Sinking City Solution: Pump Groundwater Back?
The State Council recently ratified a five-year plan to address the sinking ground levels of over 79,000 square kilometres and more than 50 cities in China, which potentially threaten the stability of everything from high-rise buildings to high-speed rail lines. The problem is caused primarily by groundwater over-extraction to meet the demands of thirstily growing cities, and has awoken Beijing’s passion for ambitious water-related engineering projects. Plans are afoot to re-inflate aquifers by pumping water back in; scepticism, however, abounds. From the South China Morning Post:
Tunnelling expert Professor Wang Mengshu of Beijing Jiaotong University, who is also a member of the prestigious Chinese Academy of Engineering, said he saw too much ambition and too little practicality in the land ministry’s plan ….
Professor Feng Zhiming, with the Chinese Academy of Sciences’ Institute of Geographic Sciences and Natural Resources Research, said pumping water underground was too costly for most mainland cities ….
Jiang [Mingjing, who teaches underground engineering at Tongji University in Shanghai] said Beijing’s most urgent task was not to stop land subsistence, but to set up a network to monitor sensitive areas and buildings.
“A city may take centuries to sink, but a skyscraper can collapse overnight,” he said. “We must have some focus, or we will be lost.”