Water conservation

Terrawatch: What the world can learn from the sinking of the Chinese city | Science

Fproblems and sinkholes are the norm in China’s Shanxi Province. Intensive agriculture combined with heavy charcoal production put enormous pressure on water resources and dried up the land, leaving Taiyuan City, with a population of 5 million, and its surroundings suffering from high rates of highest sag in the world. Pipelines, roads, bridges and railroads require constant repair, and gaping cracks in buildings have resulted in the relocation of entire communities.

Since 2003, the Chinese government has tried to solve this problem by diverting excess water from the Yellow River. From now on, satellite measurements, published in Remote sensing of the environment, reveal that this gigantic feat of engineering – taking 1.2 billion cubic meters of water each year – partially solved the problem, with the diverted water rehydrating underground pores and reversing the sinking trend.

But it didn’t work everywhere: the interstitial spaces in the clay-rich areas cannot be completely reopened. And even where it has worked, the bounce is limited.

The greatest successes have been recorded in areas where water diversion has been associated with water conservation, tree planting and modernization of irrigation techniques. Other areas of the world under water stress and prone to subsidence, including the central Iranian plateau, the American high plains and northwestern India, would do well to learn from the Chinese experience.