Chinese (Wade-Giles) Ch'ang Chiang, or (Pinyin) Chang Jiang, longest river in both China and Asia and the third longest river in the world, with a length of 3,915 miles (6,300 kilometres). Its basin, extending for some 2,000 miles from west to east and for more than 600 miles from north to south, drains an area of 698,265 square miles (1,808,500 square kilometres). From its source on the Plateau of Tibet to its mouth on the East China Sea, the river traverses or serves as the border between 10 provinces or regions. More than three-fourths of the river's course runs through mountains. The Yangtze has eight principal tributaries. On its left bank, from source to mouth, these are the Ya-lung, Min, Chia-ling, and Han rivers, while on the right bank are the Wu, Yüan, Hsiang, and Kan rivers.
The name Yangtze—derived from the name of the ancient fiefdom of Yang—has been applied to the river mainly by Europeans. Ch'ang Chiang (「Long River」) is the name used in China, although it also is called Ta Chiang (「Great River」) or, simply, Chiang (「The River」). The Yangtze is the most important river of China. It is the country's principal waterway, and its basin is China's great granaryand contains nearly one-third of the national population.
The upper course
The upper course of the Yangtze flows across the Plateau of Tibet and descends through deep valleys in the mountains east of the plateau, emerging onto the Yunnan-Kweichou (Yunkwei) Plateau. The summers are warm and the winters cold. The source of the Yangtze is the Wu-lan-mu-lun (Ulan Muren) River, which originates in glacial meltwaters on the slopes of the T'ang-ku-la Mountains in southern Tsinghai province on the border with the Tibet Autonomous Region. From the confluence of this stream with several others, the river flows generally easterly through a shallow, spacious valley, the bottom of which is studded with lakes and small reservoirs. This part of its course lies in the higher regions of the Tibetan highlands.
The river's character changes sharply upon reaching the eastern limits of the highlands. There the river—which in this stretch is called the Chin-sha—descends from a great altitude, winding its way southof the high Pa-yen-k'a-la Mountains and forming a narrow valley between one and two miles in depth. Individual mountain peaks exceed elevations of 16,000 feet (4,900 metres) above sea level and are crowned with glaciers and perpetual snow. The steep, rocky slopes are cut with gorges and deep valleys.For several hundred miles the Yangtze flows in a southeasterly direction, before turning south to flow downward in rushing rapids. For a considerable distance the river flows through passes that are so steep that no room is left even for a narrow path. Villages, which are rarely found, are located high above the river. In this region the Yangtze runs close and parallel to both the Mekong and Salween rivers;all three rivers are within 15 to 30 miles of one another and continue to flow in mutual proximity for a distance of more than 250 miles.
North of latitude 26° N these great rivers diverge, and the Yangtze turns east to pass through a winding valley with steep slopes. The river receives the waters of many tributaries, among which the Ya-lung River is the largest and contributes the most water. The Yangtze then widens to between 1,000 and 1,300 feet, reaching depths often exceeding 30 feet. In narrower gorges the water width decreases by almost half, but the depth increases sharply.
Near the end of the upstream part of its course, the Yangtze descends to an elevation of 1,000 feet above sea level. Thus, over the first 1,600 miles of its length, the river has fallen more than 17,000 feet, or an average of more than 10 feet per mile (2 metres per kilometre) of its course. In the mountains, however, there is a substantial stretch where the fall of the river is considerably greater.
The middle course
The middle course of the Yangtze stretches for about 630 miles between the cities of I-pin in Szechwan province and I-ch'ang in Hupeh province. The climate is characterized by hot summers and relatively mild winters, as the high mountains to the west protect the region from the cold north and west winds. Annual precipitation measures from 40 to 60 inches (1,000 to 1,500 millimetres), a large part of it occurring in summer; the growing season lasts for more than six months. In most of this segment, the river crosses hilly Szechwan province, where the lower mountains and plateaus connect the highlands of southwestern China with the Tsinling Mountains lying between the Yangtze and Huang Ho (Yellow River) basins. Located in this area is Chungking (Ch'ung-ch'ing), a major industrial centre and river port. The river's width there is from about 1,000 to 1,600 feet, and the depth in places exceeds 30 feet. The current is swift; the banks often are high and steep. The river falls some 820 feet in Szechwan province, more than a foot per mile of flow.
