Turpan water system

The Turpan water system or Turfan karez system kariz) in Turpan, located in the Turpan Depression, Xinjiang, China, is a vertical tunnel system adapted by the Uyghur people. The word karez means "well" in the local Uyghur language. Turpan has the Turpan Karez Paradise museum (a Protected Area of the People's Republic of China) dedicated to demonstrating its karez water system, as well as exhibiting other historical artifacts. Turpan's karez well system was crucial in Turpan's development as an important oasis stopover on the ancient Silk Road skirting the barren and hostile Taklamakan Desert. Turpan owes its prosperity to the water provided by its karez well system. 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 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 Depression. The canals are mostly underground to reduce water evaporation and to make the slope long enough to reach far distances being only gravity fed. 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 groundwater 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 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. In Xinjiang, the greatest number of karez wells are in the Turpan Depression, where today there remain over 1100 karez wells and channels having a total length of over . The local geography makes karez wells practical for agricultural irrigation and other uses.