Taisser Zumlot

Hydrochemical Facies and Ionic Ratios of the Coastal Groundwater Aquifer of Saudi Gulf of Aqaba: Implication for Seawater Intrusion

ABSTRACT Batayneh, A.; Zaman, H.; Zumlot, T.; Ghrefat, H.; Mogren, S.; Nazzal, Y.; Elawadi, E.; Qaisy, S.; Bahkaly, I., and Al-Taani, A., 2014. Hydrochemical facies and ionic ratios of the coastal groundwater aquifer of Saudi Gulf of Aqaba: implication for seawater intrusion. It is now fairly documented that major ion chemistry of the groundwater can be used to determine an interaction between the groundwater and saline water in the costal aquifers, and that there exists a relationship between total dissolved solids and Cl−, Na+, Mg2+, and concentrations of groundwater. This hypothesis is tested on an aquifer located along the Saudi Gulf of Aqaba coast (Red Sea). Groundwater samples collected from 23 locations show the abundance of ions in the order of: Ca2+ > Na+ > Mg2+ > K+ = Cl− > > > . The Piper trilinear diagram reveals two dominant clusters, i.e. the Ca2+–Cl−– facies and the Na+–Cl−– facies. Besides the major chemical compositions, ionic ratios ( /Cl−, Na+/Ca2+, Na+/Cl−, Ca2+/Cl−, Mg2+/Cl−, K+/Cl−, /Cl−, Ca2+/Mg2+, Ca2+/ , and Ca2+/ ) are used to evaluate the effects of saline water intrusions. Factor analysis of the studied samples demonstrates that changes in the groundwater composition are primarily controlled by mineral dissolution, human activities, weathering of marine sediments, evaporation/salinization of groundwater, and the residence time of water. An attempt has been made to identify hydrochemical processes accompanied with the current intrusion of seawater through the use of ionic exchanges. Following this procedure, about 7.97% mixing rate of seawater intrusion has been estimated for the month of March 2012. Furthermore, the seawater mixing index has also been applied, which resulted in a range of values from 0.395 to 7.922. These results determine 13 of 23 groundwater samples (57%) as saline, with electrical conductivity > 3000 μS/cm.

Major ion chemistry and weathering processes in the Midyan Basin, northwestern Saudi Arabia

Chemical characteristics of 72 groundwater samples collected from Midyan Basin have been studied to evaluate major ion chemistry together with the geochemical and weathering processes controlling the water composition. Water chemistry of the study area is mainly dominated by Na, Ca, SO4, and Cl. The molar ratios of (Ca + Mg)/total cations, (Na + K)/total cations, (Ca + Mg)/(Na + K), (Ca + Mg)/(HCO3 + SO4), (Ca + Mg)/HCO3, and Na/Cl reveal that water chemistry of the Midyan Basin is controlled by evaporite dissolution (gypsum and/or anhydrite, and halite), silicate weathering, and minor contribution of carbonate weathering. The studied groundwater samples are largely undersaturated with respect to dolomite, gypsum, and anhydrite. These waters are capable of dissolving more of these minerals under suitable physicochemical conditions.

Structural interpretation of the Ifal Basin in north-western Saudi Arabia from aeromagnetic data: hydrogeological and environmental implications

The Ifal (Midyan) Basin is one of the well defined basins along the Red Sea coast, north-western Saudi Arabia. Location, geometry, thick sedimentary cover and structural framework qualify this basin for groundwater, oil and mineral occurrences. In spite of being studied by two airborne magnetic surveys during 1962 and 1983, structural interpretation of the area from a magnetic perspective, and its uses for hydrogeological and environmental investigations, has not been attempted. This work thus presents interpretation of the aeromagnetic data for basement depth estimation and tectonic framework delineation, which both have a role in controlling groundwater flow and accumulation in the Ifal Basin. A maximum depth of 3.5 km is estimated for the basement surface by this study. In addition, several faulted and tilted blocks, perpendicularly dissected by NE-trending faults, are delineated within the structural framework of the study area. It is also observed that the studied basin is bounded by NW- and NE-trending faults. All these multi-directional faults/fracture systems in the Ifal Basin could be considered as conduits for groundwater accumulation, but with a possibility of environmental contamination from the surrounding soils and rock bodies.

Statistical analysis of different chemical elements in groundwater of northwestern Saudi Arabia

A total of 72 water samples were collected from the sub-surface aquifer system in the Midyan basin and analyzed for 24 major, minor and trace elements. Histograms and normal quantile plots were used to delineate the sub-populations of the chemical constituents in the studied groundwater samples. Some of the elements such as Al, K, Ca, Mg, Na and Cl have concentrations that could be linked to the weathering of the surface rock strata. On the other hand, the elements like As, Pb and Sb have concentration, that can be linked to agricultural practices in the area. The use of simple statistical analysis, frequency histograms, and Q-Q plots were useful for the detection and evaluation of elemental constituents in the groundwater of the study area.

