Evolution and driving factors of the spatial association network of urban flood resilience in the Yangtze river delta urban agglomeration

Abstract

Against the dual backdrop of increasingly frequent extreme precipitation and rapid urban expansion, urban flood risk has continued to intensify and increasingly exhibits cross-regional transmission. This study assesses urban flood resilience in 41 cities in the Yangtze River Delta (YRD) from 2011 to 2023. A modified gravity model, social network analysis, block model and quadratic assignment procedure (QAP) regression are adopted to investigate its spatiotemporal evolution, network structure, and driving factors. Urban flood resilience in the YRD increased overall with fluctuations and showed a clustered pattern centered on Shanghai. Intercity linkages evolved from localized agglomeration toward cross-regional networking. Network connectivity remained relatively high, with Shanghai, Suzhou, Wuxi, Changzhou and Nanjing occupying core positions. The network contained four spillover blocks with shifting primary recipients. Geographic proximity, urbanization gaps, public attention differences, fiscal self-sufficiency gaps and institutional proximity significantly promoted network linkages, while the effect of infrastructure disparities weakened gradually. These findings can inform the optimization of regional disaster-prevention resource allocation, foster complementarity in urban disaster-mitigation capacities, and improve mechanisms for coordinated cross-regional flood governance.