ABSTRACT
Bank retreat is a key component of the channel evolution in the Upper Jingjiang Reach (UJR). A conceptual model was proposed for bank retreat, comprising three submodules of bank-toe erosion, ground water level change and bank stability analysis. The model applications at two typical sections in the UJR shown: calculated bank-retreat widths and profiles agreed relatively well with the measurements, with a higher frequency of bank failure during flood-peak and recession periods, due to intensive bank-toe erosion and high ground water levels. Effects of bank soil properties on bank retreat were investigated, which indicated that bank failure frequency and retreat width generally reduced with increases in soil shear strength and permeability, with a unidirectional change tendency for the frequency, while the width was also affected by bank-toe erosion degrees at failures. The delayed change in ground water level increased the frequency of bank failure during recession stage.
