Evaluation of calibration characteristics of SWAT hydrological model in a mountainous watershed

Accurate data about runoff in the future in a watershed facilitates managers' decisions in water-related decisions and helps conserve natural resources for sustainable development. The two factors of cost and exact time are directly related to accurate runoff estimation. Using computer models to simulate natural phenomena such as the hydrological cycle is one way to reduce costs and increase accuracy.

The information for this research was obtained through the SWAT model website and global data. This study evaluates the accuracy of different calibration and validation methods in the hydrological simulation of Qarasu watershed, the SWAT (hydrological model) and a comparison between GLUE and PSO methods with the SUFI-2 method were used to calibrate the SWAT model. For simulation, 13 specific parameters were selected in all methods in the same situation. It should be noted that the data required for this research were collected from (SWAT model website) and (Water Resources Management Company).

All three methods were able to simulate runoff with acceptable R2 and NSE results (above 0.7), and the sensitivity analysis showed that Sol_K, CH_N2 and CN2 were more sensitive than other parameters.

Although the SUFI-2, PSO, and GLUE algorithms can reduce the difference between the observed and simulated data, the performance of the SUFI-2 algorithm in runoff simulation is more accurate than other algorithms. Therefore, it is suggested to use this algorithm to predict runoff.