Img credit: ultimatescience.org

Dams in themselves are engineering and construction marvels that use the flow of water predominantly for irrigation and generating hydroelectricity. The Three Gorges Dam in China is by far the largest hydroelectric plant on earth but it’s not without controversy. While it certainly looks like an engineering masterpiece, there are a few things you may not have known. We take a look at the good, the bad and the ugly truth behind this man-made marvel.

Building The Three Gorges Dam

The concept behind this giant dam traces back to Sun Yat-sen during The International Development of China, in 1919. However, construction of the dam only began in 1994 when The National People’s Congress signed off on the project.  

To give an idea of how just how big this engineering project was, they required 16 million cubic meters of concrete and used 510,000 tons of steel which is enough to build 63 Eiffel Towers. The dam is 1,4 miles long and 607 ft (+-180 m) above sea level. They installed 34 massive generators, each weighing 6,000 tons and produce a total energy capacity of 22,500 MW. That is enough power to provide electricity to 60 million Chinese people. Did you know that The Three Gorges dam generates 11 times more power than the Hoover Dam?

It took a total of 40,000 workers 12 years to build this massive dam and while the actual cost is unknown, estimates are anywhere between $28 and $88 billion. The Three Gorges Dam is a shining light for renewable energy as it replaces burning nearly 30 million tons of coal annually. In terms of crude oil, that equates to 25 million tons. These statistics alone are cause for celebration and justification for the Chinese people and government considering it an engineering masterpiece.

Engineering To The Extreme

While The Three Gorges Dam has attracted negative attention, there are also some really positive benefits. It was essentially made with three main purposes in mind, i.e. flood control, hydroelectric power production and navigation improvement.

The dam solves one big problem which is keeping the river at bay during flooding season. It helps protect millions of people downstream including important cities adjacent to the Yangtze such as Wuhan, Nanjing, and Shanghai. The reservoir that the dam creates measures an area of around 405 square miles which is pretty impressive.

Adding to the engineering prowess, The Three Gorges Dam also has ship lifts and locks to manage all the shipping vessels that use the Yangtze River. Normal cargo goes through the ship locks while passenger ships use the lifts where the journey takes 36 minutes. This is what it looks like when a ship uses the lift to pass through.

The Three Gorges Dam Controversies

While the Three Gorges Dam may offer there are several benefits, it’s been riddled with controversy and delays since they announced the construction in 1994. They originally stated that the project would be completed in 2008 but progress was slow and even stopped at times. This was as a result of overwhelming costs, environmental concerns, political corruption and resettlement issues.

Environmental Concerns

One of the biggest concerns is undoubtedly the environmental damage of the Three Gorges Dam. Statistics show that 70% of China’s freshwater is polluted and that the dam could well make it much worse. The fact that the dam is located on top of old waste facilities and mining operation certainly doesn’t help. Another shocking number is the 265 million gallons of raw sewage that goes into the Yangtze River every year.

The sheer size of the dam has actually created a micro-climate that has threatened the region’s ecosystem. Areas surrounding the Three Gorges Dam are home to many plant, insect, fish and vertebrate species that have all been affected. While engineering teams have found a way to pass some of the sediment through the dam, they estimate that 30-60% still remains trapped.

Continued erosion of the reservoir has resulted in numerous landslides. In fact, one of them actually caused another nearby hydroelectric dam to crumble. The landslides have also threatened one of the world’s largest fisheries in the East China Sea. Because the reservoir is located on top of two fault lines, many believe it is responsible for increased seismic activity.

Is The Three Gorges Dam Slowing The Earth’s Rotation?

If you don’t yet comprehend the sheer size of the dam and how it could possibly affect the Earth’s rotation, maybe this will help. When the dam reaches maximum level, the reservoir can hold 42 billion tons of water or 9 trillion kilograms. The rumours about China affecting the Earth’s rotation is not science-fiction, its physics.

The secret behind this phenomenon is called inertia and occurs as a result of Newton’s First Law Of Motion. According to NASA scientist, a shift in mass that size does affect the Earth. Raising 42 billion tons of water 180 meters above sea level increases the Earth’s moment of inertia which slows its rotation. It increases the length of a day by 0.06 microseconds while shifting the pole position by about 2 cm (0.8 inch). Watch this video to learn more interesting facts.

While it’s nearly impossible to predict the long-term engineereffect, there may be a bigger risk due to seismic activity. If the dam fails because of a massive earthquake or weakening the structure in another way, the resulting flood would be devastating. A flood on such a scale has never been recorded and we hope it never will.

What do you think of The Three Gorges Dam? Is it an engineering masterpiece or a disaster waiting to happen? Please comment in the section below or find us on social media. Follow our weekly blog posts for more interesting articles and get in touch if you need help with your engineering, manufacturing, fabrication or construction project.