HISTORICAL, STRUCTURAL AND ENVIRONMENTAL FEATURES OF THE QANAT IN IRAN

Average rainfall in Iran (With 250 mm) is less than one-third of the global average annual rainfall and similar to that of arid and semi-arid countries of the world. For overcome water shortage in Iran, an old and interesting technique called as qanats was devised which convey water from an aquifer to lower-elevation fields. The qanats consist of a horizontal tunnel that taps ground water in an alluvial fan, brings it to the surface due to gravitational force. It provides required water for production of agricultural crops. Construction and exploitation of qanats have some environmental benefits. For instance, qanats waters don't have any contaminations. Also, improving vegetation cover without a biological changes in vegetative population are local achievements of the qanats. Other environmental advantages, historical and structural features in Iran were presented in the paper as detail.

کلیدواژه ها:

Qanat ، Irrigation history ، Structural and environmental features of the qanat