Evaluating flood risk in the Yangtze River Delta region using explainable machine learning
摘要
Intensifying climate change and urbanization have led to more frequent and widespread urban floods, threatening lives, property, and sustainable development. This study uses machine learning to assess flood risk across 41 cities in the Yangtze River Delta Region by integrating 14 geospatial indicators spanning hydrometeorological, geomorphological, and socioeconomic dimensions. Results demonstrate that Random Forest achieves superior accuracy, F1‑score, and AUC compared to alternative models, confirming its suitability for regional flood risk assessment. The distribution of flood risk within the study area exhibits significant spatial autocorrelation, with high-risk clusters predominantly located in central and southern Zhejiang Province and northern Jiangsu Province. Moreover, SHAP (SHapley Additive exPlanations) values identify typhoon frequency, GDP, runoff depth, maximum three-day precipitation, and DEM as the most influential drivers of flood risk, and their relative contributions differ across geographic areas that exhibit different watershed characteristics or observed flood risk levels. The findings offer a scientific basis for context-specific flood risk governance across the extended Yangtze River Delta region.