Determination of the Geo-electrical Zones and the Depth of Groundwater Aquifer by Using 2D Electrical and Induced Polarization Surveys for A Selected Area in Bahar Al-Najaf Region/Iraq

Abstract

The electrical survey method along with the 2D induced polarization method were used to determine the depth of the Groundwater table and to locate the geo-electrical zones within the area of interest in Bahar Al-Najaf region . The surveys were conducted in three lines using Schlumberger protocol . The lines were 400 m in length. Data analysis showed three Geo-electrical zones, these are: The top soil layer, an upper confining layer which belongs to upper member of Dammam Formation, and a water bearing layer that belongs to middle member of Dammam Formation. The induced polarization sections showed the presence of two zones that represent impermeable layer and the water-bearing layer . The resistivity values were in the range of 2-9 Ω.m. for the upper soil layer, 10-20 Ω.m for the impermeable marlstone layer and 20-40 Ω.m for the carbonate water-bearing layer. While induced polarization values ranged from 0- 700 milliseconds. Ground water depth ranging between 20-30 m and extends the aquifer to a depth of more than 70 m from the ground level