||COMB-SHAPED SHRING SYSTEMS
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Site: Wadi Saoura
Description of the local variant of the technique
The cultivation of vegetables oases, associated with the cultivation of the palm, need a constant distribution of water. These, produced by underground canalization (foggara), once arrived at the surface accumulate in a triangular basin (the Qasri) which at its base presents a particular device in stone by the comb shape (kesria). The gaps between the "teeth" quantify the water due to each owner and they distribute the water to the open air canals which crossing the kesria and an intricate plot of conductors decreasing in size, they continue to subdivide the water in the fields. The measurement system with the comb splitter responds perfectly to the needs of the oasis. The water continually produced, shall be used continuously (the "foggara" is said to not have a tap) because the strong evaporation in the desert does not allow the collection of liquid in the open and at the same time, the possibility of groundwater reserves is limited. Furthermore, given the need to irrigate the vegetables and because of the innumerable subdivisions of ownership shares, the calculation of the volume of water and its distribution can not be done by stopping the flow and dividing the time of use. In addition to that, the method used can simultaneously and automatically distribute any changes in the overall scope. (due to changes in production volume) proportionally according to the amount due. the determination of the gaps of the kesria is an extremely important and delicate task: it is entrusted to the Masters of the water (Kiel el ma), the guardians of complex knowledge, who are able to take measurements with remarkable rapidity following the evolution of the water system conditions.
Preserved and Functional 80%
Schematic representation of the breakdown, by inheritance, of the share of water through the successive generations of three large families: A, B, C. These divide the water supply of foggara (2) via the kesria (3). Over time the water is divided between the generations (I-VII), creating an intricate web of pipelines, distributors and secondary particles grown.