Excessive pumping of groundwater is causing the geology under the city to collapse, according to a new study using satellite imagery that reveals parts of Beijing – particularly its central business district – are subsiding each year by as much as 11 centimetres, or more than four inches.
The authors of the study warn that continued subsidence poses a safety threat to the city of more than 20 million, with “a strong impact on train operations” one of the predictions. [...]
In 2015 China inaugurated a mega-engineering project aimed at mitigating Beijing’s water crisis. The state completed construction of the South-North Water Diversion, a £48bn, 2,400km network of canals and tunnels, designed to divert 44.8bn cubic metres of water to the capital.
Even before the canal began delivering water, Beijing was easing up on some groundwater pumping. In January of 2015 the Chaoyang district announced plans to phase out 367 water wells, reducing the use of 10m cubic meters of underground water. [...]
Other cities around the world are experiencing subsidence caused by excessive water pumping or other factors. Mexico City is sinking by up to 28cm a year and Jakarta is subsiding at a similar rate. Bangkok is dropping annually by as much as 12cm, similar to Beijing, according to the Remote Sensing researchers.
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