The Karez Irrigation System, located in the Turpan Basin, Xinjiang, China, is a qanat system that has been listed as one of the three greatest water projects of ancient China together with the Du Jiang Yan Irrigation System, and the Grand Canal. The karez is an important invention by the Turpan people. The word karez means "well" in the local Uyghur language.

 

 

Turpan's Karez Irrigation System is made up of a horizontal series of vertically dug wells that are then linked by underground water canals to collect water from the watershed surface runoff from the base of the Tian Shan Mountains and the nearby the Flaming Mountains. The canals channel the water to the surface, taking advantage of the current provided by the gravity of the downward slope of the Turpan Basin. The canals are mostly underground to reduce water evaporation.

 

 

The system has wells, dams and underground canals built to store the water and control the amount of water flow. Vertical wells are dug at various points to tap into the water current flowing down sloping land from the source, the mountain runoff. The water is then channeled through underground canals dug from the bottom of one well to the next well and then to the desired destination, Turpan's irrigation system.