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The property includes five aflaj irrigation systems and is representative of some 3,000 such systems still in use in Oman. The origins of this system of irrigation may date back to AD 500, but archaeological evidence suggests that irrigation systems existed in this extremely arid area as early as 2500 BC. Using gravity, water is channelled from underground sources or springs to support agriculture and domestic use.
Source: UNESCO TV / © NHK Nippon Hoso Kyokai
Oman’s aflaj irrigation system
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Over recent years increased value has been placed on environmentally sound projects with a strong community base. If Oman’s aflaj irrigation system was built from scratch today it might well be regarded as a shining example of how a civil engineering project can be implemented according to contemporary and sustainable environmental principles. Yet the canals and waterways are centuries old.
List of World Heritage Sites in Western Asia
The UNESCO (United Nations Educational, Scientific and Cultural Organization) has designated 95 World Heritage Sites in 18 countries (also called "state parties") of Western Asia: Armenia, Azerbaijan, Bahrain, Cyprus, Georgia, Iran, Iraq, Israel, Jordan, Lebanon, Oman, Palestine, Saudi Arabia, Syria, Turkey, United Arab Emirates, Qatar and Yemen. While Egypt is partially in Western Asia, its World Heritage Sites are listed under Africa instead. One site is located in Jerusalem. [nb 1] Kuwait is the only country in the region that does not have any World Heritage Sites.   Arabian Oryx Sanctuary was designated as a World Heritage Site of Oman in 1994 but was delisted in 2007. As the protected area was reduced by 90% as a result of Oman's decision, UNESCO delisted the site. 
In this region, Iran is home to the most inscribed sites with 23 sites.  The first sites to be recognized by UNESCO from the region were Persepolis, Meidan Emam, Esfahan, Tchogha Zanbil (Iran) and the Ancient City of Damascus (Syria).  Each year, UNESCO's World Heritage Committee may inscribe new sites on the list, or delist sites that no longer meet the criteria. Selection is based on ten criteria: six for cultural heritage (i–vi) and four for natural heritage (vii–x).  Some sites, designated "mixed sites," represent both cultural and natural heritage. In Western Asia, there are 67 cultural, 1 natural, and 3 mixed sites. 
The World Heritage Committee may also specify that a site is endangered, citing "conditions which threaten the very characteristics for which a property was inscribed on the World Heritage List." Seven sites in this region are currently listed as endangered one site (Bahla Fort) had been listed previously, and possible danger listing has been considered by UNESCO in a number of other cases. 
This ancient Arab irrigation system invented before Rome’s aqueduct
Falaj, also known as qanat or aflaj, is an ancient water management system, that has watered the Arabian Peninsula’s arid lands for centuries. Long-ago tribesmen found underground springs in the foothills of the region, and engineered a technology that channels the water over the land, irrigating farms and oases and supplying households with water as needed. Although some say that falaj is a concept 3000 years old, others claim 5000 years. We reported on the Al-Baydha project for regenerative agriculture in Saudi Arabia with similar aims here.
What we do know is how admirable and sustainable the falaj system is, built entirely from local materials and hewed out of rock and earth by hand. First deep wells were dug, or underground springs redirected, to flow into tunnels that emerge on land and into stone channels containing the streaming water. The waterflow moves across miles of land, as determined by the ancients, entirely by gravity.
Shafts whose function is to regulate the flow of water are sunk in the channels about every 20 meters. Today, field irrigation is managed by government-appointed overseers, who monitor which fields receive water, and for how many hours. This is done in some areas by removing covers of brick, stones and sheep fleeces from the openings of the shafts to let the water run in another given direction, then replacing the covers to force the water back.
The Aflaj Irrigation Systems of Oman are ancient water channels from 500 AD located in the regions of Dakhiliyah, Sharqiyah and Batinah. However, they represent a type of irrigation system as old as 5000 years in the region named as Qanat or Kariz as originally named in Persia. This one is in the UAE.
In other falaj, slab-like barriers are inserted into points built into the channel walls to divert the water, then put back as needed.
Falaj comes from the word aflaj, meaning split, or divided. As the photo above shows, the channels may be split to provide field irrigation on one side, and household water on the other.
Walk through a village in Oman, and you’ll see pure, channeled water flowing in the streets and between houses. Some channels may be partially covered with slabs of stone placed at regular intervals over the top, to prevent night animals that come to drink from falling in and polluting the water.
There might even be a bath house for the community, with the water provided by the falaj. In the 14th and 15th centuries, governments whose falaj systems had deteriorated rebuilt the tunnels and overland channels. Recognizing the huge value of the ancient waterways, today’s Emirati and Omani governments have repaired many and put them back in use. Some areas in Oman have over 50 working falaj.
In the UAE there are seven oases, the largest in Al Ain. The stream rippling and burbling between thriving date palms and water greenery is a beautiful thing to see, and it also irrigates 1.200 acres of land, supplying over 550 farms.
Community areas were once cleared around the mouths of the channels, where the tribes met to take their share of the crop and hold festivities. Forts and castles were built around the Al Ain oasis to protect it from marauders, and important archaeological discoveries have been made there. UNESCO declared five of the UAE falaj systems to be heritage sites in 2011.
The falaj system is said to have originated in ancient Iran early in the first millennium BCE, spreading to China and India. Tribal laborers known as muqannis hand-built and maintained the water channels and shafts, as their descendants do to this day.
United Arab Emirates - 15-Feb-15 -
I was the Resident Architect for the new Souq in Nizwa from 1990-1992, working for CowiConsult. Marfa Daris Park began as a provisional sum in a local roads improvements contract, and I was given the opportunity to come up with a design and oversee the construction of the park.
We had some prior experience for this, having designed a "pocket park" at the base of the new road bridge upstream from the souq. Up to that time the local kids had never seen play equipment, and it was very popular.
The design philosophy for Marfa Daris Park recognised its importance as a historic stopping point on the former Frankincese Trail, a place of religious significance long before there was a local mosque, where the broad steps down to the falaj were used for washing prior to prayers on a level area of stony ground adjacent. The same point, close to the emergence of the falaj out of the main wadi bed, was also a place of great cultural significance: HM Sultan Qaboos would often make stops there to show visiting dignitaries the falaj and explain its importance.
The masterplan for the park was an outcome of its geography, the religious and ceremonial importance, and the need for a local park that would be popular with the local populace. Falaj Daris itself forms the boundary to the main wadi, with a meandering path alongside that loops up to an elevated bandstand on a prominence at the western end of the park.
The stone steps down to the falaj are the focus of the religious/ceremonial axis. A magnificent Ficus Religiosa fig was located in a large circular planter with stone benches opposite the steps, and this acts as a fulcrum for a ceremonial axis that is straddled by a Reception Building in the form of a traditional tower with a watchman's apartment accommodated at the upper levels.
Gardens and lawns flank the ceremonial axis, intersected by paths and gazebos along its length and leading to an amenities building adjacent to play areas for children. The local kids love excitement, and scrambling around the hills in the area, so the play areas were zoned up the side of the wadi from safe areas for toddlers at the bottom, past a series of play areas for older kids and culminating in long slope slides on a rocky hillside shaded by canopies to protect them from the heat of the summer sun. A BMX track was formed in the original scrub and acacia trees along the hillside, much to the pleasure of the neighborhood children.
