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Flow modelling of strategically vital freshwater aquifers in Kuwait

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Flow modelling of strategically vital freshwater aquifers in Kuwait

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An oil flow from the oil wells damaged during the 1991 Gulf War and the sea water used for extinguishing the resulting oil fire have contaminated the freshwater aquifers of Raudhatain and Umm Al-Aish water fields in north Kuwait. The numerical flow modelling of the aquifers was undertaken to create a calibrated and validated model that could be used in the future to explore a viable remediation strategy for the aquifers. The Environmental Visualization Software (EVS-pro) 3-D data presentation program was used to construct a conceptual model as a preliminary step. A 3-D numerical model was developed using the MODFLOW-SURFACT code that overcame the limitations of the classical MODFLOW. This model was able to combine both freshwater lenses in one model domain simulating the vadose zone together with the saturated zone. The model domain covered an area of 580 km2 encompassing the Al-Raudhatain and Umm Al-Aish basins. A steady-state model was developed first to study regional flow patterns in the aquifer. A transient model was developed subsequently to assess seasonal recharge on groundwater and investigate their effects on flow patterns. Analysis of the calibrated steady-state model output indicated that the model simulated the groundwater elevation and flow direction across the model domain to an acceptable level. The calibrated transient flow model is of significant importance to assess the vertical and lateral plume migration in the area and helps to come up with a plausible remediation strategy.
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... However, none of these studies address the transient nature of IFLs over varying temporal and spatial scales. A threedimensional, numerical model of the Raudhatain and Umm Al-Aish IFLs in Kuwait by Al-Weshah and Yihdego [30] used MODLFOW-SURFACT code to predict water table elevations over 22 years but does not account for the freshwater extent in the vertical or horizontal direction as it migrates laterally through space and time. Research into the geometry of IFLs is needed to adequately predict the position and sustainability of exploitable freshwater resources. ...
... The average velocities estimated by the numerical model aligned with velocities measured from the physical model, as well as the average velocities reported by Al-Weshah and Yihdego [30] of 6.34 × 10 −7 -2.85 × 10 −6 m/s. The numerical model showed an increase in average velocity during the recharge stress period by an order of magnitude (10 −5 m/s), which aligns with the range of recharge rates used in the physical and numerical model simulations 3.33 × 10 −6 -6.67 × 10 −6 m/s. ...
... Estimates such as these inform geochemical studies that aim to approximate IFL water age, such as the study by Kuldzhayev [45], which determined the onset of freshwater accumulation of an IFL in the Karakum desert to be 3400 years. Investigations into the formation, geometry, and extent of freshwater lenses over long temporal scales are needed for inland and coastal environments to quantify the supply of drinking water and the effects of external changes such as precipitation and sea-level rise [13,30], but also geomorphological [46] and anthropogenic impacts [47,48]. ...
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Brackish to saline groundwater in arid environments encourages the development and sustainability of inland freshwater lenses (IFLs). While these freshwater resources supply much-needed drinking water throughout the Arabian Peninsula and other drylands, little is understood about their sustainability. This study presents a numerical model using the SEAWAT programming code (i.e., MODFLOW and the Modular Three-Dimensional Multispecies Transport Model (MT3DMS)) to simulate IFL transient evolution. The numerical model is based on a physical laboratory model and calibrated using results from simulations conducted in a previous study of the Raudhatain IFL in northern Kuwait. Data from three previously conducted physical model simulations were evaluated against the corresponding numerical model simulations. The hydraulic conductivities in the horizontal and vertical directions were successfully optimized to minimize the objective function of the numerical model simulations. The numerical model matched observed IFL water levels at four locations through time, as well as IFL thicknesses and lengths (R2 = 0.89, 0.94, 0.85). Predicted lens degradation times corresponded to the observed lenses, which demonstrated the utility of numerical models and physical models to assess IFL geometry and position. Improved understanding of IFL dynamics provides water-resource exploration and development opportunities in drylands throughout the Arabian Peninsula and elsewhere with similar environmental settings.
... FFGLs have been detected and studied in Australia, Kuwait, Nambia, Oman, UAE (see e.g. Al-Weshah and Yihdego, 2016, Cendón et al., 2010, Kwarteng et al., 2000, Laattoe et al., 2017, Macumber, 2003, Milewski et al., 2014, Rizk and Al-Sharhan, 2003, Young et al., 2004. Unlike humid lenses in Europe (Voortman et al., 2015), infiltrationevaporation on the water table of these FFGLs and ensued groundwater motion inside is much less investigated (Laattoe et al., 2017). ...
Article
A fully-saturated lens of steady fresh groundwater floating in a homogeneous and isotropic desert sandy aquifer is analytically studied based on a hydrological model by Kunin and interface solution by Van Der Veer. A static saline groundwater is beneath the lens. A phreatic surface of moving fresh water inside the lens is partially recharged (either naturally or by managed aquifer recharge ) from the vadose zone and partially exfiltrates to it. A spatially focused recharge and intensive evapotranspiration preserve a steady downward-upward topology of fresh water motion. In terms of the 1-D Dupuit-Forchheimer approximation in a horizontal in-lens saturated flow a boundary value problem (BVP) for an ODE for the Strack potential is solved. The shape of the water table and, based on the Ghijben-Herzberg assumption , the interface are found. The total volume of the positive-pore pressure water flowing within the lens is evaluated. Constant infiltration and evaporation rates as well as evaporation linearly decreasing with depth of the water table (counted from the ground surface) are considered. The case of 2-D flow is tackled by the Toth model. A triangular analytic element approximates a half of the flow domain and consists of an isobaric side and two no-flow sides. Conformal mapping of this triangle onto a reference plane and solution of the Dirichlet BVP in a half-plane deliver the distribution of infiltration-exfiltration intensity along the water table, total flow rate and locus of the hinge point. A mathematically more cumbersome approximation of the flow domain assumes the water table to be a tilted straight line but the interface to be found as a free boundary. Solution of the corresponding BVP uses a curvilinear triangle in the hodograph plane.
