Deposition of Sediment in Transient Flow

Abstract

An analytical method of predicting the change in riverbed elevation at transient phases is developed. A computer solution is presented along with the method in order that a sample computation can be made to check the stability and convergency of the method. For channels in which the sediment-laden water can be considered completely homogeneous and in which the velocity can be considered uniform over the cross-section, equations of continuity and the equation of motion of sediment-laden water are presented. Introducing the assumption that the difference between the original bed slope and the new bed slope within a short period is very small, these three basic partial differential equations are successfully reduced to two partial differential equations. The method of characteristics is then employed to solve for the mean velocity, v , and the mean depth of flow, h . In order to estimate the sediment deposit thickness, z , the equation of continuity for sediment is transformed directly into finite-difference form.