The Persian Qanat

A qanat or kariz is a system for transporting water from an aquifer or water well to the surface through an underground aqueduct. Constructed in Iran, Iraq, and numerous other societies, this is an ancient water supply system that allows water to be transported over long distances in hot, dry climates without loss of much of the water to evaporation. The system has the advantage of being resistant to natural disasters such as earthquakes and floods and to deliberate destruction in war. Furthermore, it is almost insensitive to precipitation levels, delivering a flow with only gradual variations from wet to dry years.