University of Tabriz Water and Soil Science 2008-5133 28 3 2018 09 23 Comparison of two Calibration-Uncertainty Methods for Soil and Water Assessment Tool in Stream Flow and Total Suspended Solids Modeling Comparison of two Calibration-Uncertainty Methods for Soil and Water Assessment Tool in Stream Flow and Total Suspended Solids Modeling 53 64 8123 FA MT Aalami Professor, Faculty of Civil Engineering, University of Tabriz, Tabriz, Iran H Abbasi Phd candidate, Faculty of Civil Engineering, University of Tabriz, Tabriz, Iran MH Niksokhan Associate Professor , Department of Environmental Engineering, , University of Tehran, Tehran, Iran Journal Article 2018 11 19 Estimation of total suspended solids in upland watershed of reservoirs using simulation models is a vital key to manage reservoirs water quality. It is consequently essential that these models undergo calibration and uncertainty analysis before their application. In this study, Soil and Water Assessment Tool model was applied to estimate stream flow and total suspended solids for Sofichai Watershed upstream of the Alavian Reservoir located in East-Azarbayjan province. The Generalized Likelihood Uncertainty Equation (GLUE) and Sequential Uncertainty Fitting (SUFI-2) were used in this study to calibrate and analyze the uncertainty of SWAT model. The performance of the GLUE and SUFI-2 was evaluated using four objective functions namely: Nash–Sutcliffe Efficiency (NS), coefficient of determination (R²), RMSE-observations standard deviation ratio (RSR) and the adjusted R² coefficient (bR²). Uncertainty statistics used were the <em>P-factor </em>and <em>R-factor</em>. SUFI-2 proved to be a very efficient optimization algorithm for Calibration and uncertainty analysis. The model calibrated with SUFI-2 can therefore be applied confidently for water resources management, for quantification of scenarios of climate and land use change, and for estimation of the Best Management Practices efficiencies in the watershed. Estimation of total suspended solids in upland watershed of reservoirs using simulation models is a vital key to manage reservoirs water quality. It is consequently essential that these models undergo calibration and uncertainty analysis before their application. In this study, Soil and Water Assessment Tool model was applied to estimate stream flow and total suspended solids for Sofichai Watershed upstream of the Alavian Reservoir located in East-Azarbayjan province. The Generalized Likelihood Uncertainty Equation (GLUE) and Sequential Uncertainty Fitting (SUFI-2) were used in this study to calibrate and analyze the uncertainty of SWAT model. The performance of the GLUE and SUFI-2 was evaluated using four objective functions namely: Nash–Sutcliffe Efficiency (NS), coefficient of determination (R²), RMSE-observations standard deviation ratio (RSR) and the adjusted R² coefficient (bR²). Uncertainty statistics used were the <em>P-factor </em>and <em>R-factor</em>. SUFI-2 proved to be a very efficient optimization algorithm for Calibration and uncertainty analysis. The model calibrated with SUFI-2 can therefore be applied confidently for water resources management, for quantification of scenarios of climate and land use change, and for estimation of the Best Management Practices efficiencies in the watershed. https://water-soil.tabrizu.ac.ir/article_8123_87a527b0352d8a0c933d8cd46fc07af5.pdf