Who invented the qanat

The Qanat systems of Mexico came into use after the Spanish conquest. While the above diffusion model appears to be orderly and logical Fig. Since the systems in South America may predate the Spanish entry into the New World, their development may have occurred independently from any Persian influence. The Chinese, while acknowledging a possible Persian connection, found an antecedent to the Qanats of Turpan in the Longshouqu Canal constructed approximately BC.

The Romans used Qanats in conjunction with aqueducts to serve urban water supply systems a Qanat-aqueduct system was built in Roman Lyons. A Roman Qanat system was also constructed near Murcia in southeastern Spain. Qanat technology exists in more than 35 countries in the world but most are concentrated in present day Iran [ 2 ]. The methods used in Iran today are not greatly different from the system devised thousands of years ago [ 6 ].

However, the current problem with Qanats worldwide is that they are rapidly drying up on a large scale. This volume of water production would be sufficient to irrigate 3,, acres of arid land if it were used entirely for agriculture. It has made a garden of what would otherwise have been an uninhabitable desert [ 6 ]. Qanats are still found throughout the regions that came under the cultural sphere of the Persians, Romans, and Arabs Fig. The Qanat system in Turpan, China, is still very much in use.

The Palestinians and their neighbors had for some 2, years irrigated terraces of olive groves, vineyards, and orchards with water tapped from some Qanat-like tunnels beneath the hills on the eastern shores of the Mediterranean. However, today the terraces and tunnels are largely unused and abandoned since the day in when Palestinians vacated following the creation of the state of Israel. The demise of these irrigation systems is, according to Zvi Ron, an Israeli geographer from the University of Tel Aviv who has mapped the tunnels, a human, ecological and cultural tragedy.

Qanats are to this day the major source of irrigation water for the fields and towering hillside terraces that occupy parts of Oman and Yemen. They have for some 2, years allowed the villages of the desert fringes of the Arabian Peninsula to grow their own wheat as well as alfalfa to feed their livestock.

In these villages, there are complex ownerships of water rights and distribution canals. Advantages of the Qanat System There are several significant advantages to a Qanat water delivery system when compared to the simple well or other water supplying technologies available today: Qanat exploits ground-water as a renewable resource, in contrast to the simple well. The rate of flow of water in a Qanat is always controlled by the level of the underground water table.

Thus a Qanat cannot cause significant drawdown in an aquifer because its flow varies directly with the subsurface water supply Fig. Evaporation returns large quantities of water to the atmosphere from wet surfaces such as ponds and lakes of dams [ 7 ]. By placing the majority of the channel underground, the Qanat reduces water loss from seepage and evaporation.

Since the system is fed entirely by gravity, the Qanat delivers large quantities of water to the surface without the need for using a pump and an energy supply. Instead by using a special instrument such as a water mill Fig. The Qanat system has the advantage of being relatively immune to human destruction during wars and in natural disasters [ 8 ]. On the other hand, by absorbing runoff from the surface through the vertical shafts, the Qanat system can reduce the risk of floods Fig.

Therefore, the Qanat system can also be used in wet areas with high annual rainfall for control of flash floods and groundwater level. The Qanat is relatively insensitive to the level of seasonal and annual precipitation so a Qanat typically delivers a relatively constant flow with only gradual variation from wet to dry years.

In some cases, water from Qanats is stored in a reservoir which typically stores night flow for daytime use. An Ab-Anbar is an example of a traditional Qanat fed reservoir for drinking water in Persian antiquity [ 8 ]. A Qanat can be used for cooling as well as water supply [ 9 ].

In the system shown in Fig. Hot dry air enters the Qanat through one of its vertical shafts and is cooled as it flows along the cold water. Since the underground water is usually cold, the rate of cooling is quite high. The Qanat system can be used as a fish farm Fish have been observed in most Qanats. Smith [ 3 ] found that in flooding periods, mountainous rivers containing some fish overflow, and send streams of water down to the mountainsides and over the openings to the Qanats, and deposit fish in them in this manner.

The fish that Smith [ 3 ] found were edible. Why Will Qanats Be Abandoned? Notwithstanding the above mentioned advantages and long term value of the qanat to the community, this artificial ground-water system will be abandoned for the following reasons:. Suggestion for Future Water Management The Qanat system is a traditional way to supply agricultural water in arid areas that suffer from the absence of permanently flowing rivers, and where aquifers are too deep for convenient simple wells.

