Groundwater Vulnerability Mapping in the Karstic System of Ghar Boumaza, Using the C.O.P. Method

Abstract

After an extensive literature review on the methods of vulnerability mapping, analysis of the European project COST action 620, a geological and hydrological study of Merchich watershed, we saw the possibility of the application of COP method. It has been selected to assess the value of intrinsic vulnerability of groundwater resources in the watershed, with varying degrees of karstification. The cartography of the intrinsic groundwater vulnerability of this system was realized by applying the COP method (Concentration of flow, overlying and precipitation).The resulting map has shown that more than 38% of the surface of the system is in high vulnerability area,more than 18% in low vulnerability,44% with moderate vulnerabilit. The superposition of the map of intrinsic groundwater vulnerability with the map of polluting sources established for Ghar Boumâaza system helped to develop a map of pollution risks in which the areas that are most threatened by the pollution of the surrounding area A.Taga are highlighted.Indeed a bacteriological analysis campaign of water of this system performed recently allowed to see that some water sources are contaminated and therefore undrinkable. The water analyses of the fourth points assessed showed the real pollution of the groundwater which should be controlled and protected.