A New Era in the History of Water Conservancy in Ancient China_Ancient Science and Technology in China

Dujiangyan is a large-scale water conservancy project built by Li Bing and his sons during the Warring States Period. It is located in the west of Chengdu City, Sichuan Province, and on the Minjiang River in the west of the Chengdu Plain.

Fifty-one years before King Qin Zhaoxiang (256 years ago), Li Bing and his son, the prince of Shu Kingdom of Qin Kingdom, learned the water control experience of their predecessors, led the local people, and began to host the Dujiangyan Water Conservancy Project. The project consists of the three main projects of the Yuzui diversion levee, the Feishayan spillway, and the treasure bottle mouth water intake, as well as ancillary projects such as Baizhang dike and herringbone dike.

Li Bing and his son invited a lot of farmers with experience in water control, made a site survey of the terrain and water conditions, and determined to cut through the water at Yulei Mountain. However, the mountains and rocks in Yulei Mountain were hard. The migrant workers used iron to chisel, dig, and pry, and the progress of the project was extremely slow. Later, an experienced veteran laborer suggested that some grooves should be made in the rocks, and then firewood should be placed and burned. The rocks will burst when the firewood burns, which can speed up the digging speed. Practice has proved that this method is very effective.

After a period of hard work, a 20-meter-wide, 40-meter-high, and 80-meter-long mouth was finally excavated in Yulei Mountain. Because it is shaped like a bottle mouth, it is called a treasure bottle mouth. The endless stream of the Minjiang River flows continuously through the aquarium mouth to the eastern dry area, so that the eastern farmland is irrigated. The first major project of Dujiangyan was finally completed.

After the completion of the Dibao bottleneck diversion project, although it played a role of diversion and irrigation, the Jiangdong terrain was relatively high and it was difficult for the river water to flow into the treasure bottle mouth. In order to enable the Minjiang River to flow smoothly eastward and maintain a certain flow, and to fully play the flood diversion and irrigation functions of the Aquarium mouth, Li Bing decided to build a diversion weir in the Minjiang River after the excavation of the Aquarium mouth. Branch: One went down the river, and the other was forced to flow into the mouth of the treasure jar. However, the construction of a water diversion weir in Jiangxin is a very difficult project, because the river has high waves and rapid currents, and the constructed weir is very strong, otherwise it will be washed away by the flood at any time.

Li Bing invited many bamboo workers, and asked them to make large bamboo cages 3 feet long and 2 feet wide, and then filled them with cobblestones, and then let the migrant workers sink the heavy bamboo cages one by one into the bottom of the river . The large bamboo cage remained stable in the turbulent water, and was firmly fixed there. The surrounding area was reinforced with large stones, and the water diversion was finally completed. Because the shape of the big advance is like the head of a fish, it is called a fish mouth. The completion of Yuzui divides the flowing river water into two: the west is called the outer river and the east is called the inner river. The river flows through large and small channels to form a crisscross irrigation network.

In order to further control the amount of water flowing into the mouth of the aquarium and prevent the water volume in the irrigation area from fluctuating, Li Bing built a flat water tank for flood diversion and a Feisha weir at the end of the fish mouth diversion ditch near the aquarium mouth. Spillway is used to regulate the amount of water in the inner and outer rivers. When the water level in the Neijiang River is too high, the floodwater flows through the flat flume into the outer river through the flat flume, so that the amount of water entering the mouth of the treasure bottle is not too large, and the Neijiang irrigation area is protected from floods. The currents in the Waijiang River generate vortices. Due to the centrifugal effect, mud and even boulders will be thrown over the flying sand weir, which can also effectively reduce the sediment deposition around the mouth of the treasure jar.

Dujiangyan has unique ingenuity in designing, designing, and selecting sites; taking advantage of the current situation and adapting to the times, water management strategies that are not opposed to water are unique. It is a great initiative that closely integrates natural ecology, science and culture, and people and nature. It has become a country of Tianfu that floods and droughts follow the people. For more than two thousand years, it has been playing a role in flood control and irrigation.

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