Application of resistivity method in environmental study of the appearance of soil water in the central part of Tenth of Ramadan City, Egypt

Tenth of Ramadan City is an important industrial and urban area in Egypt. The appearance of soil water seepages in the central part of the city represents a great environmental problem. Direct current resistivity measurements in the form of 1D and 2D surveys were carried out to show the relation between this problem and both lateral and vertical variations of a clay layer that may act as a geological barrier in the area. Twenty-seven Schlumberger sounding points were distributed over a grid with unequal spacing depending on the civil constructions and topography of the area. These sounding points were quantitatively interpreted to obtain the subsurface layer distribution and define the expected clay barrier. Five 2D resistivity profiles were measured along some interpreted anomalies from the 1D sounding survey. A Wenner array was selected because of its sensitivity in detecting vertical changes in the subsurface resistivity. The results of the resistivity inversion indicate that the subsurface resistivity can change rapidly within a short distance. However, from the resulting models it was possible to correlate the resistivity ranges with subsurface geological data obtained from shallow boreholes. This correlation shows the importance of 2D resistivity imaging for mapping of the clay barrier layer.