The region of Chelghoum Laid - Tadjenanet is located in eastern Algeria, in the high plains. This area is characterized by a varied age (Mio-Plio-Quaternary) formations and the human demand is ...answered by the groundwater hosted into the superficial aquifer of the Mio-Plio-Quaternary formations. However, the overexploitation of this aquifer leads to a drop in the piezometric surface and an increase in salinity. of this aquifer leads to a drop in the piezometric surface and an increase in the salinity of the water. A hydrochemical study using characteristic ratios and statistical tools such as principal component analysis and hierarchical ascending classification, was performed using 28 water samples. Chemical analyzes show that the waters of this aquifer are of the calcium bicarbonate type on the limits of the study area, and calcium sulphate to sodium chloride in the centre. The spatial evolution of chemical water facies is explained by the phenomenon of dissolution and ion exchange between the alkali metals and alkaline earth metals coinciding with the West-East flow direction. The application of the various tools shows that the aquifer is recharged by precipitation at the plains border, where the water acquires its original mineralization from the carbonate formations, and becomes more mineralized in chlorides, sodium and sulphates concentrations in contact with the salt-bearing terrigenous formations of the Mio-Plio-Quaternary. The salinization of the waters seems to be mainly due to the dissolution of gypsum, halite and epsomite. The application of the ascending hierarchical classification and the principal component analysis shows the existence of two groups of water whose salinity increases from the borders towards the center of the plain following the main flow direction.
The population of Mila is increasing and local authorities are looking for new lands to develop the town and provide housing. However, the soil of these lands is unstable and requires detailed ...studies to serve as a foundation. This work presents the geotechnical and the geophysical characteristics of the Marechau soils, which forms the southeast extension of the Mila town. To provide an idea about the soil condition, to choose the type of adequate constructions and to make decision for building it, we adopted a geotechnical approach, where we analysed the soils by carrying out core drilling tests, dynamic penetration tests and the laboratory tests. We also, employed the geophysical approach in determining the electrical resistivity so as to map the depth of bedrock roof. Furthermore, we conducted a comprehensive hydrogeological study, monitoring precipitation and the piezometric level of the aquifer over a period of 200 days, and determined the flow direction. The core drilling test results indicate a clayey soil with limestone blocks. The dynamic penetration test show two categories of soil. The laboratory tests show that the materials analysed are very plastic, over-consolidated and medium to very compressible. They have a medium to high swelling potential and medium amount of aggressiveness to concrete. Besides, the tomography results also showed a single layer land (clay) with massive rocks embedded in it. The piezometric monitoring reveals the presence of two aquifer systems. The first is superficial and the second is deep. They don’t recharge directly after the rain falls and the groundwater flows in the direction of the slope. All the results indicate that solutions must be found for soil movements in the area under study before urbanization takes place. The combination of these results with the location, land morphology, tectonic activity, and seismotectonic aspects suggest that the area presents a high risk, and its urbanization requires rigorous and mandatory precautionary measures.
