A comprehensive three-dimensional (3D) urban geology information system, which will provide geological assistance for urban planning and development, is expected to be established in more than 100 cities in the country.

The Ministry of Land and Resources said it has finished urban geology research and information collection work in six cities, where 3D urban geology information platforms have been established as a trial.

The information system will monitor geo-environmental changes and help local governments and policy makers better plan urban functions and layouts.

"As China's urbanization process is in progress at an ever-increasing pace, many construction problems crop up because urban safety and geological factors are not adequately considered ahead of time," Wang Min, vice-minister of land and resources, told the International Symposium on Urban Geology, which concluded on Thursday, in Shanghai.

"Urban geological work is urgently needed for city planning, construction, safety and management. We are exploring more effective and useful methods to solve the problems related to city development, and promote sustainable development," he said.

As of now, the country still lacks systematic urban geological work, such as hydrogeological surveys of water supply, special investigation services for engineering and the overall understanding of underground geological structures, he added.

Since 2003, the 3D urban geology information system has been established in Beijing, Tianjin, Shanghai, Hangzhou, Nanjing and Guangzhou, which suffer from different geological problems, such as subsidence and groundwater problem. After the trial run in these cites is complete, the information platform will be established in more than 100 cities across the country, according to the ministry.

Among the trial cities, Shanghai has made trailblazing achievements in curbing subsidence. The city's subsidence rate in 2009 was about 5.4 millimeters, its slowest over the past decade, according to the Shanghai Institute of Geological Survey.

Built on a swamp along the Yangtze River Delta, Shanghai, like Venice, Bangkok and Tokyo, has long suffered from creeping subsidence. Meanwhile, the mushrooming skyscrapers in the country's financial center only add to the problem.

Some experts even warned the city would be theoretically flooded in the next 50 years if no measures are taken.

"We have indeed made great achievements in preventing the city's subsidence over the past decade," said Wei Zixin, director of the Shanghai Institute of Geological Survey.

"In addition to a 3D model of bedrock geology, quaternary geology and hydrogeology to enhance the accuracy of the geology survey, the city has also established a land quality monitoring network," Wei said. "Safety monitoring and early warning systems were also set up in lifeline projects, such as subways, elevated bridges and flood walls."

(China Daily October 22, 2010)