Abstract: The aim of this study is to explore the status of water resources and its variation characteristics in Beijiang river basin in the presence of different degrees of drought. The streamflow in Beijiang river basin was simulated using SWAT model, and on this basis, the temporal and spatial variation characteristics of blue water and green water and their responses to droughts were evaluated. Results unraveled that: (1) Blue water accounted for the main part in the water resources in Beijiang river basin, with the average annual blue water reaching 1 149.08 mm, green water 981.08 mm, and green water coefficient 0.48. (2) From 1966 to 2010, blue water and green water experienced no significant changes, whereas in spatial scale, blue water distributed more in the south than that in the north, and the opposite for green water. (3) Blue water was more sensitive to drought than green water. Under severe droughts, the blue water in Beijiang river basin dropped by 16.94% from annual average, and the pattern of water resource distribution changed from blue water dominated to green water taking a lead, with the green water coefficient of 0.53. The research findings will be beneficial for the formulation of water resources management strategies, the designation of drought risk response measures and the guarantee of water security in the basin.

Key words: water resources, blue water, green water, drought response, SWAT model, Beijiang river basin