The progression from formality to the natural ruggedness of the area continued beyond the play area and culminates at the bandstand, high on the hillside and providing a visual focus at the far end of the ceremonial axis.
Wadi Daris floods regularly following thunderstorms on the jebel, so it was necessary to ensure that floodwaters would not damage the buildings, and the stone bases and level changes ensured that they were protected and kept above normal flood levels. Runoff from the roads and populated areas uphill of the park is all intercepted by stone-lined culverts which carry it beyond the falaj into the main wadi to avoid polluting the falaj water and the fish that can be seen swimming in it.
The buildings themselves were constructed in modern materials, but rendered with traditional sarooj plaster - a rich-coloured render that is made by firing large quantities of clay plugs on pyres of date-palm trunks, with the ash and fired clay crushed and mixed into a powder and mixed with water.
Recent photos attest to the success of the landscaping design carried out by Paul Cracknell, the success of the park in its unique combination of cultural and recreational facilities, and its selection as the focus of the UNESCO award.
Five UNESCO World Heritage Sites that need to be seen In Oman
There are five UNESCO World Heritage Sites in Oman. All of these sites are of cultural significance, the list of which is given below:
- Bahla Fort (listed with UNESCO in 1987)
- Archaeological Sites of Bat, Al-Khutm and Al-Ayn (listed with UNESCO in 1988)
- Land of Frankincense (listed with UNESCO in 2000)
- Aflaj Irrigation Systems of Oman (listed with UNESCO in 2006)
- Ancient City of Qalhat (listed with UNESCO in 2018)
1. Bahla Fort
The Bahla Fort is a monumental and immense fort that was built for by the tribe of Banu Nebhan during the peak of its power (maybe from the 12th to the 15th centuries). Currently, the remaining of the fort includes the main walls, towers, and maximum of its stone foundation. Archaeological experts consider this of important cultural significance to the region in Gulf. It is believed to be one of the best examples of a fortification in the region that attests to the power of the Tribes.
Bahla Fort. Image courtesy of Wikimedia
Bahla Fort is a fascinating structure of walls and towers built of mud brick laid on stone foundations. The monument is a historical fortress situated in Djebel Akhdar highlands located in the Omani deserts. The great sur-wall had sentry walks, numerous watchtowers all around the labyrinth mud fortress, cultivated lands, and several gateways. The oasis was watered by wells and underground channels using the Aflaj system. Bahla Fort is an outstanding monument of a fortified oasis settlement dating back to the medieval Islamic era, which used the Aflaj system for domestic and agricultural purposes. UNESCO declared this fort as a cultural world heritage site in 1987.
2. Archaeological Sites of Bat, Al-Khutm and Al-Ayn
These sites are considered as the best example of ancient settlements in Oman and necropolises that long back around 3rd millennium BC. The whole archaeological complex/area consists of a large rural settlement, a monumental tower, few necropolises, and an irrigation system for agriculture. The remains of this Bronze Age landscape are of an exceptional value for preservation. By including it in the list of UNESCO World Heritage Sites in Oman, the researchers and government hope that they will be able to protect this cultural beauty.
Archaeological Sites of Bat, Al-Khutm and Al-Ayn (Oman). Image © UNESCO
3. Land of Frankincense
The Land of Frankincense was listed as one of the UNESCO World Heritage Sites in Oman in the year 2000. It is an area along the incense road in Oman that features frankincense trees. Before petroleum and Gas, the trade of frankincense in the Gulf region brought about success to the economy and this went on for many centuries. In fact, the trade of frankincense was considered as one of the most important trading activities in the medieval and ancient times.
Land of Frankincense. Image courtesy of Times of Oman
Artefacts from Ming, China, and the world beyond portray the fortress as an important harbor in the Silk Road to the Sea where frankincense was also traded. In the 15th century, the Portuguese and the European countries changed the trading patterns and soon the fortress died. The Omani Royal Decree No. 6/80 protects this site. There is a fence enclosing the site and all buffer zones.
4. Aflaj Irrigation Systems of Oman
This UNESCO site consists of five irrigation systems that showcase the traditional irrigation method of Omanis from long back centuries. This UNESCO site is also listed of cultural significance under in Oman as it is used to distribute water for irrigation and other purposes using gravity. The water flows through these systems, is still utilized by Omani people for agricultural use, as well as for some domestic use in various regions of Oman.
Aflaj Irrigation System in Oman. Image Courtesy of Adventure Philes
The UNESCO listing has five Aflaj irrigation schemes, representing about 3000 similar systems still in use in Oman. Archaeological evidences, suggests that the ancient irrigation systems existed in Oman as early as 2500 BC. The water flowed from the underground sources or natural springs to croplands and homes through the use of gravity. There are also numerous watchtowers built in between to protect the water systems. UNESCO declared this irrigation scheme a World Heritage Site in 2006. Now a day the main threat facing these cultural sits is the falling level of underground water.
5. Ancient City of Qalhat
Recently in July 2018, the ancient city of Qalhat located between Shab and the main city of Sur in central region of Oman, has been in the list UNESCO world heritage sites. Very little remains of this ancient site exist. The only surviving structure is the dome-less mausoleum of Biwi Maryam. Covering more than 60 acres of area, this ancient city was surrounded by fortified walls which contain residences and shops. Artefacts from as far away as Persia and China were found on site. Its inclusion in the list of world heritage site, as the delegation of Oman has proposed, is because the ancient city of Qalhat stands as a unique testimony of cultural traditions and an ancient civilisation moreover it is an outstanding example for an early typical city port representing important stages in the history of mankind.
Dome-less mausoleum of Biwi Maryam in Ancient City of Qalhat. Image courtesy of Flickr/Rita Willaert
Common variants of qanat in English include kanat, khanat, kunut, kona, konait, ghanat, ghundat. 
Qanāh ( قناة ) is an Arabic word that means "channel".  In Persian, the words for "qanat" are kārīz (or kārēz كاريز ) and is derived from earlier word kāhrēz ( كاهریز ). The word qanāt ( قنات ) is also used in Persian. Other names for qanat include kahan (Persian: کهن ), Kahn (Balochi), kahriz/kəhriz (Azerbaijan) khettara (Morocco) Galerías, minas or viajes de agua (Spain) falaj (Arabic: فلج ) (United Arab Emirates and Oman), foggara/fughara (North Africa).  Alternative terms for qanats in Asia and North Africa are kakuriz, chin-avulz and mayun.
According to most sources, qanat technology was developed in ancient Iran by the Persian people sometime in the early 1st millennium BCE and spread from there slowly westward and eastward.       However, some other sources suggest a Southeast Arabian origin.   In addition, analogous systems appeared to be developed independently in China and South America, specifically, Southern Peru.
Cotton is indigenous to South Asia and has been cultivated in India for a long time. Cotton appears in the Inquiry into Plants by Theophrastus and is mentioned in the Laws of Manu.  As transregional trade networks expanded and intensified, cotton spread from its homeland to India and into the Middle East where it devastated the agricultural systems already in place there [ citation needed ] . Much of Persia was initially too hot for the crop to be cultivated to solve that problem, the qanat was developed  first in modern-day Iran, where it doubled the amount of available water for irrigation and urban use.  Because of this, Persia enjoyed larger surpluses of agriculture thus increasing urbanization and social stratification.  The qanat technology subsequently spread from Persia westward and eastward. 
