What did Dujiangyan Irrigation System look like?

Composed of three main structures: the Yuzui (Fish Mouth) diversion levee, the Feishayan (Flying Sand Weir) spillway, and the Baopingkou (Bottle-Neck) intake. The Yuzui splits the Min River into the Inner and Outer Rivers.

How did Dujiangyan Irrigation System work?

Yuzui bend → surface clear water enters Inner River, bottom sediment-laden water enters Outer River → Inner River water reaches Feishayan → excess floodwater automatically spills into Outer River → Baopingkou constriction → constant flow rate enters the Chengdu Plain irrigation network.

← DiscoveriesS-Tier · Foundational

都江堰

Dujiangyan Irrigation System

A dam-free gravity-flow diversion project: bend circulation automatically discharges sediment, the Baopingkou throat controls flow rate, and the Feishayan weir automatically spills floods. Still operating after 2200+ years — a masterpiece of fluid mechanics.

都江堰

Scientific Principle

Bend circulation: water surface slope drives surface flow toward the concave bank and bottom flow toward the convex bank. Critical flow control: the Baopingkou constriction creates a Venturi effect for constant flow rate.