CityNews: City's sinking to be monitored A monitoring center to help control land subsidence in the Yangtze Delta region will go into full operation in Shanghai by 2007, the city's Housing and Land Administrative Bureau said yesterday. The geological problem is causing hundreds of billions of yuan in economic damages, and the new center will help regional officials plot tactics to control the sinking of the land. The network, headquartered at No. 930 Linshi Road, will comprise hundreds of monitoring stations in Shanghai and 13 major cities in Zhejiang and Jiangsu provinces, including Nanjing, Suzhou and Hangzhou. "The network is a collective effort to monitor land subsidence in the Yangtze Delta region, the country's most developed economic region," Liu Shouqi, a senior engineer in the bureau's geological supervision department, told Shanghai Daily yesterday. He said 32 monitoring stations have already been set up around the city. Each station consists of two steel tubes, one reaching base rock some 60 to 300 meters below ground and the other sunk into the surrounding soft earth. Subsidence is calculated by observing changes in distance between the two tubes. Shanghai has been sinking by an average 10 millimeters each year, mainly as a result of the overuse of underground water and the rapid construction of skyscrapers, geologists said. The situation is much better than in the 1960s, when the city sank by more than 100 millimeters a year - a rate that would have put it below sea level by 1999 if measures such as limiting building height and pumping water back underground hadn't been employed. A recent study overseen by the national Ministry of Land and Resources showed subsidence in the Yangtze Delta region has caused some 300 billion yuan (US$36 billion) in economic losses. "Land subsidence has caused extensive 'geological disasters' in the region," Guo Kunyi, the Nanjing-based chief engineer of the survey, told Wenhui Daily. Though he didn't specify the projects involved, he did say subsidence has caused damage to roads, bridges, ports, underground pipes, wells and flood management system in the delta region.