Qanat is the Arabic equivalent of Kariz, it is a name used for an Iranian irrigation system. In this system, underground channels bring water from underground water sources to the lowlands. Moghani or well diggers build a Kariz.
Through Qanat, Iranians made life possible in arid plateaus and provided water for the purpose of agriculture and drinking. Besides, in some cases, the Qanat is equipped with a place for its workers to rest and shower, and some of which had even watermills. This application of Qanat offers an exclusive cultural tradition and collective management of water reservoir over centuries. This is the reason that the Iranian central plateau’s civilization is known as Qanat Civilization. What is more important is the fact that in many rural regions, Qanat is still used for agricultural purposes.
Qanat is a series of parallel wells with different height linked together under the ground by a horizontal channel. The horizontal channel is the water passage that moves the water from the mountain to the city.
The main stages of digging Qanat consist of mother-Qanat, subsidiary wells and Qanat outlet.
Mother-Qanat or Mother-Well is the main vertical channel and the first one to be dug; it is the furthest well to the outlet. Finding its location is the most sensitive stage of digging Qanat. Usually, the place having plenty of vegetation is the right place of digging Mother-Qanat. The depth of Mother-Well is different which is determined by the well digger. Today, the deepest Iranian Mother-Well is Qanat of Ghasabe in Gonabad, the depth of its Mother-Well is about 300 meters.
Subsidiary wells or the mills are like a cylindrical channel that help transfer excavated material out, control the quality of water and ease repairing if necessary.
The outlet of Qanat is the place that water comes out and appears on the surface of land. The depth of channels from mother Qanat to the outlet decreases so the deepest one is the Mother-Well and the shallowest one is the Outlet Well.
The size of Kariz depends on the features of geolocation of the area. In mountainous areas, they are short and having low depth while in deserts they are long and deep. The most important factor in determining the length of Qanat is the slope of land, when the land is not steep the length of Qanat becomes longer.
11 Iranian Qantas registered on the UNESCO Heritage List:
Ghasabe Qanat (Khorasan Razavi): This oldest and largest Qanat of the world was excavated between 4th to 6th centuries B. C., at the time of the Achaemenid Empire. This Qanat consists of more than 400 shafts, while the depth of mother shaft (main shaft) is 300 meters.
Mozdabad Qanat (Isfahan): The presence of stalactites and stalagmites in this Qanat represent an exclusive feature of a cave. Archaeological excavations suggest that this Qanat is the second oldest Qanat in Iran and exists since two thousand years ago.
Qanat of Baladeh (South Khorasan): The construction of this Qanat dates back to Sassanid Empire. The shaping and development of Ferdows city and its surrounded villages were highly depended on this Qanat. It has 15 shafts and four fluent wells.
Qanat of Zarch (Yazd): With a length of 120 km, Qanat of Zarch is the longest one in Iran. Surprisingly, this Sassanid Qanat consists of two thousand and fifteen shafts.
Hasan Abad-e Moshir Qanat (Yazd): This Qanat was constructed in the 14th century CE in Mehriz. The relatively high discharge rate and low depth of Qanat stretched between Mehriz and Yazd and the quality of water have made this Qanat unique. Since the water stream in the channels contains salt and is limestone free, people of distant areas can have pure water without any residual minerals.
Qanat of the Moon (Isfahan): This 800-year-old Qanat is exclusive with two levels of water lying over each other. In this Qanat because of its soil formation, water of second level does not penetrate the first level.
Qanat of Vazvan (Isfahan): The Qanat of Vazvan with 1800-meter length was built at the time of Sassanid Empire. Three underground dams are constructed on its channels. The exclusive feature of this Qanat is the feasibility of closing its exit shaft in winters. In turn, this function helps to save water behind dams for agricultural purposes during spring.
Qanat of Goharriz (Kerman): Goharriz is a fully operational Qanat in Jupar County built in Safavid era. With a total of 3556-meter channels, it waters more than 330-hectare arid lands in Kerman province.
Ebrahim Abad Qanat (Markazi): The Qanat of Ebrahim Abad (12th century CE) consists of 311 shafts and the mother well is 53 meters deep.
Qanat of Ghāsem Abad and Qanat of Akbar Abad (Kerman): These two lines of Qanat are close to each other have provided sufficient water for farming and agriculture for many villages in Kerman. Qanat of Ghāsem Abad and Qanat of Akbar Abad are relatively new aged only 100 years.