Contribution to the hydrogeology of the Lower Cretaceous aquifer in east Central Sinai, Egypt

Abstract

The Lower Cretaceous aquifer (Malha sandstone aquifer) represents the main aquifer in east Central Sinai. The hydrogeological evaluation of the aquifer is based on the data of 14 selected deep wells. The objective of this paper aims to elucidate the hydrogeological characteristics of the Lower Cretaceous aquifer. The groundwater of Lower Cretaceous aquifer exists under confined conditions. The top surface of the Lower Cretaceous dips steeply towards the southwest direction. The average sand percent of the penetrated aquifer attains 54%. The groundwater flow direction of Lower Cretaceous aquifer is concentric to the center of study area related to the influence of the graben block. The general hydraulic gradient reaches 0.0011 in southwestern portion, while it reaches 0.0028 in central portion of study area. The average effective porosity and transmissivity and hydraulic conductivity of the Lower Cretaceous aquifer are 17.3%, 416m2/day and 1.4m/day, respectively. They increase towards the northeast direction with increasing of the sand percentage.Durov diagram plot revealed that the groundwater has been a final stage evolution represented by an NaCl water type. The groundwater salinity increases towards the central portion of study area coinciding with groundwater flow. The groundwater salinity of the Lower Cretaceous aquifer is brackish water and varies from 2510 to 5256ppm. It is unsuitable for drinking and domestic purposes.