**5. Conclusion**

The hydrochemistry of BouHafna and Haffouz aquifer was investigated employing multivariate statistical approach in order to identify different processes that control groundwater mineralization. This investigation reveals the predominance of Ca-Mg-HCO<sup>3</sup> and Ca-Mg-SO<sup>4</sup> water-types. These water facies are derived mainly from water-rock interaction processes, i.e., the dissolution of halite, gypsum, the dedolomitization, and the cation exchange. On the other hand, return flow of irrigation water has resulted in elevated nitrate concentrations in groundwater especially in the agricultural zones, which are characterized by an excessive use of fertilizer. Thus, it is important to protect the aquifers against overexploitation and groundwater quality deterioration related to the evaporate dissolution and agricultural contamination. For these reasons, in the BouHafna and Haffouz regions where groundwater resources are under the great development stress and environmental pressure, some preventive measures should be taken. These are (1) control the exploitation groundwater; (2) the definition of special groundwater resources protection zones; (3) control the potential processes and sources of salinization; and (4) improvement of diffuse source groundwater pollution.
