Qanat

The qanat was an underground irrigation system, used in dry, mountainous regions as a method of transporting water over long distances for agricultural use. Evaporation was kept to a minimum, and the systems used groundwater, a more reliable source than seasonal rivers. A horizontal tunnel was dug, by hand, into a cliff or mountainside. Vertical shafts were then cut into it to allow ventilation and easy access to keep the main tunnel clean. Cleaning was a task often carried out by children who were lowered down through the vertical shafts on ropes and buckets.