Securing water supply in the face of increasing water scarcity is one important challenge faced by humanity in sustainable development. Inter-basin water transfer is widely applied to provide water supply security in regions where water demand exceeds water availability. In China, the authority constructed a number of big water transfer projects which advance the development of society and economy in an effective way in recent years. However, the effect of inter-basin water transfer on alleviating water scarcity and its inequality is poorly understood especially at the national scale.
Based on a newly compiled database of inter-basin water transfer projects in China, here we report a first national assessment of their effect on securing water supply in different basins. We developed a number of indices to facilitate quantifying the effect of water transfer on water scarcity and its inequality. The capacity of inter-basin transfer projects has been steadily increased, which achieved ∼48.5 billion m3 yr−1 by 2016 (equivalent to ∼8% of the national water use). Approximately three quarters of people in China are affected by water transfer. More than a half of the national population (705 million) benefit from alleviated water scarcity, leading to the inequality coefficient reduced from 0.64 under natural water availability condition to 0.59 considering water transfer in 2016. However, 357 million people in water transfer source basins are subject to increased water scarcity, in which ∼21% are from water stressed sub-basins.
Our study reveals for the first time water transfer induced water scarcity and inequality change across sub-basins in China, and highlights the challenges to secure water supply across basins.
Link to the paper.