Abstract
Groundwater quality is a critical issue in arid and semiarid countries, where it is one of the most reliable sources of water on which people depend. Water quality is a vital concern in the Kingdom of Saudi Arabia as it affects the health of its people, the growth of its agriculture, and its economic development. In this study, the objectives were to: (1) investigate the depletion rate of groundwater storage (GWS) in the study area by using Gravity Recovery and Climate Experiment (GRACE) data from April 2002 to April 2016 to quantify terrestrial water storage; (2) determine the ionic composition of cations and anions for 24 samples (12 samples from Arabian Shield and 12 from Arabian Shelf in Saudi Arabia); and (3) assess the water quality of the aquifer. The results show a GRACE-derived GWS depletion of − 2 ± 0.13 km3/year. Ionic compositions reveal two main groups: group I, with well depths of 144–607 m, and group II, with well depths of 12–150 m. Group I waters (all from the Saq aquifer) appear to be fossil waters, while group II waters (alluvial aquifer) appear to be mixed waters. As illustrated by the use of a Piper diagram, 85% of the samples in Arabian Shelf are characterized as a mixed water of calcium, magnesium, chloride, and sulfate (SO4). In the Arabian Shield, 50% of the samples are characterized as Ca–Cl waters. Since most of the samples (98%) are from domestic wells used for drinking water and have the potential for radioactivity in the groundwater, it is essential to complete radioactive analysis and confirm acceptable water quality, based on the standards of the Water Health Organization and the Saudi Arabian Standards Organization.
Highlights
Freshwater resources in the Kingdom of Saudi Arabia (KSA) are extremely vulnerable to both climate change and human interventions [1, 2]
To quantify the Gravity Recovery and Climate Experiment (GRACE)-derived groundwater storage (GWS) variations over the Saq aquifer system, the Global Land Data Assimilation System (GLDAS)-derived soil moisture estimates are subtracted from the GRACE-derived terrestrial water storage (TWS) averaged from the University of Texas Center for Space Research (UT-CSR) mascons as shown in Eq (1)
This study focused on examining water quality in two regions of Saudi Arabia with distinctly different geological characteristics
Summary
Freshwater resources in the Kingdom of Saudi Arabia (KSA) are extremely vulnerable to both climate change and human interventions [1, 2]. The present study focuses on the water quality of groundwater samples from the Arabian Shield and Arabian Shelf and how the depletion rate affects it. It examines their suitability for drinking water and domestic purposes, by comparing it to World Health Organization (WHO) global standards and Saudi Arabian Standards Organization (SASO) standards for bottled and unbottled drinking water [22]. It is worth mentioning that this study (1) investigates the depletion rate of groundwater storage (GWS) in the study area by using Gravity Recovery and Climate Experiment (GRACE) data (from April 2002 to April 2016) to quantify terrestrial water storage (TWS); (2) determines the ionic composition of cations and anions for 24 samples (12 samples from Arabian Shield and 12 from Arabian Shelf in Saudi Arabia); and (3) assesses the water quality of the aquifer
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