Evaluation des zones potentielles d’eaux souterraines avec l’utilisation des SIG et de la télédétection Cas du sous-bassin de la Sandougou (bassin de la Gambie)

Groundwater is an important natural resource for domestic, agricultural and industrial use. Today, due to climate change, population growth, advanced irrigation practices and industrial uses, the demand for groundwater has increased considerably, and needs to be assessed. This article aims to delimit the potential groundwater zones in the Sandougou basin using GIS and remote sensing. The multi-criteria decision analysis technique (MCDA) is used by integrating different thematic layers. The thematic layers of land cover, drainage density, linear density, soil, geology, geomorphology, terrain, slope and rain were prepared and used to make the map potential groundwater areas. Weights have been assigned and standardized to each thematic layer according to their characteristic and their relation to the groundwater recharge. Finally, the thematic maps were integrated by a tool for analyzing the weighted sum of overlays to develop the areas for prospecting for groundwater. According to this method, the basin is classified as excellent for 30.9% of the surface, very good for 27.8%, moderate for 20.5%, poor for 15.3% and very poor for 4.4% in term of groundwater potential. This analysis of the data demonstrates the importance of the use of GIS and remote sensing techniques in mapping the potential groundwater sector on a regional scale and suggests that similar techniques could be applied to other regions of this country.