Built around 256 BC under
李冰, the Qin governor of Shu, it splits the
岷江 (Min River) into an inner and an outer channel with a levee shaped like a fish's mouth instead of a dam, so floods pass by and water reaches the fields. It made the Chengdu Plain the
天府之国, the 'land of abundance', and is a World Heritage site. The city around it is
都江堰市.