Turpan Karez Well
Image Karez Well is a kind of underground water works invented and built by laboring people of various Chinese ethnic groups to transform the natural environment of the dry region.Karez Well system is the pride of Turpan. It along with the Great Wall and Grand Beijing-Hangzhou Canal is regarded as the three most important achievements of ancient time.
Karez well was listed as one of the three greatest irrigation systems in ancient China together with the Jinghang manmade cannel, and the Dujiangyan Irrigation System. Karez means “underground” in the Uygur language. Xinjiang Province has over 1,600 Karez such systems with most of which are in Turpan. There are about 1,200 such systems in Turpan, some 850 of which are in active use.
The water comes from snow on Tianshan Mountain and underground water. The reason Karez well was built underground is to prevent water from evaporating. Melting snow from the Tianshan Mountain is the water source of the karez. Water is collected by vertical wells and conducted by the underground canals to the oasis, where the water is held in the ground canals for irrigation. The vertical wells near the water source may be 100 meters (328 feet) deep while further downstream they are less than 10 meters (32.8 feet) deep.
Keraz systems are very elaborate irrigation systems. It make up of vertical wells, underground ditches, ground ditches and small reservoirs. The depth of the vertical wells and the space between them depends on their distance to the water source. Generally speaking, the ones in the upriver are deeper and more spaced than that in the lower reaches. Space between each vertical well in the up reaches ranges from 30 to 70 meters while in lower reaches it is about 10 to 20 meters. The deepest vertical well is over 90 meters. Karez Well system is usually 3 to 8 kilometers long with the longest one measuring up to 20 kilometers. The vertical wells are for ventilation and maintenance of the Karez. The underground ditches are connected with the surface ones to lead the water up to the ground.For most Turpan people, Karez wells still play the role of a lifeline, given the special weather condition. A Karez well normally consists of a silo, underground and above ground canals, and a water-storage dam.
There are, altogether, over 1000 Karez wells in the Turpan basin, the total length of which would exceed that of Yangtze River, the longest river in China. The earliest construction dates back to at least 1000 years ago. Karez wells are only to be found in the Turpan area of Xinjiang.
Karez systems also functions as the natural air conditioner for the locals because they can sit in one while chatting or doing some chores. When exhausted during the scorching weather, sit in a karez, pick some grapes as they hang over the vertical wells and savour their taste, you will be thoroughly refreshed!