August 4, 2009
Subsidence areas are appearing in Beijing, the result of long overexploiting the groundwater to the extent of about 100 million litres a year. Five main subsidence areas have emerged. They are already challenging city planning, as well as endangering residential conditions.
By the end of 2003, these five subsidence areas came into being in the Beijing Plain. They are located to the east of the city from Balizhuang to Dajiaotin, in northeast Laiguangying, from Shahe in Changping District to Baxianzhuang, Yufa in Daxing District to Lixian, and Pinggezhuang in Shunyi District. In the center of these areas, the apparent horizon has fallen about 722mms.
This phenomenon has had serious results such as fissures in the earth, demolition of buildings, and deterioration of soil quality. Worse still, it will become more difficult to drain floods or measure geological benchmarks.
Beijing Bureau of Exploration and Development of Geology and Mineral Resources vice-chief engineer Lu Xiaojian emphasized that, although it is a serious problem, earth subsidence can be prevented and need not be a source of worry.
Lu told Beijing Youth Daily that the subsidence areas are mainly located in the east, north and south parts of the city. Because there is much soft gravel in the stratum in the west part of Beijing, subsidence does not occur there. So, we can conclude that the key cause of this problem is a stratum lacking soft gravel. We should not exploit groundwater in this stratum. Lu also emphasized that moderation in exploiting the groundwater is the most important thing at present. Over- or under-exploitation will harm the stability of the ground.
Categories: Beijing Water