SWAT Model Background and Application Reviews

Watershed scale hydrologic and nonpoint source pollution models must be thoroughly tested by applying them to watersheds of different sizes and characteristics and from different geographic and geologic locations before using them to assess environmental conditions, evaluate best management practices, and making water resources management decisions. A clear understanding of a model is important for its appropriate use. In an earlier study, eleven watershedscale hydrologic and nonpoint-source pollution models were reviewed: SWAT, HSPF, AGNPS, AnnAGNPS, ANSWERS, ANSWERS-Continuous, PRMS, KINEROS, DWSM, CASC2D, and MIKE SHE, and the mathematical bases of different components of these models were identified and compiled. Among the fully developed hydrologic and nonpoint source pollution models having all the three major components: hydrology, sediment, and chemical, SWAT was found to be one of the promising models for long-term continuous simulations in predominantly agricultural watersheds. Applications of SWAT and a few other promising models, as available in the literature, are currently being reviewed. In this paper, applications of the SWAT model are compiled and discussed, along with a brief background of the model.