Predicting possible bank erosion and bed incision in the Zhengzhou Reach of the Yellow River with hydrodynamic modeling

ABSTRACT The Zhengzhou Reach of the Yellow River (YR) frequently undergoes significant channel changes during flooding, leading to bank erosion, deposition, and bed incision. These changes result in adverse impacts such as land loss, channel movement, and overbank flooding. This study proposes a two-dimensional hydrodynamic model combined with rough set theory (RST) to simulate these phenomena in the alluvial channel of the YR. The model was calibrated and validated using data from 2006 to 2018. Results demonstrate that the model accurately predicts bank erosion and bed incision, with predicted widths closely matching measured data. The mean error was 14 m in 2006 and 18 m in 2018. The most severe erosion was observed 78 m downstream of Huayuankou, with the river bed incised by 3.7–4.9 m along the right bank. Based on RST, the shear stress, velocity, width/depth ratio, gradient, suspended sediment, and bed load are the dominating factors that affect the channel-shape changes. These findings will aid in implementing river-engineering strategies and provide guidance for managing similar channel reaches. This research highlights the effectiveness of a coupled model for predicting morphological changes in river systems, thereby contributing to better flood management and river bank protection strategies.