Diversion wall

Diversion walls are linear earth and/or stone structures that divert part of a watercourse into a canal to supply an irrigation system.

Unlike a dam, diversion walls, which are usually set up at an angle on the side of a watercourse, do not completely interrupt it and thus do not hold water in a reservoir (Gentelle 2003: 122).

Diversion walls have been widely used on the desert margins of Southwest Arabia as they allowed for the optimal exploitation of the main local water resource. Indeed, it was technically difficult to retain the large and unpredictable flash floods rushing from the surrounding mountain in reservoirs. It was thus preferable to use structures that could break in case of heavy floods in order to prevent too much water from entering the irrigation system and damaging it.

With this system, the sedimentary load, which contributed to the formation of crop soils, could also reach the fields instead of being trapped in the reservoir (Brunner and Haefner 1986: 82).

See also Water Management

Julien Charbonnier

References and suggested reading

• Brunner, U. & H. Haefner 1986. The Successful Floodwater Farming System of the Sabaeans, Yemen Arab Republic. Applied Geography 6: 77–86. DOI: 10.1016/0143-6228(86)90030-5.
• Gentelle, P. 2003. Traces d’eau. Un géographe chez les archéologues. Paris: Belin.

_{Alternate spellings: Deviation, Deflection, wall}