The Dujiangyan Dam, 45km north of Chengdu, is an ancient technological wonder of the country. More than 2000 yers ago, Li Bing(250-200BC), as a local governor of the Shu State, designed this water control and irrigation dam and organized thousands of local people to complete the project to check the Mingjiang River.For many years the river,flooded the Chengdu agricultural area and local farmers suffered a lot from the water disaster. Due to the success of the project, the dam automatically diverts the Mingjiang River and channels it into irrigation canals. For many years the dam has continued to make the most of the water conservancy works.

　　Expansion has been undertaken since 1949 and at present the system does a good job of irrigating farming land across 33counties of the western part of Sichuan Province. Local people feel proud of the system becaude it has supported a large amount of people in their daily life.

　　What makes this system so good?

　　The system is a large hydraulic water project which consists of three main parts: the Fish Mouth Water-Dividing Dam, the Flying Sand Fence, and the Bottle-Neck Channel.

　　The Fish mouth functions to divide the flow of water into an inner river and an outer river. Long ago, when Li Bing worked as the local governor of the Shu State, he found the old river canal was too narrow to hold much water, which often overflowed the banks and caused disastrous flood. Based on natural geographic conditions, he organized the people to build a man-made dam. The whole dam looks like a fish, and the front dam has a circular cone shaped like a fish mouth. It is the dam that channels water into an outer canal and an inner canal. The outer water canal functions as the main stream and holds sixty percent of water in the river. The extra water goes through the inner canal for irrigation in Chengdu areas.

　　The Flying Sand Fence joins the inner and outer canals. The fence functions to controll the flow of w