The Impact and Controversies of China's Three Gorges Dam

China's Three Gorges Dam, a monumental feat of engineering, is located in Hubei province and spans the Yangtze River, the longest river in Eurasia. Construction of this massive hydroelectric project began in 1994 and took nearly a decade, culminating in a total expenditure estimated at £29 billion. Standing at 181 meters high and 2,335 meters long, it holds an impressive 27.2 million cubic meters of water and boasts a maximum power capacity of 22,500 megawatts, supporting the energy needs of approximately 5.4 million households for a month when at full capacity.

The dam's construction coincided with scientific investigations prompted by the devastating 2004 Boxing Day earthquake and tsunami, which initiated research into how significant geological shifts could influence the Earth's rotation. Changes in mass distribution due to tectonic plate movements were found to affect the Earth's "Moment of Inertia," leading to a reduction in the length of a day by 2.68 microseconds. A NASA geophysicist, Dr. Benjamin Fong Chao, indicated that the mass relocation caused by filling the Three Gorges Dam could similarly lengthen days by 0.06 microseconds and shift the Earth's poles by around two centimeters. Although these changes are marginal in everyday life, they could complicate high-precision timekeeping, prompting discussions among scientists about implementing a negative leap second in the near future.

The dam's construction was not without considerable social cost, as it necessitated the relocation of roughly 1.3 million people whose homes were submerged. Besides electrification, the dam aims to enhance shipping on the Yangtze River and decrease flood risks downstream through its flood storage capabilities. The Chinese government heralds the dam as a historic success in engineering and environmental policy, highlighting the use of advanced turbines and a commitment to reducing greenhouse gas emissions. Nonetheless, the project has drawn criticism for flooding irreplaceable archaeological and cultural locations while also contributing to environmental degradation and heightening landslide risks. The extensive construction used an unprecedented 27.2 million cubic meters of concrete and 463,000 tonnes of steel, comparable to the materials required to build 63 Eiffel Towers, while displacing more than 102.6 million cubic meters of earth.