The only thing keeping the Huangpu River out of the Peace Hotel’s Art Deco lobby on Shanghai’s waterfront this summer is a concrete flood wall.
It’s not that the river has risen more than usual during the rainy season. Instead, Shanghai is sinking.
The land under the skyscrapers and 13 million people of this bustling metropolis is deflating like a giant air mattress, slowly settling as its shallow water table collapses after decades of overuse.
Sinking Widespread
Sinking cities are common in chronically dry China, which is guzzling water from underground aquifers to supply a booming economy and growing population.
Land under 46 cities is sinking, the government says. Areas around Beijing, the capital, have sunk by up to 14 inches over the past decade.
Although Chinese officials warn publicly about relying too heavily on wells, drought in recent years has complicated their efforts. As rivers dry up, cities and farms drill more wells. More than 100 cities in northern China are short of water, the official Xinhua News Agency has reported. Some reservoirs are dry.
Shanghai has switched to river water for most uses, slowing its annual descent to less than two-fifths of an inch. But after years of rapid decline, even that threatens China’s business capital, which sprawls across flat land less than 10 feet above the Huangpu.
“If we didn’t control this, the ground would collapse” by three feet every decade, said Liu Yi, a government geologist who tracks the sinking. “The damage would be unbelievable — floods and wrecked buildings.”
Drained Water
Shanghai, one of the world’s most densely populated cities, switched fairly easily to water from the Huangpu and Yangtze rivers. But it still suffers the legacy of long, severe bouts of ground subsidence.
The problem stems from Shanghai’s rapid 19th century metamorphosis into a foreign colonial base. Shallow aquifers that had supported a Chinese trading port were quickly strained supplying factories and a populace that tripled by 1900 to more than 1 million.
