China abounds in rivers. More than 1,500 rivers each drain 1,000 sq km or larger areas. Most of the large rivers have their source on the Qinghai-Tibet Plateau, and drop greatly between source and mouth. As a result, China is rich in water-power resources, leading the world in hydropower potential, with reserves of 680 million kw.
China's rivers can be categorized as exterior and interior systems. The catchment area of the exterior rivers that empty into the oceans accounts for 64 percent of the country's total land area. The Yangtze, Yellow, Heilong, Pearl, Liaohe, Haihe and Huaihe rivers flow east, and empty into the Pacific Ocean. The Yarlungzangbo River in Tibet, which flows first east and then south into the Indian Ocean, boasts the Yarlungzangbo Grand Canyon, the largest canyon in the world, 504.6 km long and 6,009 m deep. The Ertix River flows north from the Xinjiang Uygur Autonomous Region to the Arctic Ocean. The catchment area of the interior rivers that flow into inland lakes or disappear into deserts or salt marshes makes up about 36 percent of China's total land area. Its 2,179 km make the Tarim River in southern Xinjiang China's longest interior river.
The Yangtze, 6,300 km long, is the largest river in China, and the third largest in the world, next only to the Nile in Africa and the Amazon in South America. Passing through high mountains and deep valleys, the upper section of the Yangtze River is abundant in water resources. Known as the "golden waterway," the Yangtze is a transportation artery linking west and east, its navigation benefiting from excellent natural channels. The middle and lower Yangtze River areas have a warm and humid climate, plentiful rainfall and fertile soil, making them important agricultural regions. The Yellow River is the second largest river in China with a length of 5,464 km. The Yellow River valley was one of the birthplaces of ancient Chinese civilization. It has lush pasturelands along its banks, flourishing agriculture and abundant mineral deposits. The Heilong River is a large river in north China with a total length of 4,350 km, of which, 3,101 km are in China. The Pearl River (Zhujiang), 2,214 km long, is a large river in south China. In addition to those bestowed by nature, China has a famous man-made river - the Grand Canal, running from Beijing in the north to Hangzhou in Zhejiang Province in the south. Work first began on the Grand Canal as early as in the fifth century A.D. It links five major rivers: the Haihe, Yellow, Huaihe, Yangtze and Qiantang. With a total length of 1,801 km, the Grand Canal is the longest as well as the oldest man-made waterway in the world.
China's territory includes numerous lakes, most of which are found on the Middle-Lower Yangtze Plain and the Qinghai-Tibet Plateau. Freshwater lakes such as Poyang, Dongting, Taihu, and Hongze mostly lie in the former area, while in the latter are saltwater lakes, such as Qinghai, Nam Co and Siling Co. Poyang Lake, in the north of Jiangxi Province and with an area of 3,583 sq km, is the largest of its kind. Qinghai Lake, in northeast Qinghai Province and with an area of 4,583 sq km, is the largest one of its kind.