China’s Largest Cities are Sinking.
Aug 12, 2011
Significant subsidence, of over 2m, has been found in at least 50 cities. The graph above shows just four. The greatest problems are in the Delta region of the Yangtze River, the Northern-China Plain and the Fen-Wei River graben, all areas of rapid urbanisation.
The worst affected citoes are shanghai at 2.63m and Tainjen at 3.1m, which has been susiding since the 1920s.
Such falls considerably increase the problems of flooding of low lying land, and create considerable risks from storm and tidal surges on coastal areas.
According to a paper in Natural Hazards Review 2010 the economic loss from such susbsidence has been estomated at about RMB135.6 billion (US$18.03 billion) up to 2007.
Increases in ground water pumping in some areas increased because of pollution of surface waters.
Aquafer recharge projects are underway in some cities such as Shanghai.