As the Yangtze flows through eastern Szechwan and into western Hupeh, it traverses, for a distance of 125 miles, the famous Three Gorges region before debouching onto the plains to the east. The gorges have steep, sheer slopes composed mainly of thick limestone rocks, rising from 1,300 to 2,000 feet above the river and presenting the appearance of fantastic towers, pillars, or spears. The first gorge—about 5 miles long—is the shortest, but it is considered the most dangerous for navigation; the river there is very narrow and contains many rapids and eddies. The second gorge, which stretches for about 30 miles, is a narrow, steep corridor with almost vertical walls of heights up to 1,600 or even 2,000 feet above the river. The last gorge is located upstream ofI-ch'ang and extends for a distance of 21 miles; in places limestone cliffs rise directly out of the water to heights of hundreds of feet. The gorges are rocky, and the walls are speckled with cracks, niches, and indentations. The river'swidth, some 1,600 to 2,000 feet between the gorges, narrows to about 500 to 600 feet within them. The depth in the gorges, however, also increases to between 500 and 600 feet, giving the Yangtze the greatest depths of any river in the world.
The lower course
The lower part of the Yangtze basin is centred on the extensive lowland plains of east-central China. The region experiences a temperate climate with warm springs, hot summers, cool autumns, and relatively cold winters for the latitude. Monsoons (seasonally changing winds) dominate the weather of the region, and in the summer and autumn typhoons occur periodically. As the Yangtze exits from the last gorge, near I-Ch'ang, it enters a complex system of lakes, marshes, and multiple river channels developed on the plains of Hunan and Hupeh provinces. This vast region, lying at elevations of less than 165 feet, has served as a natural flood-regulation basin in recent geologic history. Three main tributaries (the Yüan, Hsiang, and Han rivers) and many smaller ones join the Yangtze in this region, which also is where the current slows as the river reaches the plain. Water levels fluctuate considerably between the flood and low-flow seasons. In addition, the presence of a number of large lakes, including Lakes Tung-t'ing, Hung, and Liang-tzu, also causes considerable fluctuations in water volume. The total area of the lakes, at average water levels, is some 6,600 square miles (17,100 square kilometres). The lakes are of national economic significance, mainly as fisheries.
At the edge of the Lake Liang-tzu plain the Yangtze widens markedly, the course of its stream wandering in the form of a large loop. The width of the river is up to 2,600 feet, the depth is more than 100 feet, and the water current flows at a rate of 3 to 4 feet per second. The banks are built up for protection from floods. In the southern part of the plain lies Lake Tung-t'ing, which once was the largest freshwater lake in China but now has been reduced in area by silting and land reclamation; it shares four tributaries and two canals with the Yangtze, whose flow it serves to regulate. The surrounding area, agricultural and studded with lakes, is China's most important rice-producing region.
At the centre of the lakes region is the large metropolis of Wu-han. Situated on the Yangtze near the mouth of the Han River, it was formed in 1950 by the merger of the cities of Han-yang and Han-k'ou (Hankow) on the left bank and Wu-ch'ang on the right bank and has become one of China's most important metallurgical-industry centres and river ports. Farther east the Yangtze flows into a narrowing, picturesque valley and then passes onto the plain of Kiangsi province, which contains Lake P'o-yang, China's largest freshwater lake. The lake, with an average area of about 1,380 square miles, receives the Kan River tributary and, in turn, is linked to the Yangtze by a wide tributary. The river then turns to the northeast, passes through a widening valley, and flows out onto the southern North China Plain. The width of the river increases at this point to between 3,000 and 6,000 feet, and the depth in places approaches 100 feet. In this region there are a number of large cities, including An-ch'ing, Wu-hu, and Nanking (Nan-ching). The Grand Canal (Ta Yün-ho), which, with a length of nearly 1,100 miles, is one of the longest canals in the world, crosses the Yangtze in thevicinity of the city of Chen-chiang.
The Yangtze delta
The Yangtze delta, which begins beyond Chen-chiang, consists of a large number of branches, tributaries, lakes, ancient riverbeds, and marshes that are connected with the main channel. During major floods the delta area is completely submerged. Lake T'ai, with an area of about 950 square miles, is notable as the largest of the many lakes in the delta. The width of the Yangtze in the delta, as far as thecity of Chiang-yin, ranges from less than a mile to almost two miles; farther downstream the channel gradually widens and becomes a large estuary, the width of which exceeds 50 miles near the mouth of the river. Major cities in the delta include Wu-hsi, Su-chou (Soochow), and, at the river's mouth, Shanghai.
