Demarcation of Groundwater Potential Zones by Electrical Resistivity Survey (ERS) Islamabad, Pakistan

Abstract

A newly developed D-12 housing sector is at the Margalla foot-hills in Islamabad. This housing sector is
facing tremendous groundwater problem due to frequent dry boreholes. After conducting the reconnaissance survey,
data from the already drilled wells were recorded at different points throughout the study area for measuring average
water table and the average total depth. The electrical resistivity survey was conducted in the sector for exploration of
groundwater at six different locations with the help of SAS 4000 Terameter using Schlumberger configuration. The
acquired data were used to determine the true resistivity on the basis of standard curves. The curves were matched with
the borehole data and the surface geological map to prepare lithologic columns based on the true resistivities. Two
zones have been categorized for future domestic use, i.e. prospective and non-prospective. The study shows
dependence of localization of the aquifers upon the fault-related folding of the area. The aquifers are of two types i.e.
shallow unconfined and deeper confined. The unconfined aquifers are found in the alluvium, whereas the confined
aquifers are found in the sands of the Murree Formation. The confining beds constitute Murree clays and the shales.