In 1918, The first provisional President of the Republic of China, Sun Yat-Sen proposed the construction of the Three Gorges Dam across the Yangtze River in Hubei province as a measure to control the flooding of the Yangtze River.
It is the world’s largest hydroelectric power station by total capacity, which will be 22,500 MW when completed.
When the Three Gorges Dam was built, 39 trillion kilograms of water from the Yangtze River was built up behind it to 175 meters above sea level. This altered the Earth’s moment of inertia changed ever so slightly, causing the rotation to move more slowly.
How can a dam slow down a planet?
The dams are of huge mass and because of this, they can affect the rotation of the earth through a moment of inertia.
The longer the distance of a body from its axis, the higher is its moment of inertia or slower rotation speed.
The Three Gorges Project Took Decades to Become a Reality
Over the years, the idea of building a dam large enough to hold the Yangtze River at bay seemed unfeasible. After Sun Yat-Sen proposed the creation in 1919, the Three Gorges Dam was not discussed until 1944 into 1946.
The first day of construction on the Three Gorges Dam did not officially begin until December 14, 1994, with it being in operation by 2009.
Negative impact of the dams
Water Pollution: Estimates state that 70% of China’s freshwater is polluted and the dam could be making it a lot worse.
Massive Migration: When the project was constructed, 1.2 million people were forced to relocate and find new homes.
Environmental degradation: Erosion of the reservoir has triggered landslides and has even threatened one of the world’s biggest fisheries in the East China Sea.
NASA scientists have said that the Earth’s rotation fluctuates occasionally due to events like natural disasters and also due to the moon.
Thus the change caused by the dam is fairly insignificant in the larger scheme of things. But the fact that the Three Gorges Dam is the only man-made object to date that can’t the Earth’s rotation can’t be ignored.