In arid and semi-arid regions, owing to high evaporation, transportation routes were in the form of qanats, which lead groundwater to consumption areas along the tunnels. In the long run, the qanat system is not only economical but also sustainable for irrigation and agricultural purposes.… The ground water flow was known to depend on grain size of sediments, and, therefore, the tunnels in qanats are filled in with coarser material than the surrounding hose geological formations. The qanats are constructed mainly along the valleys where Quartenary sediments are deposited.
Qanats are constructed as a series of well-like vertical shafts, connected by a gently sloping tunnel which carries a water channel. Qanats efficiently deliver large amounts of subterranean water to the surface without need for pumping. The water drains by gravity, typically from an upland aquifer, with the destination lower than the source. Qanats allow water to be transported over long distances in hot dry climates without much water loss to evaporation. 
It is very common for a qanat to start below the foothills of mountains, where the water table is closest to the surface. From this source, the qanat tunnel slopes gently downward, slowly converging with the steeper slope of the land surface above, and the water finally flows out above ground where the two levels meet. To connect a populated or agricultural area with an aquifer, qanats must often extend for long distances. 
Qanats are sometimes split into an underground distribution network of smaller canals called kariz. Like qanats, these smaller canals are below ground to avoid contamination and evaporation. In some cases water from a qanat is stored in a reservoir, typically with night flow stored for daytime use. An ab anbar is an example of a traditional Persian qanat-fed reservoir for drinking water.
The qanat system has the advantage of being resistant to natural disasters such as earthquakes and floods, and to deliberate destruction in war. Furthermore, it is almost insensitive to the levels of precipitation, delivering a flow with only gradual variations from wet to dry years. From a sustainability perspective, qanats are powered only by gravity, and thus have low operation & maintenance costs once built. Qanats transfer freshwater from the mountain plateau to the lower-lying plains with saltier soil. This helps to control soil salinity and prevent desertification. 
Qanat vs spring-flow tunnel Edit
The qanat should not be confused with the spring-flow tunnel typical to the mountainous area around Jerusalem. Although both are excavated tunnels designed to extract water by gravity flow, there are crucial differences. Firstly, the origin of the qanat was a well that was turned into an artificial spring. 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. Secondly, the shafts essential for the construction of qanats are not essential to spring-flow tunnels.
A typical town or city in Iran, and elsewhere where the qanat is used, has more than one qanat. Fields and gardens are located both over the qanats a short distance before they emerge from the ground and below the surface outlet. Water from the qanats defines both the social regions in the city and the layout of the city. 
The water is freshest, cleanest, and coolest in the upper reaches and more prosperous people live at the outlet or immediately upstream of the outlet. When the qanat is still below ground, the water is drawn to the surface via water wells or animal driven Persian wells. Private subterranean reservoirs could supply houses and buildings for domestic use and garden irrigation as well. Further, air flow from the qanat is used to cool an underground summer room (shabestan) found in many older houses and buildings. 
Downstream of the outlet, the water runs through surface canals called jubs (jūbs) which run downhill, with lateral branches to carry water to the neighborhood, gardens and fields. The streets normally parallel the jubs and their lateral branches. 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. 
The lower reaches of the canals are less desirable for both residences and agriculture. The water grows progressively more polluted as it passes downstream. In dry years the lower reaches are the most likely to see substantial reductions in flow. 
Traditionally qanats are built by a group of skilled laborers, muqannīs, with hand labor. The profession historically paid well and was typically handed down from father to son. 
The critical, initial step in qanat construction is identification of an appropriate water source. The search begins at the point where the alluvial fan meets the mountains or foothills water is more abundant in the mountains because of orographic lifting and excavation in the alluvial fan is relatively easy. The muqannīs follow the track of the main water courses coming from the mountains or foothills to identify evidence of subsurface water such as deep-rooted vegetation or seasonal seeps. A trial well is then dug to determine the location of the water table and determine whether a sufficient flow is available to justify construction. If these prerequisites are met, the route is laid out aboveground.
Equipment must be assembled. The equipment is straightforward: containers (usually leather bags), ropes, reels to raise the container to the surface at the shaft head, hatchets and shovels for excavation, lights, spirit levels or plumb bobs and string. Depending upon the soil type, qanat liners (usually fired clay hoops) may also be required.  
Although the construction methods are simple, the construction of a qanat requires a detailed understanding of subterranean geology and a degree of engineering sophistication. The gradient of the qanat must be carefully controlled: too shallow a gradient yields no flow and too steep a gradient will result in excessive erosion, collapsing the qanat. And misreading the soil conditions leads to collapses, which at best require extensive rework and at worst are fatal for the crew. 
Construction of a qanat is usually performed by a crew of 3–4 muqannīs. For a shallow qanat, one worker typically digs the horizontal shaft, one raises the excavated earth from the shaft and one distributes the excavated earth at the top. 
The crew typically begins from the destination to which the water will be delivered into the soil and works toward the source (the test well). Vertical shafts are excavated along the route, separated at a distance of 20–35 m. The separation of the shafts is a balance between the amount of work required to excavate them and the amount of effort required to excavate the space between them, as well as the ultimate maintenance effort. In general, the shallower the qanat, the closer the vertical shafts. If the qanat is long, excavation may begin from both ends at once. Tributary channels are sometimes also constructed to supplement the water flow.  
Most qanats in Iran run less than 5 km (3.1 mi), while some have been measured at ≈70 km (43 mi) in length near Kerman. The vertical shafts usually range from 20 to 200 m (66 to 656 ft) in depth, although qanats in the province of Khorasan have been recorded with vertical shafts of up to 275 m (902 ft). The vertical shafts support construction and maintenance of the underground channel as well as air interchange. Deep shafts require intermediate platforms to simplify the process of removing soil.  
The construction speed depends on the depth and nature of the ground. If the earth is soft and easy to work, at 20 m (66 ft) depth a crew of four workers can excavate a horizontal length of 40 m (130 ft) per day. When the vertical shaft reaches 40 m (130 ft), they can excavate only 20 meters horizontally per day and at 60 m (200 ft) in depth this drops below 5 horizontal meters per day. In Algeria, a common speed is just 2 m (6.6 ft) per day at a depth of 15 m (49 ft). Deep, long qanats (which many are) require years and even decades to construct.  
The excavated material is usually transported by means of leather bags up the vertical shafts. It is mounded around the vertical shaft exit, providing a barrier that prevents windblown or rain driven debris from entering the shafts. These mounds may be covered to provide further protection to the qanat. From the air, these shafts look like a string of bomb craters. 
The qanat's water-carrying channel must have a sufficient downward slope that water flows easily. However the downward gradient must not be so great as to create conditions under which the water transitions between supercritical and subcritical flow if this occurs, the waves that result can result in severe erosion that can damage or destroy the qanat. The choice of the slope is a trade off between erosion and sedimentation. Highly sloped tunnels are subject to more erosion as water flows at a higher speed. On the other hand, less sloped tunnels need frequent maintenance due to the problem of sedimentation.  A lower downward gradient also contributes to reducing the solid contents and contamination in water.  In shorter qanats the downward gradient varies between 1:1000 and 1:1500, while in longer qanats it may be almost horizontal. Such precision is routinely obtained with a spirit level and string.  
