Assessment of subsurface lithology, groundwater depth, and quality of UET Lahore, Pakistan, using electrical resistivity method

Abstract

Rapidly depleting resources of surface water necessitate the exploration of groundwater reservoirs to cope with the water demand in Lahore and its periphery. For this purpose, a study was conducted to investigate groundwater depth, water quality, and subsurface lithology through Geo-electrical Resistivity Survey (ERS). Vertical electrical soundings (VES) at six (06) stations in the city of Lahore were performed using Schlumberger array. Apparent resistivity values were recorded at surface and processed with a computer software IPI2win to assess groundwater depth, quality, and subsurface formations. The VES resulted that the study area comprises of three layers. Top layer was determined as fill up to depth of 2 m followed by an unsaturated alluvium up to depth of 40 m, and the bottom layer was saturated alluvium up to the study depth of 100 m. The average water table depth was appeared to be at 39 m below the ground surface. The computed groundwater depths were also compared with the previous studies conducted in the proximity by different agencies in the past using destructive techniques and showed close resemblance. The study also shows that the groundwater up to depth of 100 m was having excess amount of total dissolved solids and was not drinkable as per quality standards set by the World Health Organization.