100 research outputs found
Assessment of Aquifer Storage and Recovery (ASR) feasibility at selected sites in the Emirate of Abu Dhabi, UAE
No full textAquifer 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
Impact of sea level rise and tidal effects on flux-controlled and partially isolated shallow aquifer on the southeast coast of India
No full textA rise in sea level is the most important threat to the coastal aquifers in which the intensity of threat also depends on the local hydrogeological settings. The present study seeks to identify the impacts of sea level rise and tidal effects on the shallow and complex aquifer located south of Chennai, India. The aquifer geometry is isolated dune surfaces due to the presence of enclosing saline surface water. The freshwater is available as an elongated lens, and replenishment occurs by rainfall, with limited regional influx. Numerical simulation was carried out to understand the response of groundwater table to sea level rise until the year 2100. Initially, the tidal effects were investigated for the duration of 3 years. A sinusoidal fluctuation of groundwater table is noticed only in the northern part and the tidal impact seems infinitesimal because of steep hydraulic gradient in the south. Simulation of groundwater table without considering sea level rise predicts a decline in the elevation of groundwater table/freshwater lens by − 0.35 m in the dune surfaces. The simulation with reported sea level rise of 2 mm year −1 with the same rate of groundwater pumping results in a total increase of 0.5 m in groundwater table. The study infers that the tidal effects are high in the shallow groundwater gradient, and sea level rise will be beneficial to the isolated coastal freshwater aquifers by increasing the elevation of groundwater table/freshwater lens and further deepening the interface between seawater and freshwater
Regional groundwater flow model for Abu Dhabi Emirate: scenario-based investigation
No full textDespite the continuous increase in water supply from desalination plants in the Emirate of Abu Dhabi, groundwater remains the major source of fresh water satisfying domestic and agricultural demands. Groundwater has always been considered as a strategic water source towards groundwater security in the Emirate. Understanding the groundwater flow system, including identification of recharge and discharge areas, is a crucial step towards proper management of this precious source. One main tool to achieve such goal is a groundwater model development. As such, the main aim of this paper is to develop a regional groundwater flow model for the surficial aquifer in Abu Dhabi Emirate using MODFLOW. Up to our knowledge, this is the first regional numerical groundwater flow model for Abu Dhabi Emirate. After steady state and transient model calibration, several future scenarios of recharge and pumping are simulated. Results indicate that groundwater pumping remains several times higher than aquifer recharge from rainfall, which provides between 2 and 5% of total aquifer recharge. The largest contribution of recharge is due to subsurface inflow from the eastern Oman Mountains. While rainfall induced groundwater level fluctuation is absent in the western coastal region, it reaches a maximum of 0.5 m in the eastern part of the Emirate. In contrast, over the past decades, groundwater levels have declined annually by 0.5 m on average with local extremes spanning from 93 m of decline to 60 m of increase. Results also indicate that a further decrease in groundwater levels is expected in most of Emirate. At other few locations, upwelling of groundwater is expected due to a combination of reduced pumping and increased infiltration of water from nonconventional sources. Beyond results presented here, this regional groundwater model is expected to provide an effective tool to water resources managers in Abu Dhabi. It will help to accurately estimate sustainable extraction rates, assess groundwater availability, and identify pathways and velocity of groundwater flow as crucial information for identifying the best locations for artificial recharge
Modeling the mitigation of seawater intrusion by pumping of brackish water from the coastal aquifer of Wadi Ham, UAE
No full textThe control and management of seawater intrusion in coastal aquifers is a major challenge in the field of water resources management. Seawater intrusion is a major problem in the coastal aquifer of Wadi Ham, United Arab Emirates, caused by intensive groundwater abstraction from increased agricultural activities. This has caused the abandonment of salinized wells and ultimately affected farming activities and domestic water supply in the area. In this study, the 3D finite element groundwater flow and solute transport model is developed using FEFLOW to simulate pumping of brackish water from the intrusion zone to control seawater intrusion in the aquifer. The model was calibrated and validated with available records of groundwater levels and salinity distribution. Different simulation scenarios were conducted to obtain optimum pumping locations, rates as well as a number of wells. A comparison between scenarios of non-pumping and pumping of brackish water was conducted. Results showed an increase in the concentration of groundwater salinity under the non-pumping scenario, while it decreased under the pumping scenario. Under the non-pumping scenario, isoline 30,000 mgl−1 was observed to have intruded into the south-eastern part of the aquifer, while the maximum isoline observed for the same area under the pumping scenario was 20,000 mgl−1. This result showed an overall improvement in the quality of groundwater and ultimately halted seawater intrusion in the aquifer
