China's Cities Sinking Due to Groundwater Pumping

While China's economic star continues to rise, some parts of the country are sinking — literally. Rapid development and overused groundwater supplies threaten to pull the soil out from under the nation's cities.

Alarmed by the grave results of a geological survey that 46 cities in China are sinking due to the excessive pumping of groundwater, the central government recently kicked off construction of two surface subsidence monitoring networks focusing on the Yangtze River Delta and the North China plain, respectively.

Under the administration of the China Geological Studies Bureau, the networks, which are to be completed in 2006, are expected to monitor the rate at which the ground is sinking as well as groundwater levels.

The cross-regional efforts are expected to unite the individual battles of the suffering cities with better coordinated measures, an official with the bureau said.

According to the survey conducted by the Ministry of Land and Resources, the rapid depletion of groundwater has produced more than 100 massive tunnels covering a total area of 150,000 square kilometers across the country.

The Yangtze River Delta network will monitor roughly 100,000 square kilometers of land area, including Shanghai, eight cities in southern Jiangsu Province and six cities in the northern and eastern parts of Zhejiang Province.

The areas suffer from both severe surface water pollution and heavy economic losses caused by surface subsidence, said the official, who declined to be identified.

The North China plain network will oversee Beijing, Tianjin and parts of the provinces of Hebei, Shandong and Henan, covering 140,000 square kilometers.

This region has witnessed the most excessive pumping of groundwater in the world and covers the largest subsidence area with the most funnels on the planet, he said.

And the groundwater level of approximately 70,000 square kilometers in this region falls below sea level.

The cities of Shanghai, Tianjin and Taiyuan report the worst sinking, each of them having dropped by more than two meters since the early 1900s.

Meanwhile, the rate of groundwater pumping in the country has been increasing by 2.5 billion cubic meters annually during the past 20 years, according to Zhang Zonghu, a professor with the China Academy of Sciences.

Groundwater accounted for 19.8 percent of the national water supply in 2000 as compared with 14 percent in 1980, Zhang said. The percentage for cities in the dry northern and northwestern regions now stands at 72 and 66 percent, respectively.

Source: China Daily