Freshwater ecosystems are of massive importance to China, and a huge percentage of the population is directly dependent on wetlands - marshes, rivers, and lakes - for economic production, flood control and, somewhat obviously, drinking water.

Seven of the most important rivers in the world begin in the highlands of western China. The Yellow River, Yangzi River, Lancang Jiang (Mekong) and the Salween rise in the east of the Qinghai-Tibet plateau. The Indus, Ganges and Brahmaputra rise in the south. Downstream these rivers serve as sources of irrigation and drinking water, modes of transport and centres of cultural and religious importance for probably two billion people in China, India, Pakistan, Bangladesh and throughout Southeast Asia. These rivers rise and gather strength from many of the thousands of freshwater lakes of the region. The black-necked crane breeds in marshland in Tibet and western Sichuan and winters in southeast Tibet, Bhutan, northern Yunnan and by western Guizhou. The bar-headed goose also breeds here.

China's northeast is the focus for much of the country's freshwater marshes . Two million hectares on the Sanjiang Plain of Heilongjiang Province are essentially a collection of shallow freshwater lakes and reed-beds where the Heilongjiang, Sungari and Wusuli rivers come together. Jilin, Liaoning and Inner Mongolia all share these ecosystems. One of the most well-known wildlife areas in this ecosystem is Zhalong Nature Reserve , a 2,000-square-kilometre area which was created in 1979 to protect breeding areas for the red-crowned crane, and other wintering migrants. These marshes are also of great value for reed production, the bulk of which is turned into pulp for paper. Waterfowl and reed production can usually coexist, at least at present levels, so this is a useful confluence of conservation and economic uses.

China's freshwater lakes include the country's best-known wetlands: Jiangxi's Poyang Hu and Hunan's Dongting Hu. Dongting Hu , China's second largest fresh-water lake, is vitally important for wildlife, including the highly endangered Yangzi river dolphin and Chinese sturgeon, as well as more wintering wildfowl. Current threats include increasing siltation and land reclamation , which have caused the lake to shrink to almost half its size since 1949, as well as water pollution from nearby Yueyang city. Poyang Hu is a similar complex of small lakes and marsh areas which fluctuate seasonally; summer floods cede to fertile agricultural land being exposed in autumn, attractive both to farmers and visitng birds. In recent years, however, some of Poyang's larger lakes have also been drained at the end of autumn, leaving waterfowl with inadequate shallow land on which to feed. The importance of Poyang Hu is hard to overstate, as the lake provides wintering habitat for almost the entire world population of two hundred Siberian cranes , and as many as five hundred thousand birds may be on Poyang Hu at any one time during the winter months.