Turpan's karez water 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 Turfan Depression. The canals are mostly underground to reduce water evaporation.[7]
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, Turfan's irrigation system.[7] This irrigation system of special connected wells originated during the Han Dynasty (206 BC – 24 AD).[1]
In Xinjiang, the greatest number of karez wells are in the Turfan Depression, where today there remain over 1100 karez wells and channels having a total length of over 5000 kilometers. The local geography makes karez wells practical for agricultural irrigation and other uses. Turfan is located in the second deepest geographical depression in the world, with over 4,000 square kilometers of land below sea level and with soil that forms a sturdy basin.[7] 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 Turfan summer is very hot and dry with periods of wind and blowing sand. The water from the underground channels provides a stable water source year round, independent of season.
Turfan water system - Wikipedia, the free encyclopedia
