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Gone with the flow

It may look like a scene from a Hollywood movie depicting the end of the world but, in fact, it is a routine event at the Xiaolangdi dam on the Yellow River in China.

Every year, this carefully choreographed operation in Henan province moves 30 million tonnes of silt downstream, as part of efforts to remove silt from the Yellow River in Luoyang.

Silt builds up in massive amounts on the river bed, which can slow the water flow and raise the level of the river, increasing the risk of flooding.

More than 390 million tonnes of silt have been moved this way over the last 13 years. The silt-carrying water gushes out of three specially made holes in the dam.

The Yellow River authority said the operation lowers the river bed in the lower reaches of the river by an average of 2.03m each year.

The dam, which is located about 20km north-west of Luoyang city, stands at 154m tall and is 1,317m wide.

When it was opened in 2000, following a six-year construction, it had cost US$3.5 billion to build.

A version of this article appeared in the print edition of The Straits Times on June 30, 2016, with the headline 'Gone with the flow'. Print Edition | Subscribe