The Dujiangyan Irrigation System, 45km north of Chengdu, is the great technological achievement of ancient China. For more than 2,300 years of irrigation, Dujiangyan has benefited the local people just as it prevents Min River basin from annual flooding and made the ancient Shu State a famed ‘land of abundance'. This system still plays an indispensable function in agriculture. Beside, Dujiangyan survived from the 2008 Wenchuan earthquake because of its firm structure. So it really deserves a visit.
This irrigation system was designed and implemented first in the china in the middle of 200 B.C. This is one of the oldest irrigation systems and this is still in function these days. They are the major source of water for many fields in china. They are placed in the min river in china. This irrigation system has a major function to regulate the flow of water. That is, during the rainy season they need to store the water so that they can manage the next summer season. This river was selected first as fields which are situated in the banks were flooded often in a single year. So the best method to stop this is by building an irrigation system in its banks.
The irrigation system consists of three sections: the Fish Mouth, which splits the Min River into the inner and outer rivers, the Feisha Dike, which helps reduce the amount of silt carried by the inner Min River before it flows into the Baopingkou ("mouth of the treasure bottle") Aqueduct, the third section which leads the waters into the Chengdu Plain. The bed of the outer river is convex while that of the inner river is concave. This fact, an integral part of Li Bing's original design, results in less slit going into the inner river which is primarily used for irrigation.