China’s Biggest Dam in the World
Three Gorges Dam is a dam on the Yangtze River (Chang Jiang) in Hubei Province, China, located immediately west of the city of Yichang. This China dam was the greatest engineering project when it first began construction in 1994. It was the biggest dam in the world at the time of its completion in 2006. The dam and related hydropower plant were constructed in stages over several years. In 2012, it attained its maximum generation capacity. The dam allows ocean-going freighters to navigate and generates hydroelectric electricity.
It was also designed to provide flood protection, although its effectiveness on this front is unknown and has been contested. While the Three Gorges Dam was an engineering accomplishment, it was also plagued with controversy: the dam’s construction resulted in the displacement of at least 1.3 million people as well as the loss of natural features and several unique architectural and archaeological monuments. The reservoir of the dam is being blamed for an increase in the number of landslides and earthquakes in the area.
Layout of Three Gorges Dam of China
The concrete gravity dam for the Three Gorges project has a crest elevation of 185 metres and a maximum height of 175 metres. The dam axis is 2,309.47 metres long, which is longer than the well-known Grand Coulee Dam in the United States. The 483-metre spillway, which is positioned in the centre of the main dam, has 23 79-metre bottom exits. The 22 surface sluice gates are each 8 metres wide. The Three Gorges Dam’s maximum discharge volume is 116,000 cubic metres, making it the world’s largest.
Two powerhouses on either side of the spillway host a total of 26 turbine generators. Each unit has a generating capacity of 700 megawatt (MW) and is the world’s largest unit ever built. Fourteen sets of generators are housed in the 643.6-metre-long left powerhouse, which is 60 metres longer than the 584.2-metre-long right one. The Three Gorges project is planned to generate 84.7 TW/h of power with all of these massive turbines.
Three Gorges Dam Facts
The Three Gorges Dam is the world’s biggest power generation facility as well as the world's largest hydroelectric dam. The dam was built for a variety of reasons, including its historical significance and other factors. The Three Gorges Dam was erected across the Yangtze River to regulate the quantity of water that could pass through. This resulted in the formation of a gigantic artificial lake, which has become a popular international tourist destination. The construction of a dam on the Yangtze River had been planned since 1919, but the Civil War and Cultural Revolution put the project on hold until recently.
Flooding: One of the primary objectives for the construction of the Three Gorges Dam was to prevent floods further downstream. The necessity for a dam was underscored in 1954, when the Yangtze River flooded, killing hundreds of people.
Power Generation: Another purpose for the construction of this China dam was to generate power. Within the dam, numerous generators create power by using the potential energy held in the water.
Environmental Impact: The dam has been constructed to have as little influence on the environment as feasible. Some ancient objects have been lost or are no longer accessible as a result of this. However, it is said that the environmental impact is minimal.
Visiting the Dam: The dam is a major tourist attraction as well as a means of saving lives and generating power. Thousands of people visit each year since it is the world’s biggest hydroelectric dam.
Impacts of the Dam
Landscape and cultural heritage: Higher water levels and a broader passage after reservoir impoundment would alter the canyon’s landscape to some extent. Mountains and summits along the sides of the gorges range in elevation from 800 to 1,100 metres. The famed 12 peaks of Wuxi a Gorge have altitudes of roughly 1,000 metres. The most famous Goddess Peak rises more than 900 metres above sea level. The reservoir’s regular pool level of 175 metres will result in an elevation of 40–110 metres higher in the Gorges than is now the case. Even though the rapids and dangerous shoals will be removed, the steep canyon encircling the river basin will remain mostly unaltered. Improved navigation conditions will provide access to new picturesque sights, such as the "Lesser Three Gorges" along the Daning River. The majestic Three Gorges Project will undoubtedly become a new tourism hotspot.
Environmental: Dam supporters highlight the dam’s environmental benefits, including the availability of hydroelectric electricity, which is significantly cleaner than the coal-burning power on which China has relied largely for decades. They claim the dam will cut greenhouse gas emissions by lowering coal consumption (thereby safeguarding the ozone layer) while posing none of the radiation risks associated with nuclear power facilities.
Three Gorges Dam Problems
The threat of dam failure, the displacement of 1.3 million people (critics claimed 1.9 million) living in more than 1,500 cities, towns and villages along the river and the ruin of stunning landscape and innumerable important architectural and archaeological treasures were among the major issues. There were also worries, some of which were realised, that human and industrial waste from cities would poison the reservoir and that the massive volume of water stored in the reservoir would cause earthquakes and landslides.
