GEOELECTRICAL ANALYSIS ON THE GROUNDWATER OCCURRENCE FOR THE DEVELOPMENT OF EAST EL MINYA GOVERNORATE, EGYPT

The investigated area is a part of Nile valley which is surrounded by limestone plateaus of Egypt. It is located between Latitudes 28º 15′ - 28º 45’ N and Longitudes 30º 45- 31º 00′ E, and has a surface area of about 1362 Square kilometers. The geoelectrical resistivity measurements have been carried out, using a Schlumberger array to identify the resistivity and thicknesses of different subsurface layers and determine groundwater occurrences. For these purpose, 44 Schlumberger vertical electrical soundings (VES) were conducted with a maximum half current electrode spacing of 700 m. Results from the quantitative interpretation of sounding data indicate that, the area is generally underlain by five main geoelectrical units (A, B, C, D and E). The main characteristics of these geoelectrical layers as well as, the main features of the constructed geoelectrical cross sections have been interpreted in the case of determining the groundwater occurrences. Based on the results obtained, four water-bearing layers (aquifers) were detected in the investigated area. The Quaternary deposits represented by Pleistocene Neonile Sediments of sands and gravels with clay and Shale lenses (A3) act as the first aquifer which represents a limited distribution in the investigated area. The second water-bearing layer (C1) corresponds to water-bearing limestone of Maghagha Formation which lead to the second aquifer and represents also a limited distribution in the investigated area. The third one (D4) corresponds to water-bearing limestone of Samalut Formation which lead to the third aquifer and represents a wide distribution in the investigated area. The fourth water bearing zone (E) corresponds to water-bearing limestone of Minia Formation which lead to the fourth aquifer and represents a wide distribution in the investigated area. Two priority maps for groundwater exploitation in the investigated area have been presented for each of El Minia and Samalut aquifers. It can be concluded that, the priority is generally increasing toward the southern parts, especially at wadi El Saririia area, where El Minia Aquifer occupy the first category and at wadi El Sheikh Hasan where the two main aquifers of Samalut and El Minia facies are well represented