Assessment of seawater mixing in a coastal aquifer by high resolution electrical resistivity tomography
No full textSeawater intrusion is a major problem in urbanized coastal regions of India which is due to over exploitation of groundwater for various purposes. This study was carried out with the objective of assessing the zone of mixing between seawater and groundwater in the coastal aquifer in south of Chennai, Tamil Nadu, India using high resolution electrical resistivity tomography. High resolution electrical resistivity tomography was carried out in five profiles perpendicular to the sea using IRIS make SYSCAL Pro-96 system with 2.5 m or 5 m inter-electrode separation. The maximum length of the profile was 170 m which resulted in a depth of investigation of 28.7 m. The apparent resistivity measured in this area varies from 0.3 ohm-m to 30,000 ohm-m. The apparent resistivity of saturated zone decreases towards the sea, indicating the influence of seawater. This was also confirmed by measuring the electrical conductivity of groundwater, which gradually increases from 156 μS/cm to 3430 μS/cm towards the sea. Further, the concentration profiles of electrical conductivity, sodium, chloride and chloride / bicarbonate ratio are compared with the high resolution electrical resistivity tomography profile. The distance of influence of seawater is comparatively high in northern part than in southern part of the area. The high resolution electrical resistivity tomography was effectively used to determine the effect of seawater mixing with groundwater. © IRSEN, CEERS, IAU
Groundwater management in alluvial, coastal and hilly areas
No full textGroundwater plays a major role in the modern world being used for drinking, irrigation and industrial development. The increasing population and developments in agricultural and industrial sectors depends on groundwater as it is a reliable source, and so it leads to overexploitation of groundwater without due regard to the recharging capacity of the aquifers. Groundwater extraction from most of the aquifers around the world has exceeded its recharge capacity, and hence the water table has gone down drastically leading to adverse environmental consequences like land subsidence and water quality deterioration. A proper assessment of groundwater resource should be undertaken to ensure sustainable management of groundwater. Hence, the present study proposes empirical methods for the sustainable groundwater resource management in alluvial, coastal and hilly regions
Optimized pumping strategy for reducing the spatial extent of saltwater intrusion along the coast of Wadi Ham, UAE
Get PDFMany coastal aquifers are facing severe anthropogenic impacts such as urbanization, industrialization and agricultural activities are resulting in a saltwater intrusion. This establishes the need for a sustainable groundwater management strategy aimed to overcome the situation. Pumping of brackish/saline water to mitigate saltwater intrusion is a major potential approach to effectively control saltwater intrusion. However, this method has many challenges including selection of appropriate discharge rates under an optimum number of pumping wells and at specified wells distance from the shoreline. Hence, this study developed a Finite Element Flow and solute transport model (FEFLOW) to simulate three scenarios to assess the most appropriate pumping rates, number of wells and optimum well locations from the shoreline. These parameters were assessed and evaluated with respect to the change in groundwater saline concentration at different distance from the coastline. The 15,000 mg L-1 isosalinity contour line was used as a linear threshold to assess the progression of saltwater intrusion along three major locations in the aquifer. Scenario One was simulated with a constant number of wells and rate of pumping. Shifting of pumping wells to several distances from the shoreline was conducted. Scenario Two assessed the most appropriate number of pumping wells under constant pumping rates and distances from the shoreline and in scenario 3, the optimum pumping rates under a constant number of wells and distance from the shoreline were simulated. The results showed that the pumping of brackish/saline water from a distance of 1500 m from the shoreline using 16 pumping wells at a total pumping rate of 8000 m3 d-1 is the most effective solution in contrasting the saltwater intrusion in the Wadi Ham coastal aquifer