In cases where the gradient is steeper, underground waterfalls may be constructed with appropriate design features (usually linings) to absorb the energy with minimal erosion. In some cases the water power has been harnessed to drive underground mills. If it is not possible to bring the outlet of the qanat out near the settlement, it is necessary to run a jub or canal overground. This is avoided when possible to limit pollution, warming and water loss due to evaporation.  
The vertical shafts may be covered to minimize blown-in sand. The channels of qanats must be periodically inspected for erosion or cave-ins, cleaned of sand and mud and otherwise repaired. For safety, air flow must be assured before entry.
Some damaged qanats have been restored. To be sustainable, restoration needs to take into account many nontechnical factors beginning with the process of selecting the qanat to be restored. In Syria, three sites were chosen based on a national inventory conducted in 2001. One of them, the Drasiah qanat of Dmeir, was completed in 2002. 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. 
Irrigation and drinking water supply Edit
The primary applications of qanats are for irrigation, providing cattle with water, and drinking water supply. Other applications include cooling and ice storage.
Qanats used in conjunction with a wind tower can provide cooling as well as a water supply. A wind tower is a chimney-like structure positioned above the house of its four openings, the one opposite the wind direction is opened to move air out of the house. Incoming air is pulled from a qanat below the house. The air flow across the vertical shaft opening creates a lower pressure (see Bernoulli effect) and draws cool air up from the qanat tunnel, mixing with it. The air from the qanat is drawn into the tunnel at some distance away and is cooled both by contact with the cool tunnel walls/water and by the transfer of latent heat of evaporation as water evaporates into the air stream. In dry desert climates this can result in a greater than 15 °C reduction in the air temperature coming from the qanat the mixed air still feels dry, so the basement is cool and only comfortably moist (not damp). Wind tower and qanat cooling have been used in desert climates for over 1000 years. 
Ice storage Edit
By 400 BCE, Persian engineers had mastered the technique of storing ice in the middle of summer in the desert. 
The ice could be brought in during the winters from nearby mountains. But in a more usual and sophisticated method they built a wall in the east–west direction near the yakhchal (ice pit). In winter, the qanat water would be channeled to the north side of the wall, whose shade made the water freeze more quickly, increasing the ice formed per winter day. Then the ice was stored in yakhchals—specially designed, naturally cooled refrigerators. A large underground space with thick insulated walls was connected to a qanat, and a system of windcatchers or wind towers was used to draw cool subterranean air up from the qanat to maintain temperatures inside the space at low levels, even during hot summer days. As a result, the ice melted slowly and was available year-round. 
The Qanats are called Kariz in Dari (Persian) and Pashto and have been in use since the pre-Islamic period. It is estimated that more than 20,000 Karizes were in use in the 20th century. The oldest functional Kariz which is more than 300 years old and 8 kilometers long is located in Wardak province and is still providing water to nearly 3000 people.  The incessant war for the last 30 years has destroyed a number of these ancient structures. In these troubled times maintenance has not always been possible. To add to the troubles, as of 2008 the cost of labour has become very high and maintaining the Kariz structures is no longer possible. [ dubious – discuss ] Lack of skilled artisans who have the traditional knowledge also poses difficulties. A number of the large farmers are abandoning their Kariz which has been in their families sometimes for centuries, and moving to tube and dug wells backed by diesel pumps. [ citation needed ]
However, the government of Afghanistan is aware of the importance of these structures and all efforts are being made to repair, reconstruct and maintain (through the community) the kariz. [ citation needed ] The Ministry of Rural Rehabilitation and Development along with National and International NGOs is making the effort.
There are still functional qanat systems in 2009. American forces are reported to have unintentionally destroyed some of the channels during expansion of a military base, creating tensions between them and the local community.  Some of these tunnels have been used to store supplies, and to move men and equipment underground. 
Qanats have been preserved in Armenia in the community of Shvanidzor, in the southern province of Syunik, bordering with Iran. Qanats are named kahrezes in Armenian. There are 5 kahrezes in Shvanidzor. Four of them were constructed in XII-XIVc, even before the village was founded. The fifth kahrez was constructed in 2005. Potable water runs through I, II and V kahrezs. Kahrez III and IV are in quite poor condition. In the summer, especially in July and August, the amount of water reaches its minimum, creating a critical situation in the water supply system. Still, kahrezes are the main source of potable and irrigation water for the community.
The territory of Azerbaijan was home to numerous kahrizes many centuries ago. Archaeological findings suggest that long before the ninth century CE, kahrizes by which the inhabitants brought potable and irrigation water to their settlements were in use in Azerbaijan. Traditionally, kahrizes were built and maintained by a group of masons called ‘Kankans’ with manual labour. The profession was handed down from father to son.
It is estimated that until the 20th century, nearly 1500 kahrizes, of which as many as 400 were in the Nakhichevan Autonomous Republic, existed in Azerbaijan. However, following the introduction of electric and fuel-pumped wells during Soviet times, kahrizes were neglected.
Today, it is estimated that 800 are still functioning in Azerbaijan. These operational kahrizes are key to the life of many communities.
International Organization for Migration and the Revival of Kahriz Edit
In 1999, upon the request of the communities in Nakhichevan, taking into consideration the needs and priorities of the communities, especially women as the main beneficiaries, IOM began implementing a pilot programme to rehabilitate the kahrizes. By 2018 IOM rehabilitated more than 163 kahrizes with funds from the United Nations Development Programme (UNDP), European Commission (EC), Canadian International Development Agency (CIDA), Swiss Agency for Development and Cooperation (SDC) and the Bureau of Population, Refugees, and Migration, US State Department (BPRM) and the self-contribution of the local communities.
KOICA and IOM's kahriz rehabilitation project in Azerbaijan Edit
In 2010, IOM began a kahriz rehabilitation project with funds from the Korea International Cooperation Agency (KOICA). During the First Phase of the action which lasted until January 2013, a total of 20 kahrizes in the mainland of Azerbaijan have been renovated. In June 2018, the Second Phase has been launched and by 2022, IOM and KOICA aim to renovate fully a total of 40 kahrizes.
The oasis of Turpan, in the deserts of Xinjiang in northwestern China, uses water provided by qanat (locally called karez). The number of karez systems in the area is slightly below 1,000, and the total length of the canals is about 5,000 kilometers. 
Turpan has long been the center of a fertile oasis and an important trade center along the Northern Silk Road, at which time it was adjacent to the kingdoms of Korla and Karashahr to the southwest. The historical record of the karez extends back to the Han Dynasty. The Turfan Water Museum is a Protected Area of the People's Republic of China because of the importance of the Turpan karez water system to the history of the area.
In India, there are karez (qanat) systems. These are located at Bidar, Bijapur, Burhanpur "(Kundi Bhandara)" and Aurgangabad. The Karez does exist few other places as well, but investigations are in progress to determine the reality. The Bidar karez systems were probably the first one to have ever been dug in India. It dates to the Bahmani period. Valliyil Govindankutty Assistant Professor in Geography Government College Chittur was responsible for unraveling Karez Systems of Bidar and has been supporting District Administration with research outputs towards conservation of the Karez system. He was responsible for mapping these wonderful water system. Bidar is having three karez systems as per Gulam Yazdani's documentation. Detailed documentation of the Naubad karez system was dome by Valliyil Govindankutty in August 2013. A report was submitted to District Administration of Bidar and highlights many new facts which do not exist in previous documentations. The research support provided by Valliyil Govindankutty to the District Administration has led to the initiation of cleaning the debris and collapsed sections paving the way to its rejuvenation. The cleaning of karez has led to bringing water to higher areas of the plateau, and it has in turn recharged the wells in the vicinity. Other than Naubad there are two more karez systems in Bidar, "Shukla Theerth" and "Jamna Mori". The Shukla theerth is the longest karez system in Bidar. The mother well of this karez has been discovered by Valliyil Govindankutty and Team YUVAA during survey near Gornalli Kere, a historic embankment. The third system called Jamna mori is more of a distribution system within the old city area with many channels crisscrossing the city lanes.
