How does the world’s largest dam subtly alter the weather on Earth?
Nearly 20 years after the end of the project, the Three Gorges Damthe most powerful in the world located in China, continues to fascinate scientists and engineers, not only by the completely crazy figures that accompany it, but also by its more surprising impacts on the planet. A recent NASA study reveals that this gigantic structure would even influence the rotation of the Earth.
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The grandeur and colossal impact of the Trois-Gorges Dam
The Three Gorges Dam, an engineering feat located in China, stands 185 meters high and stretches 2,335 meters long. Its retention capacity is astonishing, capable of accumulating up to 40 km³ of water (or a mass of 40 billion tonnes of water). It is this immense amount of stored water that scientists believe has a measurable effect on the rotation of our planet.
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Scientific discovery: an influence on the Earth’s rotation
Benjamin Fong Chao, a geophysicist at NASA’s Goddard Space Flight Center, has conducted research that shows the dam has a tangible effect on Earth. Similar to the consequences of major events like earthquakes, the colossal weight of the water held back by the dam changes the Earth’s mass distribution and, therefore, its moment of inertia, slightly affecting its rotation.
The principle of inertia explained
The phenomenon observed at the Trois-Gorges dam can be compared to an ice skater who accelerates his rotation by bringing his arms towards his body. In 2004, the movement of tectonic plates following a major earthquake had already measurably altered the Earth’s rotation. The dam, by retaining a considerable mass of water, has a similar, although more modest, effect.
Impact measured: minimal but significant displacement
According to Chao’s calculations, the movement of this mass of water causes the Earth’s poles to shift by about 2 centimeters and extends the length of a day by 0.06 microseconds. This change is tiny, but it adds to other global factors such as global warming and melting ice, which concentrates more mass around the equator.
Future implications for time measurement
Scientists predict that the accumulation of such changes could require periodic adjustment of the length of minutes and seconds in our clocks. The proposal under discussion is to subtract one second from the minute every four years, thus more accurately reflecting the actual duration of an Earth rotation.
The 3 Gorges dams in figures:
Location: On the Yangtze River in China, in the Hubei province
Type: Concrete gravity dam
Dimensions :
- Length: 2,309 meters
- Height: 185 meters
Reservoir :
- Capacity: 39.3 billion cubic meters (or 40 km³)
- Surface area: 1,084 km²
- Length: 660 km
- Hydroelectric power station:
- Installed power: 22,500 MW
- 32 turbines of 700 MW each
- Annual production: 84.7 billion kWh
Locks:
- 5 successive locks for ships up to 10,000 tonnes
- 1 boat lift for ships up to 3,000 tonnes
Construction :
- Start of work: 1994
- Commissioning: 2003-2008
Cost: More than 17 billion euros
Goals :
- Electricity production
- Flood control
- Improved navigation
Impacts :
- Displacement of around 1.5 million people
- Modification of the river ecosystem
- Submergence of numerous archaeological sites
The largest building in the world is 30 times the Palace of Versailles, it is in China and it houses a real city under its roof
This article explores the surprising impact of the Three Gorges Dam on the Earth’s rotation, highlighting how human construction can interfere with the natural rhythm of our planet. Despite its minimal effect, this discovery raises important questions about the long-term implications of large construction and their management in an era of climate change.
Source : Wearewater.org
