Modeling of river discharge in the Firoozabad watershed using soil and water assessment tool model

Iran is one of the arid and semi-arid countries of the world where water supply has become a major concern in it. In recent years, the management of the country basins is proposed as an effective solution for the optimal use of water resources. Therefore, this study focuses on this subject and the hydrological simulation of the basin is believed to be an ideal solution. In this regard, this research was applied from the Soil and Water Assessment Tool for the hydrological simulation of Firoozabad basin in Fars Province, Iran. At first, the runoff was simulated using the model during 1994–2010. Then, the results of model were calibrated from 1998 to 2006 and validated from 2007 to 2010 using Sequential Uncertainty Fitting and measured discharge of river from the hydrometric station of the basin outlet (Dehrood station). With the aim of assessing the model performance, uncertainty analyses were performed. The calibration results (R2 = 0.77, NS = 0.7) were acceptable at the basin outlet. However, the accuracy of the results was reduced during the validation period (R2 = 0.01, NS = − 0.57). In spite of the limitations of this study, the results indicated that Soil and Water Assessment Tool is an appropriate model for studies and simulations of hydrology and river discharge. © Islamic Azad University (IAU) 2019.