The Bijapur karez system is much complicated. The study done by Valliyil Govindankutty reveals that it has surface water and groundwater connections. The Bijapur karez is a network of shallow masonry aqueducts, terracotta/ceramic pipes, embankments and reservoirs, tanks etc. All weave together a network to ensure water reaches the old city. 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. The system can be clearly traced up to Ibrahim Roja.
In Aurangabad the karez systems are called nahars. These are shallow aqueducts running through the city. There are 14 aqueducts in Aurangabad. The Nahar-i-Ambari is the oldest and longest. Its again a combination of shallow aqueducts, open channels, pipes, cisterns, etc. The source of water is a surface water body. The karez has been constructed right below the bed of lake. The lake water seeps through the soil into the Karez Gallery.
In Burhanpur the karez is called "Kundi-Bhandara", sometimes wrongly referred to as"Khuni Bhandara". The system is approx 6 km long starts from the alluvial fans of Satpura hills in the north of the town. Unlike Bidar, Bijapur and Aurgangabad the System airvents are round in shape. Inside the Karez one could see lime depositions on the walls. The Systems ends to carry water further to palaces and public fountains through pipe line.
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. 
In the middle of the twentieth century, an estimated 50,000 qanats were in use in Iran,  each commissioned and maintained by local users. Of these, only 37,000 remain in use as of 2015.
One of the oldest and largest known qanats is in the Iranian city of Gonabad, and after 2,700 years still provides drinking and agricultural water to nearly 40,000 people. Its main well depth is more than 360 meters and its length is 45 kilometers. Yazd, Khorasan and Kerman are zones known for their dependence on an extensive system of qanats.
In 2016, UNESCO inscribed the Persian Qanat as a World Heritage Site, listing the following eleven qanats: Qasebeh Qanat, Qanat of Baladeh, Qanat of Zarch, Hasan Abad-e Moshir Qanat, Ebrāhim Ābād Qanat in Markazi Province, Qanat of Vazvān in Esfahan Province, Mozd Ābād Qanat in Esfahan Province, Qanat of the Moon in Esfahan Province, Qanat of Gowhar-riz in Kerman Province, Jupār – Ghāsem Ābād Qanat in Kerman Province, and Akbar Ābād Qanat in Kerman Province.   Since 2002, UNESCO's International Hydrological Programme (IHP) Intergovernmental Council began investigating the possibility of an international qanat research center to be located in Yazd, Iran. 
The Qanats of Gonabad, also called kariz Kai Khosrow, is one of the oldest and largest qanats in the world built between 700 BCE to 500 BCE. It is located at Gonabad, Razavi Khorasan Province. This property contains 427 water wells with total length of 33,113 m (20.575 mi).  
According to Callisthenes, the Persians were using water clocks in 328 BCE to ensure a just and exact distribution of water from qanats to their shareholders for agricultural irrigation. The use of water clocks in Iran, especially in Qanats of Gonabad and kariz Zibad, dates back to 500BCE. Later they were also used to determine the exact holy days of pre-Islamic religions, such as the Nowruz, Chelah, or Yaldā – the shortest, longest, and equal-length days and nights of the years.  The Water clock, or Fenjaan, was the most accurate and commonly used timekeeping device for calculating the amount or the time that a farmer must take water from the Qanats of Gonabad until it was replaced by more accurate current clocks.  Many of the Iranian qanats bear some characteristics which allow us to call them feat of engineering, considering the intricate techniques used in their construction. The eastern and central regions of Iran hold the most qanats due to low precipitation and lack of permanent surface streams, whereas a small number of qanats can be found in the northern and western parts which receive more rainfall and enjoy some permanent rivers. Respectively the provinces Khorasan Razavi, Southern Khorasan, Isfahan and Yazd accommodate the most qanats, but from the viewpoint of water discharge the provinces Isfahan, Khorasan Razavi, Fars and Kerman are ranked first to fourth.
Henri Golbot, explored the genesis of the qanat in his 1979 publication, Les Qanats. Une technique d'acquisition de l'eau (The Qanats. a Technique for Obtaining Water),  He argues that the ancient Iranians made use of the water that the miners wished to get rid of it, and founded a basic system named qanat or Kariz to supply the required water to their farm lands. According to Goblot, this innovation took place in the northwest of the present Iran somewhere bordering Turkey and later was introduced to the neighboring Zagros Mountains.
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. So he managed to discover the reason why the area could stay green, and realized that there were some qanats behind the matter. In fact it was Ursa, the king of the region, who had rescued the people from thirst and turned Uhlu into a prosperous and green land. Goblot believes that the influence of the Medeans and Achaemenids made the technology of qanat spread from Urartu (in the western north of Iran and near the present border between Iran and Turkey) to all over the Iranian plateau. It was an Achaemenid ruling that in case someone succeeded in constructing a qanat and bringing groundwater to the surface in order to cultivate land, or in renovating an abandoned qanat, the tax he was supposed to pay the government would be waived not only for him but also for his successors for up to 5 generations. During this period, the technology of qanat was in its heyday and it even spread to other countries. 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. Beadnell believes that qanat construction dates back to two distinct periods: they were first constructed by the Persianse, and later the Romans dug some other qanats during their reign in Egypt from 30 BCE to 395 CE. The magnificent temple built in this area during Darius's reign shows that there was a considerable population depending on the water of qanats. Ragerz has estimated this population to be 10,000 people. 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."
During the Seleucid Era, which began after the occupation of Iran by Alexander, it seems that the qanats were abandoned.
In terms of the situation of qanats during this era, some historical records have been found. 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. The subterranean galleries excavated to obtain groundwater were named as qanat. These galleries were linked to the surface through some vertical shafts which were sunk in order to get access to the gallery to repair it if necessary.
