Water is distributed through out the oasis through the foggaras

Foggaras owe its origin in Iran where it is known as qanat. The equivalent of Foggaras is also found in Morocco where it is called rhettaras. The foggaras are found in Saharan Algeria where the occurrence of oasis is very common. This indigenous system uses the principle of gravity flow to transport water to the oasis through out the year.

The foggaras are the traditional system of water harvesting where manmade underground galleries are made to harvest water. The underground galleries run almost horizontally and carry the groundwater to the oasis. The distribution channel to the oasis shows an inclination of one or two millimeters per metre. This gentle slope of the galleries reduces the speed of the flow of water and thus the erosion of the galleries is prevented.

Water distributed to the oasis through kesaria

The system works only if the oasis is located below the groundwater level that is the oasis must be either in the valley region or at the foot of a rift. The average length of the galleries is 2.5 km, which includes vertical wells found at an interval of 20 to 30 metres. The vertical wells help in aeration and maintenance of the foggaras. The materials for the construction of this water harvesting system come from the neighboring area. The galleries are made out of palm trees and stones, clays and straws are combined together to make the cement mix for the construction purpose.

Water is distributed throughout the oasis by the ‘water deciders’.