Some Chinese and European engineers contended that a series of smaller, considerably cheaper and less problematic dams on Yangtze tributaries might generate as much electricity as the Three Gorges Dam while controlling floods just as effectively. They said that building those dams will allow the government to accomplish its key aims without danger. Because of these issues, work on the Three Gorges Dam was put on hold for over 40 years while the Chinese government tried to decide whether or not to proceed with the project's designs. However, the Three Gorges project pushed forwards and was completed in late 2015, with formal operations beginning in 2016.
FAQs on Three Gorges Dam
1. What is the Three Gorges Dam and where is it located?
The Three Gorges Dam is a hydroelectric gravity dam that spans the Yangtze River in Hubei province, China. It is the world's largest power station in terms of installed capacity (22,500 MW). Construction began in 1994 and it became fully operational in 2012. Its primary purpose is to generate electricity, control flooding downstream, and improve river navigation.
2. What were the main objectives for constructing the Three Gorges Dam?
The construction of the Three Gorges Dam was driven by three principal goals:
- Flood Control: To mitigate the catastrophic seasonal flooding of the Yangtze River, which has historically endangered millions of lives and livelihoods downstream.
- Hydroelectric Power Generation: To create a massive source of renewable energy, reducing China's reliance on coal and supporting its economic growth.
- Improved Navigation: To transform the treacherous upper Yangtze into a navigable waterway, allowing large cargo ships to travel deep into China's interior.
3. What makes the Three Gorges Dam the world's largest hydroelectric power station?
The Three Gorges Dam's status as the world's largest comes from its massive installed capacity of 22,500 megawatts (MW). This power is generated by 34 main turbines. While other dams, like the Itaipu Dam in South America, may sometimes produce more electricity in a given year due to more consistent water flow, no other dam has the sheer potential power-generating capacity of the Three Gorges Dam's infrastructure.
4. How does the Three Gorges Dam allow ships to pass through it?
The dam facilitates river navigation using two ingenious systems. For large vessels, there is a two-lane, five-stage ship lock. Ships enter a lock chamber, the water level is raised or lowered, and they proceed to the next chamber, like climbing a flight of watery stairs. For smaller vessels (under 3,000 tons), there is a vertical ship lift, which functions like a giant elevator, lifting ships and their water-filled basin straight up or down to the other side of the dam in less than an hour.
5. How can a man-made structure like the Three Gorges Dam affect the Earth's rotation?
The Three Gorges Dam affects the Earth's rotation by altering the planet's moment of inertia. By impounding a massive reservoir with over 39 trillion kilograms of water and raising it 175 metres above sea level, the dam slightly shifts the Earth's mass distribution. This tiny change increases the moment of inertia, causing the Earth's rotation to slow down by an incredibly small, almost immeasurable amount—estimated to be around 0.06 microseconds per day.
6. What are the major environmental and social controversies associated with the Three Gorges Dam?
Despite its benefits, the dam has caused significant negative impacts:
- Social Impact: The project required the relocation of over 1.3 million people, leading to social upheaval and the loss of homes, farms, and communities. Numerous important archaeological and cultural sites were also permanently submerged.
- Environmental Impact: The creation of the reservoir altered the local ecosystem, threatening native species like the Yangtze river dolphin. It has also been linked to an increased risk of landslides and seismic activity due to the immense pressure of the water on the surrounding land.
7. What would be the potential consequences if the Three Gorges Dam were to fail?
A failure of the Three Gorges Dam would be a catastrophic event. It would unleash a massive wall of water, leading to devastating flooding downstream and endangering the lives of millions of people in major cities like Wuhan and Nanjing. The economic impact would be immense, destroying infrastructure, agriculture, and major industrial centres. The downstream ecosystem would also be completely reshaped, causing irreversible environmental damage.
8. Beyond electricity, what are the other key economic benefits of the Three Gorges Dam?
While power generation is its most famous function, the dam provides other major economic advantages. The vastly improved river navigation allows for a ten-fold increase in shipping capacity, reducing transportation costs and connecting central China's industries to global trade. The reliable flood control protects billions of dollars worth of property, farmland, and infrastructure in the fertile Yangtze delta region, ensuring economic stability.
