SUMMARY
Plain of Ghriss, located in the North West of Algeria, is a semi-arid climate zone. It borders a groundwater resource heavily exploited for irrigation plots and for the needs of the local population. In the absence of other resources, conventional or not, the groundwater in the plain of Ghriss remain the driving force of the development of the region. This work was led from the results of analysis of physical-chemical parameters of water and relied on a sample of 35 boreholes. The methodology is based on multivariate statistical approach (Principal Component Analysis (PCA) and Hierarchical Classification (AHC)). The combination of these methods helped provide answers to our problems. This study identified two main mechanisms that are responsible for the evolution of the mineralization of the waters of the region. The first type, characterized by high mineralization represents the infiltration of surface water (rain and effective return of irrigation water). It is located especially in the northeastern part of the plain. The second type, rich in bicarbonates, representing recharge water from carbonate formations in the southeast of the plain.