Climate Change in Ganjiang River Basin and Its Impact on Runoff

Abstract

Predicting the change of runoff in the future is significant to the management of regional water resources. In order to estimate future climate change of Ganjiang river basin and explore its impact on runoff, the changes of precipitation and temperature under the three representative concentration pathways (RCP2.6, RCP4.5 and RCP8.5) were analyzed and the Soil and Water Assessment Tool (SWAT) hydrological model was established to simulate the corresponding runoff in the Basin. The statistical relationship between the factors and the predictor in the Ganjiang river basin was built based on Statistical Downscaling Model (SDSM). For three scenarios, the precipitation showed slight increase trends under RCP2.6 and RCP4.5, but a significant increase under RCP8.5; and generally decreased from July to October while increased from January to April. The temperature exhibited a rising trend under three scenarios, of which the rank was RCP8.5>RCP4.5>RCP2.6. The runoff had an increasing trend and the rank for the three scenarios was RCP8.5>RCP4.5>RCP2.6. Generally, runoff had a strong positive correlation with precipitation while a weak correlation with temperature. The flood risk in Ganjiang river may increase significantly in the future.