Aquifer characterization and evaluation of groundwater potential zones in the frontal part of the Himalayas using electrical resistivity tomography technique

This research focuses on characterizing aquifers and assessing groundwater potential zones in the frontal region of the Himalayas using the electrical resistivity tomography (ERT) technique. The subsurface profile is generated through a combination of electrical resistivity and drilling methods. Two different arrays, Dipole-Dipole and Schlumberger are employed in the two-dimensional Electrical Resistivity Tomography (2D-ERT) using the Syscal Pro Switch-72 instrument. Resultant profiles are obtained through the PROSYS-II and RES2DINV software. Survey alignments involve maximum electrode spans ranging from 175 to 66 m at specific sites. 2D-ERT profiles show clay, sand, and boulder distribution, marking groundwater zones. Multiple aquifers of different thicknesses with varying potentials are detected at different depths of up to 100 m in sediment layers. Faults (FF') are inferred from distinct resistivity layers and stratigraphic age. The resistivity data aids in delineating groundwater potential zones, a verification process performed through pumping tests and step drawdown data. The average maximum drawdown, discharge and yield capacity of all the sites is 5.25 m and 9812.5 gallons per hour and 13937.5 gallons per hour, respectively. The combination of Dipole-Dipole and Schlumberger arrays, along with the correlation between borehole lithology and pumping tests, proves reliable and effective in identifying areas suitable for demarcating groundwater potential zones and characterizing aquifers. This information is valuable for future planning and administrative decision-making regarding the development of new wells.