The Turpan water system or Turfan karez system ug, كارىز, kariz, 6=кариз) in

Turpan Turpan (also known as Turfan or Tulufan, , ug, تۇرپان) is a prefecture-level city located in the east of the autonomous region of Xinjiang, China. It has an area of and a population of 632,000 (2015). Geonyms The original name of the cit ...

, located in the Turpan Depression,

Xinjiang Xinjiang, SASM/GNC: ''Xinjang''; zh, c=, p=Xīnjiāng; formerly romanized as Sinkiang (, ), officially the Xinjiang Uygur Autonomous Region (XUAR), is an autonomous region of the People's Republic of China (PRC), located in the northwes ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...

, is a vertical tunnel system adapted by the

Uyghur people The Uyghurs; ; ; ; zh, s=, t=, p=Wéiwú'ěr, IPA: ( ), alternatively spelled Uighurs, Uygurs or Uigurs, are a Turkic ethnic group originating from and culturally affiliated with the general region of Central and East Asia. The Uyghu ...

. The word ''karez'' means "well" in the local

Uyghur language The Uyghur or Uighur language (; , , , or , , , , CTA: Uyğurçä; formerly known as Eastern Turki), is a Turkic language written in a Uyghur Perso-Arabic script with 8-11 million speakers, spoken primarily by the Uyghur people in the Xi ...

. Turpan has the

Turpan Karez Paradise Turpan Karez Paradise () is a museum featuring Turpan's karez water management system, in Turpan, a city in the Turpan Depression, Xinjiang, China. The karez is a vertical tunnel system connecting wells developed by the Turpan people to ir ...

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 A qanat or kārīz is a system for transporting water from an aquifer or water well to the surface, through an underground aqueduct; the system originated approximately 3,000 BC in what is now Iran. The function is essentially the same across ...

well system was crucial in Turpan's development as an important

oasis In ecology, an oasis (; ) is a fertile area of a desert or semi-desert environment'ksar''with its surrounding feeding source, the palm grove, within a relational and circulatory nomadic system.” The location of oases has been of critical imp ...

stopover on the ancient

Silk Road The Silk Road () was a network of Eurasian trade routes active from the second century BCE until the mid-15th century. Spanning over 6,400 kilometers (4,000 miles), it played a central role in facilitating economic, cultural, political, and rel ...

skirting the barren and hostile

Taklamakan Desert The Taklimakan or Taklamakan Desert (; zh, s=塔克拉玛干沙漠, p=Tǎkèlāmǎgān Shāmò, Xiao'erjing: , dng, Такәламаган Шамә; ug, تەكلىماكان قۇملۇقى, Täklimakan qumluqi; also spelled Taklimakan and T ...

. Turpan owes its prosperity to the water provided by its karez well system.

Description

Turpan's karez water system is made up of a horizontal series of vertically dug

well A well is an excavation or structure created in the ground by digging, driving, or drilling to access liquid resources, usually water. The oldest and most common kind of well is a water well, to access groundwater in underground aquifers. The ...

s that are then linked by underground water

canal Canals or artificial waterways are waterways or engineered channels built for drainage management (e.g. flood control and irrigation) or for conveyancing water transport vehicles (e.g. water taxi). They carry free, calm surface f ...

s to collect water from the

watershed Watershed is a hydrological term, which has been adopted in other fields in a more or less figurative sense. It may refer to: Hydrology * Drainage divide, the line that separates neighbouring drainage basins * Drainage basin, called a "watershe ...

surface runoff Surface runoff (also known as overland flow) is the flow of water occurring on the ground surface when excess rainwater, stormwater, meltwater, or other sources, can no longer sufficiently rapidly infiltrate in the soil. This can occur when t ...

from the base of the Tian Shan Mountains and the nearby

Flaming Mountains The Flaming Mountains () or Huoyan Mountains, are barren, eroded, red sandstone hills in the Tian Shan of Xinjiang. They lie near the northern rim of the Taklamakan Desert and east of the city of Turpan. Their striking gullies and trenches caused b ...

. The canals channel the water to the surface, taking advantage of the current provided by the

gravity In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the stro ...

of the downward

slope In mathematics, the slope or gradient of a line is a number that describes both the ''direction'' and the ''steepness'' of the line. Slope is often denoted by the letter ''m''; there is no clear answer to the question why the letter ''m'' is use ...

of the Turpan Depression. The canals are mostly underground to reduce water

evaporation Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when h ...

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 Groundwater is the water present beneath Earth's surface in rock and Pore space in soil, soil pore spaces and in the fractures of stratum, rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit ...

flowing down sloping land from the source, the mountain

runoff Runoff, run-off or RUNOFF may refer to: * RUNOFF, the first computer text-formatting program * Runoff or run-off, another name for bleed, printing that lies beyond the edges to which a printed sheet is trimmed * Runoff or run-off, a stock marke ...

. 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 Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow crops, landscape plants, and lawns. Irrigation has been a key aspect of agriculture for over 5,000 years and has been devel ...

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

, 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. Turpan is located in the second deepest geographical depression in the world, with over of land below

sea level Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardis ...

and with soil that forms a sturdy basin. 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 Turpan summer is very hot and dry with periods of wind and blowing sand.

Importance

Ample water was crucial to Turpan, so that the oasis city could service the many caravans on the Silk Route resting there near a route skirting the

. The caravans included merchant traders and

missionaries A missionary is a member of a religious group which is sent into an area in order to promote its faith or provide services to people, such as education, literacy, social justice, health care, and economic development.Thomas Hale 'On Being a Mi ...

with their armed escorts, animals including camels, sometimes numbering into the thousands, along with camel drivers, agents and other personnel, all of whom might stay for a week or more. The caravans needed pastures for their animals, resting facilities, trading

bazaar A bazaar () or souk (; also transliterated as souq) is a marketplace consisting of multiple small stalls or shops, especially in the Middle East, the Balkans, North Africa and India. However, temporary open markets elsewhere, such as in t ...

s for conducting business and replenishment of food and water.

Potential UNESCO World Heritage Site

Karez wells in the Turfan area are on the UNESCO World Heritage Sites Tentative List for China.

Threatened by global warming

There are 20,000 glaciers in Xinjiang – nearly half of all the glaciers in China. The water from the glaciers via the underground channels has provided a stable water source year round, independent of season, for thousands of years. But since the 1950s, Xinjiang's glaciers have retreated by between 21 percent to 27 percent due to

global warming In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to ...

, threatening the agricultural productivity of the region.

References

External links