Around the Regions - SOUTH AND CENTRAL ASIA

The Qanat Project
by Malia Bouayad

The twenty-ninth session of the General Conference of UNESCO invited the Director-General of UNESCO to launch a special project entitled Qanats for revitalising traditional technologies in view of sustainable water use in arid zones. The proposal was submitted by the Islamic Republic of Iran. The International Hydrological Programme is responsible for the project in co-operation with the Iranian National Committee for IHP.

Revitalising traditional water harvesting and supply technologies in arid and semi-arid areas is of crucial importance for sustainable water utilisation in these regions. The special project on ancient Qanat technologies will synthesise available information which will serve as a basis for establishing pilot rehabilitation activities in arid zones. The project will include an international symposium on qanats which will treat a variety of disciplines: hydrology, engineering, archaeology, history and anthropology and will recommend activities for the use of qanats in arid areas.

Some 3,000 years ago the Persians learnt how to dig underground aqueducts to bring mountain ground water to arid plains. Today, this system provides more than 75% of the water used in Iran.

Qanat technology was invented in Iran and originated in the ancient Urartu Kingdom, near Lake Urumiya in North West Persia. The city of Irbil still uses water from the qanats built by Sennacherib (705-681 B.C). Written records show that the Assyrian King Sargon II (722-705 B.C) claims that he learnt the secret of tapping ground water during his campaign against Urartu. As a result of such wars and the founding of the Achemenide Kingdom, qanat technology was transferred to the west of Iran, the Mediterranean region and Egypt. Qanats can also be found in Balukistan, Afghanistan and Oman. In the ninth and tenth centuries qanats were also used in certain oasis in South Algeria, Morocco, Syria and Jordan and in the XVIIIth century were to be found in Cyprus.

A qanat is a horizontal underground gallery that conveys water from aquifers in the highlands to lower level surfaces. Qanats are built by specialists called muqanni (qanat diggers), who have a great deal of experience and a very good knowledge of qanats - this knowledge is usually transmitted from father to son. A windlass is set up at the surface and the excavated soil is then hauled up in leather buckets. A vertical shaft of about three feet in diameter is then dug out, one man working with a mattock and the other with a short-handled spade. A gently sloping tunnel is thus constructed which conducts water from an infiltration section beneath the water table to the ground surface by gravity flow. Qanats are made of soil and stone, and mineral and salt deposits accumulate on the channel bed which necessitates periodical cleaning and repair by the muqanni.

In Iran, water is tapped from zones in the alluvial fans at the base of the mountains. The origin of the qanat is the mother well, which is sunk into the groundwater recharge zone. This vertical shaft can, in some cases, be over 100 meters deep.

A qanat can measure from several hundred meters to more than 100 kilometres. The qanat usually exists at surface level in cultivated areas. In fact, villages are often founded near qanats. The traditional division of water is very complicated. In Central Iran for example, the Yazd region used a cycle consisting of a specific number of days and nights, i.e., six days only per village. In other villages the cycle may be 22 days. If we look at the distribution of water in a particular village we can see that even during the same cycle the volume can differ considerably. The length of the cycle, therefore, is not based upon the flow of water.

Outflow fluctuates according to seasonal change in the level of the groundwater table. It is lowest in autumn and highest in the spring. The qanat system guarantees an ample supply of water even during periods of drought.

The distribution of water is regulated by customs and laws, often going back to pre-Islamic times and early Islamic codification. When the distribution system is applied, the fields are divided into series of rectangular strips divided by low and parallel border ridges. Large qanats may be permanently divided between parts of a village or between two settlements. The divider (raqam, maqsam) is constructed of elongated pieces of stone or wood depending upon how the water is to be divided (1/2, 1/3, 2/3). The qanat system of irrigation had and still has a profound influence on the lives of the Iranian villagers. The cycle for water use and the distribution of water rhythm their lives and has an influence on all their socio-economic activities.

The increasing demand for water followed by the fast filling of new production wells and overpumping of some aquifers has brought about a drop in the groundwater level and many qanats have dried out. At least half the qanats in Iran have fallen into disuse as their continuous flow cannot be controlled. It would be a great pity if the qanat system which is in harmony with the environment is allowed to fall into total disuse. What are the possibilities of developing the system? Should the qanat system be replaced by another system? Should it be improved and updated in line with modern technologies or should it be totally abandoned?

The qanat project will be undertaken in the framework of the Water and Civilisation project. The main objective of the Water and Civilisation project is to study past water supply in order to understand the present and prepare for the future. (See the Article published in WATERWAY No. 10)

Within the framework of the Water and Civilisation project an encyclopaedia on the History of Water will be prepared to develop public awareness of the value of water in our cultural heritage and emphasise a new water ethic. This will be done through a series of workshops on traditional systems of irrigation and water uses in the world, raising public awareness of the water resources and its civilised use according to the environment. The first workshop will be held in Iran in 1999 and will cover traditional systems of water supply around the world with special emphasis on qanat technology.