Dujiangyan Irrigation system
What is Dujiangyan Irrigation System and Why it is so unique?
The Dujiangyan Irrigation System is a water conservancy system which was built 2300 years ago.
It is the world's oldest and the only remaining hydraulic project with no dam.
It regulates the Min River and helps the Chengdu plain to be the “Land of Abundance” and it is still functioning today and survived the 2008 powerful earthquake.
Located in Dujiangyan City, which is in the transition zone of Sichuan Basin and Tibetan Plateau, Dujiangyan Irrigation System is about 70km from Chengdu and will take 1.5 hours drive to get to. It can also be reached by city trains and public transport.
The motivation and plan
Dujiangyan irrigation system was built in around 256 BC, no far from Archimedes found the principle of Buoyancy when he was bathing. At that time, China was in the war states period. The state Qin conquered Shu, centered Chengdu Plain today. Chengdu Plain is at the west edge of Sichuan Basin, adjacent to Tibetan Plateau where many big rivers originate. A main branch of Yangtze river, called Min river flow through Chengdu and flooded every year. The King of Qin State wanted it to be controlled because one is for use it as a military water channel and also develop the agriculture in the fertile Chengdu plain as to make a breadbasket for Qin.
Li Bing’s Legacy
As an outstanding hydrologist more than 2000 years ago, he was assigned to be the governor of Shu with a mission, to build a project that settle the unrest of Min River. After many local research and hearing people’s ideas, he chose the place where Dujiangyan is today and used many advanced principles and methods at that time.
The Dujingyan irrigation had successfully been bulit and from that time , Chengdu plain was free from flooding and became “the land of abundance. The rich agriculture production and convenient water transportation contributed the first unification of Qin Dynasty.
Components and Engineering Principles
Dujiangyan Irrigation System mainly composed of three parts, namely the Fish Mouth Diversion(Yuzui), the Sand-flying weir(Feishayan) and the bottle-neck channel(Baopingkou), each play a different role and function.
By separating the river into inner and outer river in a designed proportion, it can ensure the water flow into the bottle-neck channel in dry season and make the water mainly flow to the outer river in flood season in order to protect the irrigation ara.
A weir helps to reduce the silt carried by the inner river. It has used some simple but efficient hydro-mechanics principle to ensure the the sedimentation in inner river is under control.
A bottle-neck shaped waterway which leads the water to Chengdu Plain.
What else to expect in Dujiangyan
Dujiangyan has beautiful scenery and numerous cultural relics and historic sites, mainly including Fulong Temple, Erwang Temple, Anlan Suspension Bridge, Lidui park and so on.