Development and Assessment of Physically Based Numerical Sediment Transport Models for Shallow Overland Flow

Abstract

Sediment transport models for shallow water flow are important to the prediction of erosion and to support decision-makers in the development of conservation plans for agricultural and natural environments. This study proposes and evaluates two models based on empirical and numerical equations to quantify topographic change with shallow water flows. The first model is constructed with rill erosion and landscape evolution equations. The second model uses finite element methodologies to evaluate a sediment transport equation with different erosions and deposition. The hydrology of both models is generated using an uncoupled overland flow model. The models are validated against observed topography of shallow water flow with observed data of sediment discharge and runoff rate. The hydrology matches the runoff rate over the timescale used. The simulated sediment discharge matches well with observed sediment discharge for erosion equations with no deposition implemented. Preliminary results with deposition look promising but require further development. The simulated geomorphology cannot be concluded to confidently match observed geomorphology for the equations used. The two models are compared to results in literature. Further development of the models is required to improve the accuracy and capabilities of the model.