Some regions of the Sahara are rich in groundwater, which encouraged around the 1st century, piercing an extraordinary collection system and water supply. To cover the water needs and the important fight against aridity of the earth without leaving decision to evaporation, sometimes considerably in the Sahara, an irrigation means adapted was developed: It is the system of "foggaras" ( or "foguagir" the Arab Maghreb plural) which "appears to have originated in Persia and back to remote antiquity. It already finds mention in the fifth century BC, Herodotus (Melpomene 120) [... ]. It also has, through the narratives of Polybius (23.25-X), detailed information on foggaras of Persia Third and second century BC. "(JMSolignac).

A foggara is an underground pipeline built to supply the gardens in palm groves, where it is not possible to dig wells. It can have a 2- to 10 or 15 kilometers. Pipes after gentle slope (a few millimeters per meter height difference) and run for about 5 or 10 meters below the ground surface. The actual foggara has sufficient diameter (1 m to 1.20 m) for the displacement of a bent man, worker progressing from downstream to upstream at the time of drilling and circulating workers to perform maintenance. On the surface, the debris cones (kind of looks) or masonry works mark out the path of the foggara (and water) between the web and the receiving basin. All built from 12 to 15 meters, these cones protect the hole at the same time they allow to monitor the flow and, if necessary, to take to the foggara to clear the precise point of the gallery that may be obstructed. At the outlet of each water pipe is accommodated in a basin.

Its flow is carefully measured before it sparingly reparte to be redistributed between the gardens. At the exit of the sump, the water then passes by a "Chebka" (= gate), which is a copper plate - or terracotta - apertured the "Kassis" or "Kesra" (= comb ), distribution device, which enables the redistribution of water foggara calculated fingers or half-fingers, as appropriate then it can go through tiny channels ("irrigation channel") that run through the park and the lead towards the gardens.

The ingenuity of the process lies in its design and its adaptation to the conditions of life and the Saharan climate: it suppressed the strenuous fetching water, which took most of the time the inhabitants, and ensured a constant flow supply, without risk of drying up the water table and limiting evaporation to a minimum.