Development of a Flood Vulnerability Assessment Method for Wastewater Treatment Plants Based on Inundation Modeling

Localized heavy rainfall due to climate change has led to the frequent inundation of sewage treatment facilities, consequently causing significant secondary impacts such as water pollution and industrial paralysis. To address this, this study quantitatively reflected the specific characteristics and importance of environmental facilities to develop a more practical flood vulnerability assessment method. The proposed flood vulnerability index consists of a Hazard Index and a Mitigation Index. The former quantifies the risk level based on 1D/2D coupled inundation simulation results, and considers the importance of facilities and the location of key equipment. The latter evaluates structural and non-structural response capabilities through a checklist. A pilot application to the Gwangju Sewage Treatment Plant confirmed that the developed method can derive a quantitative vulnerability score reflecting both physical inundation threats and the facility’s mitigation capacity. This assessment technique is expected to serve as a practical tool for quantitatively diagnosing facility-specific vulnerabilities, thereby supporting preemptive disaster prevention planning and investment prioritization for critical environmental infrastructure.