Groundwater vulnerability assessment using GIS modeling for north-east area of Tadla plain (Morocco)

The groundwater resources in Tadla region are the most unique principal source of water for drinking, agriculture, irrigations, and agro-industrial activities. Further, they are more vulnerable to pollution, especially aquifers those situated in arid and semi-arid regions, as the north-east area of the Tadla plain. The growing up of demography, economics, intensive agriculture and agro-industrial activities affect directly the basin by more susceptible contaminations. This negative impacts on the hydro -geological system intensifying the risk of the aquifer to pollution. For these reasons, the aim of this study is to define the degree of intrinsic vulnerability of this groundwater to any type of contaminants introduced from the soil surface. The importance of this research revolved around evaluating the vulnerability of groundwater aquifers using DRASTIC method coupled with Geographic Information System, the method is founded on diverse parameters: recharge of the tablecloth, the nature of the soil, depth of the water table, topography and the impact of the unsaturated area. The analysis of the intrinsic vulnerability maps allowed for determining three classes ranging from low to high vulner-ability. The southeastern part of the study area shows the highest vulnerability class, and the north part show a minor vulnerability class, this area is localized in a desert and uninhabited sectors of the study area, which are less populated, where human impact on the groundwater is minimal. The highest class indicating that it is the most vulnerable to contamination due to the hydrogeological intrinsic factors. The advantage of this approach make it easily possible to investigate and control vulnerability of the area.