Three Gorges Dam: Critics, Praises and Facts

 

Critics, Praises and Facts on The Three Gorges Dam

The Yangtze River in China has a long history of destructive floods, and there was a need to find a renewable energy source and address the river's negative effects. A project called the Three Gorges Dam (TGD) was proposed to solve these issues. The TGD is a massive hydroelectric gravity dam located in Sandouping, Yiling District, Yichang, Hubei Province, Central China. It is the world's largest power station in terms of installed capacity and holds several other world records. The dam has been a source of pride for civil engineers worldwide. Additionally, there are other remarkable parts of the project, such as ship lifting and locking, which have impressed people around the world.

The Three Gorges Dam (TGD) project fulfilled the energy needs of many Chinese people, generating 22,500 MW of electricity through 34 generators. In 2020, it produced a total of 111.8 TWh of electricity. Despite being located near six fault lines, the dam is designed to withstand earthquakes up to a magnitude of 7.0. The project cost around 203 billion renminbi (31.765 billion dollars) and used 27.2 million m3 of concrete, 463,000 tonnes of steel, and moved about 102.6 million m3 of earth. The dam is 185 meters high, 2,335 meters long, with a top width of 18 meters and a base width of 124 meters. The reservoir created by the dam covers an area of 1,045 km2, with a volume of 39.3 km3. The reservoir also flooded an area of 632 km2. The ship lock system allows vessels up to 10,000 tonnes to pass through the dam, with each lock measuring 280 meters in length, 35 meters in width, and 5 meters in depth. It takes 2.5 to 3 hours to transit through a sequence of five locks. Alternatively, the ship elevator can transport vessels up to 3,000 tonnes over the dam in just 30 to 40 minutes.

Five Stages Ship Lock

TGD has had both positive and negative impacts on the environment and society, owing to its massive scale. It submerged several cities, towns, villages, factories, and farmland upon completion, displacing 1.24 million residents. Numerous cultural heritage sites and historical monuments were also lost, although some were preserved. The dam's construction triggered landslides, seismic activities, and the reactivation of old faults. It poses a threat to various endangered species such as the Chinese Paddlefish, Siberian Crane, and Chinese River Dolphin. The dam has also led to a decline in water quality due to the accumulation of reserved water, toxic materials, and human activities, necessitating the need for sewage treatment plants. Concerns have been raised about the dam's vulnerability as a target during times of conflict or protests. 

Despite these challenges, the TGD has brought positive changes. The relocation of residents to safer areas has ensured their safety, while the dam's flood control measures have saved countless lives. Improved navigation benefits the people, and downstream cities and farms now enjoy an additional 11 km3 of freshwater supply, even during the dry season. 

Dam had a significant positive impact on China's economy, surpassing expectations in several areas. The project achieved full cost recovery earlier than anticipated, by December 2013. Additionally, the dam brought increased fame to the Yangtze River, attracting a large number of tourists. It was estimated that, in the initial years after completion, around 13 million visitors would travel to the TGD annually, generating approximately 242 million in revenue each year. Other activities such as fishing, boating, and additional tourism in the TGD area further contributed to economic benefits. The sale of electricity generated by the dam also proved to be profitable. 

The Gigantic structure has had some interesting effects on the Earth. It has caused a very tiny slowdown in the Earth's rotation, increasing the length of a day by 0.06 microseconds. However, NASA has stated that this has a minimal impact since it is an incredibly small change. The Earth's rotation speed can fluctuate due to various factors like the moon, earthquakes, and movements of the North Pole caused by climate change. Additionally, the TGD has slightly altered the shape of the Earth, making it a bit rounder in the middle and flatter at the poles. It has also caused a shift in the Earth's pole position by about 2 centimeters. These changes are a result of the massive amount of water, approximately 39 trillion kilograms, that has been raised to a height of 175 meters above sea level in the TGD project. This displacement of water has increased the Earth's moment of inertia, affecting its rotation. 

Dam raises intriguing questions about the future. What if many countries build massive dams like the TGD? Could it further slow the Earth's rotation, lengthening our days beyond 24 hours? Some might even consider constructing more dams to extend the workday and fit in more tasks. Engineers would need to calculate the limits of such dams to prevent significant effects on Earth's rotation. Perhaps we should focus on finding better alternatives to energy sources instead of altering nature with more dams. The benefits of these dams compared to natural rivers remain open to debate. The future holds uncertainties, and exploring sustainable practices and innovative solutions is crucial. Only time will reveal the answers to these intriguing possibilities.

-Rajan Kumar Sah