Flood waters have raised doubts about China’s Three Gorges Dam this week, but it’s only the latest in a series of concerns and controversies that have marred the history of this mighty structure…

It is of mythical proportions, impossible to truly grasp. It makes mountains look like molehills and molehills look like very small piles of dust. That’s right, I’m talking about China’s Three Gorges Dam, astride the Yangtze River in Hubei Province.

Whence came the Three Gorges Dam?

Three Gorges Dam: Image by Le Grand Portage via A Plan to Development Industry’, which is a bit clunky but gets to the point. He publishes it in The International Development of China.

The gist is, he wants to build a great big dam to control the flooding of the Yangtze River and embody the ‘new might’ of China. Brilliant idea, they all said.

Well actually, no they didn’t. Did they get to work on it straight away? Did they heck.

Outsiders with bigger sticks

It was actually the Japanese who moved the thing along when, in 1939, they occupied Yichang and surveyed the area. They were so excited about the prospect of owning all of China that they commissioned and completed the Otani plan in anticipation of the big day.

Then, obviously, the United States weighed in with a my-stick’s-bigger-than-yours in the shape of John L. Savage, who did his own surveys and came up with his own proposals. This, he called the Yangtze River Project. 54 Chinese engineers went to the States for training. Unfortunately, however, the Chinese Civil War had other, less productive plans and the project was put on hold in 1947.

Communist leader Mao Zedong came to power shortly after, building hundreds of dams during his ‘Great Leap Forward’ and began planning a site for a dam across the Yangtze in 1955. In 1956, he wrote a poem about dams and called it ‘Swimming’, in which the reader will find the phrase:

The mountain goddess if she is still there
Will marvel at a world so changed.

Which is just darling.

A not so gorge-ous episode

The power of a dam: Image by Mao had them sent to labour camps. The government did not look favourably on those who dissented the dam.

The dam project was subject to many further delays over the next three decades, as China went through huge social and economic turmoil.

Criticism of the project had as its backdrop a string of disasters that took place in Henan Province during a typhoon in 1975. A series of catastrophic structural failures in the Banqiao Dam caused the release of 600 million cubic metres of water — a wall of water 6 metres high and 12km wide.

Survivors became sick from contaminated water, and were trapped without food for many days. It was one of the most devastating floods in history, affecting a total population of over 10 million people. Entire villages were swept away, and as many as 230,000 people were killed as a result.

Despite the failure of the Banqiao dam, the idea of breaching the Yangtze re-emerged in the 1980s. During the Tiananmen protest of 1989, journalist Dai Qing published Yangtze, Yangtze, a book of essays opposing the project, but the dam was finally approved in 1992.

It is visible from space (via satellite)

NASA satellites show footage of the dam being constructed bit by bit over the 17 years it took to build, so it’s size–2.3km long by 185m high–really can’t be exaggerated.

When the quantity of concrete is written down, it merits the use of standard form. It is more fun to use objects than measurements. Example: it took 63 Eiffel Towers worth of steel to construct!

Clone the longest known animal ever to have lived on the earth (average female blue whale = 25m) and place 93 of them end to end, and you have the length of the dam.

In fact, it’s a whopping five times as big as the US Hoover Dam. But it is still less than half the reservoir flooded by the Itaipu Dam in Brazil. Props, South America.

How well does the dam work?

View of a dam and reservoir
Aerial view of a dam: Image by relocating 1.3 million people out of its flood zone.

But it also provides energy to lots of people. The Three Gorges Dam has an estimated power output equivalent to a regular power station, burning 25 million tons of crude oil a year. It generates 11 times more power than the Hoover Dam. It could power the entirety of New Zealand, Ireland, Iceland, Costa Rica, The Bahamas and Rwanda, combined (which, incidentally, is just 1.5% of China’s total energy consumption).

Well done on that count, but it could also be doing a lot of harm, causing a different kind of pollution.

The region surrounding the Three Gorges Dam is home to thousands of plant, insect, fish and terrestrial vertebrate species. Landslides and water pollution threaten (read: throw into disarray) the interrelatedness of a bunch of unique ecosystems.

The eco-stability of the region is, to put it lightly, dumped on by a heck ton of dirty water, which is good for business, but not so good for the planet.

So what’s all this about the earth slowing down?

Here’s the rub: when the dam closes its doors to fill its reservoir, it accumulates a total of 38 trillion kg of water. While this is only a teeny proportion of the total weight of the earth, it is enough to have an effect… on the earth’s rotation.

The maths has to do with moments of inertia and angular velocity. If you’re spinning on ice and you tuck your arms in, you’ll spin faster, and vice versa. Collecting such a weight of water in one location on the earth’s surface literally makes the earth spin slower. The crux is, it’s really damn big.

It increases the length of each day by 0.06 microseconds. Can you feel it? If you add up all those microseconds over a human lifetime, you’ll have approximately one and a half seconds to contemplate dams!


*This article also appears on ONURBICYCLE and Age of Awareness / Medium

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