The River Today
Today, the Yangtze River provides for the water needs of one-third of China’s population. Modern irrigation systems supply billions of gallons of water so that farmers can grow food and other crops year-round. The river provides people with fish to eat and water to drink. The Yangtze’s Three Gorges Dam also provides hydroelectricity to the people of central and eastern China.
But increased economic development and a growing population threaten the future of the river and the land around it.
Deforestation in the Basin
One of the most serious problems in China is the destruction of forests. Land is cleared for agriculture, which wipes out the habitats of thousands of plant and animal species that live in the Yangtze River basin. Deforestation also contributes to flooding and erosion, or the gradual wearing away of soil by wind and water. Flooding occurs because clearing forests dramatically increases the surface runoff from rainfall. Without tree roots to anchor soil, the soil washes away into rivers and streams. Some experts say that as much as 40 percent of the Yangtze basin area has soil erosion problems.
Water and Air Pollution
The Yangtze River is polluted with untreated sewage and industrial waste. Chemicals used to kill pests on farmland enter the river in surface-water runoff.
Air pollution in the river basin is also a serious problem. Coal is burned to produce about three-quarters of China’s electricity. But the process of burning coal releases carbon dioxide and other gases into the air. These gases build up in Earth’s atmosphere and trap more of the Sun’s heat close to Earth’s surface. The trapped heat speeds up the rate of climate change. Other gases released during the burning of coal combine with moisture in the atmosphere, forming acid rain. When acid rain falls to Earth, it harms crops, forests, and waterways.
LEFT: People cross polluted water from the Yangtze River in Chongqing. The river is threatened by pollution from many sources, including discharge from about 10,000 chemical factories along its banks.
Impact of the Three Gorges Dam
Harnessing the force of the Yangtze River to create hydroelectricity is a clean solution to China’s increasing power demands. However, many scientists and other observers say that the environmental effects of the Three Gorges Dam are serious. Hundreds of factories, mines, and waste dumps were covered with water when the reservoir was created. Those submerged sites, along with huge industrial centers upstream, are creating pollution problems in the reservoir. Erosion of the steep hills around the reservoir is
Areas of grassland in China are becoming desert. Overgrazing by livestock strips the land of vegetation, and winds blow away the topsoil causing landslides. Erosion of downstream riverbanks threatens one of the world’s biggest fisheries in the East China Sea.
The Silt Situation
Before huge dams were built along the Yangtze River, the river carried hundreds of millions of tons of silt in the flow of its water. When the river flooded, silt nourished the lands along the riverbanks, making them fertile and productive. Where the river is dammed, silt collects at the bottom of reservoirs. This process is called siltation. The silt no longer reaches the Yangtze River’s floodplain.