Before emptying into the sea, the Yangtze divides into two arms that drain independently into the East China Sea. The left branch has a width of from 3 to 6 miles, the right branch of from 6 to 15 miles. Between the branches is situated Ch'ung-ming Island, which was formed over the centuries by the deposit of alluvium at the mouth of the Yangtze. The depth of the river in places approaches 100 to 130 feet but decreases to several feet near the sea at the mouth of the river because of the presence of sandbars.
The section of river from the mouth to 250 miles upstream is subject to the influence of tides. The maximum range of the tides near the mouth is 13 to 15 feet.
The present bed of the Yangtze in this area is several yards above the plain. Thus, for protection of the surrounding region from floodwaters, the banks of the main and other rivers are built up; the total length of banks on the Yangtze on which levees have been constructed is about 1,700 miles. Dams also have been built for flood protection on the shores of several lakes; the Ch'ing-chiang Reservoir, for example, built for this purpose near Lake Tung-t'ing, has a capacity of 194 million cubic feet (5.5 million cubic metres). The delta is protected from the sea by two gigantic parallel banks that are faced with stone in most parts.
The Yangtze basin is comparatively well irrigated; the average yearly rainfall amounts to about 43 inches.Most of the precipitation is brought by the monsoon winds and falls primarily as rain in the summer months. In the mountainous part of the basin the precipitation is mainly snow. Floods, which result fromthe monsoon rains in the middle and lower parts of the basin, usually begin in March or April and can occur at any time during the next eight months. In May the water level decreases somewhat but then sharply increases again, continuing to rise until August, when it reaches its highest level. After that the water level gradually falls to the premonsoon levels, the decrease continuing through the autumn and most of the winter until February, when the lowest annual level is reached.
The annual range of water-level fluctuations is considerable—an average of about 65 feet—with 26 to 35 feet during years of low water. In the gorges the range of water levels caused by flooding reaches huge proportions —from 130 to 150 feet. Downstream the impact of the water-level variation is lessened by the regulating effect of the lakes. In the delta tides exert the greatest influence on the water level. Near the city of Wu-sung the daily tidal range is 15 feet, and the yearly range is 20 feet.
A breakdown of the water volume delivered to the mouth of the Yangtze shows that the highland part of the basin contributes 10 percent of the flow, while the remainder of the water in the river is contributed by the middle and downstream parts of the basin, with runoff from the basins of Lakes Tung-t'ing and P'o-yang being responsible for about 40 percent of the volume.
The Yangtze carries a tremendous volume of water. In the upstream areas the average flow exceeds 70,000 cubic feet (1,980 cubic metres) per second, which is more than the discharge rate of the second longest river in China, the Huang Ho, at its mouth. After the inflow from the first large tributary—the Ya-lung River—the volume in the Yangtze increases sharply, approaching an average of 194,000 cubic feet per second. Farther downstream the Yangtze admits many tributaries, and the volume gradually increases, reaching 529,000 cubic feet per second at the end of the Three Gorges area, 847,000 cubic feet per second at Wu-han, and some 1,100,000 cubic feet per second at its mouth. The total volume entering the sea annually is roughly 235 cubic miles (979 cubic kilometres), ranking it third in volume of flow behind the Amazon and Congo rivers.
During the seasonal rains the Yangtze widely floods the lower areas, and the maximum volume of water entering the sea can be more than double the average flow. During the dry season the flow decreases, sometimes to about one-fourth the average flow. In spite of the fact that the discharge volume of the Yangtze vastly exceeds that of the Huang Ho, the Yangtze is significantly less silty than the Huang Ho. This is because in the Yangtze basin the soil generally is secured by better vegetation cover. In the mountainous part of the basin, particularly in the Plateau of Tibet, the waters of the Yangtze contain little silt.
Downstream, however, the waters become muddy and acquire a coffee colour. It is estimated that the Yangtze annually carries between 280 million and 300 million tons of alluvium to its mouth, depositing an estimated 150 million to 200 million tons on the river bottom in addition. Thus, the total amount of suspended material carried or deposited is between 430 million and 500 million tons per year. As a result of the depositing of alluvium at the river's mouth, the delta extends into the sea an average of one mile every hundred years.
During the period of monsoon rains, the Yangtze and its tributaries spill over, creating extensive floods. If the floods in the main channel coincide with flooding in one or more of the major tributaries, powerful, destructive flood waves can result, an occurrence thathas happened repeatedly in the history of China.
