Case 2. Excessive extraction of groundwater

Some foreign experts pointed out that if we want to solve the water crisis in North China, we must first have a correct understanding of the threats to the critical groundwater supply.

The aquifer situation in northern China is very serious. Many areas are now facing irreparable consequences of excessive groundwater extraction, including land subsidence and seawater infiltration in coastal aquifers. Others have suggested that in order to produce water, the deeper the well is dug, the drilling costs continue to increase. At the same time, due to agricultural activities, industrial pollution and natural filtration of toxic components, groundwater quality problems are also emerging. In Tianjin and other Bohai Rim cities, groundwater exploitation for agriculture, drinking water supply and salt production has caused seawater to erode several kilometers inland, and more and more groundwater wells become salty. Extensive over-exploitation of groundwater has led to regional and local subsidence cones, indicating that the pumping rate of groundwater exceeds the natural recharge of aquifers and the ability to release water. It is true that, on the whole, if the pumping can stop or fall below the recharge rate, the aquifer does have the ability to “bounce”. However, due to water quality problems such as subsidence and seawater erosion, physical degradation of the aquifer structure is difficult or impossible to reverse in many cases. The aquifers in North China are not used as renewable resources in some senses, but as 'water mines': once depleted, they are irreversibly degraded and can never be reused, at least not the previous level.

Clearly, underground aquifers are a vital part of meeting these challenges, and if they are used correctly, they can continue to meet irrigation and domestic water needs. However, we must first break the inherent mentality of the past few decades and form more sensible ways of groundwater utilization and management based on scientific data and understanding of aquifer recharge rates, water storage capacity and sensitivity to pollution.

By / Niu Jingmei