According to the historical records, the Parthian kings did not care about the qanats the way the Achaemenid kings and even Sassanid kings did. As an instance, Arsac III, one of the Parthian kings, destroyed some qanats in order to make it difficult for Seleucid Antiochus to advance further while fighting him. The historical records from this time indicate a perfect regulation on both water distribution and farmlands. All the water rights were recorded in a special document which was referred to in case of any transaction. The lists of farmlands – whether private or governmental – were kept at the tax department. During this period there were some official rulings on qanats, streams, construction of dam, operation and maintenance of qanats, etc. The government proceeded to repair or dredge the qanats that were abandoned or destroyed for any reason, and construct the new qanats if necessary. A document written in the Pahlavi language pointed out the important role of qanats in developing the cities at that time. 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. But the qanats stayed intact, because the economic infrastructure, including qanats was of great importance to the Arabs. As an instance, M. Lombard reports that the Moslem clerics who lived during Abbasid period, such as Abooyoosef Ya’qoob (death 798 CE) stipulated that whoever can bring water to the idle lands in order to cultivate, his tax would be waived and he would be entitled to the lands cultivated. Therefore, this policy did not differ from that of the Achaemenids in not getting any tax from the people who revived abandoned lands. The Arabs’ supportive policy on qanats was so successful that even the holy city of Mecca gained a qanat too. The Persian historian Hamdollah Mostowfi writes: "Zobeyde Khatoon (Haroon al-Rashid's wife) constructed a qanat in Mecca. After the time of Haroon al-Rashid, during the caliph Moghtader’s reign this qanat fell into decay, but he rehabilitated it, and the qanat was rehabilitated again after it collapsed during the reign of two other caliphs named Ghaem and Naser. After the era of the caliphs this qanat completely fell into ruin because the desert sand filled it up, but later Amir Choopan repaired the qanat and made it flow again in Mecca." [ citation needed ]
There are also other historical texts proving that the Abbasids were concerned about qanats. 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. The inhabitants of Neyshaboor used to come to Abdollah bin Tahir in order to request him to intervene, for they fought over their qanats and found the relevant instruction or law on qanat as a solution neither in the prophet's quotations nor in the clerics’ writings. So Abdollah bin Tahir managed to bring together all the clergymen from throughout Khorasan and Iraq to compile a book entitled Alghani (The Book of Qanat). This book collected all the rulings on qanats which could be of use to whoever wanted to judge a dispute over this issue. Gardizi added that this book was still applicable to his time, and everyone made references to this book.
One can deduce from these facts that during the above-mentioned period the number of qanats was so considerable that the authorities were prompted to put together some legal instructions concerning them. Also it shows that from the ninth to eleventh centuries the qanats that were the hub of the agricultural systems were also of interest to the government. Apart from The Book of Alghani, which is considered as a law booklet focusing on qanat-related rulings based on Islamic principles, there is another book about groundwater written by Karaji in 1010. This book, entitled Extraction of Hidden Waters, examines just the technical issues associated with the qanat and tries to answer the common questions such as how to construct and repair a qanat, how to find a groundwater supply, how to do leveling, etc.. Some of the innovations described in this book were introduced for the first time in the history of hydrogeology, and some of its technical methods are still valid and can be applied in qanat construction. The content of this book implies that its writer (Karaji) did not have any idea that there was another book on qanats compiled by the clergymen.
There are some records dating back to that time, signifying their concern about the legal vicinity of qanats. For example, Mohammad bin Hasan quotes Aboo-Hanifeh that in case someone constructs a qanat in abandoned land, someone else can dig another qanat in the same land on the condition that the second qanat is 500 zera’ (375 meters) away from the first one.
Ms. Lambton quotes Moeen al-din Esfarzi who wrote the book Rowzat al-Jannat (the garden of paradise) that Abdollah bin Tahir (from the Taherian dynasty) and Ismaeel Ahmed Samani (from the Samani dynasty) had several qanats constructed in Neyshaboor. Later, in the 11th century, a writer named Nasir Khosrow acknowledged all those qanats with the following words: "Neyshaboor is located in a vast plain at a distance of 40 Farsang (≈240 km) from Serakhs and 70 Farsang (≈420 km) from Mary (Marv) … all the qanats of this city run underground, and it is said that an Arab who was offended by the people of Neyshaboor has complained that what a beautiful city Neyshaboor could have become if its qanats would have flowed on the ground surface and instead its people would have been underground." These documents all certify the importance of qanats during the Islamic history within the cultural territories of Iran.
In the 13th century, the invasion of Iran by Mongolian tribes reduced many qanats and irrigation systems to ruin, and many qanats were deserted and dried up. 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. There is a 14th-century book entitled Al-Vaghfiya Al-Rashidiya (Rashid's Deeds of Endowment) that names all the properties located in Yazd, Shiraz, Maraghe, Tabriz, Isfahan and Mowsel that Rashid Fazl-Allah donated to the public or religious places. This book mentions many qanats running at that time and irrigating a considerable area of farmland. At the same time, another book, entitled Jame’ al-Kheyrat, was written by Seyyed Rokn al-Din on the same subject as Rashid's book. In this book, Seyyed Rokn al-Din names the properties he donated in the region of Yazd. These deeds of endowment indicate that much attention was given to the qanats during the reign of Ilkhanids, but it is attributable to their Persian ministers, who influenced them. 
In the years 1984–1985 the ministry of energy took a census of 28,038 qanats whose total discharge was 9 billion cubic meters. In the years 1992–1993 the census of 28,054 qanats showed a total discharge of 10 billion cubic meters. 10 years later in 2002–2003 the number of the qanats was reported as 33,691 with a total discharge of 8 billion cubic meters.
In the restricted regions there are 317,225 wells, qanats and springs that discharge 36,719 million cubic meters water a year, out of which 3,409 million cubic meters is surplus to the aquifer capacity. in 2005, in the country as a whole, there were 130,008 deep wells with a discharge of 31,403 million cubic meter, 33,8041 semi deep wells with a discharge of 13,491 million cubic meters, 34,355 qanats with a discharge of 8,212 million cubic meters, and 55,912 natural springs with a discharge of 21,240 million cubic meters. 
A survey of qanat systems in the Kurdistan region of Iraq conducted by the Department of Geography at Oklahoma State University (USA) on behalf of UNESCO in 2009 found that out of 683 karez systems, some 380 were still active in 2004, but only 116 in 2009. Reasons for the decline of qanats include "abandonment and neglect" prior to 2004, "excessive pumping from wells" and, since 2005, drought. Water shortages are said to have forced, since 2005, over 100,000 people who depended for their livelihoods on karez systems to leave their homes. The study says that a single karez has the potential to provide enough household water for nearly 9,000 individuals and irrigate over 200 hectares of farmland. UNESCO and the government of Iraq plan to rehabilitate the karez through a Karez Initiative for Community Revitalization to be launched in 2010. Most of the karez are in Sulaymaniyah Governorate (84%). A large number are also found in Erbil Governorate (13%), especially on the broad plain around and in Erbil city. 
In Japan there are several dozen qanat-like structures, locally known as 'mambo' or 'manbo', most notably in the Mie- and Gifu Prefectures. Whereas some link their origin clearly to the Chinese karez, and therefore to the Iranian source,  a Japanese conference in 2008 found insufficient scientific studies to evaluate the origins of the mambo. 
Among the qanats built in the Roman Empire, the 94 km (58 mi) long Gadara Aqueduct in northern Jordan was possibly the longest continuous qanat ever built.  Partly following the course of an older Hellenistic aqueduct, excavation work arguably started after a visit by emperor Hadrian in 129–130 CE. The Gadara Aqueduct was never quite finished and was put in service only in sections.
In Pakistan qanat irrigation system is endemic only in Balochistan. The major concentration is in the north and northwest along the Pakistan-Afghanistan border and oasis of Makoran division. The Karez system of the Balochistan desert is on the Tentative List for future World Heritage Sites in Pakistan. 
