Outstanding Features

Qanat (karez or foggara) irrigation systems are ancient (ca. 800 BC) and consist of underground tunnels constructed into a cliff, scarp or base of a mountainous area, following an aquifer, or from rivers, to bring water out to the surface. The tunnels are straight and horizontal with a slope to allow the water to drain out into an oasis or irrigation system. Qanats are important in arid zones where water is scarce and minimize evaporation loss; they provide 80% of the water around the central plateau of Iran (e.g. Husseinieh, Isfahan).

The volume of water produced depends on the type and extent of the aquifer, and its recharge rate. When tunnelling horizontally, air shafts 50-180 ft deep are constructed every 50-150 ft to remove the mined soil, clean the tunnels of silt, and aerate the tunnels. One of these shafts is a mother well (‘madaarchah'). While the men and boys construct and clean the qanats, a suitable female (e.g. widow, older woman, virgin) volunteers to be the bride of the qanat to ensure adequate water supply, and has to be faithful to the qanat for a season (or a year) by bathing ritually in the qanat during the warmer months. Farmers donate part of their crop (usually 1 bushel of wheat) to the bride after harvest. Qanats are owned communally, and their water is distributed on a rotational basis (‘madaar') over a period (10-14 days) to community members. Qanats irrigate cereal crops (barley, wheat) in autumn and other crops (e.g. sugar beet, tobacco, melons, turnips, onions, pomegranates) in spring, with land being left fallow every third year.

Goods and Services Provided

Qanats provide ecosystem goods and services such as water, staples, fruits and vegetable; and promote social cohesion through participation and cultural rituals.

Threats and Challenges

Qanat irrigated agriculture is threatened by silt sedimentation in canals, moving sand dunes, urban migration of youth, and decline of experts for managing such systems. There is a need to find approaches to maintaining these systems including their agro-biodiversity on a sustainable basis.

Policy and Development Relevance

There is a need to assess the policy, institutional and economic dimensions of qanat irrigation with reference to agro-biodiversity maintenance in the dry zones.

Global Importance

Qanats are a relic form of underground irrigation important for dryland agriculture, and have been introduced in many parts of the world. They occur in Sinkiang, Western China (e.g. Turfan oasis), South-western Afghanistan, South-western Turkmenistan, the Arab world, Libya (e.g. Zella), Tunisia, Algeria (e.g. Germa), and Morocco; and were introduced by the Romans into Egypt and Syria, and into Southern Spain by the Moors.