Simulation of Soil Erosion and Sediment Transport Using a Physically-Based Integrated Surface-Subsurface Model

Understanding the hydrologically-driven erosion processes that control sediment detachment, transport and deposition on upland surfaces is a major challenge in watershed erosion modeling. This paper presents a sediment transport algorithm with a coupled 2-D surface and 3-D subsurface flow model that can simulate surface responses and also consider subsurface contributions during a rainfall event, hi the model, the sediment transport algorithm utilizes the non-equilibrium concept to simulate both erosion and deposition. The flow and sediment transport equations are discretized using the finite volume method and solved implicitly using the Picard iteration method. The flow and sediment transport are computed in a decoupled way; that is, the depth-averaged 2-D sediment model is solved after the flow field simulation at each time step. The developed sediment transport model is tested using measurement data from published experiments. The ability to simulate sediment transport due to rainfall in a watershed is demonstrated.