The ancient northwestern China city of Xi'an is trying to inject water underground in a bid to alleviate the worsening surface subsidence, which has resulted in a tilting Dayan Pagoda built more than 1,000 year ago.
Excessive exploitation of groundwater is attributable to several large sinking funnel areas found around in the city, where an area of 30 square kilometers has subsided as deep as 50 centimeters.
To curb surface subsidence, the city government has, since 1999, sealed hundreds of wells, cut down groundwater consumption, and diverted water from nearby rivers.
However, to raise the level of groundwater quickly, water has to be re-injected underground since rain water can hardly seep into the ground when most of the surface is covered with cement roads or buildings, according to experts.
Testing is underway and experts believe this is what must be done to save the surface of the city from sinking.
(eastday.com 06/24/2001)
