Poor land use practices and improper management systems have played a significant role in causing high soil erosion rates, sediment transport and loss of agricultural nutrients. In this research a physically based watershed model, AVSWATX is applied to the Upper Ribb River watershed for modelling of the hydrology and sediment yield to predict the sediment yield to Ribb dam reservoir. The model is calibrated and validated taking the Upper Ribb gauging station near Debretabor. 20 years daily meteorological, flow and sediment rating curve equation for sediment data BCEOM (1999) are used for model calibration and validation. The model is calibrated and validated for both flow and sediment concentration at upper Ribb (844km2) and run at Ribb dam reservoir outlet (686km2) to estimate the sediment yield. The result indicated that the observed values show good agreement with simulated value for both flow and sediment yield. In this study the SWAT model yields average annual sediment of 72.79 ton/km2 (7279 ton/ha) at Ribb dam site. The result of the study could help different stakeholders to plan and implement appropriate soil and water conservation strategies.