Impacts of Desalinated and Recycled Water in the Abu Dhabi Surficial Aquifer
Get PDFIn Abu Dhabi, one of the most arid regions in the world, in recent decades, desalinated water has been identified as a prime solution in solving the water demand issues. In this study, a three-dimensional coupled density-dependent flow and solute transport model was set up in order to study the effect of the artificial recharge using desalinated water and the influence of nonconventional water with a salt concentration in the range 0.1–2 g/L The results confirm that this region demands the adoption of a more rational use of irrigation water or additional usage of desalinated water and recycled water together with optimizing groundwater pumping at locations that are vulnerable to further quality degradation and depletion. The long-term storage of desalinated freshwater with a maximum radial distance of 653 m in the dune surface is ensured with the formation of the transition zone, and change in the groundwater head up to 5 km. The maximum recovery obtained by immediate recovery is 70%. The study expresses the long-term feasibility of desalinated freshwater storage and the need for further management practices in quantifying the contribution of desalinated and recycled water for agriculture activities which might have improved groundwater quality and increased hydraulic head at some locations
Abundant cilantro derived high surface area activated carbon (AC) for superior adsorption performances of cationic/anionic dyes and supercapacitor application
No full textWith the growing concern about water quality requirements and the looming energy crisis, researchers all over the world have committed to the development of novel single low-cost porous materials for a variety of applications (ex: environmental and energy applications). Treatment of dye contaminants before they are released into the environment is considered as a significant challenge in the field of water treatment. Treatment of such dye contaminants remains as challenging task and evolved as the most persistent issues in the environmental remediation field. To address all these specific limitations present investigation involves the conversion of inexpensive Cilantro plants (C. sativum) into Activated Carbon (AC) which can be utilized as a fascinating alternative potential low-cost AC material for the treatment of toxic dye contaminants (environmental) and supercapacitor (energy) applications with improved performances. The fundamental physical–chemical properties of AC were confirmed by using various analytical and spectroscopic techniques. It is substantial to mention, obtained AC possesses a microporous structure and a large specific surface area of 2200 m²g⁻¹. Further, AC was employed for the adsorption of methyl orange (MO) and rhodamine-6G (Rh-6G) dyes from aqueous solutions. The rapid adsorption process occurred within the contact time of 14 and 20 min for MO and Rh-6G. In addition, demonstrated with > 99 % removal efficiencies and an outstanding maximum adsorption capacity of 467.29 mg/ g for MO and 143.47 mg/g for Rh-6G was witnessed surpassing the commercially available activated carbon material (CAC). To prove the efficacy of AC, the real-time application was evaluated by taking an industrial wastewater sample which showed 99.45 % of removal efficiency. Furthermore, a cartridge was developed and utilized for the treatment of dye solution for an on-field demonstration to assess potable water. Moreover, the synthesised AC witnessed a removal efficiency of > 80 % even up to the 4th cycle. Most importantly, to mark the waste management process the regenerated AC adsorbent and desorbed pollutants are treated effectively and can be utilized for further applications. Interestingly, the AC material obtained at 700 °C displayed optimum specific surface area (SSA), surface functionalities which help electrode wetting, surface redox reaction and pseudocapacitance from ion diffusion and showed specific capacitance of 162.4F/g at 1 A/g (three electrode system). Notably, the AC symmetric supercapacitor provides a high-power density of 243.94 W/kg and could be reversibly cycled with very minimal capacitance loss over 5000 cycles at 10 A/g.Shrinath Bhat, U.T. Uthappa, T. Sadhasivam, Tariq Altalhi, Sung Soo Han, Mahaveer D. Kurkur
Oscillatory behavior of three dimensional α-fractional delay differential systems
No full textIn the present work we study the oscillatory behavior of three dimensional α-fractional nonlinear delay differential system. We establish some sufficient conditions that will ensure all solutions are either oscillatory or converges to zero, by using the inequality technique and generalized Riccati transformation. The newly derived criterion are also used to establish a new class of systems with delay which are not covered in the existing study of literature. Further, we constructed some suitable illustrations
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