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ARS Home » Southeast Area » Oxford, Mississippi » National Sedimentation Laboratory » Watershed Physical Processes Research » Research » Publications at this Location » Publication #192771
Title: A deterministic bank-stability and toe-erosion model for stream restoration

Author
item Simon, Andrew
item Langendoen, Eddy

Submitted to: Environmental and Water Resources Institute World Congress Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 2/14/2006
Publication Date: 5/22/2006
Citation: Simon, A., Langendoen, E.J. 2006. A deterministic bank-stability and toe-erosion model for stream restoration. In: Proceedings of the Environmental and Water Resources Congress (R. Graham, Ed.), May 21-25, 2006, Omaha, Nebraska. CDROM.

Interpretive Summary: Sediment is one of the principle pollutants of surface waters of the United States and sediment eroded from streambank failures has been found to be the single largest contributor to suspended-sediment loads to streams draining unstable systems in the mid-continent. With the recent focus on stream restoration, a quantitative means was needed to predict critical conditions for stability and the effects of riparian vegetation on attaining stable bank geometries. A numerical model of bank stability was developed that accounts for erosion at the base of the bank by flowing water and the potential collapse of the upper part of the bank by gravity. The model also accounts for the stabilizing effects of riparian vegetation. The model is useful for predicting the stability of streambanks and for testing potential stabilization measures.

Technical Abstract: Sediment is one of the principle pollutants of surface waters of the United States and sediment eroded from streambank failures has been found to be the single largest contributor to suspended-sediment loads to streams draining unstable systems in the mid-continent. With the recent focus on stream restoration, a quantitative means was needed to predict critical conditions for stability and the effects of riparian vegetation on attaining stable bank geometries. A deterministic bank-stability model was developed in the late 1990's at the USDA-ARS National Sedimentation Laboratory and has undergone substantial enhancements since that time. The original model (Simon et al. 1999) allowed for 5 unique layers, accounted for pore-water pressures on both the saturated and unsaturated parts of the failure plane, and the confining pressure from streamflow. The enhanced Bank Stability and Toe Erosion Model (Version 4.1) includes a sub-model to predict bank-toe erosion and undercutting by hydraulic shear. This is based on an excess shear-stress approach that is linked to the geotechnical algorithms. Complex geometries resulting from simulated bank-toe are used as the new input geometry for the geotechnical part of the bank-stability model. The enhanced bank-stability submodel allows the user to select between cantilever and planar failure modes. In addition, the mechanical effects of riparian vegetation are included.