Watershed Simulation with an Enhanced Distributed Model

Distributed watershed hydrological and erosion modeling is gaining popularity in recent years due to increased computing power and availability of detailed spatial hydrological data. Models of this type are widely believed to provide greatest opportunities to examine hydrologic impact of land use change and climate change (Sharika et al. 2000); they also have immense utility to forecast the movement of pollutants and sediments (Beven 1985). So far, quite a number of distributed models have been developed, and many were reviewed by Yang et al. (2003) and Lai and Yang (2004). Among them, WEPP (Nearing et al. 1989) and CASC2D (Julien et al. 1995; Johnson et al. 2000) are the two leading models used in the US.