Universal Bank Erosion Coefficient for Meandering Rivers

Abstract

An equation for bank erosion, and thus channel migration rate, is derived theoretically from the equation of sediment continuity. The relation so derived lends credence to the hypothesis that bank erosion is proportional to a nearbank “excess” velocity, defined to be the difference between near‐bank and centerline depth‐averaged streamwise flow velocity. The theory also leads to the definition of a coefficient of bank erosion of a general nature. Based on data for channel shift for several Japanese rivers, it could be concluded that the universal erosion coefficient decreases as the index (number of blows) of the standard penetration test, as applied to the river bank, increases. Two trends appear, however, depending on whether or not bank texture is sandy or clayey.