Geoinformatics and geophysical survey-based estimation of best groundwater potential sites through surface and subsurface indicators

Abstract

Groundwater is the most important natural resource around the world which needs new and advanced technologies for control and monitoring. This investigation was to check the groundwater potential zones by integrated techniques of geoinformatics and geophysical investigation through a vertical electrical sounding in Rawalakot, Azad Kashmir, Pakistan. The study area being a sedimentary basin, sandstone is the major rock type with good porosity and permeability. Satellite data were used to generate different thematic maps such as slope percent, lineament density, land use/cover, drainage density, geology, roughness index, curvature, topographic wetness index, and rainfall. Subsequently suitable rank and weightage was assinged for final weight overlay analysis to identify the groundwater potential zones. Final potential map was generated with good, moderate, and poor zones. This analysis revealed that 92.60% of the area is categorized to be having good to moderate groundwater potential. Then, an electrical resistivity survey was done by vertical electrical sounding (VES) using Schlumberger electrode configuration, at 32 locations to check the subsurface condition. The predominant curve types were Q type, A type, H type, and K type. The apparent resistivity was calculated at 20-m, 40-m, and 60-m depths. Dar-Zarrouk parameters were calculated to identify the subsurface aquifers and protective capacity rating. Integrating the outcome of GIS and geophysical studies, the region with good groundwater potential was delineated with more accuracy.