||INTEGRATED USE OF WATER CATCHMENT, HARVESTING AND DISTRIBUTION
Definition characters description and diffusion
In deserts and arid zones, knowledge of water management techniques is used to preserve soil humidity and to collect underground water.
General characters description and diffusion
The subsoil area for water supply looks like a big rocky sponge rather than an underground basin. Because of the temperature range from night to day there is a lot of night condensation on the ground that wets the sand. The wet sand is dried by the sun's rays and creates a hard crust which typically cracks when trod upon. This is the phenomenon of hidden precipitations that is of primary importance in the ecology of the desert. If the smallest traces of moisture and the supply of night condensation of fog and dew are properly managed, then they can form sizeable water reserves. Hydraulic arrangements can then collect the water vapour from the air and preserve it in the subsoil before it fades away at the first light of dawn. Some of the foggara networks, which are typical of Touat, are fed in this way. Along the steep Deir, around the area of Petra, in Jordan, the khottara are structures which provide water all the year round: the weak exudations from the walls, as a result of the condensation at high altitudes, are harvested by dripping into tanks and cisterns. This kind of device is probably the origin of the biblical episode in which Moses made water spring forth by mean of his rod. By hitting the wall, the superficial coating is removed and there is a greater water flow.
Advantages and sustainability
Underground water is collected as well as soil humidity ensured by utilizing knowledge of various water management techniques.