Grand Canal (China)

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 1,776 km (1,104 mi) 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 Project—intended to provide clean potable water to the north—has led to regulations and several projects to improve water quality along the canals.

The greatest height on the canal is an elevation of 42 m (138 ft) 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. 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).

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. This became known as the Han or Hangou Canal (t 邗溝, s 邗沟, Hángōu). 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 鴻溝, s 鸿沟, Hónggōu, "Canal of the Wild Geese" or "Far-Flung Canal") most likely preceded it. 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. 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. 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). 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.

The Grand Canal was fully completed from the years 604 to 609 under Emperor Yang of Sui, first by linking his southern capital Yangzhou northwest to Luoyang by the Tongji Canal (t 通濟渠, s 通济渠, 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 (t 永濟渠, s 永济渠, Yǒngjì Qú). After this network's completion in 609, Emperor Yang was said to have led a flotilla of boats 105 km (65 mi) long from the north down to his southern capital at Yangzhou. This process again involved massive levies of conscripted labor and was detailed at length in the Record of the Opening of the Canal (t 《開河記》, s 《开河记》, 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. 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. 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.

By the year 735, it was recorded that about 149,685,400 kilograms (165,000 short tons) 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. 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.

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. 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.

The city of Kaifeng grew to be a major hub, later becoming the capital of the Song dynasty (960–1279). Although the Tang and Song dynasty international seaports—the greatest being Guangzhou and Quanzhou, respectively—and maritime foreign trade brought merchants great fortune, it was the Grand Canal within China that spurred the greatest amount of economic activity and commercial profit. During the Song and earlier periods, barge ships occasionally crashed and wrecked along the Shanyang Yundao section of the Grand Canal while passing the double slipways, and more often than not those were then robbed of the tax grain by local bandits. This prompted Qiao Weiyue, an Assistant Commissioner of Transport for Huainan, to invent a double-gate system known as the pound lock in the year 984. This allowed ships to wait within a gated space while the water could be drained to appropriate levels; the Chinese also built roofed hangars over the space to add further protection for the ships.

Much of the Grand Canal was ruined for several years after 1128 when Kaifeng's governor Du Chong (杜充, Dù Chōng, d. 1141) decided to break the dykes and dams holding back the waters of the Yellow River in order to decimate the oncoming Jurchen invaders during the Jin–Song wars. Over a series of floods, this entirely shifted the river south of Shandong, capturing the course of the Si River and emptying the Yellow River into Hongze Lake and the East China Sea for centuries. The Jurchen Jin dynasty continually battled with the Song in this region. The warfare led to the dilapidation of the canal until the Mongols invaded in the 13th century and began necessary repairs.

During the Mongol Yuan dynasty (1271–1368) the capital of China was moved to Beijing, eliminating the need for the canal arm flowing west to Kaifeng or Luoyang. A summit section was dug across the foothills of the Shandong massif during the 1280s, shortening the overall length by as much as 700 km (430 mi), making the total length about 1,800 km (1,100 mi) and linking Hangzhou and Beijing with a direct north–south waterway for the first time. As in the Song and Jin era, the canal fell into disuse and dilapidation during the Yuan dynasty's decline.

The Grand Canal as infrastructure has had influence on other architectural works in the west. The Erie Canal in North America is designed and draws inspiration from the Chinese architecture. Many saw the canal as an economic advantage that could bring economic prosperity, like the canal and its benefits. Matteo Ricci's Journals describes the canal in great detail documenting the economic prosperity. The pound lock is one of the more notable features of the Erie canal that is directly connected to the infrastructure of the Grand Canal as it is used in other similar bodies of water.

