Hydrogeophysical investigation for groundwater potential through Electrical Resistivity Survey in Islamabad, Pakistan
Keywords:Groundwater exploration; Vertical electrical sounding (VES); Aquifer; Climate change; Hydrogeology; Pakistan
Background: The hydrological cycle has been disturbed because of global climate change. The rising global ocean level due to melting of ice with substantial increment in temperature led to climate warming. These circumstances have a negative influence on water resources, especially groundwater. The groundwater is one of the extraordinary natural resources used in maintaining life on the earth. It has a direct relationship with the population. The population growth, along with climate factor, has raised the demand for freshwater. Hence, there is an ultimate need to search for the location of new wells that can be utilized to fulfil population needs.
Objectives: The primary purpose of research is to carry out an electrical resistivity survey to determine potential aquifer capacity, properties and propose the location of the new wells in sector G-14/3, Islamabad.
Methods: Vertical Electrical Sounding (VES) was used with the Schlumberger configuration. ABEM Terameter SAS4000 was employed to perform 2D geoelectrical resistivity imaging surveys to obtain resistivity values. IX1D software was utilized for the data interpretation and the development of different geological layers.
Results: Results from the VES models shows that the subsurface is divided into different lithological layers. The depth and thickness of these layers vary due to tectonic activities and depositional environments. Clay is the dominant lithology along with sandy gravel layers. The Dar-Zarrouk parameters result specifies that VES-3 and VES-5 have an excellent protective capacity, moderate transmissivity, and a high coefficient of anisotropy
Conclusions: Due to variations in lithology and thickness, a single layer cannot be described as an aquifer. At depth >35 meters, only two points, i.e., VES-3 and VES-5, are marked as the zone of probable exploitable well locations. The higher values of the anisotropy coefficient indicate that the groundwater is highly polluted