The Grand Canal () is a system of interconnected canals linking various major rivers and lakes in North and East China, serving as an important waterborne transport infrastructure between the north and the south during Medieval and premodern China. It is the longest artificial waterway in the world and a World Heritage Site.
The Grand Canal has undergone several route changes throughout history. Its current main stem, known as the Jing–Hang Grand Canal, is thought to extend for linking Beijing in the north to Hangzhou in the south, and is divided into 6 main subsections, with the southernmost sections remaining relatively unchanged over time. The Jiangnan Canal starts from the Qiantang River at Hangzhou's Jianggan District, looping around the east side of Lake Tai through Jiaxing, Suzhou and Wuxi, to the Yangtze at Zhenjiang; the Inner Canal from Yangzhou across the Yangtze from Zhenjiang, going through the Gaoyou Lake to join the Huai River at Huai'an, which for centuries was also its junction with the former course of the Yellow River; the Middle Canal from Huai'an to Luoma Lake at Suqian, then to the Nansi Lakes at Weishan; the Lu Canal from the Nansi Lakes at Jining and into the present course of the Yellow River at Liangshan, splitting off downstream at Liaocheng's Dong'e County before continuing to the Wei at Linqing; the Southern Canal (named for its location within Hebei) from Linqing to the Hai River at Tianjin; and the Northern Canal from Tianjin to Tongzhou on the outskirts of Beijing. As such, it passes through the provinces of Zhejiang, Jiangsu, Shandong, Hebei, and the municipalities of Tianjin and Beijing. In 2014, the Chinese government and UNESCO recognized the Eastern Zhejiang Canal from Hangzhou to Ningbo along the former Tongji and Yongji Canals also as official components of the Grand Canal.
The oldest sections of what is now the Grand Canal were completed in the early 5th century BC during the conflicts of China's Spring and Autumn period to provide supplies and transport routes for the states of Wu and Yue. The network was expanded and completed by Emperor Yang of Sui in 609, linking fertile Jiangnan in the south to his capital at Luoyang in the Central Plain and to his armies in the northern frontiers. His unsuccessful and unpopular Goguryeo–Sui War and the massive amounts of civil conscription involved in creating the canals were among the chief factors in the rampant rebellions during his reign and the eventual rapid fall of the Sui, but the connection of major watersheds and population centers proved enormously beneficial during the subsequent Tang dynasty.
Additional canals supplied Chang'an (now Xi'an) even further west were rebuilt under the Tang to better connect the Guanzhong heartland to the Central Plain, while stopover towns along the main course became the economic hubs of the empire. Sections of the canal gradually degraded and faded into ruins during the Five Dynasties and Ten Kingdoms period and the Song dynasty, and periodic flooding of the Yellow River associated with climate changes during the Medieval Warm Period had eroded and threatened the safety and functioning of the canal while, during wartime, the rivers' high dikes were sometimes deliberately breached to delay or sweep away advancing enemy troops. Even so, restoration and improvement of the canal and its associated flood control works was assumed as a duty by each successive dynasty. The canal played a major role in periodically reuniting northern and southern China, and officials in charge of the canal and nearby salt works grew enormously wealthy. Despite damage from floods, rebellions and wars, the canal's importance only grew with the relocation of the national capital to Khanbaliq (now known as Beijing) under Kublai Khan during the Mongol Yuan dynasty, and again later under Yongle Emperor during the Ming dynasty and under Shunzhi Emperor the Manchu Qing dynasty. Despite the importance of railways and highways in modern times, the People's Republic of China has worked to improve the navigability of the canal since the end of the Chinese Civil War and the portion south of the Yellow River remains in heavy use by barges carrying bulk cargo. Increasing concern over pollution in China and particularly the use of the Grand Canal as the eastern path of the South-North Water Diversion Projectintended to provide clean potable water to the northhas led to regulations and several projects to improve water quality along the canals.
The greatest height on the canal is an elevation of above sea level reached in the foothills of Shandong. Ships in Chinese canals did not have trouble reaching higher elevations after the Song official and engineer Qiao Weiyue (926–1001) invented the pound lock in the 10th century.Needham, Volume 4, Part 3, 350–352 The canal has been admired by many visitors throughout its history, including the Japanese monk Ennin (794–864), the Persian historian Rashid al-Din Hamadani (1247–1318), the Korean official Choe Bu (1454–1504), and the Italian missionary Matteo Ricci (1552–1610).Needham, Volume 4, Part 3, 308 & 313.Brook, 40–51.
History Early periods In the late Spring and Autumn period, King Fuchai of Wu (whose capital was in present-day Suzhou), ventured north to attack the State of Qi. He ordered a canal to be constructed for trading purposes, as well as a means to ship ample supplies north in case his forces should engage the northern states of Song and Lu.Needham, Volume 4, Part 3, 271–272. This became known as the Han or Hangou Canal Hángōu).Needham, Volume 4, Part 3, 271. Work began in 486 BC, from south of Yangzhou to north of Huai'an in Jiangsu, and within three years the Han Canal had connected the Yangtze with the Huai River utilizing existing waterways, lakes, and marshes.
