LES FOGGARAS DU GRAND ERG OCCIDENTAL ALGERIEN

Abstract

The present study evokes a national cultural inheritance or even a world-wide one, since it exists in only 50 countries all over the world. Known as qanât in Iran, Khettara in Morocco, Kariz in Pakistan and in Afghanistan, Foggara is an ancestral hydraulic system for collecting and distributing water. Consisting of a subterranean tunnel equipped with ventilation shafts, Foggara collects aquifer water in order to supply the Ksar and to ensure irrigation of the palm-plantation. There are many Foggaras which drain off Continental Intercalary aquifer water of the so-called Tadmait tableland. This is truly a water tank for Foggaras. One can observe another Foggaras which canalize phreatic aquifer water from the well known Great Western Erg. Downstream the tunnel, water flows with a free surface and irrigates under gravity the last garden of the Ksar. This is ensured by the use of a performer irrigation system which is well adapted to the topography conditions. According to the last inventory carried out by the National Agency of Hydrous Resources in 1998, there are only 903 operating Foggaras. Currently, the number of operating Foggaras is being revised downwards, since many of them are in a state of total collapse due to silting or flooding effects.