Mitigating urban flood Hazards: Hybrid strategy of structural measures

Effective reduction of urban flood risk can be accomplished through structural mitigation measures such as underground drainage tunnels and implementing drainage practices, such as green infrastructure (GI) techniques. In this study, we employed an urban runoff model to quantitatively evaluate the impact of these flood mitigation measures and GI technology in reducing urban flood vulnerability (UFV). Specifically, we assessed the flood control capabilities of underground drainage tunnels and detention reservoirs, among others, exploring various combinations to formulate a comprehensive flood prevention plan (CFPP) for the studied basin. Additionally, our study analyzes the effectiveness of GI technologies, such as impervious area reduction (IAR) and ground retention (GR) and introduces a method for assessing their impact on flood-prone areas. To enhance flood mitigation strategies, we propose a hybrid approach that combines CFPP with GI techniques. The effectiveness of this hybrid strategy was assessed through comparisons with a basic scenario and multiple GI technology scenarios. As a result of applying the hybrid strategy proposed in this study, the reduction rates of peak flow (PF), flood volume (FV), and flooded area (FA) in this basin were up to 37.3 %, 71.5 %, and 93.6 %, respectively. These findings offer valuable insights for designing strategies to enhance urban flood resilience in the face of a changing climate.