Climate change is having short-and long-term impacts on surface and groundwater in the northern part of the African continent. This has led to a wide range of consequences that have added pressure on the groundwater systems in this part of the world. Among such pressures, we can cite the mal-distribution and the irregularity of precipitation and ice, flooding, evaporitic sediments input by the drainage net, water degradation, mud stagnation in dams, dead tranche, drought, decreasing of the natural recharge and increasing of the groundwater abstraction, conflict between trans-boundary waters, desertification, imbalance between the regions, migration, revolution, socio-economic imbalance, etc. Actually, watermonitoring networks indicate noticeable hydrogeologic variations and a rise of the groundwater salinity. It was confirmed by the geochemical analysis of water resources that showed scattered data between the northern part characterized by low mineralized groundwater (TDS ranging 0.4-3 g/l) and the southern area where the salinity ranges from 2.5 to 90 g/l. The obtained values are far above the permissible limits for both human consumption, agricultural and tourist activities. These effects, when compounded, are anticipated to worsen the situation and to constitute veritable threats for social and economic development in these regions of North Africa (Morocco, Algeria, Tunisia, Libya, Egypt, etc.). The potential solutions consist of taking urgent to utilize the intelligent technology (bio and nano-technology), policies relevant policies to manage water resources, and the engagement of private, civil, and international sectors if a major crisis is to be averted (collective effort).

This work presents results of the hydrogeological and hydrochemical studies on groundwater samples from the alluvial aquifer of Merdja in Tébessa, located in the Western part of this town. Its groundwater resources are used mainly for crop irrigation in an agriculture dominated area. Hydrochemical and water quality data obtained through a sampling period (December 2008) and analysis program indicate that nitrate pollution can be a serious problem affecting groundwater due to the use of nitrogen (N) fertilizers in agriculture. The concentration of nitrate in groundwater ranged from 19 to 281 mg/l. Considerable seasonal fluctuations in groundwater quality were observed as a consequence of agricultural practices and other factors such as annual rainfall distribution and the wadi El Kebir flow regime. The chemical composition of the water is not only influenced by agricultural practices, but also by interaction with the alluvial sediments. The dissolution of evaporites accounts for part of the Na + , K + , Cl − , SO 4 2− , Mg 2+ , and Ca 2+ , but other processes, such as calcite precipitation and dedolomitization, also contribute to groundwater chemistry.

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Hydrogeochemical investigations were carried out around Fetzara Lake, Northeast Algeria, to assess the quality of groundwater for its suitability for drinking and irrigation purposes. The groundwater chemistry is mainly controlled by the water-rock interactions, but also influenced by other processes such as evapotranspiration and ion exchange. Groundwater samples collected, during two periods (1993 and 2007) from wells in the area were analyzed for pH, EC, TDS, Ca 2+ , Mg 2+ , Na + , K + , CO 3 2− , HCO 3 − , Cl − , SO 4 2− , and NO 3 −. The chemical relationships in Piper's diagram and Gibbs's diagram suggest that groundwaters mainly belong to noncarbonate alkali type and Cl − group and are controlled by evaporation dominance, respectively, due to the sluggish drainage conditions, greater water-rock interaction, and anthropogenic activities. A comparison of the groundwater quality in relation to drinking water quality standards proves that most of the water samples are not suitable for drinking. US Salinity Laboratory's and Wilcox's diagrams and %Na + used for evaluating the water quality for irrigation suggest that the majority of the groundwater samples are not good for irrigation.