Qanat550-331 BC |
Qanat, courtesy of Bruce Salters, W.P. Law Inc. |
Year: 550 BCType: QanatTypical use: Agriculture(Kareze in Mesopotamia) The development of this technique allowed the use of ground water to become the primary source for crop irrigation.
A Qanat was built by first digging a vertical well into sloping ground. Once the well was completed a tunnel was dug nearly horizontal to the lower end of the well. The natural slope would allow well water to travel by gravity down the tunnel and emerge some distance down slope from the well.
Construction of Qanats was labor intensive and vertical openings were placed every 20-30 meters to allow the tunnel diggers to breathe and to remove the debris from the tunnel. Once the tunnel was completed, the area had a constant source of water. Qanats are still in use today and at least 20,000 still operate from China to Morocco. |
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