This is a brief introduction of Dujiangyan.
One of the oldest water conservancy projects in the world. Located in Dujiangyan City, Sichuan Province, the middle reaches of Minjiang River. Also known as Hundred Weirs, Tail Weirs and Golden Embankments. Founded in 250 BC, it was officially named Dujiangyan in 1335. Now it is a national key cultural relics protection unit. The head of the canal is in guanxian, including four major projects, namely, Yu Zui, Jingang Dike, Sha Fei Weir and Baojiangkou, with thousands of canals and weirs. When the Minjiang River flows to the foot of Lei Yu Mountain, it is divided into two tributaries by the "Yu Zui" project. The south side is called Waijiang, which is the main stream of the Minjiang River, mainly for flood discharge and irrigation. To the north is Neijiang, also known as Dujiangyan, which is about 160 km long and mainly irrigates farmland. Its downstream tributaries include Zouma River, Baitiao River and Puyang River. Part of the tail water of Zouma River and Baitiao River flows into Fuhe River in the south of Chengdu, and then flows back to Minjiang River. Behind the fish mouth is the internal and external "King Kong Dike" made of huge pebbles, which is integrated with the fish mouth and is the main part of the water diversion project. Behind the "Jingang Dike" is the "flying sand weir", which is mainly used for flood discharge and sediment discharge, so as to keep an appropriate amount of water in Neijiang. Behind the weir is a huge cliff with piles left, and under the cliff is the "Treasure Bottle Mouth" project. Dujiangyan was built by the working people in ancient China by using the natural terrain conditions that the river trend is perpendicular to the contour line on the Chengdu Plain. After the founding of New China, Dujiangyan Irrigation Area Project was completely rebuilt and expanded, which made the irrigation area rapidly expand from the original 14 counties and cities173,000 hectares of farmland to 573,000 hectares of farmland in 30 counties and cities.