Dynamic analysis of floodplain degradation in the Andong Dam Reservoir, Korea from a socio-hydrological perspective

Abstract

This study investigates the mechanisms underlying floodplain degradation in dam reservoirs from a socio-hydrological perspective. Specifically, it aims to understand how human behavior, flood dynamics, and policy interventions interact to influence long-term changes in floodplain conditions. To achieve this, the study developed a dynamic modeling framework using differential equations that incorporate the memory of inundation, impact perception, economic incentives, and policy penalties. The model is applied to the Andong Dam in Korea, and simulations are performed under both historical period and future climate conditions (RCP 4.5 and 8.5). The impact of the strengthened penalties on the degradation control is also analyzed. The simulation results reproduce the historical period degradation trend and reveal that low inundation frequency leads to rapid floodplain conversion due to dominant economic incentives. In contrast, more frequent inundation under future climate scenarios helps maintain public memory and reduce degradation rates. However, floodplain degradation was fully suppressed only when the penalty level became comparable to the expected agricultural gain.