The flooding frequently results from the deposit of silt in the bed of the Yangtze. Upon leaving the mountains and entering the plain, the current in the Yangtze sharply decreases, and thus the flow cannot continue to carry the entire amount of silt. As a result, a significant portion is deposited in the bed, causing the bottom to rise. A similar situation occurs in many of the Yangtze's tributaries. Flooding thus presents a great danger to the inhabitants of the adjacent plains.
Human adaptation to and utilization of the plains of the Yangtze valley have evolved in the context of such floods. Among the legends and myths handed down from protohistoric times are accounts of floods that submerged vast areas. These are said to have turned the plains into inland seas, with water remaining in the lowest places for many years at a time. Catastrophic floods have occurred throughout recorded history. During the period from 206 BC to AD 1960, China experienced more than 1,030 major floods. Especially extensive flooding has occurred on the Yangtze more than 50 times and on the tributary Han River more than 30 times. On the average, the Yangtze basin is the scene of catastrophic flooding every 50 to 55 years.
Widespread flooding also may take place at shorter intervals. This has been the case since the mid-19th century, as the Yangtze basin has flooded in 1870, 1896, 1931, 1949, and 1954. Of these, the 1931 and 1954 floods were national disasters. The 1931 flood resultedfrom heavy, continuous monsoon rains that covered most of the middle and lower parts of the basin. During May and June, six huge flood waves swept down the river, destroying the protecting dams and levees in 23 places and flooding more than 35,000 square milesof land; 40 million people were rendered homeless or otherwise suffered. Many population centres, including Nanking and the Wu-han conurbation, were underwater. In Wu-han the water remained for more than four months, the depth exceeding 6 feet and in places more than 20 feet. In the summer of 1954 another powerful flood occurred, again the result of continued monsoon rains. The water level sharply increased and at times exceeded the 1931 flood levels by almost 5 feet. Effective flood-control measures developed since the 1930s, however, averted many of the potential consequences of the flood.
The Yangtze basin contains a significant portion of China's population, but distribution is uneven. The highland area of the river's upper reaches is among the most sparsely settled regions in China, while the Yangtze delta has the country's highest population density. Outside the delta the greatest concentrations of people are in the plains that adjoin the banks of the river and its tributaries in the middle and lower basins, especially in the vicinity of the cities of Ch'eng-tu and Chungking, Wu-han, and Nanking. These cities are among the largest in China, and Shanghai is the country's most populous.
In the highlands of the upper basin, the population consists mainly of ethnic Tibetans engaged in traditional animal husbandry and the cultivation of such hardy grains as barley and rye. The population of the Yunnan-Kweichou Plateau is a mixture of Chinese (Han) agriculturalists and numerous ethnic minorities who combine some farming with herding and hunting. The population of the middle and lowerbasins becomes progressively more Chinese, although, especially in the middle basin, many other national minorities are represented.
The economy of the Yangtze basin is focused largely on agricultural production, although such cities as Shanghai, Wu-han, and Chungking are among China's most important industrial centres. The lower basin and the delta are among the most economically developed areas in the country. Mineral resources include reserves of iron ore near Wu-han and Nanking and such deposits as coal, copper, phosphorus, gold, oil, and natural gas in Szechwan province.
The Yangtze basin contributes nearly half of China's crop production, including more than two-thirds of the total volume of rice. Among the other crops grown are cotton, wheat, barley, corn (maize), beans, and hemp. Of note is eastern Szechwan province, which its people call the 「Land of Plenty.」 The soil there is extremely fertile, and the climatic conditions are highly favourable to agriculture. The mild climate also facilitates sericulture, the production of raw silk by raising silkworms. Cultivation is most intensive, however, in the lower basin and delta, where the natural conditions are exceptionally favourable: the growing period ranges from 8 to 11 months, and in some areas two or three crops can be harvested annually.
The extensive territory under cultivation in the Yangtze basin—especially for rice—requires man-made irrigation facilities. Even in the areas of highest precipitation, severe droughts are experienced, resulting in crop losses. This is explained by the extremely irregular distribution of precipitation over the course of the year, with 60 to 80 percent falling in the summer. Rainless periods sometimes last for six to eight weeks. Irrigation has existed in the Yangtze basin since ancient times, but many modern irrigation projects have been undertaken.
