The SWAT (Soil and Water Assessment Tool) model was applied to simulate the sediment yield in the watershed Ribeirão dos Marins, in Piracicaba, Brazil, for the biennial period of 1999/2000. The application of this model requires georeferenced input data, provided by an interface between the model and a Geographic Information System (GIS). The watershed was divided into sub-basins, and parameters were separately determined for each area. The simulated sediment yields were compared to the observed data of a gauge station located in the upper third of the watershed, using the Nash and Sutcliffe Coefficient (COE) and the deviation between simulated and measured data (Dv). After calibration the simulation results of the sediment yield showed a COE of 0,83 and a Dv of -3,2%, indicating that the simulated and observed data tally basically.
erosion; hydrological models; non-point source pollution; GIS; SWAT
