Watershed model to study hydrology, sediment, and agricultural chemicals in rural watersheds

A Dynamic Watershed Simulation Model (DWSM) is being developed at the Illinois State Water Survey, USA to simulate surface and subsurface runoff, soil erosion, and entrainment and transport of sediment and agricultural chemicals in rural watersheds. The model has routing schemes developed using approximate analytical solutions of the physically based equations preserving the dynamic behaviors of water, sediment, and the accompanying chemical movements within a watershed. An overview of the model and its theoretical basis and application to a 100-km 2 watershed in Illinois, USA are presented. The model reasonably predicted the water and sediment discharges at the watershed outlet, however, the agricultural chemical transport simulations of the model needs further improvements for watersheds of this size.