Two-dimensional bank erosion model for noncohesive bank material

Bank erosion happens frequently in alluvial channels, which may cause serious economic and environmental problems, such as land loss, channel sedimentation and property damage. Due to its complexity, even though extensive research has been done in the past, it is still difficult to predict bank erosion. Therefore, a two dimensional numerical model has been developed to simulate the bank erosion processes by using computer. The model is based on a hydrodynamic model CCHE2D developed in the Center for Computational Hydroscience and Engineering, the University of Mississippi. In CCHE2D, depth averaged Navier-Stokes equations were solved by finite element method to obtain the depth averaged flow properties. Boundary shear stress is calculated by the flow model. From the boundary shear stress, bed load transport rate is computed. Assuming bed load only, the sediment continuity equation is solved numerically. Bank erosion is then related with the vertical erosion at the bank toe. The model has been validated against a physical experiment conducted by Ikeda (1981), and good agreements are observed.