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Magaritz, M., Nadler, A., Kafri, U., & Arad, A. (1984). Hydrogeochemistry of continental brackish waters in the southern Coastal Plain, Israel. Chemical Geology, 42(1), 159–176.
Abstract: The southern Coastal Plain in Israel incorportates a transitional fringe of the desert in which three different chemical types of groundwater are found: (1) near-surface waters from springs along the Besor River course: (2) shallow- to moderate-depth waters from the slightly westward-dipping Pleistocene coastal aquifer (this aquifer, which consists of sandstone layers of the Kurkar Group, is recharged in the Coastal Plain); and (3) deep waters of the westward-dipping Upper Cretaceous Judea Group carbonates, which are recharged in the mountains in the east. A thick aquiclude of Upper Cretaceous-Tertiary rocks separates the Judea Group aquifer from the overlying coastal aquifer in the southern Coastal Plain. Isotopically light oxygen and depleted deuterium characterize the Judea Group waters, as expected from high-altitude recharge. The isotopic composition of the Coastal Plain waters is variable, but for the most part enriched in 18O and D. Within the southern Coastal Plain aquifer a southern subgroup comprises waters more depleted in heavy isotopes than those of either the northern or eastern subgroups. The Besor waters are isotopically similar to the Judea Group waters, reflecting their origin in the mountain region, and flow through the surficial river gravels and sands. It is suggested that leakage of the Besor waters into the underlying southern Coastal Plain aquifer results in mixing of the two water types. The most prominent chemical feature characterizing the groundwater of the southern Coastal Plain is Na+Cl− \textgreater 1. This Na+Cl− ratio can be maintained only by a continuous input from a non-marine source of Na. The most plausible source of this Na is the dissolution of feldspar derived from the windblown loess deposits which cover the area and/or leaching of trona minerals found in the unsaturated zone, combined with base-exchange processes.
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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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Lu, C., Xin, P., Kong, J., Li, L., & Luo, J. (2016). Analytical solutions of seawater intrusion in sloping confined and unconfined coastal aquifers. Water Resources Research, 52(9), 6989–7004.
Abstract: Abstract Sloping coastal aquifers in reality are ubiquitous and well documented. Steady state sharp-interface analytical solutions for describing seawater intrusion in sloping confined and unconfined coastal aquifers are developed based on the Dupuit-Forchheimer approximation. Specifically, analytical solutions based on the constant-flux inland boundary condition are derived by solving the discharge equation for the interface zone with the continuity conditions of the head and flux applied at the interface between the freshwater zone and the interface zone. Analytical solutions for the constant-head inland boundary are then obtained by developing the relationship between the inland freshwater flux and hydraulic head and combining this relationship with the solutions of the constant-flux inland boundary. It is found that for the constant-flux inland boundary, the shape of the saltwater interface is independent of the geometry of the bottom confining layer for both aquifer types, despite that the geometry of the bottom confining layer determines the location of the interface tip. This is attributed to that the hydraulic head at the interface is identical to that of the coastal boundary, so the shape of the bed below the interface is irrelevant to the interface position. Moreover, developed analytical solutions with an empirical factor on the density factor are in good agreement with the results of variable-density flow numerical modeling. Analytical solutions developed in this study provide a powerful tool for assessment of seawater intrusion in sloping coastal aquifers as well as in coastal aquifers with a known freshwater flux but an arbitrary geometry of the bottom confining layer.
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Cui, G., Lu, Y., Zheng, C., Liu, Z., & Sai, J. (2019). Relationship between soil salinization and groundwater hydration in Yaoba Oasis, Northwest China. Water, 11(1), 175.
Abstract: Precipitation is scarce and evaporation is intense in desert areas. Groundwater is used as the main water source to develop agriculture in the oases. However, the effects of using groundwater on the ecological environment elicit widespread public concern. This study investigated the relationship between soil salinity and groundwater characteristics in Yaoba Oasis through in situ experiments. The relationship of the mineral content, pH, and main ion content of groundwater with soil salt was quantitatively evaluated through a gray relational analysis. Four main results were obtained. First, the fresh water area with low total dissolved solid (TDS) was usually HCO3− or SO42− type water, and salt water was mostly Cl− and SO42−. The spatial distribution of main ions in groundwater during winter irrigation in November was basically consistent with that during spring irrigation in June. However, the spatial distribution of TDS differed in the two seasons. Second, soil salinization in the study area was severe, and the salinization rate reached 72.7%. In this work, the spatial variability of soil salinization had a relatively large value, and the values in spring were greater than those in autumn. Third, the soil in the irrigated area had a high salt content, and the salt ion content of surface soil was higher than that of subsoil. A piper trilinear diagram revealed that Ca2+ and K+ + Na+ were the main cations. SO42−, Cl−, and HCO3− were the main anions, and salinization soil mainly contained SO42−. Fourth, the changes in soil salt and ion contents in the 0–10 cm soil layer were approximately similar to those of irrigation water quality, both of which showed an increasing trend. The correlation of surface soil salinity with the salinity of groundwater and its chemical components was high. In summary, this study identified the progress of irrigation water quality in soil salinization and provided a scientific basis for improving the oasis ecosystem, maintaining the healthy development of agriculture, managing oasis water resources, and policy development. Our
findings can serve as a reference for other, similar oasis research. |
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Greene, R., Timms, W., Rengasamy, P., Arshad, M., & Cresswell, R. (2016). Soil and Aquifer Salinization: Toward an Integrated Approach for Salinity Management of Groundwater. In A. J. Jakeman, O. Barreteau, R. J. Hunt, J. - D. Rinaudo, & A. Ross (Eds.), Integrated Groundwater Management: Concepts, Approaches and Challenges (pp. 377–412). Cham: Springer International Publishing.
Abstract: Degradation of the quality of groundwater due to salinization processes is one of the key issues limiting the global dependence on groundwater in aquifers. As the salinization of shallow aquifers is closely related to root-zone salinization, the two must be considered together. This chapter initially describes the physical and chemical processes causing salinization of the root-zone and shallow aquifers, highlighting the dynamics of these processes and how they can be influenced by irrigation and drainage practices, thus illustrating the connectivity between soil and groundwater salinization. The processes leading to aquifer salinization in both inland and coastal areas are discussed. The roles of extractive resource industries, such as mining and coal bed methane operations, in causing aquifer salinization are also outlined. Hydrogeochemical changes occurring during salinization of aquifers are examined with the aid of Piper and Mixing Diagrams. The chapter then illustrates the extent of the problem of groundwater salinization as influenced by management and policy using two case studies. The first is representative of a developing country and explores management of salt-affected soils in the Indus Valley, Pakistan, while the second looks at a developed country, and illustrates how through monitoring we can deduce causes of shallow aquifer salinity in the Namoi Catchment of NSW, Australia. Finally, there is a section on integration and conclusions where we illustrate how management to mitigate salinization needs to be integrated with policy to diminish the threat to productivity that occurs with groundwater degradation.
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