Evaluation of SWAT Hydrological Model Performance for Runoff Simulation Using Multi-Site Calibration and Validation Techniques in Mun River Basin

Abstract

The application of hydrological model is important in the assessment of hydrological conditions at the watershed level. Configuring the model to maximize the accuracy of the results is an important step in determining the effectiveness of hydrological models, especially in large watersheds with multiple observed stations. The aim of this study was to present a technique for calibration and validation the results of runoff simulations in Mun River Basin, Northeastern of Thailand when using SWAT and SWAT-CUP between 1991-2020, compared with data from 29 observed stations. The results indicated that the technique of dividing the area into 3 main areas (upstream, midstream and downstream) and the determination of the outlet point of the sub-basins at the observed station could be effectively implemented. In addition, after adjusting the values of 8 sensitivity parameters in SWAT-CUP covered all areas to determine the optimal values of the model. This was indicated by the R2 index of most of the comparative positions in the 29 Mun River Basin areas at satisfactory level. However, to adjust the calculations to bring the NS and PBIAS indexes to an acceptable level, it was necessary to find a suitable procedure for SWAT-CUP analysis. The techniques presented in this study are expected to be applied to simulate hydrological conditions for large river basins with adequate observed stations. This is to confirm the development of accurate, efficient, reliable and most effective tools for sustainable water resource management.