Comparison of Single- site and Multi-site Based Calibrations of SWAT in Taleghan Watershed, Iran

Calibration of model is critical for hydrologic modeling of large watersheds in a mountain watershed. In this study Soil and Water Assessment Tool (SWAT) used to comparison a single-site calibration procedure that employed streamflow measurement at outlet of watershed to a multi-site calibration method that used streamflow measurements at three stations (Galinak, Joestan and Dehdar). Results showed that the single-site calibration was able to sufficiently simulate the streamflow for total stations (NS: 0.66–0.81). Results of multi-site calibration method also, shows slightly improve in total stations, whereas it was improved in upper stations i.e. Joestan and Dehdar (NS: 0.70–0.82). But, in validation period, there were clearly apparent differences between the simulated results provided by multi-site and the single-site calibration methods. The results of this study showed that the multi-site calibration method has better calibration of SWAT in Taleghan watershed and generally has advantages to the single-site calibration