Dynamic Coupling of Topographic Stability and Socio-Economic Exposure in Flood Risk Mapping: A Decadal Analysis of Honghu Dong Flood Detention Basin, Yangtze River (2014–2024)

Dynamic flood risk mapping is crucial for adaptive management of Flood Detention and Retention Areas. This study proposes a novel “topography-socioeconomics-risk” dynamic coupling framework to quantify flood risk evolution in the Honghu Dong Flood Detention Basin (2014-2024), integrating MIKE FLOOD-based hydrodynamic modeling and Geographic Information System-driven spatial analysis. Multi-source data (LiDAR topography, socio-economic statistics) revealed: (1) Negligible topographic changes (<0.01 m elevation shift) maintained stable inundation patterns under the 1954 flood scenario; (2) Rapid socioeconomic transitions increased population by 11.1% (28.6 thousand people) and GDP by 123.3% (from 4 to 9 billion CNY), while cultivated land shrunk 42.8% (203 km2), intensifying exposure of high-value assets; (3) Economic losses surged from 2.96 to 4.94 billion CNY, with commercial losses contributing 39.1% (782 million CNY) to the increment. The framework uniquely deciphers synergies between geomorphic stability and socio-economic dynamics, demonstrating that urbanization-driven asset concentration dominates risk escalation, rather than terrain changes. This paradigm provides a actionable tool for optimizing flood storage strategies in rapidly developing basins, prioritizing adaptive policies for high-value zones.