From Flood Vulnerability Mapping Using Coupled Hydrodynamic Models to Optimizing Disaster Prevention Funding Allocation: A Case Study of Wenzhou

Urban areas face increasing flood risks due to extreme precipitation and anthropogenic activities, which threaten residents’ livelihoods. However, conventional research often lacks a forward-looking perspective, failing to integrate future flood vulnerability assessments with pre-disaster resource allocation. To address this gap, the combination of spatiotemporal flood vulnerability distributions and a pre-disaster funding allocation model serves to enhance urban flood resilience and recovery capabilities. Using Wenzhou City as a case study, a Hydrodynamic Flood Vulnerability Framework (VHCF) was applied to assess current and future vulnerabilities based on hydrodynamic modeling, which revealed distinct spatial patterns in vulnerability. Specifically, a coupled hydrological–hydrodynamic model and the Patch-generating Land Use Simulation (PLUS) model were integrated to simulate flood dynamics under future land-use scenarios for the years 2020 and 2030. A subsequent funding optimization model, based on the VHCF, was developed to prioritize disaster prevention resources for both current and projected high-risk areas. This approach achieves efficient resource allocation by balancing multidimensional flood vulnerability dynamics. The results indicate that extremely high-risk and high-risk zones are predominantly distributed along river corridors and urban centers. From 2020 to 2030, the areal proportion across all vulnerability levels exhibited an increasing trend. Following funding optimization, the coverage rates for low-risk and extremely low-risk zones reached 88.29% and 87.93% in 2020 and 2030, respectively. This methodology provides a scientific basis for decision-makers to enhance urban flood resilience, facilitate post-disaster recovery, and advance sustainable disaster prevention and mitigation strategies.