Applying SWAT model to simulate streamflow in Ben Hai River Basin in response to climate change scenarios

Abstract

SWAT model was used to assess the impacts of climate change on the streamflow of Ben Hai River Basin. The daily streamflow for 1979 - 1996 and 1997 - 2006 was used to calibrate and validate the SWAT model, respectively. Nash efficiency values for the daily comparison were 0.72 for the calibration period and 0.74 for the validation period. Three scenarios were analyzed relative to the baseline with 28-year time series. A doubling of the atmospheric C02 content to 660 ppm (while holding other climatic variables) resulted in a 7.2% increase in average annual streamflow while the average annual streamflow changes of 59.75%; 81.9%; 75% and 190% were predicted for two periods of B2 and A1FI scenarios respectively. The seasonal variability was predicted to be high for the individual climate change scenarios and in specific months the streamflow variability was also large between scenarios. The results also show that the hydrology of Ben Hai River Basin is sensitive to climate changes.