Dujiangyan, located in the upper reaches of Minjiang River in the west of Chengdu Plain, was a large-scale water conservancy project founded by Li Bing, the prefect of Shu County of Qin State, in the fifty-first year of Zhao Haoqi (256 BC). It is the oldest existing water conservancy project in China, and it is still irrigating fields, benefiting the people and making Shu a "land of abundance". It is a monument in the history of science and technology in China, and is known as the miracle of the world. It has been playing the role of water diversion irrigation for more than two thousand years, and it has been successfully operated for more than two thousand years, and the irrigation area has increased to more than ten million mu.
Chengdu Plain was a place where floods and droughts were very serious in ancient times. Minjiang River is the main tributary of the upper reaches of the Yangtze River, which flows through the western Sichuan Basin. The Minjiang River runs out of Minshan Mountain and flows south from the west side of Chengdu Plain. For the whole Chengdu Plain, it will be a river hanging on the ground, and it will be very hanging. Whenever the Minjiang River floods, the Chengdu Plain is a Wang Yang; Once there is drought, it is thousands of miles away and there is no harvest. The flood of Minjiang River has long harmed Xichuan, which has become a major obstacle to the survival and development of Sichuan. Therefore, Zhao Haoqi, the king of Qin, appointed Li Bing, who lived in Minshan and was familiar with astronomy and geography, as the prefect of Shu County. After Li Bing took office, he made up his mind to eradicate floods in Minjiang River, develop agriculture in western Sichuan and benefit Chengdu Plain.
Dujiangyan headwork project consists of Baojiangkou drainage project, Yuzui diversion dike and Feisha weir spillway. It has many benefits, such as irrigation, flood control and drainage. It is a masterpiece of ancient working people and unique in the world.
First of all, Li Bing and his son investigated the terrain and water conditions on the spot, and decided to cross Leiyu Mountain to lead out the water of Minjiang River. Because gunpowder had not been invented at that time, Li Bing expanded it with flint and poured it with cold water to make the rock burst. In this way, a mountain pass with a width of 20 meters, a height of 40 meters and a length of 80 meters was finally dug in Leiyu Mountain. Because its shape is similar to that of the bottle mouth, it also leads to the precious water of Minjiang River, so it is named "Treasure Bottle Mouth". Leiyushan was opened, and the Minjiang River flowed eastward, which reduced the flow of the Minjiang River in the west and stopped it from flooding. At the same time, it also relieved the drought in the eastern region, making the turbulent river flow into the arid area and irrigate the farmland.
Under the leadership of Li Bing, people overcame many difficulties. After eight years of hard work, Dujiangyan was finally built into a historical project.