Appraisal of groundwater conditions through hydrogeophysical and hydrogeological approach in Cholistan area, district Bahawalpur, Punjab, Pakistan.

The sustainable groundwater supply has a prime importance for the development of an area. Unfortunately, the groundwater-related issues are heading towards terrible situation regionally and locally as well. As far as the different parts of Punjab Province of Pakistan are concerned, Cholistan is almost a desert region where the groundwater scarcity is being observed in its different parts since decades. The present research is an attempt to assess the latest groundwater potential and demarcation of different groundwater quality zones exist at subsurface in the study area of Cholistan. For this purpose, hydrogeophysical studies allied with hydrogeological approach were utilized. Hydrogeophysical investigations were carried out in the study area at evenly distributed 50 sites by deploying geo-electrical survey. Lithology represented by the boreholes and geo-electrical survey results altogether deduced that the eolian deposits overlie with intermixed fine and coarse alluvium. These sediments are mainly intermixed layers of sand, clay, silt, gravel and some kankars. Overall three to six subsurface geo-electric layers were identified through the geo-electrical survey and the resistivity values were categorized as high, medium and low across the study area. 2D and 3D maps were developed deciphering different groundwater quality zones in terms of electrical resistivity behaviour with depth. Spatial maps of hydrogeological values in terms of Dar-Zourrak parameters were also developed for further precise demarcation of different qualities of groundwater pockets. Furthermore, hydraulic parameters were estimated and represented in 2D maps to evaluate aquifer potential zones across the study area. Hydrogeophysical and hydrogeological approaches integrally depict that most of the part of study area holds better groundwater conditions with high potential but the salinity prevails in some parts that goes to persist with depth.