RELATION ENTRE L’EVAPORATION DE LA NAPPEPHREATIQUE ET LE POUVOIR EVAPORANT DE L’ATMOSPHERE EN ZONE ARIDES

Abstract

The majority of area highlighted in arid and semi-arid regions of Algeria based on groundwater excessively mineralized (saline) whose level is close to the soil (0 – 1,5m). These levels are close to the ground in the presence of very severe weather conditions favor the process of evaporation of these layers, which contribute a large part to the salinization of land and environmental degradation. The analysis of results of work done on the determination of evaporation of groundwater in the region of Ouargla shows that evaporation decreases gradually as the level of the water away from the surface thoroughly. The results show that the evaporation of the water table is maximum and equal to evapo-transpiration when the level is close to the surface and becomes minimal below 2meter (than 10% of evapo-transpiration).The distribution of salts accumulated in the soil layers follows the same pattern of, The amount of salt deposited are closely related to the amount of water evaporated from the water table. For better development of land and high agricultural production it is necessary to know the location of maintaining the level of the water table (drainage) depending, hydrogeo-logical conditions and the salinity of the groundwater.