the middle-based analytical method offers a feasible pathway to evaluate system performance under disruptive events, prioritizing the consequences of system breakdowns rather than merely the occurrence probability of specific hazards. This study further elaborates on how emergency preparedness and disaster-proof communication mitigate service disruptions and accelerate restoration. Ultimately, the paper concludes that resilient urban drinking water infrastructure cannot be achieved without public preparedness and multi-stakeholder shared accountability. A holistic social-natural-engineering integrated framework is therefore required to facilitate the development of adaptive, resilient urban drinking water systems against the backdrop of intensifying extreme weather events.