Simulation of Outflow Time Series at Shahid Rajaee Dam using SWAT model

Increasing global temperature and its impacts on the water cycle as well as increasing population growth are problems that nowadays focus on better resource consumption and better management for accurate planning to meet future needs. Various hydrological models such as the water and soil assessment (SWAT) model are used to solve this problem. In this study, changes in the outflow of Tajan basin from 2005 to 2015 were simulated using the SWAT model. Then, the results were calibrated, verified and uncertain analysis using SWIT-CUP software using flood measurements at Solomon Strait station and SUI2 algorithm. Then, the results were calibrated, verified and uncertain analysis using SWAT-CUP software using outflow measurements at Soleymantange station and SUFI2 algorithm. The accuracy of the SWAT model was evaluated in the simulation of the outflow using the parameters of P-factor, R-factor, Nash-Sutcliff coefficient (NS) and correlation coefficient (R2). The values of NS and R2 for the calibration stage were 0.57 and 0.58, respectively, and in the validation stage were 0.7 and 0.71, respectively, that indicating a good correlation between the observational and the simulation data. The uncertainty results showed that the simulation curve was well arranged in the uncertainty range, and the distance between the peak points was minimum, in other words, the maximum discharge was simulated with high accuracy (the coefficient of agreement equal to 0.8). Therefore, the SWAT model is a suitable tool for simulation of flow rate in the Tajan basin.