A qanāt (Persian: قَنَات) or kārīz (کَارِیز) is a water system created in ancient Iran to move water from underground sources, like aquifers or wells, to the surface through underground tunnels. This system was developed about 3,000 years ago and works similarly in many areas of Asia and North Africa, though it has different names in other regions. For example, it is called kārēz in Afghanistan and Pakistan, foggāra in Algeria, khettāra in the Atlas Mountains, daoudi-type falaj in Oman and the United Arab Emirates, and ʿuyūn in Saudi Arabia. The largest working qanats today are found in Iran, Afghanistan, Xinjiang in China (known as the Turpan water system), Oman, and Pakistan. These systems were also used in parts of Europe during the Roman Empire and later in Muslim-ruled Spain. Some experts believe similar systems may have existed in the Americas before European explorers arrived.
This system is especially important in hot, dry areas because it helps move water long distances without much of it evaporating. It is also strong against natural events like floods and earthquakes, as well as human-caused problems like wartime damage or attacks on water supplies. The system is not greatly affected by changes in rainfall, providing a steady water flow even during dry years.
A typical qanat has a gently sloping underground tunnel that is accessed by vertical shafts, which look like wells at the surface. This design allows groundwater to flow by gravity to a lower location far away, without needing pumps. The vertical shafts are used for maintenance, and water is only used once it reaches the surface.
Today, qanats still provide water for drinking and farming in hot, dry, and semi-dry areas. However, their usefulness depends on the quality, amount, and consistency of groundwater in the region. Since ancient times, qanats have been vital for many communities outside of Iran, and many long-inhabited areas in West Asia and North Africa are located where qanats could be built and maintained.
Etymology
The word "qanat" comes from Akkadian, where it was "qanû(m)," meaning "reed." This refers to the reed beds that grew in the wetlands of southern Mesopotamia. The Hebrew word "qāne" means "wild reed plant" or "tubular rod, stick," which was passed down from this Akkadian term. In Arabic, the word "qanāh" (قناة) means "spear" or "channel." In Persian, two terms are used: "kārīz" or "kārēz" (کاريز), which comes from the earlier word "kāhrēz" (کاهریز); and "qanāt" (قنات). Other names for qanat include "kahan" (Persian: کهن), "kahn" (Balochi), "kahriz/kəhriz" (Azerbaijan), "khettara" (Morocco), "galerías, minas, or viajes de agua" (Spain), "daoudi-type falaj" (Arabic: فلج) (United Arab Emirates and Oman), and "foggara/fughara" (North Africa). In Asia and North Africa, other names for qanats are "kakuriz," "chin-avulz," and "mayun."
The Oxford English Dictionary says the origin is "Persian, from Arabic qanät 'reed, pipe, channel.'" Common English variations of "qanat" include "kanat," "khanat," "kunut," "kona," "konait," "ghanat," "ghundat," and "quanat."
Origins
Qanat technology was created by ancient Iranians around the early 1st millennium BCE. It gradually spread to the west and east from there. Some sources suggest it may have originated in Southeast Arabia. Similar water systems were developed separately in China and southern Peru.
A type of cotton, Gossypium arboreum, is naturally found in South Asia and has been grown in the Indian subcontinent for many years. Cotton is mentioned in ancient writings, including Theophrastus’s Inquiry into Plants and the Laws of Manu. As trade routes expanded, cotton spread from South Asia to the Middle East. One theory suggests qanats were built to irrigate cotton fields in what is now Iran, doubling the water available for farming and city use. This led to greater food production in Persia, which increased city growth and social differences. Later, qanat technology spread from Persia to the west and east.
In the dry coastal desert of Peru, a water system similar to qanats called puquios was developed. Most archaeologists believe puquios are indigenous and date to about 500 CE. A few think they were introduced by Spanish people in the 16th century. Puquios were still used in the Nazca region as recently as the 21st century.
Features
The Underground Aqueducts Handbook (2016)
Qanats are built using a series of vertical shafts, similar to wells, connected by a gently sloping tunnel that carries a water canal. Qanats move large amounts of underground water to the surface without needing pumps. Water flows by gravity, usually from an aquifer in higher areas, to a lower destination. Qanats transport water over long distances in hot, dry climates with little loss to evaporation.
