a Aghakhani Afshar - Ph.D Student of Hydraulic Structures, Aras Campus Tabriz University, Tabriz, Iran
y Hassanzadeh - Professor of Civil Engineering Department, University of Tabriz, Tabriz, Iran

Soil and water conservation is important for the Torogh reservoir area in Khorasan razavi province, and quantification of soil loss is a significant issue. In this study, two widely used models-the Water Erosion Perdiction Project (WEPP) and the Soil and Water Assessment Tool (SWAT)-were applied to simulate runoff and sediment yield for the Torogh watershed in the Torogh reservoir area. The models were run and the simulated runoff and sediment yield values were compared with the measured runoff and sediment yield values. In the calibration period, the model efficiency (ENS) values for the WEPP and SWAT were 0.864 and 0.711 for runoff, and 0.847 and 0.678 for sediment yield, respectively. In the validation period, the ENS values for WEPP and SWAT were 0.835 and 0.690 for runoff, and 0.828 and 0.818 for sediment yield, respectively. The results of ENS and the other criteria indicate that the results of both models were acceptable. WEPP simulation were better than SWAT in most cases, and could be used with a reasonable confidence for soil loss quantification in the Torogh watershed.

WEPP, SWAT, Sediment yield, Runoff, Calibration