Flood Risk Assessment Based on the Historical Disaster Statistics and the Index System Method: A Case Study of Hubei Province, China

Abstract Flood risk assessment is a critical aspect of flood management. The historical disaster statistics method and the index system method are commonly employed for this purpose. In this study, we combine these approaches to assess the risk of flooding in Hubei province, China. Our methodology includes compiling flood disaster data from 1949 to 2000 to calculate the flood disaster extent and trend in each geographic unit, and flood hazard is assessed using these aspects. Additionally, we also select relevant indicators such as elevation difference, distance to water bodies, GDP, population, and percentage of construction land as flood vulnerability measures, and the weights for these indicators are determined using the Analytic Hierarchy Process (AHP). Subsequently, a risk assessment model is developed by integrating the hazard and vulnerability factors, and the flood risk assessment is conducted at a high-resolution grid scale of 1km × 1km. The results show that about 36.7% of the territory of Hubei Province falls into the medium-high risk category. It is observed that the risk level is higher in the eastern and southern regions, and lower in the western and northern regions. Notably, flood risk decreases radially outward from two high-value centers such as Wuhan and Yichang. Our assessment method demonstrates operational simplicity, high accuracy, and robustness. Moreover, the assessment results provide a high spatial resolution that can be further refined to the relative risks in different administrative hierarchical areas.