INVENTORY OF TRADITIONAL KNOWLEDGE TO COMBAT DESERTIFICATION

PHOTOGRAPHICAL  AND  TYPOLOGICAL  INVENTORY

B12 - SUNKEN-DAMS
Yemen. On the left, at the bottom of the marbid the stone walls which organize the terraced slope and collect humidity. On the right, the stone walls and dams called harrah which share out the water quotas.
In Petra (Jordan) the stone terracing systems called khaur, typical of the Nabatean agriculture used in the Negev desert, are still visible. In rural environments, they are mere semi-circular terracing systems which retain the soil, whereas in urban areas they are more complex building systems. Some examples of these systems made with carbon layers to filter water and make it fit for drinking have been discovered.
Yemen. Ploughing the soil enables the field to absorb the humidity from the atmosphere. Below, the water distribution to the fields by means of a device which conveys water through a hole, the iglamah.
Along the upper course of wadi Saoura (Algeria) the dams stop the underground flow and produce surface water for the crops planted along both sides of the riverbed. When floods occur and form water courses flowing on the ground, the latter are conveyed to the lateral terraces (A) in order to allow irrigation by gravity at a higher level than the natural run-off (B). In periods of aridity, humidity is retained in the subsoil and water is drawn up from an outlet situated at the foot of the dams (C).
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SUNKEN DAMS
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INVENTORY OF TRADITIONAL KNOWLEDGE TO COMBAT DESERTIFICATION