For managing the freshwater in the worldwide coastal aquifers, it is imperative to understand the hydrogeochemical processes and flow patterns in the mixing freshwater/saltwater zone. The Egyptian Nile Delta aquifer is a typical example. The management of seawater intrusion (SWI) requires detailed investigations of the intrusion wedge and the dynamic processes in the mixing zone. Thus, a multidisciplinary approach was applied based on holistic hydrogeochemical, statistical analysis, and DC resistivity measurements to investigate the lateral and vertical changes in groundwater characteristics undergoing salinization stressor. The results of cross plots and ionic deviations of major ions, hydrochemical facies evolution diagram (HFE-D), and seawater mixing index (SMI) were integrated with the resistivity results to show the status of the SWI where the intrusion phase predominates in ~2/3 of the study are (~70 km radius) and the compositional thresholds of Na, Mg, Cl, and SO4 are 600, 145, 1200, and 600 mg/L, respectively, indicating that the wells with higher concentrations than these thresholds are affected by SWI. Moreover, the results demonstrate the efficiency of combining hydrogeochemical facies from heatmap and resistivity investigations to provide a large-scale characterization of natural and anthropogenic activities controlling aquifer salinization to support decision-makers for the long-term management of coastal groundwater.

In archaeo-geophysical investigations, the accuracy and resolution of the generated geophysical models are crucial parameters for excavation decision. Therefore, the combined use of different geophysical data sets is necessary to improve the interpretability of archaeological ruins, particularly in case of low physical contrast objects.The present study's objective is to validate the outputs of integrated ground penetrating radar (GPR) and electrical resistivity tomography (ERT) surveys in Tanis, which is considered one of the most important archaeological sites in the Nile Delta, Egypt.The GPR survey was carried out along an area of 24 × 31.5 m with profile interval of 0.5 m in two orthogonal directions using 100, 200 and 600 MHz shielded antenna.Moreover, nine ERT profiles were performed along the same GPR lines for comparison and integration using Wenner-beta (WB) and dipole-dipole (DD) arrays with 1 m

No abstract

No abstract

Among all geophysical techniques, electrical resistivity and magnetic surveying as an integrative approach has been used widely for archaeological prospection at different scales of investigations. In this study, DC resistivity (1D vertical sounding and/2D/3D ERT) and magnetic surveys (total and gradient) as a multi-scale approach was applied in a highly terraneous archaeological site (Tell) with a case study to characterize and image the various archaeological assets at different depths with different spatial resolutions. Four critical zones of great interest within the considered Tell were surveyed. At the heart of the study area, three layers were depicted clearly from 1D resistivity sounding. A thick conductive zone of mostly clay is sandwiched between two resistive layers. The topmost layer contains construction debris (dated back to the Islamic Era), whereas the deeper layer could be related to Gezira sand on which the probable Pharaonic temple was constructed. A long 2D ERT profile using Wenner Beta (WB) and Dipole–Dipole (DD) arrays with a 5-m electrode spacing identified shallow high resistivity anomalies that could be related to construction ruins from fired bricks. Additionally, it succeeded in imaging the turtleback-shaped deeper resistive layer of mostly sand. At an elevated rim to the east and west of the Tell, total and vertical magnetic gradient maps clearly delineated different archaeological structures: the walls of the rooms of ancient Islamic settlers and the walls of water tanks from the Byzantine Era. Magnetic modeling assuming 2.5-dimensional magnetic models constrained by the 2D ERT inversion models could be used to create a realistic representation of the buried structures. Toward the northern part of the Tell, the joint application of the quasi-3D ERT inversion scheme and the magnetic survey revealed an anomaly of a well-defined geometric shape of an archaeological interest thought to be a crypt or water cistern based on nearby archaeological evidence. The overall results of the geophysical survey integrated with the image of some partially excavated parts provided the archaeologists with a comprehensive and realistic view of the subsurface antiquities at the study area.