This paper focuses on the integration of basin sediment transport with a physically-based hydrological model that links the water budget model WaSiM (Water Simulation Model) to the erosion model AGNPS_5. The results of the water budget simulation are then incorporated into the AGNPS_5 model to calculate sediment transport. The surface runoff calculated in WaSiM replaces the SCS curve number runoff calculation in AGNPS_5 to obtain a more accurate and physically-based sediment transport simulation of the basin. Data from a mesoscale river basin in Germany is used to compare two different simulations: (a) WaSiM (TopModel) + AGNPS_5 (sediment only); and (b) only AGNPSji (both SCS curve number runoff and sediment). The results and the advantages/disadvantages of each simulation method are discussed in light of integrated computerized management systems for river basin planning.