The Yangtze or Yangzi (in Chinese Chang Jiang) is the longest river in China and Asia, 6,380 km for some, (6,418 for others) , and collects the waters of a basin of over 1.8 million km2, all in Chinese territory.
According to some, the Yangtze River is shorter (about 5,800 km or only 5,200). As with other large rivers, its length is disputed: it all depends on which branch is considered to be the main one. According to the length, the Chang Jiang would be the third or fourth river on Earth. It originates in northeastern Tibet, from the glaciers of the Tanggula Mountains, at about 4,800 m above sea level.
The name Chang Jiang or Yang Tze Kiang originates from an ancient kingdom of Yang, which had Yang-chow as its capital. The etymology given by M. Martini “son of the ocean” from yang “ocean” and tze “son” would therefore be incorrect.
The name Yangzi was originally used by the local people of the delta for one of its main branches; later it was used to indicate the whole river, since this was the first name heard by the first Westerners.
Geographic Features –
The Yangtze River originates from various tributaries, among which the two most important are those of the Tuotuo River and the Dan Qu River. The 2,300-kilometer-long upper section of the river, which runs from Yushu in Qinghai Province to Yibin in Sichuan, is called the Jinsha (or “Golden Sands River”). On its way to the sea, the river passes from an elevation of about 4,900 meters to 305 meters in Yibin, Sichuan, and then passes 192 meters in Chongqing. From Chongqing to Yichang, it passes at an altitude of 40m after crossing a 320km route, which includes the spectacular Yangtze River gorges.
As it flows through the Sichuan Basin, the river collects the waters of numerous rivers, significantly increasing its flow rate. It breaks at Wushan Mountain on the border between Chongqing and Hubei, where the famous three gorges of the Yangtze River form. Entering the province of Hubei, the river receives the waters of the lakes in the region, among which the largest lake is Lake Dongting, which forms the border between the provinces of Hunan and Hubei. In Wuhan the Yangtze River receives its largest tributary, the Han River, which carries the distant waters of Shanxi. The river receives further load from Poyang Lake and countless small rivers as it passes through Anhui and Jiangsu, finally ending its course in the East China Sea through Shanghai.
Furthermore, as it crosses regions inhabited by populations speaking different languages on its long journey, it also changes its name several times; in the initial section, for example, he is referred to by the Tibetan name of Dre Chu.
The course of the river is very tortuous, with frequent turns. Descending from the Tibetan plateau, it follows a north-easterly direction, then turns southeast and then south, and takes Chinese names: Tongtian, Jinsha Jiang. In this stretch, the river runs through a very deep valley, which has not been dug by the erosion produced by the river, but is a fissure caused by movements of the earth’s crust (a fault); other major rivers run parallel to the Chang Jiang, at the bottom of other fault lines: the Saluen, which flows into Burma (whose official name is Myanmar), and the Mekong, which runs through Indochina to the southern tip of Vietnam.
Historical Notes –
Since prehistoric times, the Yangtze has played a very important role in the development of the civilizations it crosses and their productive activities, first of all agriculture, determining a fundamental role as regards the cultural origins of southern China. It has been discovered that human activities have existed around the area of the present Three Gorges Dam for as many as twenty-seven millennia, thus contributing to a great debate regarding the origins of the Chinese people.
In the Spring and Autumn Period, there were the states of Ba and Shu along the west bank of the river, in Sichuan, present-day Chongqing and western Hubei; the State of Chu stood in the middle of the course, more or less covering the area of Hubei, Hunan, Jiangxi, and southern Anhui. The Wu and Yue states lay east of the river in present-day Jiangsu, Zhejiang, and Shanghai. Even though the Yellow River region was richer and more prosperous at the time, the milder climate and more peaceful environment made the Yangtze River area more suitable for agriculture.
Since the Han Dynasty, the Yangtze River region has become increasingly important to China’s economy. The construction of irrigation systems (the most famous is the Dujiangyan, northwest of Chengdu, made during the Warring States period) made agriculture very stable and productive. Early in the Qing Dynasty, products from the region called Jiangnan (which includes southern Jiangsu, northern Zhejiang, southeast Anhui) made up one-third of the national total.
In history, the Yangtze River has repeatedly become the political border between North and South China due to the difficulty of crossing it. Many battles took place near the river, the most famous being the Battle of Red Cliffs, in AD 208, during the Three Kingdoms period.
Nanjing has served as a capital several times, although most often its authority only covered parts of southern China, such as during the Wu Kingdom in the Three Kingdoms period, the Jin dynasty, and smaller states in the Northern and Southern dynasties periods. South and the Five Dynasties and Ten Kingdoms. Only the Ming dynasty occupied large parts of China from the capital Nanjing, although it later moved the capital to Beijing. The capital of the Republic of China was Nanjing from 1911 to 1912, from 1927 to 1937 and finally from 1945 to 1949.
Furthermore, the importance of this river has always been linked to the importance of its long navigability which is 2,800 km, even by large boats. It is then connected to many canals: among these, the ancient Imperial Canal (1,700 km) starts from Beijing, crosses the Yellow River and the Chang Jiang and reaches the city of Hangzhou to the south. The navigable network connected to the Yangtze extends over 40,000 km.
Part of the canals is also used for irrigation and to divert water from the river during the summer floods, so as to avoid flooding, which has been frequent and terrible in the lower course.
The Yangtze River, as mentioned, is an important physical and cultural dividing line between North and South China. The Chinese living north of the Yangtze speak several dialects of Mandarin. Most of the provinces south of the river have their own languages that are incomprehensible to Mandarin speakers.