The Han Canal is known as the second oldest section of the later Grand Canal since the Hong Canal (t s Hónggōu, "Canal of the Wild Geese" or "Far-Flung Canal") most likely preceded it.Needham, Volume 4, Part 3, 269–270. It linked the Yellow River near Kaifeng to the Si and Bian rivers and became the model for the shape of the Grand Canal in the north.Needham, Volume 4, Part 3, 269. The exact date of the Hong Canal's construction is uncertain; it is first mentioned by the diplomat Su Qin in 330 BC when discussing state boundaries.Needham, Volume 4, Part 3, 270. The historian Sima Qian (145–90 BC) knew of no historical date for it, placing his discussion of it just after the legendary works of Yu the Great; modern scholars now consider it to belong to the 6th century BC.
Sui dynasty
The reunification of China under the Sui dynasty (581–618) ended three centuries of chaos since the Upheaval of the Five Barbarians, and the renewed political stability allowed both the thorough repair of existing canals and flood control systems as well as the construction of new canals. The primary consideration of the Sui canals was the need to tap into the expanding economic and agricultural resources of Jiangnan in the southeast to enrich the capital at Luoyang to the west and to supply the expeditionary Sui armies in the Goguryeo–Sui War to the northeast. The institution of the Grand Canal also obviated the need for army garrisons to become self-sufficient part-time militia-farmers while guarding the dry frontiers between China, Goguryeo, and the First Turkic Khaganate.
A levee-building project in 587 along the Yellow River—overseen by engineer Liang Rui—established canal lock gates to regulate water levels for the canal. Double slipways were installed to haul boats over when the difference in water levels was too great for the flash lock to operate. Similarly, by the year 600, there were major buildups of silt on the bottom of the Hong Canal, obstructing river barges whose drafts were too deep for its waters. The chief engineer of the Sui dynasty, Yuwen Kai, advised the digging of a new canal that would run parallel to the existing canal, diverging from it at Chenliu (Yanzhou).Needham, Volume 4, Part 3, 307. The new canal was to pass not Xuzhou but Suzhou, to avoid connecting with the Si River and instead make a direct connection with the Huai River just west of Hongze Lake. With the recorded labor of five million people under the supervision of Ma Shumou, the first major section of the Grand Canal was completed in the year 605 and was called the Bian Qu.Needham, Volume 4, Part 3, 308.
The Grand Canal was fully completed from the years 604 to 609 under Emperor Yang of Sui,Ebrey, Cambridge Illustrated History of China, 114: "[…] the Grand Canal, dug between 605 and 609 by means of enormous levies of conscripted labour." first by linking his southern capital Yangzhou northwest to Luoyang by the Tongji Canal Tōngjì Qú). He then proceeded to connect Yangzhou southeast to Suzhou and Hangzhou by the Jiangnan Canal and to connect Luoyang northeast to his war with Goguryeo by the Yongji Canal Yǒngjì Qú).Ebrey, Cambridge Illustrated History of China, p. 115 After this network's completion in 609, Emperor Yang was said to have led a flotilla of boats long from the north down to his southern capital at Yangzhou.Ebrey, Cambridge Illustrated History of China, 116. This process again involved massive levies of conscripted labor and was detailed at length in the Record of the Opening of the Canal Kāihéjì).
At this point, the Grand Canal continued to use noncontiguous artificial channels and both canalized and natural waterways rather than presenting a single continuous manmade canal. However, running alongside and parallel to the course of the canals was an imperial roadway with stables maintained at regular intervals to support a rapid courier system. Enormous lines of trees were also planted along parts of the canal as windbreaks.
Tang to Yuan dynasties Although the Tang dynasty (618–907) capital at Chang'an was the most thriving metropolis of China in its day, it was the city of Yangzhou—in proximity to the Grand Canal—that was the economic hub of the Tang era.Benn, 46. Besides being the headquarters for the government salt monopoly and the largest pre-modern industrial production center of the empire, Yangzhou was also the geographical midpoint along the north–south trade axis, and so became the major center for southern goods shipped north. One of the greatest benefits of the canal system in the Tang dynasty—and subsequent dynasties—was that it reduced the cost of shipping grain that had been collected in taxes (caoyun) from the Yangtze Delta to northern China.Benn, 7. Minor additions to the canal were made after the Sui period to cut down on travel time, but overall no fundamental differences existed between the Sui Grand Canal and the Tang Grand Canal.Needham, Volume 4, Part 3, 309.
By the year 735, it was recorded that about of grain were shipped annually along the canal. The Tang government oversaw canal lock efficiency and built granaries along the route in case a flood or other disaster impeded the path of shipment.Needham, Volume 4, Part 3, 310. To ensure smooth travel of grain shipments, Transport Commissioner Liu Yan (in office from 763 to 779) had special river barge ships designed and constructed to fit the depths of each section of the entire canal.Needham, Volume 4, Part 3, 311.
After the An Lushan rebellion (755–763), the economy of North China was greatly damaged and never recovered due to wars and to constant flooding of the Yellow River. Such a case occurred in the year 858 when an enormous flood along the Grand Canal inundated thousands of acres of farmland and killed tens of thousands of people in the North China Plain.Bowman, 105. Such an unfortunate event could reduce the legitimacy of a ruling dynasty by causing others to perceive it as having lost the Mandate of Heaven; this was a good reason for dynastic authorities to maintain a smooth and efficient canal system.