Assessment of Aquifer Storage and Recovery (ASR) feasibility at selected sites in the Emirate of Abu Dhabi, UAE

Aquifer storage and recovery (ASR) is considered as a strategy for the storage of water to ensure a sustainable water supply in the Abu Dhabi emirate. Earlier investigations have been conducted, and two sites were proposed for the installation of ASR in the surficial aquifer. Recently, the site located in the center of Abu Dhabi (sand dune area) was executed, and the second site is undergoing the pilot phase of the study. However, the performance and influence of the regional groundwater system may vary depending on regional hydrogeological characteristics, which have not been investigated. Hence, this study attempts to understand the feasibility of the proposed ASR sites in the surficial aquifer using a regional model developed by the finite-difference approach with an accuracy of 0.28 m mean residual difference. Additionally, six sites were selected on the basis of the literature and aquifer parameters and were investigated for their suitability for future ASR installation. Six cycles of injection and recovery at various rates were analyzed at each ASR site by using a transient calibrated model until the end of the year 2030. The area of influence is axisymmetrical in the sand dune area and non-symmetrical in the east and northeastern areas because of the steep topography and groundwater table gradient. At the sites that possess a non-symmetrical influence, the area of influence is always high upstream of the groundwater flow. Heterogeneity-induced variation in the fluctuation of the groundwater table is noted in all sites. Even with 100% recovery, the groundwater table did not reach the ambient groundwater table during the recovery period. This finding confirms the contribution of regional groundwater to the site during recovery. All sites selected for future ASR installation, except site 5, are capable of storing the volume needed to meet expected water demand. Site 2 is considered the most suitable site for ASR installation in the future. This study will facilitate the scientific communities and authorities in understanding the feasibility of ASR installation for sustainable water storage and supply in the Abu Dhabi emirate.