A novel grid cell–based urban flood resilience metric considering water velocity and duration of system performance being impacted

• Published in: Journal of hydrology (Amsterdam) Vol. 617; p. 128911
• Main Authors: Zheng, Jiaxuan, Huang, Guoru
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2023
• Subjects: Duration of system performance being impacted; Flood resilience; Instability mechanisms; System performance curve; Water velocity; Water velocity; System performance curve; Duration of system performance being impacted; Instability mechanisms; Flood resilience
• ISSN: 0022-1694; 1879-2707
• DOI: 10.1016/j.jhydrol.2022.128911

[Display omitted] •Water velocity and duration of system performance being impacted were considered.•Objective thresholds were used to ensure the objectivity of the resilience metric.•Instability mechanisms were considered for the system performance of traffic land.•An increase in rainfall intensity has adverse effects on flood resilience.•Traffic land should be the primary land-use type for flood resilience improvement. Flood risks are increasing due to climate change and urbanization. To alleviate flooding problems, the development of flood resilience is necessary. However, existing metrics based on the system performance curve and grid cells only consider the impacts of the water depth. The system performance thresholds are typically determined based on expert experience and study area conditions, resulting in the subjectivity of resilience metrics. This study proposes a novel flood resilience metric that considers the water velocity and duration of system performance being impacted. The Flood Hazard rating index and incipient velocity were used to objectively determine system performance thresholds. The system performance of traffic land was determined by considering the instability mechanisms of residents and vehicles during floods. The proposed metric was evaluated in the Minzhi region of Shenzhen City, China, under different rainfall intensities. Comparisons with an existing metric were conducted, and the contributions of flood resilience area loss of different land-use types under different rainfall intensities were analyzed. The results suggest that an increase in rainfall intensity reduces flood resilience; the higher the rainfall intensity, the longer the flood impact duration is in the study area and in different land-use types. Floods and rainfall intensity have larger influences on traffic land than on other land-use types. The proposed metric provides better performance for quantifying the impacts of floods than the existing metric. Under the rainfall intensity variation, the land-use type with the greatest impact on the overall flood resilience changes from residential land to traffic land. A decrease in the flood resilience of greenspace contributes the least to a decrease in the overall flood resilience. Traffic land should be the priority land-use type in flood resilience improvement projects. The results of the in-depth analysis of urban flood resilience assessment in this study provide reference for flood mitigation and risk reduction.