Keywords:Groundwater, South to North Water Diversion Project in China, Beijing
As China’s Capital, Beijing currently has a population of 22 million people with per capital water resources of less than 100 m3, one twentieth of the national average and one eightieth of the global. Groundwater withdrawals (2.3 billion m3/year) account for approximately two thirds of total water use (3.5 billion m3/year) in Beijing, resulting in significant groundwater depletion and associated environmental issues, such as land subsidence. Ever-growing population and economy will add further pressure on Beijing’s groundwater resources. Unsustainable groundwater use threatens societal and economic development of Beijing and poses a large uncertainty in future water supply. To partly alleviate the water shortage issue in the more arid and industrialized North China, the Chinese government has launched the largest water diversion project in the world, i.e., the South to North Water Diversion Project (SNWD), which is a multi-decadal mega-infrastructure project, with the aim to transfer 44.8 billion m3 of fresh water annually from the Yangtze River in the more humid south through three canal and pipeline systems (east, central, and west routes). Its central route flows from the upper reaches of the Han River, a tributary of the Yangtze River to Beijing, Tianjin and other major cities in Hebei and Henan Provinces. Since Dec 2014 when the water transferred by the central route reached Beijing to Feb 2017, totally 2 billion m3 of water has been transferred. This has profoundly altered the structure of water supply in Beijing. This study quantifies how the SNWD project impacts groundwater storage of Beijing using modeling, and ground and satellite observations, and projects how groundwater storage changes in the future under different climate and, social and economic scenarios.