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The study area lies in Southwestern part of Sahiwal District, Punjab, Pakistan, which is the central part of interfluves system, i.e., Bari Doab. Hydrogeophysical investigations were carried out for the spatial appraisal of groundwater aquifers resources in the study area through electrical resistivity survey. A total of forty vertical electrical soundings through Schlumberger electrode configuration are conducted in the study area. The interpreted results of electrical resistivity survey along with interactive modeling suggest that four to six numbers of geo-electric layers exist in the subsurface in the study area. The alternating alluvium comprised of silt, sand, gravel, and kanker layers has been interpreted. The interpreted resistivities are categorized from very high to very low in the study area. Below the water table, very low resistivity values interpreted mainly as sand and sand-gravel saturated with saline water. Moreover, the interpretation of our developed maps also leads to demarcate the fresh and saline groundwater zones. Interpreted results decipher that this gigantic saline water zone starts below the depth of 150 m and extends below the depth of 300 m. The models of true resistivities are also calibrated with the lithological logs of test holes and tube wells within the study area. The sandy and gravel layers are the most promising zones for good-quality groundwater that leads to the development tube wells up to the depth of 150 m within the study area.

Geostatistical variogram and inversion techniques combined with modern visualization tools have made it possible to re-model one-dimensional electrical resistivity data into two-dimensional (2D) models of the near subsurface. The resultant models are capable of extending the original interpretation of the data to depict alluvium layers as individual lithological units within the 2D space. By tuning the variogram parameters used in this approach, it is then possible to visualize individual lithofacies and geomorphological features for these lithologic units. The study re-examines an electrical resistivity dataset collected as part of a groundwater study in an area of the Bannu basin in Pakistan. Additional lithological logs from boreholes throughout the area have been combined with the existing resistivity data for calibration. Tectonic activity during the Himalayan orogeny uplifted and generated significant faulting in the rocks resulting in the formation of a depression which subsequently has been filled with clay-silt and dirty sand facies typical of lacustrine and flood plain environments. Streams arising from adjacent mountains have reworked these facies which have been eroded and replaced by gravel-sand facies along channels. It is concluded that the sediments have been deposited as prograding fan shaped bodies, flood plain, and lacustrine deposits. Clay-silt facies mark the locations of paleo depressions or lake environments, which have changed position over time due to local tectonic activity and sedimentation. The Lakki plain alluvial system has thus formed as a result of local tectonic activity with fluvial erosion and deposition characterized by coarse sediments with high electrical resistivities near the mountain ranges and fine sediments with medium to low electrical resistivities towards the basin center.