Qanat

Originating approximately 3,000 years ago,[1] its function is essentially the same across the Middle East and North Africa, but it is known by a variety of regional names beyond today's Iran, including: kārēz in Afghanistan and Pakistan; foggāra in Algeria; khettāra in Morocco; falaj in Oman and the United Arab Emirates; and ʿuyūn in Saudi Arabia.

[1] In addition to those in Iran, the largest extant and functional qanats are located in Afghanistan, Algeria, China (i.e., the Turpan water system), Oman, and Pakistan.

To date, the qanat system still ensures a reliable supply of water for consumption and irrigation across human settlements in hot, arid, and semi-arid climates, but its value to a population is directly related to the quality, volume, and regularity of the groundwater in the inhabited region.

[19] In arid and semi-arid regions, owing to high evaporation, transportation routes were in the form of qanats, which led groundwater to consumption areas along underground tunnels.

In contrast, the origin of the spring-flow tunnel was the development of a natural spring to renew or increase flow following a recession of the water table.

As a result, the cities and towns are oriented consistent with the gradient of the land; this is a practical response to efficient water distribution over varying terrain.

Selection criteria included the availability of a steady groundwater flow, social cohesion and willingness to contribute of the community using the qanat, and the existence of a functioning water-rights system.

The width is approximately 60 cm (24 in), but the height ranges from 5 to 9 meters; it is likely that the qanat was deepened to enhance seepage when the water table dropped (as is also seen in Iran).

On the margins of the Sahara Desert, the isolated oases of the Draa River valley and Tafilalt have relied on qanat water for irrigation since the late 14th century.

The 1971 Hassan Adahkil Dam's build in the main course of the Ziz River[32] and its subsequent impact on local water tables is said to be one of the many reasons for the loss of half of the khettara.

According to an inscription left by Sargon II, the king of Assyria, in 714 BCE he invaded the city of Uhlu lying in the northwest of Uroomiye lake that lay in the territory of Urartu empire, and then he noticed that the occupied area enjoyed a very rich vegetation even though there was no river running across it.

For example, following Darius's order, Silaks the naval commander of the Persian army and Khenombiz the royal architect managed to construct a qanat in the oasis of Kharagha in Egypt.

The most reliable document confirming the existence of qanats at this time was written by Polybius who states that: "the streams are running down from everywhere at the base of Alborz mountain, and people have transferred too much water from a long distance through some subterranean canals by spending much cost and labor."

In a study by Russian orientalist scholars it has been mentioned that: the Persians used the side branches of rivers, mountain springs, wells and qanats to supply water.

In Iran, the advent of Islam, which coincided with the overthrow of the Sassanid dynasty, brought about a profound change in religious, political, social and cultural structures.

For example, according to the "Incidents of Abdollah bin Tahir's Time" written by Gardizi, in 830 CE a terrible earthquake struck the town of Forghaneh and reduced many homes to rubble.

Later, in the era of the Ilkhanid dynasty especially at the time of Ghazan Khan and his Persian minister Rashid al-Din Fazl-Allah, some measures were taken to revive the qanats and irrigation systems.

[52] Valliyil Govindankutty, assistant professor in geography at Government College, Chittur, was responsible for rediscovery and mapping of the Naubad Karez System in 2012-2013.

[56][57] Detailed documentation of the Naubad karez system was done in August 2013 and a report was submitted to District Administration of Bidar that found several new facts.

The system starts at Torwi and extends as shallow aqueducts and further as pipes; further it becomes deeper from the Sainik school area onward which exists as a tunnel dug through the geology.

It has been suggested that underground temples at Gua Made in Java reached by shafts, in which masks of a green metal were found, originated as a qanat.

[61] Partly following the course of an older Hellenistic aqueduct, excavation work arguably started after a visit by emperor Hadrian in 129–130 CE.

The role of sarrishta in some cases hierarchical and passing from generations within the family and he must have the knowledge of the criteria of unbiased distribution of water among different issadar.

The twelve-hour water quota again subdivided into several sub-fractions of local measuring scales such as tas or pad (Dr Gul Hasan Pro VC LUAWMS, 2 day National conference on Kech).

[33] In Oman from the Iron Age period (found in Salut, Bat and other sites) a system of underground aqueducts called 'Falaj' were constructed, a series of well-like vertical shafts, connected by gently sloping horizontal tunnels.

[66] Islamic geographer Al Muqqadasi stated: "Hafit {Tuwwam} abounds in palm trees" in the 10th century, indicating extensive use of the falaj system.

The falaj system is still operating in the city of Al Ain, as well as in multiple mountainous settlements, including the villages of Wadi Shees and Masafi.

The 5,653 m (3.513 miles) long Tunnels of Claudius, intended to partially drain the largest Italian inland water, Fucine Lake, was constructed using the qanat technique.

[75] In an August 21, 1906, letter written from Tehran, Florence Khanum, the American wife of Persian diplomat Ali Kuli Khan, described the use of qanats for the garden at the home of her brother-in-law, General Husayn Kalantar,[76] January 1, 1913[77] "The air is the most marvellous I ever was in, in any city.

(This omnipresence of water, which doubtless spread from Persia to Baghdad and from there to Spain during its Muslim days, has given Spanish many a water-word: aljibe, for example, is Persian jub, brook; cano or pipe, is Arabic qanat—reed, canal.