Seawater intrusion characterization based on electrical resistivity and hydrogeochemical methods; surrounding Rosetta branch area, Egypt

Abstract

Seawater intrusion (SWI) is one of the most common environmental issues in recent years, posing a threat to groundwater quality and sustainability, especially in coastal aquifers. The current climate changes linked to rising sea levels as well as the excessive pumping of groundwater, linked to the lack of natural recharge, have exacerbated this environmental problem. As a result, to characterize and detect seawater intrusion in this region. This paper presents a comprehensive combination of geoelectric methods represented by artificial vertical electrical soundings (VES) and hydrogeochemistry of groundwater. Vertical electrical resistivity values are obtained by Schlumberger's array of twenty-six VESes distributed all over the area using the Eleric-T device. However, the electrical resistivity sounding method succeeded to outline the aquifer depth, extension and thickness. The hydrogeochemical techniques outline the ions, cations, water types and water quality based on the chemical analysis of 26 groundwater samples. Both two types are contributed to emphasis the results. The VES results succeeded to describe the Pleistocene aquifer lithology and subdivides it into fresh, brackish and salt zones (freshwater – saltwater interface). The hydrochemical characteristics of groundwater samples through the physiochemical parameters, Chadha diagram, ionic relations and DWQI confirm the influence of SWI on the chemistry of groundwater in the concerned area. Consequently, these results confirm that the integration between the electrical resistivity and hydrochemical methods are effective tools for the characterization of seawater intrusion in this important region in terms of agricultural activity in Egypt.