Modeling watershed erosion with CASC2D

CASC2D is a physically-based, distributed model that simulates the response of a watershed to precipitation. Basic processes in the model include: precipitation, interception, infiltration, surface runoff and channel flow, and erosion and deposition of upland soil and channel bed sediment. Model performance is demonstrated by applications to numerous sites such as Goodwin Creek, MS. This watershed is 21 km2 and has been extensively monitored. The model was calibrated and validated using rainfall data from 16 meteorological, six flow, and six sediment gaging stations. The spatial and temporal variation of sediment erosion and deposition was successfully simulated. CASC2D is readily coupled with standard GIS tools to facilitate data exploration, model set-up, and analysis and visualization of model results. More recently, CASC2D has been expanded to simulate chemical transport aswell as extreme floods in largewatersheds. CASC2D applications to theCalifornia Gulch, CO and Arkansas River, CO watersheds demonstrate these enhancements.