Simulation of Streambank Erosion Processes with a Two-Dimensional Numerical Model

Abstract

Channel stabilization is critical for the success of channel restoration. A stable channel, from a geomorphic perspective, is one that has adjusted its width, depth, and slope such that there is no significant aggradation or degradation of the streambed or significant platform changes within an engineering time frame, generally less than 50 years (Biedenharn et al., 1997). Even though the bed of a stream in dynamic equilibrium is neither degrading nor aggrading, erosion may be occurring in stream banks and result in bank instability. Bank protection is often required even for a stream in dynamic equilibrium. Due to the lack of understanding of bank erosion mechanisms, the hydraulic and sediment transport models, including the series of U.S. Army Corps of Engineers Hydrologic Engineering Center models, CH3D-SED, etc., which have been widely applied to engineering projects to design stable channels, can only predict the vertical bed adjustments due to degradation and aggradation. Alluvial channels adjust themselves to reach regime conditions not only through bed elevation changes but also through platform evolution, for example, the migration of meandering channels.