Ming dynasty restoration

The Grand Canal was renovated almost in its entirety between 1411 and 1415 during the Ming dynasty (1368–1644). A magistrate of Jining, Shandong sent a memorandum to the throne of the Yongle Emperor protesting the current inefficient means of transporting 4,000,000 dan (428,000,000 liters) of grain a year by means of transferring it along several different rivers and canals in barge types that went from deep to shallow after the Huai River, and then transferred back onto deep barges once the shipment of grain reached the Yellow River. Chinese engineers built a dam to divert the Wen River to the southwest in order to feed 60% of its water north into the Grand Canal, with the remainder going south. They dug four large reservoirs in Shandong to regulate water levels, which allowed them to avoid pumping water from local sources and water tables. Between 1411 and 1415 a total of 165,000 laborers dredged the canal bed in Shandong and built new channels, embankments, and canal locks.

The Yongle Emperor moved the Ming capital from Nanjing to Beijing in 1403. This move deprived Nanjing of its status as chief political center of China. The reopening of the Grand Canal also benefited Suzhou over Nanjing since the former was in a better position on the main artery of the Grand Canal, and so it became Ming China's greatest economic center. The only other viable contender with Suzhou in the Jiangnan region was Hangzhou, but it was located 200 km (120 mi) further down the Grand Canal and away from the main delta. Even the shipwrecked Korean Choe Bu (1454–1504)—while traveling for five months throughout China in 1488—acknowledged that Hangzhou served not as a competitor but as an economic feeder into the greater Suzhou market. Therefore, the Grand Canal served to make or break the economic fortunes of certain cities along its route and served as the economic lifeline of indigenous trade within China.

The scholar Gu Yanwu of the early Qing dynasty (1644–1912) estimated that the previous Ming dynasty had to employ 47,004 full-time laborers recruited by the lijia corvée system in order to maintain the entire canal system. It is known that 121,500 soldiers and officers were needed simply to operate the 11,775 government grain barges in the mid-15th century.

Besides its function as a grain shipment route and major vein of river-borne indigenous trade in China, the Grand Canal had long been a government-operated courier route as well. In the Ming dynasty, official courier stations were placed at intervals of 35 to 45 km (22 to 28 mi). Each courier station was assigned a different name, all of which were popularized in travel songs of the period.

Qing dynasty

The Manchus invaded China in the mid-17th century, allowed through the northern passes by the Chinese general Wu Sangui once the Ming capital at Beijing had fallen into the hands of a rebel army. The Manchus established the Qing dynasty (1644–1912), and under their leadership, the Grand Canal was overseen and maintained just as in earlier times.

In 1855, the Yellow River flooded and changed its course, severing the course of the canal in Shandong. This was foreseen by a Chinese official in 1447, who remarked that the flood-prone Yellow River made the Grand Canal like a throat that could be easily strangled (leading some officials to request restarting the grain shipments through the East China Sea). In 1855 the dikes of the canal were opened to flood advancing troops of the Taiping Rebellion's Northern Expedition.

Modern China

Because of various factors—the difficulty of crossing the Yellow River, the increased development of an alternative sea route for grain-ships, and the opening of the Tianjin-Pukou Railway and the Beijing-Hankou Railway—the canal languished and for decades the northern and southern parts remained separate. Many of the canal sections fell into disrepair, and some parts were returned to flat fields. Even today, the Grand Canal has not fully recovered its importance prior to the floods of the mid-19th century. After the founding of the People's Republic of China in 1949, the need for economic development led the authorities to order heavy reconstruction work.

The Grand Canal played a major role during Mao Zedong's Great Leap Forward as it provided an efficient way to transport grain. It was further refurbished following Deng Xiaoping's Reform and Opening Up, with improving economic conditions leading to greater infrastructure investment. The economic importance of the canal will likely continue. The provincial governments of Shandong, Jiangsu, and Zhejiang undertook dredging intended to increase shipping capacity by 40 percent by 2012. The central government has also made the main route of the Grand Canal the eastern path of the South-North Water Diversion Project, using enormous pumping stations to redirect water from the Yangtze Delta to the drier north.