The Use of Ground Penetrating Radar for Mapping Rock Stratigraphy and Tectonics： Implications for Geotechnical Engineering

This paper presents results from ground penetrating radar surveys using the SIR-10B GPR instrument (manufactured by Geophysical Survey System Inc., USA), with 400 MHz monostatic antenna (model 5 103). Survey was made over 3 excavation levels along the highway section at the Ras en Naqab escarpment area, Southwest Jordan. A total of 217 m along 4 profiles were covered in the winter of 2012. The objectives of the study are (i) to evaluate the resolution of the GPR technique in the field for detecting and locating anomalies caused by subsurface structures like cavities, fractures and faults, and (ii) to describe stratigraphic nomenclature of the subsurface rocks of the area. 2D interpretation of the obtained data and the geological information demonstrate a strong correlation between the GPR anomalies and the subsurface geology. Based upon the lateral and vertical velocity changes with depth, the thickness and orientation of the subsurface layers are outlined. Analysis of the exposed section shows good agreement between the estimated thicknesses of lithostratigraphic units and the quantitative assessment of the radar waves velocity inferred from GPR data.

Pollution assessment of arsenic and other selected elements in the groundwater and soil of the Gulf of Aqaba, Saudi Arabia

Forty-six soil and groundwater samples were collected from the agricultural farms of the Gulf of Aqaba coast. Additionally, 24 granitic and marine sedimentary rock samples were collected from the study area. The collected samples were analyzed for As, Al, Au, B, Ba, Be, Fe, Sb, Se, Sn, Ti, and V using inductively coupled plasma mass spectrometry. Levels of the studied metals in the groundwater samples lie within the acceptable limits of the World Health Organization (WHO). The rock samples exhibit a significant variation in mean metal content from one rock type to another. Concentrations of As and B in the soil samples were determined to be higher than those of Canadian Soil Quality Guidelines (CSQG) and were primarily due to agricultural and seawater inputs. Chemical weathering of various rock units also plays a significant role. The calculations of geoaccumulation index are found to be more reliable than of those of enrichment factor for Arsenic contamination levels assessment. The study area is not significantly affected by As contamination. The correlation coefficient analysis results for the soil and groundwater data reveal a variable degree of correlations between As and other metals in the study area.

Integrated application of geoelectrical techniques for structural investigations: case study of Wadi Marsad Graben, Jordan

An integrated geoelectrical survey has been conducted at the Wadi Marsad area, south of Jordan, to map the dominant structural features associated with the Arabian-African plate movements. The area is known to be tectonically affected by the epeirogenic movements of the Arabian shield which originated several major and minor structural features. Fifty-four vertical electrical soundings (VES) using Schlumberger configuration and nine induced polarization (IP) profiles (both resistivity and metal factor parameters were determined) were carried out in the investigated area. The integrated use of IP and VES surveys has proved to be efficient in mapping the lateral and vertical extensions of a major graben structure existing in the investigated area.

Statistical characterization of the hydrochemical data’s of groundwater in the arid land of Wadi AdDawasir area, Saudi Arabia : A probabilistic assessment

The main purpose of this research is to determine the quality of ground water in Wadi AdDawasir by the assessmentof 12 chemical parameters: pH, EC, Eh, TDS, TH, Ca2+, Cl–, HCO3–, Mg2+, Na+, NO3–, and SO42–. Statistical analyseswere carried out using descriptive statistics, histograms, and normal quantile plots. The SPSS 15 software package(SPSS Inc. 2006) and JMPIN (version 4.0.4) were used as the main statistical software. Many locations withinthe study area show thatf pH, EC, HCO3–and Na+ values exceed permissible limits. The concentration of anions isin the order SO42–>Cl–>HCO3–. Some of the analyzed parameters approach a normal distribution, as both their skewnessand kurtoses are close to zero. However, skewness for some parameters such as Mg2+ and HCO3–is high. Kurtosisfor most of the elements varies from moderate to low. Only pH, HCO3– and SO42– have kurtoses. Both the resultsof cluster tree and geochemical features of variables could be generally classifi ed into three main groups. Group1 is comprised of Na and SO42–. The relationships within this group are strong. Group 2 consisted of Mg2+, NO3–,pH, HCO3–, and Ca2+. The fact that this group has a close relationship with group 1 demonstrates that the increase inthe concentration of some elements could be the same. Group 3 is comprised of TH, Cl–, Eh, and EC.