Hydroelectric dams are important because of the advantages they provide. Electric power, flood defense and better navigation, among others. However, they also have their disadvantages, since their construction requires the flooding of fields, valleys and even entire cities. In addition, we must not forget the damage they cause to the ecosystem. Such is the case of the construction of the Three Gorges Dam in China, where more than one million people had to be relocated.
The dam is the largest hydroelectric work in the world. A titanic work that even changed the rotation of the planet, lengthening the day by 0.06 microseconds. The dam is just over 2 kilometers long (2209 meters), and has a height of 182 meters. A total of 510,000 tons of steel were used in its construction (equivalent to 60 Eiffel Towers). In addition, 28 billion cubic meters of concrete were used and more than 27,000 people worked on its construction.
It is built on the Yangtze River, which is the third longest river in the world (Yangtze means “long river”).
Why did they build Three Gorges?
The objectives of its construction were:
- To keep the river in its channel, during the flood season it provides protection to cities such as Wuhan, Nanjing and Shanghai.
- Improve navigation. The dam has the world’s largest boat elevator, which helps boats overcome the 113-meter drop.
- Electric power generation. It contains 34 turbines that generate 22,500 MW. The dam can hold up to 42 billion tons of water at its peak, generating 11 times more power than the Hoover Dam.
What does the story tell us?
The Three Gorges Dam was planned more than a century ago. In 1919, China’s first president, Sun Yat-sen, began planning to build a dam on the Yangtze River. The aim was to put an end to flooding and also to generate a large amount of power. It was all secret, however, as the construction was to be a symbol of China’s power.
For various reasons, such as the civil war in the country and economic crises, construction did not begin until 1994. The work was fully commissioned in 2009.
In July 2003, the first hydroturbine began operating in the northern sector. There they had to relocate 1,200,000 people, who were forced to leave their homes. The film “Naturaleza muerta” (Still Life) commemorates this event.
However, such work brought consequences of another kind, such as physicochemical changes in the environment caused by the construction. One of the losses is the disappearance of the baiji dolphin, which was endemic to the area. There are also countless archaeological losses that were lost when vast areas of fields were flooded.