Qanats often begin below mountain foothills, where groundwater is close to the surface. The tunnel slopes gently downward, matching the land’s slope above, and the water flows out where the two levels meet. To bring water to populated or farmland areas, qanats may extend for long distances.
Sometimes, qanats are divided into smaller underground canals called kariz. These canals stay underground to prevent water from evaporating or becoming polluted. In some cases, water from a qanat is stored in a reservoir, often for use during the day. An ab anbar is a traditional Persian reservoir that stores drinking water from qanats.
Qanats are strong against natural disasters like floods and damage during wars. They also work well regardless of rainfall levels, providing steady water flow even during dry years. Since qanats rely only on gravity, they have low costs for operation and maintenance. They bring fresh water from mountain plateaus to lower areas with saltier soil, helping to reduce soil saltiness and stop desertification.
Qanats should not be confused with spring-flow tunnels found near Jerusalem. Both use gravity to move water, but they differ in key ways. First, qanats began as artificial springs made from wells, while spring-flow tunnels were created by improving natural springs after water levels dropped. Second, qanats require vertical shafts for construction, but spring-flow tunnels do not.
Impact on settlement patterns
A typical town or city in Iran and other places where qanats are used has more than one qanat. Fields and gardens are often found just above the qanats, near where they come out of the ground. They are also located below the surface where water exits. Water from the qanats determines the social areas in the city and the way the city is laid out.
The water is freshest, cleanest, and coolest in the upper parts. Wealthier people usually live near the outlet or just upstream from it. When the qanat is still underground, water is brought to the surface through wells or Persian wells powered by animals. Private underground reservoirs can supply water for homes, buildings, and gardens. Air from the qanat is used to cool a cool underground room called a shabestan, which is found in many older homes and buildings.
After the water exits the qanat, it flows through surface canals called jubs, which run downhill. These canals have side branches that carry water to neighborhoods, gardens, and fields. Streets in the city usually run parallel to the jubs and their branches. Because of this, cities and towns are arranged in a way that matches the slope of the land. This helps distribute water efficiently across different types of terrain.
The lower parts of the canals are less desirable for homes and farming. Water becomes more polluted as it moves downstream. In dry years, the lower parts are most likely to experience a large drop in water flow.
Construction
Traditionally, qanats are built by a group of skilled workers called muqannīs using manual labor. This profession was historically well-paid and often passed from father to son.
The first step in building a qanat is finding a suitable water source. The search usually begins where mountain slopes meet flat areas called alluvial fans, as water is more plentiful in mountains due to a process called orographic lifting. Excavation is easier in alluvial fans. Muqannīs follow the paths of water flowing from mountains to look for signs of underground water, such as plants with deep roots or wet spots on the ground. A test well is then dug to check the depth of the water table and determine if enough water flows to justify building the qanat. If these conditions are met, the route is marked aboveground.
Tools needed include containers (usually leather bags), ropes, reels to lift materials to the surface, hatchets and shovels for digging, lights, and tools like spirit levels or plumb bobs and string. Depending on the soil type, fired clay hoops may also be used to line the qanat.
Although the methods are simple, building a qanat requires knowledge of underground geology and careful engineering. The slope of the qanat must be precise: too shallow and water will not flow, while too steep can cause erosion and collapse. Misjudging soil conditions can lead to collapses, which may require major repairs or even endanger workers.
A qanat is typically built by a crew of 3–4 muqannīs. For shallow qanats, one worker digs the horizontal tunnel, one lifts the excavated soil to the surface, and one spreads the soil at the top.
The crew usually starts at the point where water will be delivered and works toward the source (the test well). Vertical shafts are dug along the route, spaced 20–35 meters apart. The spacing balances the effort needed to dig the shafts and the tunnel between them, as well as future maintenance. In shallow qanats, the shafts are closer together. For long qanats, work may begin from both ends. Additional channels may be built to increase water flow.