The canal became greatly polluted during China's industrialization. By the 1990s, canal barge crews could tell when they neared Hangzhou by the stench of the visibly black water they passed through. Similarly, fishermen on Dongping Lake in Shandong objected to the introduction of water from the Yangtze as part of the South-North Water Diversion Project when they saw it noticeably killing fish and affecting their catch. During the 21st century, increasing efforts have been made to improve environmental conditions along the canal. Around Hangzhou, for instance, a $250 million restoration project begun in 2001 improved water quality to the point where it no longer produces a noticeable odor and is once again capable of supporting some fauna.

On 22 June 2014, UNESCO's Conference on World Heritage listed the Grand Canal as a World Heritage Site. In 2021, the China Grand Canal Museum was opened.

Historical sections

As well as its present-day course, fourteen centuries of canal-building have left the Grand Canal with a number of historical sections. Some of these have disappeared, others are still partially extant, and others form the basis for the modern canal. The following are the most important but do not form an exhaustive list.

Jia Canal

In 12 BC, in order to solve the problem of the Grand Canal having to use 160 kilometers (100 mi) of the perilous course of the Yellow River in Northern Jiangsu, a man named Li Hualong created the Jia Canal. Named after the Jia River whose course it followed, it ran 140 kilometers (87 mi) from Xiazhen (modern Weishan) on the shore of Shandong's Weishan Lake to Suqian in Jiangsu. The construction of the Jia Canal left only 100 kilometers (62 mi) of Yellow River navigation on the Grand Canal, from Suqian to Huai'an, which by 1688 had been removed by the construction of the Middle Canal by Jin Fu.

Nanyang New Canal

In 1566, to escape the problems caused by flooding of the Yellow River around Yutai (now on the western shore of Weishan Lake), the Nanyang New Canal was opened. It ran for 75 kilometers (47 mi) from Nanyang (now Nanyang Town, located in the center of Weishan Lake) to the small settlement of Liucheng (in the vicinity of modern Gaolou Village, Weishan County, Shandong) north of Xuzhou City. This change in effect moved the Grand Canal from the low-lying and flood-prone land west of Weishan Lake onto the marginally higher land to its east. It was fed by rivers flowing from east to west from the borders of the Shandong massif.

Huitong Canal

North of the Jizhou Canal summit section, the Huitong Canal ran downhill, fed principally by the River Wen, to join the Wei River in the city of Linqing. In 1289, a geological survey preceded its one-year construction. The Huitong Canal, built by an engineer called Ma Zhizhen, ran across sharply sloping ground and the high concentration of locks gave it the nicknames chahe or zhahe, i.e. 'the river of locks'. Its great number of feeder springs (between two and four hundred, depending on the counting method and season of the year) also led to it being called the quanhe or 'river of springs'.

Jizhou Canal

This, the Grand Canal's first true summit section, was engineered by the Mongol Oqruqči in 1238 to connect Jining to the southern end of the Huitong Canal. It rose to a height of 42 meters (138 ft) above the Yangtze, but environmental and technical factors left it with chronic water shortages until it was re-engineered in 1411 by Song Li of the Ming. Song Li's improvements, recommended by a local man named Bai Ying, included damming the rivers Wen and Guang and drawing lateral canals from them to feed reservoir lakes at the very summit, at a small town called Nanwang.

Duke Huan's Conduit

In AD 369, General Huan Wen of the Eastern Jin dynasty connected the shallow river valleys of the Huai and the Yellow. He achieved this by joining two of these rivers' tributaries, the Si and the Ji respectively, at their closest point, across a low watershed of the Shandong massif. Huan Wen's primitive summit canal became a model for the engineers of the Jizhou Canal.

Yilou Canal

The Shanyang Canal originally opened onto the Yangtze a short distance south of Yangzhou. As the north shore of the Yangtze gradually silted up to create the sandbank island of Guazhou, it became necessary for boats crossing to and from the Jiangnan Canal to sail the long way around the eastern edge of that island. After a particularly rough crossing of the Yangtze from Zhenjiang, the local prefect realized that a canal dug directly across Guazhou would reduce the journey time and thus make the crossing safer. The Yilou Canal was opened in 738 and still exists, though not as part of the modern Grand Canal route.