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)

Changjiang Institute of Survey, Planning, Design and Research Co., LTD, Key Laboratory of Water Grid Project and Regulation of Ministry of Water Resources, Wuhan, China

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Abstract

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.