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The urban district in north China's port city of Tianjin has dropped by about two meters due to the excessive use of underground water sources, experts believe.
The problem is getting worse as an expanding funnel-shaped area, covering 40,000 square kilometers, has taken shape in northern China as a result of underground water tapping.
Water resources experts have found more than 30 small funnel areas on the North China Plain that are joining together to become a large funnel-shaped area, believed to be the largest of its kind in China.
Wei Zhimin, a water resources expert, attributed the funnel's formation to excessive use of subterranean water. In Hebei Province alone, four billion cubic meters of water were extracted annually, dragging the surface water level down by 12 meters since1980.
An estimated 100,000 cubic meters of earth is needed to refill areas of subsidence on the North China Plain.
Ground sinkage often leads to cracks in pipelines and buildings and erosion of seawater in coastal areas, Wei said, calling for measures to save water.