The Beijing-Hangzhou Grand Canal is the longest canal in the world with a total length of 1,600 km and 30–61 meter wide [Source : encyclopedia.farlex.com]. It starts from Beijing and crosses Tianjin and the provinces of Hebei, Shandong, Jiangsu and Zhejiang to the city of Hangzhou. The oldest parts of the canal date back to the 5th century BC, although the various sections were finally combined during the Sui Dynasty (581–618 CE). Though the canal nominally crosses the watersheds of five river systems, in reality the variation between these is so low that it has only a single summit section. The elevation of the canal bed varies from 1 m below sea level at Hangzhou to 38.5 m above at its summit. At Beijing it reaches 27 m, fed by streams flowing downhill from the mountains to the west. The water flows from Beijing toward Tianjin, from Nanwang north toward Tianjin, and from Nanwang south toward Yangzhou. The water level in the Jiangnan Canal remains scarcely above sea level (the Zhenjiang ridge is 12 meters higher than the Yangzi River). The Grand Canal served as the main artery between northern and southern China and was essential for the transport of grain to Beijing. Although it was mainly used for shipping grain, it also transported other commodities and the corridor along the canal developed into an important economic belt. The Grand Canal also enabled cultural exchange and political integration to mature between the north and south of China. The canal even made a distinct impression on some of China's early European visitors. Since the founding of the People's Republic of China in 1949, the canal has been used primarily to transport vast amounts of bulk goods such as bricks, gravel, sand, diesel and coal.
As well as its present-day course, there are a number of historical sections after fourteen centuries of canal-building. Some of these are still partially extant, some of them have disappeared and others form the basis for the modern canal. The following are the most important.
Jia Canal : In 12 BC, a man named Li Hualong opened the Jia Canal to solve the problem of the Grand Canal having to use 100 miles (160 km) of the course of the Yellow River in Northern Jiangsu, . It was named after the Jia River whose course it followed.
Nanyang New Canal : In 1566, the Nanyang New Canal was opened to escape the problems caused by flooding of the Yellow River around Yutai. It ran for 47 miles from Nanyang to the small settlement of Liucheng, north of Xuzhou City.
Huitong Canal : In 1289, a geological survey preceded its one-year construction. The Huitong Canal ran downhill and being fed principally by the River Wen. The Huitong Canal was built by an engineer called Ma Zhizhen.
Jizhou Canal : Jizhou Canal was engineered by the Mongol Oqruqci in 1238. It was built to connect Jining to the southern end of the Huitong Canal. It rose to a height of 138 feet above the Yangtze. Environmental and technical factors left it with chronic water shortages. It was re-engineered in 1411 by Song Li of the Ming.
Because of its very ancient origins, its vast scale, its continuous development and its adaptation to circumstances down the ages, The grand canal is the greatest masterpiece of hydraulic engineering in the history. Its an example of creativity, technical capabilities and a mastery in hydrology and provides tangible proof of human wisdom, determination and courage.