What is a canal?

Concept canal refers to an artificial waterway used to communicate water transport between regions or waters, which is usually connected with natural waterways or other canals. Besides shipping, canals can also be used for irrigation, flood diversion, drainage and water supply.

Waterways are divided into natural rivers, channelized rivers and artificial canals, each with its own special problems. Natural rivers are often forced to stop sailing seasonally because of floods, droughts and freezing, which even leads to the diversion of rivers and the formation of sandbars. Waterway engineering should focus on strengthening riverbeds and embankments and maintaining existing rivers. The method is nothing more than eliminating tributaries, unifying river sections, cutting and straightening, and making the water flow smooth. On the channelized river, cascade locks can be built for navigation, and low dams and gates are set at the gates where ships pass to discharge excess water. When an artificial canal crosses a mountain valley, the river bank and riverbed of the canal must have protective facilities to prevent erosion and leakage. In order to choose the artificial canal route, it is necessary to create conditions to build a long-distance horizontal reach that can sail quickly. The shiplock can adopt stepped multi-stage shiplock or stepped shiplock, which is separated by a short river between the two shiplocks. In the construction of water storage reservoirs, high-level reservoirs should supply water to high places to make up for the evaporation loss of water discharged after crossing the sluice; In addition, a low-level reservoir must be built to accommodate the water discharged when ships frequently pass through the sluice.

China has a long history of canal construction. It was excavated in Sugagawa in 506 BC. It is the oldest artificial canal in the world and the earliest recorded canal in China.

In the 28th year of Qin Shihuang (2 19 BC), a canal was dug to communicate the shipping between Xiangjiang River and Lijiang River.

The Beijing-Hangzhou Grand Canal, mainly built in the Sui Dynasty in China, is the longest canal in the world and a great water conservancy construction project created by the working people in ancient China. Dredged in the Yuan Dynasty, it was further introduced to Beijing, with a total length of 1, 794 kilometers, becoming the present Beijing-Hangzhou Grand Canal.

There are canals connecting the Mississippi River, Hudson River and the Great Lakes (Lake Superior, Lake Michigan, Lake Huron, Lake Erie and Lake Ontario). The former Soviet Union connected moscow river, Volga River, Don River, Caspian Sea, Black Sea, Azov Sea, White Sea and Baltic Sea with canals to form a waterway network. The main Danube Canal in Germany will connect the rivers of Europe 13 countries into a network.

Historical source

The improvement of ancient rivers and the construction of artificial waterways are all for irrigation. As early as the 7th century BC, Assyrians opened a canal 80 kilometers (50 miles) long and 20 meters (66 feet) wide to bring in fresh water. In the 5th century, Persia dug a canal from the Nile to the Red Sea. Egypt once built dams on the Nile to prevent floods and established irrigation systems in vast river basins. From 3rd century BC to 1 century BC, the China River Opening Project was even more impressive. In fact, as early as the Spring and Autumn Period, Fu Cha, the king of Wu, dug the first canal in human history in Yangzhou today, with the purpose of connecting the north and the south and facilitating the transportation of military pay to the northern front. Still in use today, it should be the earliest canal recorded in history books in the world. In addition, there are Lingqu in Guangxi, the water road from Chang 'an, the capital of Han Dynasty, to the Yellow River, and the old Bianhe River in Henan. The most striking thing is the Grand Canal, which was opened to traffic for 960 kilometers (600 miles) in June10, enabling grain to be transported from the lower reaches of the Yangtze River and Huaihe River to Kaifeng and Luoyang. The water level of these canals changes gently, and a stone pier or wooden column gate is set up every 4.8 kilometers (3 miles) to store water or drain water to control the water level. /kloc-in the 20th century, the expansion of commerce promoted the revival and perfection of European canal construction. 1373, a water storage gate was built in the Netherlands, with internal and external gates to control the water level. This method was widely used in14th century. China canal architecture is ahead of Europe. 1280 to 1293, the Beijing-Hangzhou Grand Canal was built from Huai 'an to the north of Beijing, with a total length of 1,120km (700 miles), which flows through a hilly area in Shandong with rolling mountains along the way, making it the earliest ridge-crossing canal.

The development of miter gate marks the arrival of canal expansion period in 16 ~ 17 century. The Briare Canal in France was completed on 1642. The water level of the river rises by 39 meters (128 feet), flows through the plateau, and then drops by 8 1 meter (266 feet) to flow into the Loin River. * * * There are 40 sluices, of which 6 cascade sluices are used to cross the Loing River. The European canal era began at the end of 17. The main achievements of waterway construction in various countries during this period include the bridgewater Canal built in Britain in 176 1, which made outstanding contributions to the prosperity of Britain in the half century before the arrival of the railway era. After that, the Grand Canal, which runs through the whole of Britain, was built, providing water transportation convenience for exporting to the European market. France built the Central Canal, connecting the Royal River and the Thorne River, and completed the first inland waterway in Europe from the English Channel to the Mediterranean Sea. 1840, the Ludwig Canal was built in Central Europe, forming a part of the Rhine, Main and Danube rivers. 17 18 The entire Russian-scale canal system has connected the Baltic Sea and the sea through the neva river and the Wawa rivers. By the19th century, the shipping of Wawa River, Nibo River, Don River, Devinast River and the upper reaches of ob river were also concentrated. American canal architecture started late, but developed rapidly. /kloc-At the beginning of the 0/9th century, the canal was only 160 km (100 miles). By the end of19th century, the voyage had exceeded 6,400 kilometers (4,000 miles). The major projects include the Erie Canal, which is 580 kilometers (363 miles) long and has 82 shiplocks, dug at New York State 18 17 to 1825. It has developed the prairie in the central and western regions, promoted industrial and agricultural production, and made new york superior to other Atlantic ports. 1829, Canada built the Welland Canal connecting Lake Erie and Lake Ontario, making navigation with Lake Michigan and Chicago possible. /kloc-in 0/834, the United States opened canals in Philadelphia and Pittsburgh, with a total length of 630 kilometers (394 miles), connecting the Susquehanna River and the Ohio River.

/kloc-in the 0/9th century, three world-famous Grand Canal constructions appeared, namely Kiel Canal, Suez Canal and Panama Canal. The Kiel Canal between Kiel Bay and Lake Ed was opened for trial on 1784. More than a hundred years later, it was widened, deepened and straightened, with a total length of 95 kilometers (59 miles), shortening the voyage from the English Channel to the Baltic Sea by hundreds of miles. The Suez Canal is a passage from the Mediterranean to the Indian Ocean, and its voyage is much shorter than that around Africa. The whole project lasted 10 years and was officially opened to traffic on 1869+065438+ 10/7. It is a sluice-free waterway connecting the Mediterranean Sea and the Red Sea, with a total length of 169 km (105 mile). Since the canal was built, it has been constantly being repaired. The main channel of 1954 can sail large ships with a draft of 1 1.3 meters (37 feet). This river was nationalized by Egypt in 1956. After the Israeli-Arab war in 1967, the canal was closed until 1975. The Panama Canal is a waterway connecting the Atlantic Ocean and the Pacific Ocean. 1906 high water level sluice was started, and 19 14 was completed. This river is 85 kilometers (5 1.2 miles) long, and the channels along it are at least 1 1.3 meters (37 feet) deep and 9 1 meter (300 feet) wide.