Urban Flood Risk Assessment and Improvement: Integrating Flood Simulation Results with Refined GDP

The increasing frequency and intensity of urban floods, driven by rapid urbanization and global climate change, underscore the importance of risk assessment in supporting effective disaster mitigation and prevention. A scientific, accurate, and detailed risk assessment for urban floods enables the effective identification of high-risk areas and reveals the evolutionary characteristics of flood risk, which is crucial for risk management and socio-economic sustainable development. A risk evaluation index system was developed using simulation results from an urban flood model and refined GDP of spatial reconstruction, integrating the ISA and SSA methods. Subsequently, based on the calculated comprehensive indicator weights, the flood risk within the study area was quantitatively assessed through the FCE method. The results demonstrated that the highest-risk areas were primarily located in eastern Futian District and southwestern Luohu District. Urban flood risk was dynamically changing with RP increased. With an increase in the RP, the proportion of lowest-risk areas decreased, whereas the proportion of other risk areas increased. When the RP increased from 2a to 100a, the proportion of highest-risk areas rose from 2.74% to 5.48%. Under a small RP (RP = 2a), the POP indicator had the strongest explanatory power for the spatial heterogeneity of urban flood risk. The explanatory power of the MFD indicator increased with the RP, making it the strongest explanatory indicator. The comprehensive assessment framework proposed in this study overcomes the limitations of traditional assessments in dynamics and fineness. It provides an important basis for identifying high-risk areas and formulating disaster prevention and mitigation strategies, and guiding similar assessments in other regions.