The acute shortage of water resources give water a decisive role in the regional conflicts arose in the course of history of Balochistan. Therefore, in Balochistan, the possession of water resources is more important than ownership of land itself. Hence afterward a complex system for the collection, channeling and distribution of water were developed in Balochistan. Similarly, the distribution and unbiased flow of water to different stockholders also necessitate the importance of different societal classes in Balochistan in general and particularly in Makoran. For instance, sarrishta (literally, head of the chain) is responsible for administration of channel. He normally owns the largest water quota. Under sarrishta, there are several heads of owners issadar who also possessed larger water quotas. The social hierarchy within Baloch society of Makoran depends upon the possession of largest quotas of water. 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 sharing of water is based on a complex indigenous system of measurement depends upon time and space particularly to the phases of moon the hangams. Based on seasonal variations and share of water the hangams are apportioned among various owners over period of seven or fourteen days. However, in some places, instead of hangam, anna used which is based on twelve-hour period for each quota. Therefore, if a person own 16 quotas it means that he is entitled for water for eight days in high seasons and 16 days in winter when water level went down as well as expectation of winter rain (Baharga) in Makran region. 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).
The Chagai district is in the north west corner of Balochistan, Pakistan, bordering with Afghanistan and Iran. Qanats, locally known as Kahn, are found more broadly in this region. They are spread from Chaghai district all the way up to Zhob district.
Qanats were found over much of Syria. The widespread installation of groundwater pumps has lowered the water table and qanat system. Qanats have gone dry and been abandoned across the country. 
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. There are three types of Falaj: Daudi (Arabic: داوودية ) with underground aqueducts, Ghaili (Arabic: الغيلية ) requiring a dam to collect the water, and Aini (Arabic: العينية ) whose source is a water spring. These enabled large scale agriculture to flourish in a dryland environment. According to UNESCO, some 3,000 aflaj (plural) or falaj (singular), are still in use in Oman today. Nizwa, the former capital city of Oman, was built around a falaj which is in use to this day. These systems date to before the Iron Age in Oman. In July 2006, five representative examples of this irrigation system were inscribed as a World Heritage Site. 
United Arab Emirates Edit
The oases of the city of Al Ain (particularly Al-Ain, Al-Qattarah, Al-Mu'taredh, Al-Jimi, Al-Muwaiji, and Hili), adjacent to Al-Buraimi in Oman, continue traditional falaj (qanat) irrigations for the palm groves and gardens, and form part of the city's ancient heritage.  
There are four main oases in the Egyptian desert. The Kharga Oasis is one that has been extensively studied. There is evidence that as early as the second half of the 5th century BCE water brought in qanats was being used. The qanats were excavated through water-bearing sandstone rock, which seeps into the channel, with water collected in a basin behind a small dam at the end. 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). From there the water was used to irrigate fields.  
There is another instructive structure located at the Kharga oasis. A well that apparently dried up was improved by driving a side shaft through the easily penetrated sandstone (presumably in the direction of greatest water seepage) into the hill of Ayn-Manâwîr to allow collection of additional water. After this side shaft had been extended, another vertical shaft was driven to intersect the side shaft. Side chambers were built, and holes bored into the rock—presumably at points where water seeped from the rocks—are evident. 
David Mattingly reports foggara extending for hundreds of miles in the Garamantes area near Germa in Libya: "The channels were generally very narrow – less than 2 feet wide and 5 high – but some were several miles long, and in total some 600 foggara extended for hundreds of miles underground. The channels were dug out and maintained using a series of regularly spaced vertical shafts, one every 30 feet or so, 100,000 in total, averaging 30 feet in depth, but sometimes reaching 130." 
The foggara water management system in Tunisia, used to create oases, is similar to that of the Iranian qanat. The foggara is dug into the foothills of a fairly steep mountain range such as the eastern ranges of the Atlas mountains. Rainfall in the mountains enters the aquifer and moves toward the Saharan region to the south. The foggara, 1 to 3 km in length, penetrates the aquifer and collects water. Families maintain the foggara and own the land it irrigates over a ten-meter width, with length reckoned by the size of plot that the available water will irrigate. 
Qanats (designated foggaras in Algeria) are the source of water for irrigation in large oases like that at Gourara. The foggaras are also found at Touat (an area of Adrar 200 km from Gourara). The length of the foggaras in this region is estimated to be thousands of kilometers.
Although sources suggest that the foggaras may have been in use as early as 200 CE, they were clearly in use by the 11th century after the Arabs took possession of the oases in the 10th century and the residents embraced Islam.
The water is metered to the various users through the use of distribution weirs that meter flow to the various canals, each for a separate user.
The humidity of the oases is also used to supplement the water supply to the foggara. The temperature gradient in the vertical shafts causes air to rise by natural convection, causing a draft to enter the foggara. The moist air of the agricultural area is drawn into the foggara in the opposite direction to the water run-off. In the foggara it condenses on the tunnel walls and the air passes out of the vertical shafts. This condensed moisture is available for reuse. 
In southern Morocco, the qanat (locally khettara) is also used. 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. In Marrakech and the Haouz plain, the qanats have been abandoned since the early 1970s, having dried up. In the Tafilaft area, half of the 400 khettaras are still in use. The Hassan Adahkil Dam's impact on local water tables is said to be one of the many reasons for the loss of half of the khettara. 
The black berbers (haratin) of the south were the hereditary class of qanat diggers in Morocco who build and repair these systems. Their work was hazardous. 
The Tunnel of Eupalinos on Samos runs for 1 kilometre through a hill to supply water to the town of Pythagorion.  It was built on the order of the Tyrant Polycrates around 550 BCE. At either end of the tunnel proper, shallow qanat-like tunnels carried the water from the spring and to the town.
The 5,653 m (3.513 mi) long Claudius Tunnel, intended to drain the largest Italian inland water, Fucine Lake, was constructed using the qanat technique. It featured shafts up to 122 m deep.  The entire ancient town of Palermo in Sicily was equipped with a huge qanat system built during the Arab period (827–1072).  Many of the qanats are now mapped and some can be visited. The famous Scirocco room has an air-conditioning system cooled by the flow of water in a qanat and a "wind tower", a structure able to catch the wind and use it to draw the cooled air up into the room.
The Raschpëtzer near Helmsange in southern Luxembourg is a particularly well preserved example of a Roman qanat. It is probably the most extensive system of its kind north of the Alps. To date, some 330 m of the total tunnel length of 600 m have been explored. Thirteen of the 20 to 25 shafts have been investigated.  The qanat appears to have provided water for a large Roman villa on the slopes of the Alzette valley. It was built during the Gallo-Roman period, probably around the year 150 and functioned for about 120 years thereafter.
There are still many examples of galeria or qanat systems in Spain, most likely brought to the area by the Moors during their rule of the Iberian peninsula. Turrillas in Andalusia on the north facing slopes of the Sierra de Alhamilla has evidence of a qanat system. Granada is another site with an extensive qanat system.  In Madrid they were called "viajes de agua" and were used until relatively recently. See  and  in Spanish.
The Americas Edit
Qanats in the Americas, usually referred to as puquios or filtration galleries, can be found in the Nazca region of Peru and in northern Chile.  The Spanish introduced qanats into Mexico in 1520 CE. 
In the Atacama Desert of northern Chile qanats are known as socavones.  Socavones are known to exist in Azapa Valley and the oasis of Sibaya, Pica-Matilla and Puqui Nuñez.  In 1918 geologist Juan Brüggen mentioned the existence of 23 socavones in the Pica oasis, yet these have since then been abandoned due to economic and social changes. 
