Hydrogeophysical assessment of the Quaternary aquifer in Northwestern Hafit mountain, Al Ain, UAE

Abstract

This study examines the geophysical and hydrogeological features of the Quaternary Aquifer System in Al Ain area of the United Arab Emirates (UAE). The study aims to achieve three main objectives: first, to investigate the geophysical properties of the Quaternary Aquifer System within the study area, which includes defining the aquifer's extent, measuring the thickness of the overburden, and analysing the underlying bedrock through the electrical resistivity methods; second, to explore the hydrogeological and hydrogeochemical characteristics of the groundwater in the Quaternary Aquifer System to assess groundwater patterns; and third, to evaluate the hydraulic properties of the aquifer through field measurements, which will present critical insights into its water-bearing capacity, sustainability, and potential for use. To address these objectives, six Electrical Resistivity Tomography (ERT) surveys and three Vertical Electrical Sounding (VES) surveys were conducted at selected sites, based on field accessibility. These geophysical methods were integrated with hydrogeological data collected from existing wells to assess the characteristics of the Quaternary aquifer. The ERT and VES results revealed a promising potential conductive layer at depths between 10 and 90 m with resistivity values of 10–100 Ohm.m. Control wells (Well 2, Well 4, and Well 7) near VES sites confirm the water aquifer zone within this depth range, with water depths measured at 14 m, 11 m, and 7 m, respectively. In addition, the key hydro-geophysical parameters, including hydraulic conductivity (K) and transmissivity (T), were estimated. Hydraulic conductivity values ranged from 1.62 to 4.1 m/day, while average transmissivity values varied between 105.3 and 200.2 m²/day. These ranges suggest the presence of relatively permeable aquifers composed mainly of coarse sand or fine gravel, as well as highly productive aquifers associated with weathered sedimentary formations, often linked to coarse sediments (e.g., sand, gravel) or karstified bedrock. In conclusion, the findings of this study enhance our understanding of the Quaternary Aquifer System in the Al Ain area and provide a solid foundation for informed, sustainable water resource management and environmental protection. By identifying the aquifer extent, geometry and hydraulic properties, stakeholders can make decisions that promote sustainable usage of the water resources. Given the increasing demand for freshwater in hyper-arid and arid regions, it is essential to integrate these insights into management practices to secure long-term water sustainability and meet community needs. This study also offers valuable baseline data for future research and monitoring efforts, stressing the current and ongoing need for scientific investigation to ensure effective groundwater management in the study area.