Simulation of hydrological of Samghan basin using SWAT model

There are several reasons to answer the question of why hydrological processes should be modeled. The main answer to this question is the limitation of measurement methods in hydrology. In this study, SWAT model, which is a conceptual and semi-distributive model in the watershed scale, was used for hydrological simulation of Samalghan watershed. After preparing the data according to the desired format, the model was implemented. After sensitivity analysis and determination of important parameters, the model was calibrated and validated. In order to reduce uncertainty, different components of water balance were considered in calibration and observational data of several measuring stations were used simultaneously. Then, SUFI 2 algorithm was used to evaluate and validate the model. The calibration process was performed for the period 2007 to 2013 and the validation process was performed for the period 2014 to 2017. To evaluate the simulation results, indices R2, bR2 (weight correlation coefficient), NS (Nash-Sutcliffe) were used. In the validation stage, the coefficients of R2, bR2 and NS coefficients were 0.74, 0.71 and 0.68, respectively, and in the validation stage, 0.69, 0.62 and 0.95 were obtained. The indicators and graphs obtained in the calibration and validation phase of the model to simulate the monthly runoff flow show that the model has been more successful in the calibration phase. Also, the model has been able to determine the peak time of the Dubai peak. This research provides useful information about the water balance of the Samolghan River basin and helps to more accurately plan water resources in this basin.