Most qanats in Iran are less than 5 kilometers long, though some near Kerman are about 70 kilometers long. Vertical shafts typically range from 20 to 200 meters deep, with some in Khorasan reaching up to 275 meters. These shafts support construction, maintenance, and airflow. Deep shafts may require platforms to help remove soil.
Construction speed depends on the depth and type of ground. In soft soil, a crew of four workers can dig 40 meters of horizontal tunnel daily at 20 meters depth. At 40 meters depth, they dig 20 meters per day, and at 60 meters, less than 5 meters per day. In Algeria, workers dig about 2 meters per day at 15 meters depth. Long qanats can take years or even decades to build.
Excavated material is usually carried up vertical shafts in leather bags and piled around the shafts to block wind or rain from entering. These mounds may be covered for extra protection. From above, the shafts look like a series of craters.
The water channel must slope downward enough to allow water to flow easily but not so steeply that it causes dangerous water flow changes, which can erode the qanat. A balance is needed between erosion and sediment buildup. Steeper slopes increase erosion, while gentler slopes require more maintenance. Shorter qanats have slopes between 1:1000 and 1:1500, while longer ones may be nearly flat. Tools like spirit levels and string help achieve this precision.
If the slope is too steep, underground waterfalls may be built with special linings to reduce erosion. In some cases, water power has been used to operate underground mills. If the qanat’s outlet cannot be placed near a settlement, an open channel called a jub may be used, though this is avoided to reduce water loss and pollution.
Vertical shafts may be covered to prevent sand from entering. Qanat channels must be regularly checked for damage, cleaned of debris, and repaired. Before entering, airflow must be ensured for safety.
Some damaged qanats have been restored. Restoration requires considering factors like groundwater availability, community support, and existing water rights. In Syria, three qanats were chosen for restoration based on a 2001 national survey. One, the Drasiah qanat in Dmeir, was completed in 2002. Selection criteria included steady water flow, community cooperation, and a functioning water rights system.
Applications
Qanats are mainly used for irrigation, giving water to animals, and supplying drinking water. Other uses include operating watermills, cooling spaces, and storing ice.
Watermills connected to qanats needed to be placed carefully to use the slow-moving water effectively. In Iran, underground mills were found in places like Yazd and Boshruyeh. In Taft and Ardestan, mills were located at the end of qanats, before water was used to irrigate fields.
Qanats can work with wind towers to cool buildings and provide water. A wind tower is a tall, chimney-like structure above a house. One side of the tower faces away from the wind to push air out of the house. Cool air is pulled from a qanat below the house. The air moving through the tower’s opening creates lower pressure, drawing cool air up from the qanat tunnel and mixing it with the air inside.
The air from the qanat enters the tunnel far from the house. It cools by touching the tunnel walls and water, and by water evaporating into the air. In dry desert areas, this can lower the air temperature by more than 15°C. The mixed air remains dry, keeping the basement cool and slightly moist. This method of cooling with wind towers and qanats has been used in deserts for over 1,000 years.
By 400 BCE, Persian engineers learned how to store ice during hot summers in the desert. Ice was sometimes brought from nearby mountains during winter. More commonly, they built walls facing east to west near a yakhchal (ice pit). In winter, water from qanats was directed to the north side of the wall, where shade helped it freeze faster. The ice was then stored in yakhchals—special underground storage areas with thick walls and wind towers. These towers pulled cool air from qanats to keep the ice from melting quickly. This allowed ice to stay available throughout the year, even in summer.
By country
Qanats, called foggaras in Algeria, provide water for irrigation in large oases like Gourara. Foggaras are also found in Touat, an area of Adrar 200 km from Gourara. The length of foggaras in this region is estimated to be thousands of kilometers. Some sources suggest foggaras may have been used as early as 200 CE. By the 11th century, they were widely used after the Arabs took control of the oases in the 10th century and the people there adopted Islam. Water is measured and distributed to users through weirs that direct flow to separate canals.
The humidity in the oases helps add more water to the foggara. Temperature differences in vertical shafts cause air to rise naturally, creating a draft that enters the foggara. Moist air from agricultural areas moves into the foggara in the opposite direction of water flow. Inside the foggara, the air condenses on tunnel walls and exits through vertical shafts. This condensed moisture can be reused.
