Turpan water system

The canals channel the water to the surface, taking advantage of the current provided by the gravity of the downward slope of the Turpan Depression.

Turpan's karez irrigation system of special connected wells is believed to be of indigenous origin in China, perhaps combined with technology arriving from more western regions.

Turpan is located in the second deepest geographical depression in the world, with over 4,000 km2 (1,500 sq mi) of land below sea level and with soil that forms a sturdy basin.

[3] Water naturally flows down from the nearby mountains during the rainy season in an underground current to the low depression basin under the desert.

The caravans needed pastures for their animals, resting facilities, trading bazaars for conducting business and replenishment of food and water.