The Chinese, while acknowledging a possible Persian connection, find an antecedent to the qanats were an important factor in determining where people lived.
The largest towns were still located at low elevations on the floors of intermontane basins and in broad river valleys.
Evidence of New World qanats technology may have been introduced into the central Sahara and later into western Sahara by Judaized Berbers fleeing Cyrenaica during Trajan's persecution in 118 AD.
Since the systems in South America may predate the Spanish entry into the New World, their development may have occurred independently from any Persian influence.
tunnels were hand-dug, just large enough to fit the person doing the digging.
A gently sloping tunnel is then constructed which transports water from groundwater wells to the surface some distance away.Not only is the work technically difficult, but also the social organization associated with a qanat has major implications on its future viability (Wessels, 2000).The precise dating of qanats is difficult, unless their construction was accompanied by documentation or, occasionally, by inscriptions.During periods of low water use in fall and winter, water-tight gates can seal off the qanat).The spoil is dumped around the opening of the shaft to form a small mound; the latter feature keeps surface runoff from entering the shaft bringing silt and other contamination with it.These amazing structures allowed Persian farmers to succeed despite long dry periods when there was no surface water to be had.Many qanats There are significant advantages to a qanat water delivery system including: (1) putting the majority of the channel underground reduces water loss from seepage and evaporation; (2) since the system is fed entirely by gravity, the need for pumps is eliminated; and (3) it exploits groundwater as a renewable resource. The rate of flow of water in a qanat is controlled by the level of the underground water table.The selection of these sites was based on a national survey conducted in 2001.The renovation of one the three (Drasiah qanat of Dmeir) was concluded in the spring of 2002.The main qanat tunnel sloped gently down from pre-mountainous alluvial fans to an outlet at a village.From there, canals would distribute water to fields for irrigation.