In an August 21, 1906 letter written from Teheran, 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,  January 1, 1913 
"The air is the most marvellous I ever was in, in any city. Mountain air, so sweet, dry and "preserving", delicious and life-giving.' She told of running streams, and fresh water bubbling up in the gardens. (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. Thus J. T. Shipley, Dictionary of Word Origins)."
One of the oldest traditions in Iran was to hold wedding ceremonies between widows and underground water tunnels called qanats. 
Rising majestically above oasis palms, Bahla Fort is Oman’s largest fortification, with archaeological remains dating back a mind-boggling 5,000 years.
The fortress has been built and rebuilt many times throughout its colourful history © Lauren Cameo, Dreamstime
Following a 24-year-long UNESCO-led renovation, the fortress sits proudly atop a small hill, adjacent to a largely abandoned mud-brick village and a traditional suq where you can find silver, spices and herbs.
What you should know about Oman’s falaj system
In almost every village, town and city in Oman, you’ll find a long deep path of water running through houses, streets and farms. These are ancient water channels, the aflaj irrigation systems that are commonly seen around both ancient and present-day Sultanate.
Falaj (or Aflaj for plural term) have been around in the region since 500 AD and in many parts can be dated back to over 5000 years ago. The word falaj literally translates to “spilt into parts” and this efficient form of water distribution is what made the arid regions of the middle east habitable, making use of the natural forces of gravity.
An original Omani irrigation system, it deeply connects the country’s heritage, culture and history.
Sourcing its water from underground sources like wells and wadis, the falaj system doesn’t use pumps or complicated machines to extract the water but purely depends on the gravitational force and the natural properties of water. These ancient yet high scientific methods ensured that the supply of water was controlled and was shared amongst its users fairly, without affecting the natural water resources negatively.
With rains being sporadic throughout the country, the falaj system ensures that its inhabitants have access to clean usable water all throughout the year.
What DOES A Falaj system consist OF?
A falaj consists of three main parts Um al Falaj, access shafts and the tunnels.
Um Falaj that translates to mother well, is the main source of the water. The water at this point has the purest quality. From here, tunnels transport the water to the different towns and villages that they were built for. The length and type of tunnel depend on the terrain of the land and the source of the water and its pressure.
Access shafts are built approximately every 20 metres along the tunnel to keep the water ventilated and remove impurities and debris that it may have collected. There is a ring of burnt clay at the shaft mouth, which has two main functions to prevent the destruction of the falaj if the tunnel collapses, and to prevent flooding water from entering the falaj. These covered rings also protect water from pollutants and prevent people and animals from falling in the falaj.
There are three main types of aflaj in Oman depending on the type of groundwater they provide.
Dawoodi falaj is a long underground channel that can be tens of metres deep and can run for several kilometres, which keeps the water constant around the year.
Ghaili falaj is usually between 3-4 metres (10-13 feet) deep and gets its water from ponds and running water. It floods when it rains heavily and dries when it doesn’t rain for a long time.
Ainy falaj gets its name from the Arabic word ‘ain‘, meaning ‘well’.The importance of the ainy falaj depends on the type of water it has. It can carry hot or cold water, fresh drinking water or saline water or alkaline water mixed with valley water.
Numerous watchtowers were also built along these waterways to defend the water systems form a part of the site reflecting the historic dependence of communities on the aflaj system. The fair and effective management and sharing of water in villages and towns are still underpinned by mutual dependence and communal values and guided by astronomical observation.
In 2006, five aflaj systems from the Sultanate were added to the Unesco list of World Heritage Sites — Falaj Al Khatmeen, Falaj Al Malki, Falaj Daris, Falaj Al Mayassar and Falaj Al Jeela.
Gift of history
What lie interred in the tomb of Bibi Maryam are never-dying memories of a splendid era. of kings and queens, of global trade, of thriving culture and of the horrors of invasion as well. They whisper to us, in words that are frozen in time, of the subtle bio-continuum across millennia called life as we perceive it, and of the inevitable and irrevocable losses that time gifts us as it gallops ahead.
The tomb is the only visible structure left in the ancient city of Qalhat — located on the east coast of the Sultanate — which has been declared a World Heritage Site by the Unesco.
All other majestic elements of a once bustling community have been lost to the ravages of time and invasion.
The site entered the heritage list as it fulfilled two major criteria: “Exhibiting an important interchange of human values over a span of time or within a cultural area of the world, on developments in architecture or technology, monumental arts, town planning or landscape design,” and “bearing a unique or at least exceptional testimony to a cultural tradition or to a civilisation which is living or has disappeared.”
Qalhat is the latest addition to the Sultanate’s four other Unesco recognized heritage sites of Bahla Fort archaeological sites of Bat, Al Khutm and Al Ayn Aflaj irrigation systems and the Land of Frankincense.
The archaeological site is spread over 35 hectares, and includes the ancient city of Qalhat, surrounded by inner and outer walls, along with areas beyond the ramparts where necropolises are located, Unesco notes, adding, Qalhat developed as a major port on the east coast of Arabia between 11th and 15th centuries CE, during the reign of the Hormuz princes. “Today, it bears unique archaeological testimony to the trade links between the east coast of Arabia, East Africa, India, China and South-East Asia,” it says.
Was the tomb built by the King of Hormuz, Bahauddin Ayez, in the 13th century in honour of his wife Bibi Maryam? Or is it the site of a mosque that Maryam built herself, and became her final resting place? No one knows for sure.
Historians believe that earthquakes and Portuguese invasion in 1508 sealed the fate of the city, reducing Qalhat to an abandoned city. But nothing could erase its past glory.
The Sultanate values its rich cultural heritage, and has formulated an effective management plan to protect its ancient heritage sites. The National Heritage Protection Law (1980) remains central to preserving the country’s priceless heritage, while the Ministry of Heritage and Culture has been tirelessly working to protect and promote its diverse heritage sites and values with innovative and visionary ideas.
As for the Sultanate’s other world heritage sites, the Wadi Dawkah’s frankincense trees and the caravan oasis of Shisr, as well as the ports of Khor Rori and Al Baleed proudly point to the brisk centuries-old trade in frankincense that counts among the major trading activities of the ancient and medieval world.
Unesco recognises this group of archaeological sites for its value as the trading centre for frankincense, which was one of the most important luxury items of trade in ancient times. “The Oasis of Shisr and the pots of Khor Rori and Al Baleed are outstanding examples of medieval fortified settlements in the Arabian Gulf region”, the organisation notes.
The pre-historic archaeological complex of Bat, Khutm and Ayn earned world heritage status as it stands tall as one of the “most complete and well preserved ensembles of settlements and necropolises from the 3rd millennium BCE,” according to Unesco.
Bahla, on the other hand, has been recognized for its stature as an outstanding fortified oasis settlement belonging to the Islamic period, and for the unique mud-brick technology and its excellent water engineering system for agro-domestic uses.
Moving on, Oman’s aflaj are more than 3,000 years old, and they are still functional, which makes them extraordinary. They demonstrate sustainable use of water resources making use of ancient water management skills that suit extremely arid landscapes. Oman’s aflaj systems reflect “time-honoured, fair and effective management and sharing of water resources, underpinned by mutual dependence and communal values,” as Unesco describes them.
That the Sultanate has five properties inscribed on the World Heritage Site is a purely academic statement. However, as anyone who experienced the ‘Jewel of the Arabian Peninsula” would agree, the entire Sultanate is a world heritage.