Minjiang River originated in Yangboling, Songpan County, Sichuan Province. Hundreds of rivers gather in the upper reaches of Minjiang River, rushing down, carrying a lot of sand and gravel, flowing into the plain, silting up the riverbed, and frequent disasters.
Li Bing, the commander of Shu County, led the working people to dig mountains and divert water to irrigate fertile fields according to the geographical conditions of high northwest and low southeast in western Sichuan. Dike and divide water in the middle of Minjiang River. At the front end of the levee is a "water-dividing fish mouth", which divides the Minjiang River into two rivers, and the outer river is the main stream of the Minjiang River, which flows into the Yangtze River through Dujiangyan, Leshan and Yibin, with a total length of more than 700 kilometers. Neijiang is an artificial channel, which flows into Chengdu Plain under the control of the "Treasure Bottle Mouth". In order to prevent more flood and sediment from flowing into Neijiang, a "flying sand weir" was built in the middle section of the diversion levee, so that flood and sediment were automatically discharged into the outer river, effectively controlling the flow of Neijiang, thus ensuring irrigation and avoiding floods.
Through the management of Dujiangyan, the working people of past dynasties have summed up a set of scientific experience in water control. For example, "deep scouring beach, low weir" and "cutting corners in the bay, the right to take the heart." According to local conditions, local materials are the characteristics of Dujiangyan project. Ancient people used bamboo, wood and pebbles to make "dikes", "bamboo cages" and "stone ridges" for water diversion, bank protection, irrigation and flood discharge, which not only saved costs, but also ensured that Dujiangyan project would not be abandoned for a long time, benefiting local people for generations.