So much sand has been scooped out, says Shankman – 30 times more than the amount that flows in from tributary rivers – that the lake’s outflow channel has been drastically deepened and widened, nearly doubling the amount of water that flows into the Yangtze. “I couldn’t believe it when we did the calculations,” says David Shankman, a University of Alabama geographer and one of the study’s authors.Īll that dredging, researchers believe, is a key reason why the lake’s water level has dropped dramatically in recent years. That makes Poyang the biggest sand mine on the planet, far bigger than the three largest sand mines in the US combined.

A recent study estimates that 236m cubic metres of sand are taken out of the lake annually. The biggest can haul in as much as 10,000 tonnes of sand an hour. Hundreds of dredgers may be on the lake on any given day, some the size of tipped-over apartment buildings. In the past few years, China has used more cement than the US used in the entire 20th century “My sand helped build Shanghai Pudong airport,” Fey brags. In the last decade, Shanghai has built more high-rises than there are in all of New York City, as well as countless miles of roads and other infrastructure. The city has added 7 million new residents since 2000, raising its population to more than 23 million. Shanghai, China’s financial centre, has exploded in the last 20 years. The global urbanisation boom is devouring colossal amounts of sand – the key ingredient of concrete and asphalt.

Dredge mining environmental impact