1 College of Hydraulic and Environmental Engineering, China Three Gorges University, Yichang 443002, China;
2 Water Resources Security Collaborative Innovation Center in Hubei Province, Wuhan 430070, China;
3 Power China Huadong Engineering Corporation Ltd., Hangzhou 310014, China
Abstract:?Yalongjiang River basin is an important hydropower base in China. The runoff variation of Yalongjiang River Basin under climate change scenarios in future will directly affect the operation safety and power generation dispatch of cascade reservoirs. Therefore, it is necessary to study the impact of climate change on the runoff of Yalongjiang River Basin. Firstly, the the monthly SWAT model of the watershed is established, then the meteorological data of each station is predicted by using SDSM from 2006 to 2100. Finally, the future runoff of Yalongjiang River Basin is simulated by using the calibrated SWAT model from 2006 to 2100. The results show that the runoff of Yalong River will increase in the future, and increase synchronously with the enhancement of radiation forcing. The annual average runoff growth rates of RCP2.6, RCP4.5 and RCP8.5 are 8.9%, 12.5% and 16.7% respectively, and the annual runoff of 2020S, 2050S and 2080S under three concentration paths shows different trends. Under the RCP2.6 concentration path, it increases gradually to the peak value and then decreases slightly. Under the RCP4.5 concentration path, it increases gradually to the peak value and then stabilizes. While under the RCP8.5 concentration path, it increases continuously. In terms of annual distribution of runoff, the proportion of runoff in flood season under three typical concentration paths decreases first and then increases in the three periods of 2020S, 2050S and 2080S. The overall trend in the whole forecast period is decreasing. Under the three concentration paths, the proportion decreases from 75.9% of the base period to 72.9%, 72.0% and 71.2%, respectively. The increase of runoff will have a greater impact on the flood characteristics of the basin. Therefore, the designed flood in the basin should be revised and flood control dispatching schemes adjusted to reduce the operational risk of cascade reservoirs and to improve the efficiency of power generation dispatching in the Yalong River basin due to climate change.