Qanats: Underground Aqueducts- A reliable Source of Water in Arid Climate

 Qanat are series of well-like vertical shafts, connected by gently sloping tunnels. they create a reliable supply of water for human settlements and irrigation in hot, arid, and semi-arid climates.

 Persians started constructed elaborate tunnel systems called qanats for getting groundwater in the dry mountain basins of present-day Iran . Qanat tunnels were hand-dug, just large enough to fit the person doing the digging. Along the length of a qanat, which can be several kilometers, vertical shafts were sunk at intervals of 20 to 30 meters to remove excavated material and to provide ventilation and access for repairs. The main qanat tunnel sloped gently down from pre-mountainous alluvial fans to an outlet at a village. From there, canals would distribute water to fields for irrigation. These amazing structures allowed Persian farmers to succeed despite long dry periods when there was no surface water to be had. Many qanats are still in use stretching from China on the east to Morocco on the west, and even to the Americas.

Qanats are constructed as a series of well-like vertical shafts, connected by gently sloping tunnels. Qanats tap into subterranean water in a manner that efficiently delivers large quantities of water to the surface without need for pumping. The water drains by gravity, with the destination lower than the source, which is typically an upland aquifer. Qanats allow water to be transported over long distances in hot dry climates without loss of much of the water to evaporation.

Etymology

Qanats are also called kārīz (or kārēz from Persian: كاريز‎) (Iran, Afghanistan, Pakistan and Central Asia, derived from Persian: كاهریز‎), kahan (from Persian: کهن‎), kahriz/kəhriz(Azerbaijan); khettara (Morocco); galería (Spain); falaj (from Arabic: فلج‎) (United Arab Emirates and Oman); Kahn (Baloch) or foggara/fughara (North Africa).[8] Alternative terms for qanats in Asia and North Africa are kakuriz, chin-avulz, and mayun. Common variants of qanat in English include kanat, khanat, kunut, kona, konait, ghanat,ghundat.

In Urban systems

In some cities, water in qanats flows in tunnels beneath residential areas and surfaces near the cultivated area. Staircases from the surface reach down to these streams. The first access is usually at a public cistern where drinking water is available to the entire community. Sometimes these cisterns are sizable vaults as much as 10 meters across and 15 or more meters deep with spiral stairs leading down to small platforms at water level. In cities like Herat in Afghanistan, these cisterns are ancient constructions encased in tile. Other more modest urban access points are found along major streets, and even in some alleys, a factor that probably played an important role in the social and physical layout of the town.

Where tunnels run beneath houses, private access points provide water for various domestic uses. In wealthy homes, special rooms are constructed beside the underground stream with tall shafts reaching upward to windtowers above roof level. Air caught by the windtowers, which are oriented to prevailing summer winds, is forced down the shaft, circulates at water level, and provides a cool refuge from the afternoon heat of summer.

Qanats are build by a special group of masons called Mugannis in Iran and Karez Kan in Afghanistan. They inherit the skill of Qanat making from there forefathers.

read more here:

http://en.wikipedia.org/wiki/Qanat

http://www.waterhistory.org/histories/qanats/

Traditional Water Harvesting Systems of India

References

Afkhami, A., 1997, “Disease and Water Supply: The Case of Cholera in 19th Century Iran,” Proceedings of Conference: Transformations of Middle Eastern Natural Environments: Legacies and Lessons, Yale University, October.

Bahadori, M. N., 1978, “Passive Cooling Systems in Iranian Architecture,” Scientific American, February, pp.144-154.

Beekman, C. S., P. S. Weigand, and J. J. Pint, 1999, “Old World Irrigation Technology in a New World Context: Qanats in Spanish Colonial Western Mexico,” Antiquity 73(279): 440-446.

English, P., 1997, “Qanats and Lifeworlds in Iranian Plateau Villages,” Proceedings of the Conference: Transformation of Middle Eastern Natural Environment: Legacies and Lessons, Yale University, October.

Lightfoot, D., 2003, “Traditional Wells as Phreatic Barometers: A View from Qanats and Tube Wells in Developing Arid Lands,” Proceedings of the UCOWR Conference: Water Security in the 21st Century, Washington, DC, July.

Pazwash, N. 1983. “Iran’s Mode of Modernization: Greening the Desert, Deserting the Greenery,” Civil Engineering, March. pp. 48-51.

United Nationals Environmental Programme, 1983. Rain and Water Harvesting in Rural Area. Tycooly International Publishing Limited, Dublin, pp 84-88.

Wessels, K (2000), Renovating Qanats in a changing world, a case study in Syria, paper presented to the International Syposuim on Qanats, May 2000, Yazd, Iran.

Wulff, H.E., 1968, “The Qanats of Iran,” Scientific American, April, p. 94-105. (http://users.bart.nl/~leenders/txt/qanats.html)

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About Rashid Faridi

I am Rashid Aziz Faridi ,Writer, Teacher and a Voracious Reader.
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One Response to Qanats: Underground Aqueducts- A reliable Source of Water in Arid Climate

  1. Pingback: Time Tested Ancient Water Harvesting Systems In India | Rashid's Blog

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