Assessment of Municipal-Level Flood Vulnerability Using Logistic Growth Function-Based Flood Damage Function

This study evaluated the flood vulnerability of 228 municipalities in South Korea by constructing logistic growth function-based flood damage functions, utilizing flood damage and rainfall data from 1998 to 2021. Among the derived parameters, a represents flood damage sensitivity to rainfall increase, b indicates the rainfall threshold for flood occurrence, and c denotes the maximum damage amount. Parameter a (0.0688-0.3203) showed regional variations without distinct spatial patterns, whereas b (76.8-343.6) exhibited higher values in the Seoul Metropolitan Area and major cities, suggesting that developed areas with well-established disaster prevention infrastructure possess higher flood thresholds. The proportion of flood reduction facilities (pumping stations, river improvements, and retention basins) exhibited positive correlations with b, suggesting the effectiveness of these measures in increasing flood damage thresholds. Flood damage was typically initiated at 127 mm of maximum daily rainfall and approached maximum levels at 272 mm. This study provides quantitative evidence to establish localized flood management strategies that contribute to the development of future climate change adaptation policies.