When finished in 2009, the Three Gorges Dam on the Chang Jiang (Yangtze River) will be the largest dam in the world. Spanning 1.2 mi (2.0 km), and standing 600 ft (175 m) above normal river level, the dam will create a reservoir more than 400 mi (644 km) long. The project was designed to control floods, ease navigation, and provide badly needed electricity for China's heartland. The 26 giant turbines in the dam's powerhouse are expected to generate 18,200 megawatts of electricity—equal to 10% of the country's current supply—to support industrialization and modernization in the region. The reservoir will flood the scenic Three Gorges, one of China's most historically significant areas. It also will displace at least 1.3 million people and will flood 150 towns and cities, and more than 1,300 villages.

Proponents of the project argue that China needs the project's electricity for modernization. With dangerous rapids drowned under the reservoir, ocean-going ships...