Sediment transport rate-based model for rainfall-induced soil erosion

A one-dimensional mathematical model, termed sediment transport rate-based model, is developed for determining rainfall-induced soil erosion and sediment transport. The model is comprised of (1) the kinematic-wave equation for overland flow, (2) a transport rate-based advection equation for rainfall-induced soil erosion and sediment transport, and (3) a semi-Lagrangian algorithm for numerical solution of the soil erosion and sediment transport equation. A series of soil flume experiments under simulated rainfalls were conducted to simulate the overland flow and sediment transport and to test the sediment transport rate-based model. Numerical results of sediment transport rate-based model indicate that (i) hydrographs display an initial rising limb, followed by a constant discharge and then a recession limb; (ii) sediment transport rate graphs exhibit the distributions similar to the hydrographs; and (iii) sediment concentration graphs show a steep-receding limb followed by a constant distribution and a receding tail. The numerically simulated hydrographs, sediment transport rate and concentration distributions are in good agreement with those measured in laboratory experiments, demonstrating the efficacy of the transport rate-based model.