TARGET 120118

HOW DO YOU WASH A RIVER?

The Big Flush

You Flush It!!

These photographs may look like scenes from an apocalyptic film. But in fact they are of an annual operation to clean out piled up silt that has collected behind the Xiao Lang Di Dam on the Yellow River in Jiyuan, Central China's Henan province. The annual flushing of silt from behind the dam moves 30 million tonnes of it downstream. Bystanders, who come to experience the annual event hold umbrellas as they are dwarfed by the tremendous rush of water gushing through opened sleuceways in the dam.

Dirt first
Coming out of the sluice gates
Gushing upwards and out

Flushing silt from the bottom

The special sluicegates for this operation are near the bottom of the dam, where the silt has settled. When they are opened, thick, muddy water gushes upwards and out at tremendous speed.

The lake behind the dam

The Xiao Lang Di Dam on the Yellow River in Jiyuan, Central China's Henan province.

There are no pumps forcing the water from behind the dam. The pressure of the vast amount of water behind the dam (seen above) is what drives the flow.

Sludge to begin with

When the sluice gates first open, the thickest sludge from the bottom comes out at a much less impressive rate. But as the thicker sludge is cleared, the runnier silt is free to move out, and that is where the flow increases to amazing proportions, as seen in the series of pictures, below.

The flow increases
...and increases
...and increases

Then, with the dirtiest of water and sand flushed, the yellow silt from which the river gets its name is free to flow. When it does, the height of the gushing rises and rises to a level several hundred feet above the river level. This is when the observers begin to open their umbrellas and get ready for the falling of silty water onto them.

The rising flow gets higher
.. and higher...

The water then rages on and on until the silt is flushed out and the water starts to run clear.

The water begins to run clear
And finally, the water runs free


For the advanced viewers viewing this target, the dam is 154m (505 ft) tall and 1,317m (4,321 ft) wide. The amount of silt flushed each year is about 30 tons (not including the weight of the water that is flushed with it). When its was completed opened in 2000, following a six-year construction, it had cost the equivalent of $3.5 billion USD to construct. It generates up to 5.1 terawatts of electricity annually with the help of six 306 megawatt turbines.

FEEDBACK MAP

Feedback Map

If you got impressions for which this feedback is insufficient, please take a look at the following web sites for more:

The Daily Mail
Amusing Planet
YouTube video
Xinhuanet (great series of additional photos)
More from The Daily Mail
Avax News
Wikipedia