The Yangtze River and its associated tributaries and lakes abound with fish. The fishing trade is widely developed and is a major livelihood for much of the population of the region. Hundreds of species are found in Chinese rivers, the majority of which inhabit the Yangtze and its tributaries. About 30 species are of economic significance, especially carp, bream, Chinese perch, gapers (a species of large burrowingclam), and lamprey; the most valuable economically are white and black amur (large members of the carp family), flatfish, and spotted flatfish. Sturgeon also are important, the gorges being a favourite spawning area. Farther downstream great amounts of roe can be found, and these are collected and distributed throughout the country for artificial cultivation. The artificial cultivation of fish for trade involves mainly white and black amur, flatfish, and carp.
The Yangtze is the principal navigable waterway of China. Along the river for 1,700 miles there is intensive cargo and passenger traffic. The river serves as a continuation of the sea routes, binding the inland and coastal ports together with other major cities into a transportation network in which Nanking,Wu-han, and Chungking play the leading roles. Motorized junks, other powered vessels, and a small number of sail craft are widely used for transporting cargo. Large ships of up to 10,000 tons displacement can travel as far upriver as Wu-han, and craft of up to 2,000 tons can reach I-ch'ang, but only smaller vessels can reach P'ing-ch'uan. Water routes in the Yangtze basin total about 35,000 miles. The Yangtze is joined to navigable stretches of the Huang Ho and Huai, Wei, and Hai rivers by the Grand Canal, which is further connected with the seaports of Hang-chou and Tientsin.
Since the 1950s navigation has been improved through the gorges to Szechwan, and large projects have been undertaken to strengthen and enlarge the levee system. In addition, bridges have been built across the Yangtze at Wu-han, Chungking, Nanking, and other cities, improving north-south transport links and reducing dependence on ferries.
The resources for the production of energy from the Yangtze are enormous, although they have not been developed to a large extent. The total potential power is estimated to be more than 200 million kilowatts, representing about two-fifths of the total energy potential of all the rivers of China. The most ambitious project completed is the Ko-chou-pa hydroelectric dam above I-ch'ang, which is the first structure to block the flow of the Yangtze. The power potential in the vicinity of the Three Gorges is especially great, amounting to about one-fifth of the Yangtze's total potential. In the early 1990s preliminary work began on a massive dam and reservoir project there. Many tributaries of the Yangtze that have significant fall and volume—such as the Ya-lung, Min, and Chia-ling rivers—and other rivers that are tributaries of Lakes Tung-t'ing and P'o-yang also have considerable potential.
Human impact on the environment
Environmental degradation in the Yangtze basin has accelerated with increased economic development since 1950. Pollution levels have risen in the rivers and lakes, soil erosion in the middle and upper basins caused by overgrazing and the overcutting of trees has increased silt loads, and land reclamation has reduced surface areas of lakes and wetlands. Engineering projects such as the Three Gorges scheme have aroused growing concern over the effects on the regional environment.
The Yangtze River basin is one of the longest-inhabited regions in China. Although much of China's political history has centred around North China and the Huang Ho basin, the Yangtze region always was of great economic importance to successive dynasties for its agricultural potential. The Grand Canal was built in order to transport grain from the Yangtze basin to the great northern capital cities; it is possible that the southernmost portion of the canal was in use as early as the 4th century BC, and much of it was constructed in the 7th century AD.
Over the course of time the Yangtze has served as both a political and cultural boundary. The river now demarcates the provinces constituting South China. The Yangtze also was the focus of many of the imperialist incursions into China in the 19th and first half of the 20th centuries, with Shanghai at the river's mouth becoming the main foreign commercial base. Since 1950 the river and its basin have been the focus of much of China's economic modernization.
Aleksandr Pavlovich Muranov
Charles E. Greer
For the Yangtze River, useful 19th-century accounts by westerners of land and life in the basin include Isabella Bird, The Yangtze Valley and Beyond (1899, reissued with a new introduction, 1987); and Archibald John Little, Through the Yang-tse Gorges: or, Trade and Travel in Western China, 3rd and rev. ed. (1898, reprinted 1972). Recent descriptions in English include Jiang Liu, China's Largest River (1980); the pictographic account of How Man Wong, Exploring the Yangtze: China's Longest River (1989); and the valuable guidebook by Judy Bonavia, A Guide to the Yangzi River (1985). Physiography, culture, and history are imaginatively linked in Lyman P. Van Slyke, Yangtze: Nature, History, and the River (1988). The issues surrounding the massive Three Gorges dam and reservoir project are presented from different points of view in Shiu-hung Luk and Joseph Whitney (eds.), Megaproject: A Case Study of China's Three Gorges Project (1993); and Margaret Barber and Gráinne Ryder (eds.), Damming the Three Gorges, 2nd ed. (1993). Charles E. Greer