Numerical model for sediment transport over nonplanar, nonhomogeneous surfaces

Sediment transport on surfaces with spatially variable microtopography, roughness, and infiltration was investigated using the diffusion wave equation. An implicit finite-difference scheme together with multivariate Newton's method was employed to solve the equation numerically. The simulation results showed that microtopography and roughness were the dominant factors causing significant spatial variations in sediment concentration. If the spatially varying microtopography was replaced by an average constant slope, the result was an overestimation of the sediment load. On the other hand, when the spatially varying roughness was replaced by the average roughness and the spatially varying infiltration rate by the average infiltration rate, the sediment discharge was not significantly affected. The sedimentograph reached an equilibrium much sooner when a constant infiltration rate was substituted for the time-varying infiltration rate.