Groundwater potential zones identification using geoelectrical sounding and remote sensing in Wadi Touil plain, Northwestern Algeria

The Wadi Touil plain is situated southwest of Tiaret city; it contains two important localities, Ksar Chellala (Reibell) and Zemalet El Amir Abdelkader (Taguine). This semi-arid region belongs to the western high plains and is characterized by scarce and irregular rainfall. The lack of surface water and the agricultural activities of this region increase the demand for groundwater. Several water boreholes were installed to meet the large water needs; however, these boreholes no longer cover the high demand for water due to the increase in population, increase in irrigated areas, and wear and tear on pumps. Therefore, in order to better define the catchment area and find new sites that meet the water quality and quantity requirements, a geoelectrical survey using the electrical resistivity method was carried out in the Wadi Touil large plain South of Tiaret to investigate the electrical characteristics of sub-surface layering and evaluate the aquifer potentials. Using the Schlumberger array, a total of 127 vertical electrical soundings were conducted along 16 profiles. The recorded data were interpreted quantitatively and qualitatively through the use of isoapparent resistivity maps, geoelectrical pseudo-sections analysis, and the established geoelectric sections. The results show the presence of three very promising levels; the surface aquifer formed by the Mio-plio-Quaternary terrain (ρ = 55 Ω m), the Barremian-Albian-Aptian complex (ρ = 300 Ω m), and the Jurassic aquifer (ρ = 1200 Ω m). In this study, we determined the extent of these aquifers, their depth and their thickness. These results provide a better understanding of the geology and the deep geo-structure of the region. The remote sensing observations using Sentinel 2A images located the wet lands and provided visual evidence of the evolution of the irrigated areas over time. Finally, according to the study results, the most favorable sites for the establishment of water exploitation boreholes are proposed.