qanat

noun

1. An underground conduit, between vertical shafts, that leads water from the interior of a hill to villages in the valley

   “Shafts are dug to the required level along the planned route of the qanat, every 300 m or so […].”

   “Elsewhere over large areas of the plateau and the foothill regions, the qanat irrigation cultures were weakened considerably.”

   “Its gardens are watered by rivers that invariably flow underground, like the subterranean qanat'''s developed by the Persians.”