Framework for Investigation of Karst Aquifer in an Arid Zone, Using Isotopes, Remote Sensing and GIS Applications: the Northwestern Coast of Egypt

Abstract

The hydrogeology of arid regions is becoming increasingly important due to diminishing projections of water resource availability in response to global environmental change. This paper aims to investigate the karst aquifer in the study area and clarifies the different factors which affect the occurrence and quality of its groundwater. The fractures systems are the main factor which controls the groundwater occurrence in the studied aquifer. The isotope analyses reveal that the groundwater has nearly similar isotopic compositions, suggesting similar recharge conditions; they also indicate that the groundwater of karst aquifer is meteoric water and the recharging source is the rainfall. The high values of total dissolved salts (TDS) of the groundwater are attributed to the rock-water interactions which lead to dissolution processes of marine salts into the aquifer matrix. Although most of the water levels in the drilled wells are under the sea level, the isotope analyses indicate that no contribution of seawater intrusion affects the groundwater. The present study reveals that some specific regions have more priorities than others in future groundwater explorations.