Dujiangyan, located in Dujiangyan City (formerly guanxian), Sichuan Province, is a large-scale water diversion project on the Minjiang River and the longest dam-free water diversion project in the world. It was built in the last years of Qin Zhao Haoqi (about 256 BC ~ 25 BC1year), and was presided over by its guardian Li Bing. It is by far the oldest and only water conservancy project in the world, which is characterized by dam-free water diversion.
It is a national key cultural relics protection unit. Irrigation is the main project, which has many benefits such as flood control, water transmission and urban water supply. Because of this, Chengdu Plain is rich, and it has been known as "Land of Abundance" since ancient times. Dujiangyan was first named in the Song Dynasty. Before the Song Dynasty, it was called Du 'an weir, weir or weir.
Dujiangyan Water Conservancy Project consists of three main projects: Yuzui Fenshui Dike, Feishayan Spillway and Baojiangkou Water Intake, as well as auxiliary projects such as Baizhang Dike and herringbone Dike. Scientifically solved the problems of automatic river diversion, automatic sediment discharge and inflow control, eliminated floods, and made the western Sichuan plain a "land of abundance" with people following floods and droughts. For more than two thousand years, it has been playing the role of flood control and irrigation. By the end of 1998, the irrigated area of Dujiangyan has reached more than 40 counties, with an irrigated area of 668,700 hectares.
Introduction of Dujiangyan project structure;
In ancient Dujiangyan, bamboo cages, wooden stakes and pebbles were the main building materials. The bamboo woven cage is filled with pebbles to build a fish mouth, a flying sand weir, an inner and outer diamond dike and a herringbone dike. More than 10,000 bamboo cages need to be replaced every year. In order to reduce the annual engineering quantity in the annual maintenance, water conservancy workers and working people in past dynasties have been seeking to transform the engineering structure, especially the fish mouth.
In the Yuan Dynasty, the fish mouth was made of stone and the turtle top was cast iron. In the Ming dynasty, the fish mouth was built, and the iron cow was placed in front. In the Qing dynasty, the stone fish mouth was reused. Due to the unstable foundation, these projects cannot be sustained. 1936 is based on bamboo cages, and the front and both sides are protected by wooden stakes, with masonry fish mouths built on them. The project took a long time, and 1974 Waijiang sluice was rebuilt into a reinforced concrete structure when it was repaired.
Refer to the above? Baidu encyclopedia-Dujiangyan