Modeling of two‐dimensional overland flow

A two-dimensional hydrodynamic and numerical model for overland flow is developed in this paper. The model allows spatial variations in hillslope physical characteristics, including surface roughness, infiltration, and microtopography. The accuracy of the model is tested by comparison with characteristic-based solutions and experimental data. The results of these tests indicate that the model is accurate and has good stability and convergence properties. The application of the model to two-dimensional overland flow on hillslopes is demonstrated by applying it to surfaces with spatially variable roughness, infiltration, and microtopography. These simulations show that microtopography is the dominant factor causing spatial variation in overland flow depth, velocity, and direction.