The Qanat system can be used as a sustainable urban water management either in dry cities for water supply or wet cities for flood control. Here, a new multi-purpose water management model has been introduced based on rainwater in-filtration management over the Qanat system RWIQ. Multi-Purpose Rainwater Infiltration Management in Qanat System A rainwater infiltration system can be applied with the Qanat system for making maximum infiltration in times of intensive rain in desert and protect Qanats from collapsing Fig.

Rainwater management RWM by infiltration in the whole watershed can be combined with the Qanat system to develop a multi-purpose water management model Fig. As previously mentioned the RWIQ paradigm can be applied for either arid or wet areas. For example as it can be seen in Fig. The red line represents the application of the RWIQ model for an arid area where a flood may occur is not the biggest problem while a sustainable water supply, groundwater level or temperatures are extremity important.

The water self-sufficiency index is an index for evaluating the integrity of the artificial urban water cycle. It is expressed as the ratio of the amount of self-supplied water to total water use, which represents both reliance on an external water resource and regional water self-sufficiency [ 11 , 12 ]. Total water use is therefore the sum of the external water supply and the internal water supply.

However, as mentioned previously, there are a number of problems with a Qanat system. Here, some new methods are suggested in order to solve these problems.

The inlet of the vertical shaft can be covered with permeable materials Fig. By building a reservoir tank or room in a location among the main channel we can separate the domestic used water from the main water. However, the water quality of a Qanat should be monitored and controlled. The system uses no pump energy, just gravity and saves energy and money. The tunnel was constructed entirely under urban areas and also passed under 13 third party tunnels along its route [ 14 ].

Flow through the main is not pumped but rather flows by gravity under the driving head of the service reservoirs at the source water treatment works. By virtue of its depth the pipeline is under some pressure, however, the hydraulic grade line rarely exceeds ground level, and to enter the supply, water must be pumped up into the distribution zones at the various pump-out shafts.

In some respects, therefore, the ring main can be considered as a reservoir albeit with negligible capacity , from which supply is drawn as required. For gravity to keep the water going the tunnel must be full [ 15 ]. The initial ring was constructed between and As of , two extensions are under construction. There are plans for further extensions through Conclusions The Qanat is an ancient water management system used to provide a reliable supply of water to human settlements and for irrigation in arid and semi-arid climates.

The Qanat system is an Asian masterpiece of climate change adaptation. However, it is a traditional water supply system that needs to be protected and refined. As technology progressed, simple wells came to be used instead of Qanats, and they thus stopped functioning.

We do not need to build new Qanats, we merely need to maintain and re-fine them. This study analyses the history of the Qanat and identifies the advantages of this groundwater water delivery system as well as the reasons why Qanats will be abandoned. The study also provides suggestions for technical methods to refine the Qanat by using new materials and modern geological techniques. The methods suggested in this study are expected to contribute to the restoration and reconstruction of the Qanat system.

Enabling people to incorporate modern scientific approaches in their traditional knowledge networks requires preparatory research, training and appropriate support. Qanats can be used as educational resources for students, technicians, professionals and researchers as well as the general public. References 1. Review of groundwater contaminant mass flux measurement. Salih A. Qanats a unique groundwater management tool in Arid regions: the case of Bam region in Iran.

Smith A. Explorations in Persia: blind white fish in Persia. New York: E. Dutton; Beaumont P. Qanat systems in Iran. Semsar Yazdi AA. A survey of the historical evolution of Qanats in Iran. Wulff HE. The Qanats of Iran. Water and wastewater engineering. Aqueduct: Qanat, Roman aqueduct, drought, earthquake engineering, goldfields water supply scheme, irrigation, leat, list of Roman bridges, pipeline transport of ancient Rome Roman engineering.

Bahadori MN. Social All right reserved. Search for:. Water Opinion. Convergence point of three qanats, Algeria. Photo: Idda Salem. Originally developed in ancient Persia, the qanat system of water channels was introduced to Arabia and then across the Mediterranean region by the Arabs, first into North Africa and then to southern Spain via the Umayyad conquests and the associated scientific transmission of knowledge.

The Spanish went on to take the concept of transporting groundwater to fields and cities all the way to South America. Qanat pit, Morocco. Photo: Sylvain Lanau. Continue reading This content is available with the free Optimist plan! Subscribe to read more Already subscribed?