The longest river of Asia is the Yangtze, with a length of 3,915 miles (6,300 kilometers). It is also the third longest river in the world after the Nile and the Amazon. The Yangtze rises in the Kunlun Mountains of Tibet in western China and flows into the East China Sea near Shanghai in east-central China.

Physical features

More than three-quarters of the Yangtze's course runs through mountains. In its upper course the river descends through snowcapped mountains. In its middle course a number of tributaries join the Yangtze. It gains force and descends steeply through the Sichuan province. The current in this section is swift, banks are steep, and soil is fertile. Leaving Sichuan, the Yangtze enters the Three Gorges, a stretch of about 125 miles (200 kilometers). These canyons are narrow and rocky with dangers for ships. In its lower course the Yangtze flows through extensive lowland plains. Before the river flows into the sea, it forms a delta known as the Yangtze Delta with a number of tributaries, lakes, and marshes.

The eight major tributaries of the Yangtze River are the Yalong, Min, Jialing, Han, Wu, Yuan, Xiang, and Gan rivers. Major lakes include Dongting, Poyang, and Tai.

People

The Yangtze River basin is one of the longest-inhabited regions in China. It contains a significant portion of China's population, but distribution is uneven. The highland area of the river's upper course is one of the most thinly populated regions in China. The Yangtze Delta has the country's highest concentration of population.

The upper course of the river basin is populated with Tibetan, Chinese, and other ethnic groups. They combine farming, herding, and hunting for a livelihood. The population of the middle and lower basins has a larger concentration of Chinese people. Some national minorities live in the middle basin.

Economy

The Yangtze basin is China's granary. It contributes almost half of China's crop production, including two thirds of its rice crop. The other crops grown include cotton, wheat, barley, corn (maize), beans, and hemp. The mild climate also facilitates sericulture, the production of raw silk by raising silkworms.

The Yangtze River and its tributaries and lakes are abundant in fish. Fishing is the livelihood of many of the people of the region. Carp, bream, Chinese perch, lamprey, flatfish, and sturgeon are among the catch.

Mineral resources in the region include reserves of iron ore near Wu-han and Nanking. Deposits of coal, copper, phosphorus, gold, oil, and natural gas are found in the Szechwan province.

The lower basin and the delta are among the most economically developed areas in the country. Shanghai, Wu-han, and Chungking are among China's most important industrial centers. The river has great possibility as a source of hydroelectricy, or waterpower.

Transportation

The Yangtze is the leading navigable waterway of China. It has been an important traffic route since the 13th century, when Marco Polo, the Italian traveler, visited China. The river connects the inland and coastal ports with major cities such as Nanking, Wu-han, and Chungking. Large ships, powered vessels, and sailboats are used for transport. The Yangtze is joined by the Grand Canal to navigable stretches of the Huang Ho, Huai, Wei, and Hai rivers. The canal is further linked with the seaports of Hang-chou and Tientsin. Railroad bridges have been built across the Yangtze at Wu-han, Chungking, Nanking, and other cities, improving north-south transport links.

Environmental issues

On average, the Yangtze basin is the scene of disastrous flooding every 50 to 55 years. The monsoon rains in the summer months cause extensive flooding in the river and its tributaries. The floods are particularly destructive when the main channel and one or more of the major tributaries are flooded in the same period. The floods of 1931 and 1954 were national disasters. Effective flood-control measures developed since the 1930s, however, have averted many of the possible consequences of flooding.

The Three Gorges Dam began operation in 1994. The dam is located west of Yichang and allows freighters to navigate 1,400 miles (2,250 kilometers) inland from the East China Sea to Chungking. Environmentalists are against the dam. It has displaced thousands of people and has destroyed the habitat of aquatic animals.