A conceptual model of sediment transport: Application to the Avon River Basin in Western Australia

This paper deals with the coupling of a sediment modelling algorithm to an existing conceptual model of water and salt fluxes (LASCAM). In the model, sediment generation is based on a modified version of the universal soil loss equation. The sediment transport processes of channel deposition and re-entrainment, and bed degradation are coupled with the existing stream-routing algorithm of LASCAM. The model is applied to the Avon River Basin, a large, dry catchment in Western Australia. The paper highlights some of the scientific issues involved in quantifying the sediment discharge processes in this catchment and presents validation results comparing model predictions with observations of sediment transport at different locations in the catchment. The results indicate that despite the strongly non-linear relationship between stream flow and sediment load, both are predicted well by the model. The model also highlights that in the Avon River Basin, disproportionately more stream sediment is generated in the wheat belt region than in the lower catchment.