The Yangtze River passes through a diverse range of ecosystems and is itself home to numerous endemic and threatened species including the Yangtze River Dolphin (now extinct), Chinese alligator, and Yangtze sturgeon. For thousands of years man has used the river for water, irrigation, sanitation, transportation, industry, boundary-marking and warfare. The Three Gorges Dam on the Yangtze River is the largest hydroelectric station in the world.
The Yangtze River flows into the East China Sea and was navigable by oceangoing vessels up to a thousand miles from its mouth even before the construction of the Three Gorges Dam. Since June 2003, China has started building the Three Gorges Dam on the river, and this is the largest complete irrigation project in the world and has a great impact on China’s agriculture. This dam crosses the river, flooding Fengjie, the first of a series of cities affected by mass flow control and generation project. Its proponents say it will free people living along the river from floods that have repeatedly threatened them in the past, and offer them transportation electricity and water, albeit causing large-scale changes in the local ecology.
The Yangtze River is lined with metallurgical, energy, chemical, auto, building materials and industrial machinery belts and high-tech development zones. It is playing an increasingly decisive role in the economic growth of the river valley and has become a vital link for international shipping to the interior provinces. The river is a major transportation artery in China, connecting the interior with the coast. And it is one of the busiest waterways in the world. Traffic includes commercial goods such as coal as well as manufactured goods and passengers. Cargo transport reached 795 million tons in 2005. River cruises over several days, particularly through the beautiful and scenic Three Gorges area, are becoming more frequent.
The interference of all these activities puts at serious risk this eco region which is bounded to the south and west by the hills that surround the plain of the lower Yangtze River and to the north by a low watershed that marks the boundary of the plain of the Huang He ( or Yellow River).
Many areas have lost their original subtropical forest cover for thousands of years. Currently, the most important areas from a conservation point of view are wetlands and aquatic habitats. Vast shallow lakes such as Poyang and Dongting are home to many rare and endemic aquatic vertebrates and a large number of aquatic birds, some of which are critically endangered.
The hydrology of Poyang Lake is characteristic. Its dimensions are variable and the level of its waters varies by as much as 11 m between the wet and dry seasons, as in summer, during the wet season, it fills up with the waters transported by the Chiang Jiang, which then, during the winter, slowly flow back into the river. However, this hydrological peculiarity risks being compromised after the construction of the Three Gorges dam.
The size and depth of Dongting Lake also varies according to the season. In summer its surface increases from 3700 to more than 13,000 km² and its depth increases by more than 10 m. This area, surrounded by some of China’s most productive rice paddies, has been heavily modified by man since prehistoric times.
The Chang Jiang Lowland Evergreen Forests is an ecoregion of the Palearctic ecozone extending into southern China.
In the past, extensive forests of evergreen phagaceae (Cyclobalanopsis spp., Castanopsis spp.), associated with lauraceae (Phoebe spp., Cinnamomum spp., Persea spp.), and other tropical forest taxa grew on these alluvial plains and low hills . Reed marshes surrounded the seasonally inundated lake basins. Today some areas still retain their original appearance, but most of the territory has been converted into rice fields.
In hilly areas such as the Dabie Shan, mixed forests of conifers (Pinus massoniana, Cunninghamia lanceolata) and deciduous hardwoods such as birches (Betula spp.) and maples (Acer spp.) once grew. Today most of these areas are covered in scrubland.
The Yangtze River has been one of the areas on the planet most anciently tampered with by human activity.
For this reason, the fauna has also been affected by this long interference and seasonal variations.
Among the mammals best adapted to the seasonal variations of flood and ebb of the Chiang Jiang is the marsh deer (Hydropotes inermis), which swims to higher areas before the onset of the rainy season. The otter (Lutra lutra) also inhabits waterways.
Among the rarest birds of this ecoregion is the Siberian crane (Grus leucogeranus), of which 3,000 specimens winter in Lake Poyang, the largest lake in China. This number is roughly equal to 98% of the entire world population. Other rare and endangered water birds that visit Poyang Lake are the eastern stork (Ciconia boyciana), swan goose (Anser cygnoides), and white-necked crane (Grus vipio). Apart from these, numerous congregations of other migratory waterfowl also use Poyang Lake as their wintering site.
Other rare aquatic creatures present here are the lipote (Lipotes vexillifer), present in the vicinity of Lake Poyang and perhaps already extinct, fish such as the Chinese sturgeon (Acipenser sinensis) and the Chinese paddlefish (Psephurus gladius), the Chinese alligator (Alligator sinensis) and the giant salamander (Andrias davidianus).
Environmental Protection Actions –
The fertile river delta areas generate about 20% of the gross domestic product of the People’s Republic of China. It crosses a wide range of ecosystems and is home to several species of protected animals. For thousands of years man has used the river for water, irrigation, sanitation, transportation, industry, borders and warfare.
Unfortunately, over the millennia, and especially in recent times, the forests have been almost completely destroyed and replaced by rice paddies, coniferous plantations and shrubby vegetation. The aquatic environments have been converted into rice paddies and fish farms. Some conservation measures have been implemented at Poyang and some other large and shallow freshwater lakes, but their enforcement is difficult. The Three Gorges Dam is the largest dam project ever. It has helped reduce downstream flood damage and generate hydroelectric power, but it has also irreparably altered the hydrological cycles critical to the ecology of lakes such as Poyang and Dongting.
Thus the river has suffered very serious environmental damage, due to the exploitation of agriculture, discharges from industry and adjacent cities, and has suffered the loss of numerous lakes, tributaries and adjacent marshes. Many segments of the river are protected nowadays, and the part of the river that passes through Yunnan (Three Parallel Rivers Protected Area) is part of the UNESCO cultural heritage.