An integrated approach to address the temporal variation of geochemistry in groundwater of an arid region.

Abstract

Kuwait is characterized with an arid climate and scarce freshwater sources. Variation in groundwater quality with space and time leads to sustainable development of the region. Evaluating the chemical properties of groundwater is of prime importance to ensure the longevity of this important source of water. In this study, the geochemical data for the years 2004 and 2018 were examined for 6 wells in the freshwater zones of Northern Kuwait. The aim of this study is to examine the geochemical variations, if any that occurred on the only existing freshwater aquifer in Kuwait. The chemical properties examined in this study include total dissolved solids, chloride, nitrate, bicarbonate, calcium, electric conductivity, sulfate, sodium, potassium, magnesium, and pH. The variation of the electrical conductivity in this region indicates an improvement in three wells located in the northern to central region of the study area as values decreased from 1210 to 956 (μS/cm); however, the electrical conductivity has deteriorated in the remaining three wells located in the central to southern part of the study area as values increased from 791 to 1401 (μS/cm). The geochemical facies of the groundwater were determined, indicating a migration of the groundwater facies towards more chloride dominant field in 2018. The saturation states of carbonates like aragonite, calcite, dolomite, and magnesite and those of sulfates like gypsum and anhydrite were determined. The increase in calcium in most of the wells facilitated the saturation index of calcium sulfates relatively more than calcium carbonate minerals. The principal component analysis was conducted for the data of 2004 and 2018; it extracted two main components accounting for the variability of the data; the main components indicate geogenic influences and anthropogenic pollution such as agriculture. The study indicates that there is no major variation observed in groundwater chemistry during the 15years, as the chemical changes which occurred are minimal and do not require immediate remediation measures. Hence, if the current groundwater extraction rate remained with no extensive land use development, it would sustain the water quality of the region.