The quality and quantity of groundwater resources have been continuously deteriorating as a result of anthropogenic activities and their excessive usage. This has intensified seawater intrusion, particularly in the coastal area of Egypt. The management of this issue and preventing ongoing groundwater contamination are crucial responsibilities. Thus, an integrated strategy using remote sensing, geophysical technique, and hydrogeochemical analysis is used in this work to identify the causes of degradation and evaluate their impacts on the groundwater quality in East Port Said, Egypt. The following points were identified: 1) Remote sensing analysis between 1984 and 2015 showed an increase in anthropogenic activities, such as the construction of fish farms and vegetation, which became their areas of 12.5 and 37.8 km² respectively. 2) Field observations demonstrated that the groundwater resources are being overexploited and it is expected that these human activities could have an impact on the groundwater quality. 3) The results of the resistivity approach indicated that sand and clay constitute the underlying layers and the shallow subsurface strata contain a high concentration of saline water. As a result, the aquifer is vulnerable to seawater intrusion due to its homogeneity. 4) Nineteen samples of groundwater were collected from the shallow Quaternary aquifer and the hydrochemical characteristic of the samples was identified. The hydrochemical analysis showed that the groundwater across the research area is of the Na-Cl water type and is highly saline (from 7,558 to 23,218 mg/L). By integrating the aforementioned techniques, it is evident that the research region is affected by anthropogenic activities as well as seawater intrusion on groundwater quality. These results serve as a solid base for further research on groundwater-surface water interactions and the evaluation of possible sources of contamination in the shallow aquifers under stress from anthropogenic activity in such environments.

The present work focuses on a comprehensive hydrochemical assessment of groundwater within a shallow aquifer located in the central region of Saudi Arabia. This aquifer serves as the principal source of groundwater supply for agricultural irrigation purposes. A total of twelve groundwater samples were systematically collected and subjected to thorough analysis to determine various physicochemical parameters. These parameters encompassed electrical conductivity (EC), pH, temperature, total dissolved solids (TDS), as well as concentrations of major ions. Analysis of major ion analysis was employed to elucidate the chemical attributes of groundwater within the research area. This approach facilitated an understanding of the geochemical evolution and the potential suitability of the groundwater for agriculture irrigation. The recorded range of electrical conductivity (EC) for the groundwater in this region falls between 3283 and 11,000 µS/cm, with an average value of 6709.4 µS/cm. The pH levels of the groundwater exhibited a slightly alkaline nature, ranging from 7.8 to 8.6. All sampled wells exhibited brackish water conditions (TDS > 1000 mg/L) based on TDS concentrations. The findings of this investigation demonstrated that the average ion concentration followed the order: Na⁺ > Ca⁺ > Mg²⁺ > K⁺ and Cl⁻ > SO₄²⁻ > HCO₃⁻ > NO₃²⁻. Applying Piper’s classification system, the groundwater samples were classified into two predominant categories: Ca-Cl and mix-Ca-Mg-Cl. The predominance of Ca²⁺ and Mg²⁺ over alkalis indicated mixed groundwater facies influenced by processes of reverse ion exchange and extensive interactions between water and rock formations. The distinct chemical characteristics of the groundwater were attributed to a combination of factors, including the percolation of irrigation-returned water, chemical transformations within the vadose zone, and extensive interactions with subsurface lithology. Despite major ion concentrations surpassing the permissible limits outlined by the World Health Organization (WHO) for drinking water, the assessment of quality indices was conducted to ascertain the suitability of the groundwater for irrigation purposes. These quality indices encompassed the permeability index (PI), magnesium hazard (MH), Kelly’s ratio (KR), sodium-adsorption ratio (SAR), residual sodium carbonate (RSC), sodium percentage (Na%), and magnesium ratio (MR). A meticulous evaluation of groundwater quality for agricultural utilization indicated that all sampled groundwater sources were deemed suitable for irrigation purposes.

It might be difficult to find possible groundwater reservoir zones, especially in arid or hilly regions. In the twenty-first century, remotely sensed satellite imagery may present a new opportunity to locate surface and subsurface water resources more quickly and affordably. In order to identify groundwater potential zones, the current study was conducted in Central Saudi Arabia, southwest of Riyadh. The present analysis employed a multi-criteria approach that relies on remote sensing and geographic information systems. The variables employed in this technique include geology, rainfall, elevation, slope, aspect, hillshade, drainage density, lineaments density, and Land Use/Land Cover (LULC). The Analytical Hierarchical Process (AHP) was used for assigning weights to the parameters, and the corresponding significance of each parameter’s several classes for groundwater potentiality. Different groundwater potential zones were identified by the study: very high (16.8%), high (30%), medium (26.7%), low (18.6%), and very low (7.9%). Only two of the observation wells were located in the “medium” potential zone, but the other ten wells were observed in the “very high and high” potential zones, according to the validation survey. Consequently, the results may demonstrate that the current approach, which combines improved conceptualization with AHP to define and map groundwater potential zones, has a greater chance of producing accurate results and can be used to reduce the threat of drought in broader arid regions.

Recently the limited freshwater resources have become one of the most significant challenges facing Egypt. Thus, new resources of drinkable water are required to meet the growing population demands and the national projects, to support the country’s economy. Saline groundwater desalination is an option that can support limited freshwater resources. This research represents a detailed analysis of hydrogeological and hydrochemical characteristics of a coastal aquifer in the West Port Said area, northeastern Egypt, to assess the desalination suitability of the aquifer, especially when the nearby seawater is contaminated. The hydrogeological characterization included various integrated approaches: geophysical survey, field investigations, wells drilling, well logging, pumping tests, and water sampling. The results show that: (1) The subsurface lithology consists of sandstone and clay, and three water bearing layers: A, B and C. (2) The average porosity values are 22%, 27.5%, and 25% for layers A, B, and C, respectively. The hydraulic conductivity values fall in the ranges of 5.8–12.7 m/day for layer A, 7.6–11.7 m/day for layer B, and 11.1–19.5 m/day for layer C, while the highest transmissivity values are in ranges of 5.8 × 10²–12.7 × 10² m²/day for layer A, 7.6 × 10²–11.7 × 10² m²/day for layer B and 11.1 × 10²–19.5 × 10² m²/day for layer C. (3) The average storage values are 2.1 × 10⁻³, 1.8 × 10⁻³ and 5.3 × 10⁻³ in layers A, B and C, respectively. (4) Layers A and B showed Na-Cl-type, similar to seawater, but free from oil pollution. These results show layer B’s higher productivity and better quality. Despite the salinity, desalination technology can improve.

Recently, groundwater resources in Egypt have become one of the important sources to meet human needs and activities, especially in coastal areas such as the western area of Port Said, where seawater desalination cannot be used due to the problem of oil spill and the reliance upon groundwater resources. Thus, the purpose of the study is the sustainable management of the groundwater resources in the coastal aquifer entailing groundwater abstraction. In this regard, the Visual MODFLOW and SEAWAT codes were used to simulate groundwater flow and seawater intrusion in the study area for 50 years (from 2018 to 2068) to predict the drawdown, as well as the salinity distribution due to the pumping of the wells on the groundwater coastal aquifer based on field investigation data and numerical modelling. Different well scenarios were used, such as the change in well abstraction rate, the different numbers of abstraction wells, the spacing between the abstraction wells and the change in screen depth in abstraction. The recommended scenarios were selected after comparing the predicted drawdown and salinity results for each scenario to minimize the seawater intrusion and preserve these resources from degradation.