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Satrio, S., Prasetio, R., Hadian, M., Syafri, I. (2016). Stable Isotopes and Hydrochemistry Approach for Determining the Salinization Pattern of Shallow Groundwater in Alluvium Deposit Semarang, Central Java. Indonesian Journal on Geoscience, 4.
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Russak, A., Sivan, O., & Yechieli, Y. (2016). Trace elements (Li, B, Mn and Ba) as sensitive indicators for salinization and freshening events in coastal aquifers. Chemical Geology, 441, 35–46.
Abstract: The current global intrusion of seawater into coastal aquifers causes salinization of groundwater and thus significant degradation of its quality. This study quantified the effect of seawater intrusion and freshening events in coastal aquifers on trace elements (Li, B, Mn and Ba) across the fresh-saline water interface (FSI) and their possible use as indicators for these events. This was done by combining field data and column experiments simulating these events. The experiments enabled quantification of the processes affecting the trace element composition and examination of whether salinization and freshening events are geochemically reversible, which has been seldom investigated. The dominant process affecting trace element composition during salinization and freshening is ion exchange. The results of the experiments show that the concentrations of major cations and Li+ were reversible during salinization and freshening, whereas B, Mn2+ and Ba2+ were not. During salinization, Li+ and B were depleted due to sorption by 10 and 100μmol·L−1, respectively, to about half of their expected conservative concentrations. The relative depletion of Li+ increased with distance from the shore, representing the propagation of salinization. Ba2+ and Mn2+ were desorbed from the sediment during salinization and enriched by tenfold in the aqueous phase compared to their concentration in seawater ( 0.1 μeq·L−1). During freshening both were depleted by almost tenfold compared to their concentration in fresh groundwater ( 0.7 μeq·L−1). The depletion of Mn2+ is a sensitive marker for freshening because Mn2+ has a strong affinity to the solid phase. Moreover, this study shows that both Mn2+ and Ba2+ can be used as sensitive hydrogeochemical tools to distinguish between salinization and freshening events in the FSI zone in coastal aquifers.
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Bouchaou, L., Michelot, J. L., Vengosh, A., Hsissou, Y., Qurtobi, M., Gaye, C. B., et al. (2008). Application of multiple isotopic and geochemical tracers for investigation of recharge, salinization, and residence time of water in the Souss–Massa aquifer, southwest of Morocco. Journal of Hydrology, 352(3), 267–287.
Abstract: Groundwater and surface water in Souss–Massa basin in the west-southern part of Morocco is characterized by a large variation in salinity, up to levels of 37gL−1. The high salinity coupled with groundwater level decline pose serious problems for current irrigation and domestic water supplies as well as future exploitation. A combined hydrogeologic and isotopic investigation using several chemical and isotopic tracers such as Br/Cl, δ18O, δ2H, 3H, 87Sr/86Sr, δ11B, and 14C was carried out in order to determine the sources of water recharge to the aquifer, the origin of salinity, and the residence time of water. Stable isotope, 3H and 14C data indicate that the high Atlas mountains in the northern margin of the Souss–Massa basin with high rainfall and low δ18O and δ2H values (−6 to −8‰ and −36 to −50‰) is currently constitute the major source of recharge to the Souss–Massa shallow aquifer, particularly along the eastern part of the basin. Localized stable isotope enrichments offset meteoric isotopic signature and are associated with high nitrate concentrations, which infer water recycling via water agricultural return flows. The 3H and 14C data suggest that the residence time of water in the western part of the basin is in the order of several thousands of years; hence old water is mined, particularly in the coastal areas. The multiple isotope analyses and chemical tracing of groundwater from the basin reveal that seawater intrusion is just one of multiple salinity sources that affect the quality of groundwater in the Souss–Massa aquifer. We differentiate between modern seawater intrusion, salinization by remnants of seawater entrapped in the middle Souss plains, recharge of nitrate-rich agricultural return flow, and dissolution of evaporate rocks (gypsum and halite minerals) along the outcrops of the high Atlas mountains. The data generated in this study provide the framework for a comprehensive management plan in which water exploitation should shift toward the eastern part of the basin where current recharge occurs with young and high quality groundwater. In contrast, we argued that the heavily exploited aquifer along the coastal areas is more vulnerable given the relatively longer residence time of the water and salinization processes in this part of the aquifer.
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Giménez-Forcada, E. (2014). Space/time development of seawater intrusion: A study case in Vinaroz coastal plain (Eastern Spain) using HFE-Diagram, and spatial distribution of hydrochemical facies. Journal of Hydrology, 517, 617–627.
Abstract: A new method has been developed to recognize and understand the temporal and spatial evolution of seawater intrusion in a coastal alluvial aquifer. The study takes into account that seawater intrusion is a dynamic process, and that seasonal and inter-annual variations in the balance of the aquifer cause changes in groundwater chemistry. Analysis of the main processes, by means of the Hydrochemical Facies Evolution Diagram (HFE-Diagram), provides essential knowledge about the main hydrochemical processes. Subsequently, analysis of the spatial distribution of hydrochemical facies using heatmaps helps to identify the general state of the aquifer with respect to seawater intrusion during different sampling periods. This methodology has been applied to the pilot area of the Vinaroz Plain, on the Mediterranean coast of Spain. The results appear to be very successful for differentiating variations through time in the salinization processes caused by seawater intrusion into the aquifer, distinguishing the phase of seawater intrusion from the phase of recovery, and their respective evolutions. The method shows that hydrochemical variations can be read in terms of the pattern of seawater intrusion, groundwater quality status, aquifer behaviour and hydrodynamic conditions. This leads to a better general understanding of the aquifers and a potential for improvement in the way they are managed.
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Stoeckl, L., Walther, M., & Morgan, L. K. (2019). Physical and Numerical Modelling of Post-Pumping Seawater Intrusion. Geofluids, 2019, 11.
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