The Middle Seydi Suyu Watershed, which is an important agricultural area in Turkey, has been modeled using the Hydrological Simulation Program - FORTRAN (HSPF). Sediment transport in the watershed and the stream drainage has been simulated for the 1991-1994 hydrologic years. Field surveys conducted at stations along the stream have been used for calibration and validation of the model results. The sediment loads contributed by the watershed to the stream have been estimated. Scenarios comprising of best management practices have been developed to reduce the sediment transported to the stream from the agricultural areas. The effects of vegetation cover on the sediment transport have also been examined.