Assessment of Climate Change Impact on the Streamflow in Be River Catchment, Vietnam

摘要

A study of Be catchment was carried out to quantify the expected impact of climate change on the streamflow using a multimodel ensemble approach. Climate change scenarios (A1B and B1) were developed by ensemble four GCMs (CGCM3.1 (T63), CM2.0, CM2.1, and HadCM3) which showed good performance for Be catchment through evaluation of statistics between 14 GCMs control simulations and the corresponding time series of observations at annual and monthly level. SWAT (Soil and Water Assessment Tool), a physically based distributed hydrological model, was used to investigate the impacts on streamflow under climate change scenarios. The model was calibrated and validated using daily streamflow records. The calibration and validation results showed that the SWAT model was able to simulate the daily streamflow well, with Nash-Sutcliffe efficiency greater than 0.78 for Phuoc Long station and 0.65 for Phuoc Hoa station, for both calibration and validation at both daily and monthly scale. Their difference in simulating the streamflow under future climate scenarios was also investigated. Results indicate a 1.01-2.93℃ increase in annual temperature and a 3 to -20% changes in seasonal precipitation corresponded to a change in streamflow of about 3 to -20%. The large decrease in precipitation and runoff are observed in the dry season.