Unraveling the effect of inter-basin water transfer on reducing water scarcity and its inequality in China

Securing water supply in the face of increasing scarcity is one important challenge faced by humanity sustainable development. Inter-basin transfer widely applied to provide security regions where demand exceeds availability. However, effect inter-basin on alleviating and its inequality poorly understood especially at national scale. Based a newly compiled database projects China, here we report first assessment their securing different basins. We developed number indices facilitate quantifying inequality. The capacity has been steadily increased, which achieved ~48.5 billion m3 yr?1 2016 (equivalent ~8% use). results indicate that impacted 43 sub-basins out total 76 sub-basins, but it hardly changes basin's level (e.g., from low scarcity). Approximately three quarters people China are affected transfer. More than half population (705 million) benefit alleviated scarcity, leading coefficient reduced 0.64 under natural availability condition 0.59 considering 2016. 357 million source basins subject increased ~21% stressed sub-basins. This study reveals for time induced change across highlights challenges secure