Introduction to Sandaoyan: The two major tributaries of Dujiangyan - Baitiao River and Xuyan River run through the ancient town. The town got its name because the ancients used bamboo baskets to intercept water in the lower reaches of the Baitiao River and made three closely spaced weirs to guide water to irrigate the fields. It is an ancient water town in western Sichuan with a long history. The town has the "Sixth Chengdu Tap Water Plant" with a water supply capacity of 1.45 million tons, which is the largest domestic water plant in the western region.