Modelling catchment processes in the Swan-Avon river basin

A conceptual hydrological model, LASCAM, is applied to the Swan-Avon catchment (area 120 000 km²) in Western Australia to predict yields of water, salt, sediment, phosphorus and nitrogen. Each of the nutrients is further discriminated into soluble and particulate components. The model uses a single set of global parameters that are applied to each of the 134 subcatchments. Spatial mapping of the model results shows that yields are closely related to the distribution of rainfall and vegetation cover. Application of the model to various land cover scenarios show that since European settlement in the catchment, there has been a five-fold increase in streamflow, a 40-fold increase in sediment yield, and approximately 16-fold increases in total nutrient yields.