ESTIMATION AND CONDITION OF GROUNDWATER RECHARGE IN SEMIARID ZONE

Abstract

In a recharge area characterized by a semi-arid or arid climate, and a low annual rainfall, aquifers can be hardly recharged adequately, as it was demonstrated by classical monthly hydrological balance computations; therefore the mathematical modeling can be difficult. The methodology proposed in this work relies on spatial and temporal interpolation of scarce climatic data. This methodology can be used to determine the recharge flow of aquifers in these zones. The Ain Sefra's syncline (Western Saharan Atlas, Southwest Algeria) forms an excellent example for this application. Three years with different annual rainfalls are chosen in this application: 1983 as dry year, 2006 as average year, and 2008 as humid one to define three conditions of groundwater level. This application requires information about the soil nature, the surface and the altitude of the recharge areas. The rainfall and the recharge flow of aquifers indicate that the principal recharge areas are the Jurassic outcrops in the humid years, when the annual rainfall exceeds 300 mm. These results helped to complete the model input data and obtained a hydrodynamic model to manage resources water in this zone.