Qanat irrigation was introduced to Egypt by King Darius I of the Achaemenid Empire during his reign from 522–486 BCE, as noted by historian Albert T. Olmstead. Egypt has four main desert oases. The Kharga Oasis has been extensively studied. Evidence shows qanats were used as early as the second half of the 5th century BCE. Qanats were dug through sandstone that holds water, with water collected in basins behind small dams. The width of the qanats was about 60 cm (24 in), and their height ranged from 5 to 9 m (16 to 30 ft). They were likely deepened to increase water seepage when water levels dropped. From there, the water was used to irrigate fields.
Another structure in Kharga Oasis was a well that dried up. Workers dug a side shaft through soft sandstone toward a water source in the hill of Ayn-Manâwîr (also called Ayn-Manawir). After the side shaft was extended, a vertical shaft was added to connect to it. Side chambers were built, and holes were drilled into the rock where water seeped from the rock.
David Mattingly reports that foggaras in Libya’s Garamantes area near Germa extend for hundreds of miles. The channels were narrow—less than 2 feet wide and 5 feet high—but some were several miles long. In total, about 600 foggaras stretched for hundreds of miles underground. Workers used regularly spaced vertical shafts, one every 30 feet, totaling 100,000 shafts. These shafts averaged 30 feet in depth, though some reached 130 feet.
In southern Morocco, qanats (called khettara locally) have been used for irrigation since the late 14th century. In Marrakech and the Haouz plain, qanats were abandoned in the 1970s after they dried up. In Tafilalt, half of the 400 khettaras are still in use. The 1971 Hassan Adahkil Dam on the Ziz River affected local water tables, contributing to the loss of half the khettaras.
In Morocco, the black Berbers (haratin) were the hereditary workers who dug and repaired qanats. Their work was dangerous.
In Tunisia, the foggara system, similar to Iranian qanats, is used to create oases. Foggaras are dug into foothills of steep mountain ranges, like the eastern Atlas Mountains. Rainwater flows into underground aquifers and moves toward the Sahara. Foggaras, 1 to 3 km long, collect this water. Families maintain foggaras and own the land they irrigate within a 10-meter width. The length of the foggaras depends on how much water is available to irrigate the land.
Qanats are called kariz in Dari (Persian) and Pashto. They have been used since before the Islamic period. Over 9,370 karizes were in use in the 20th century. The oldest working kariz, more than 300 years old and 8 km long, is in Wardak province and provides water to nearly 3,000 people.
Many qanats were destroyed during the Soviet-Afghan War and the War in Afghanistan. Maintenance has been difficult due to high labor costs and a lack of skilled workers. Some farmers have abandoned their family-owned karizes and switched to modern wells. The Afghan government and international groups have worked to repair and maintain karizes. In 2009, some qanat systems were still functional. American forces accidentally damaged some channels during military base construction, causing tension with local communities. Some tunnels were used for storage and movement of supplies.
Qanats are preserved in Armenia’s Shvanidzor village, near Iran. They are called kahrezes in Armenian. Five kahrezes exist in Shvanidzor, with four built before the village was founded. The fifth was built in 2005. Three kahrezes provide drinking water, while two are in poor condition. Water levels drop in summer, creating supply issues. Kahrezes remain the main source of water for the community.
In Azerbaijan, many kahrizes (qanats) were used centuries ago. Archaeological findings show kahrizes existed before the 9th century CE. They were built and maintained by masons called "Kankans," a tradition passed from father to son. By the 20th century, nearly 1,500 kahrizes existed in Azerbaijan, with 40
Symbolism in Iranian culture
On August 21, 1906, Florence Khanum, the wife of Persian diplomat Ali Kuli Khan, wrote a letter from Tehran. In it, she described how qanats were used to water the garden at the home of her brother-in-law, General Husayn Kalantar, in January 1913. This information was mentioned in Arches of the Years (1999).
In Iran, an old tradition involved holding ceremonies where widows symbolically married qanats. During these ceremonies, the widow was considered the "wife" of the qanat. This practice was believed to help keep the water flowing through the qanat.