... The extent of contamination was such that vast lakes of oil were created in the desert and airborne petrochemical by-products from well fires initiated by the Iraqis resulting in dark days over Kuwait for months after liberation (Al-Damkhi et al. 2009). Seawater pumped from the Gulf to extinguish the many well fires, dousing the ecologically sensitive landscape with large quantities of saline water that also intruded into fresh groundwater aquifers (Al-Weshah and Yihdego 2016). ...
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Freshwater groundwater resources at north Kuwait were contaminated by infiltrated oil as well as sea water that was used to fight the oil-well fires during the liberation of Kuwait in 1991. This paper investigates the feasibility of five remediation options to restore the polluted aquifers. These options include: (i) pump and treat of contaminated groundwater; (ii) cleaning the aquifer formation; (iii) construction of additional desalination plant; (iv) constructing additional storage tanks, and (v) development of artificial aquifer recharge schemes. The basis for this assessment study is to supply minimum basic drinking water to Kuwait City at a total rate of 50,000 m³/day in an emergency for up to one year based on essential basic need of 32 liters per capita per day. To compare these options, a decision matrix to select suitable remediation options using Multiple Criteria Decision Analysis (MCDA) approach is developed. The cost was given a relative weight of 20 whereas other criteria are given weight of 10. Based on these MCDA scores, it was found that option 3, namely, establishing an additional water desalination plant, is the most feasible option followed by option 5, artificial recharge of aquifers.
... Accordingly, the conceptual model of soil water rise in the JAWAwas constructed taking into account the key factors influencing the hydrogeology of the area of interest [18]. The conceptual hydrogeological model used to time series analysisis given in (Fig.2) [19] and [20]. ...
... The aim of this paper is to provide a somewhat detailed assessment and costing for a treatment option for the aquifers that would restore the aquifers to pre-invasion quality. The work largely considered restoration of the aquifers to potable water quality standards, considered world-best-practice for remediation options and water treatment at reasonable cost and practicality and considered the Raudhatain and Umm Al-Aish aquifers ( Figure 1) as a strategic asset being the only freshwater aquifers in Kuwait (Al-Weshah and Yihdego, 2016). ...
Article
This paper investigated approaches to treat the polluted groundwater in selected aquifers in Kuwait, which is the most extensive and second to none in terrestrial world case history. The selected aquifers are susceptible to pollution by oil spills during the first Gulf War. Experimental samplings of polluted soils were analysed. Results showed that granulated activated carbon is very effective in removing petroleum hydrocarbons from contaminated water. A pump-and-treat remediation scheme has been suggested for the affected parts of the freshwater fields. The cost estimates indicated that a treatment process involving carbon adsorption to remove petroleum hydrocarbons, followed by reverse osmosis to remove salt was highly likely to be the most cost-effective treatment system. The current treatment design and parametric costing approach can be applied elsewhere for the role of bioremediation in the treatment of petroleum contaminated environment, hazardous effects of petroleum hydrocarbon and genetic engineering in bioremediation.
... The aim of this paper is to provide a somewhat detailed assessment and costing for a treatment option for the aquifers that would restore the aquifers to pre-invasion quality. The work largely considered restoration of the aquifers to potable water quality standards, considered world-best-practice for remediation options and water treatment at reasonable cost and practicality and considered the Raudhatain and Umm Al-Aish aquifers ( Figure 1) as a strategic asset being the only freshwater aquifers in Kuwait (Al-Weshah and Yihdego, 2016). ...
Article
Full-text available
This paper investigated approaches to treat the polluted groundwater in selected aquifers in Kuwait, which is the most extensive and second to none in terrestrial world case history. The selected aquifers are susceptible to pollution by oil spills during the first Gulf War. Experimental sampling of polluted soils were analysed. Results showed that granulated activated carbon is very effective in removing petroleum hydrocarbons from contaminated water. A pump-and-treat remediation scheme has been suggested for the affected parts of the freshwater fields. The cost estimates indicated that a treatment process involving carbon adsorption to remove petroleum hydrocarbons, followed by reverse osmosis to remove salt was highly likely to be the most cost-effective treatment system. The current treatment design and parametric costing approach can be applied elsewhere for the role of bioremediation in the treatment of petroleum contaminated environment, hazardous effects of petroleum hydrocarbon and genetic engineering in bioremediation.
Article
Dryland inland freshwater lenses (IFLs) that have been topographically induced are represented using physically modeled laboratory simulations, to characterize the stages of IFL evolution (i.e. formation, migration, degradation) as a function of recharge rate. Arid regions with shallow brackish to saline groundwater possess IFLs. The position and geometry (i.e. thickness, length) of IFLs over varying temporal and spatial scales is poorly understood due to their transient nature. The physically modeled IFLs in this study formed from an initial recharge pulse, after which IFL geometry was measured over time as it flowed in the direction of simulated groundwater flow. The time required for an IFL to reach the maximum thickness exhibited a negative exponential correlation to recharge rate. At IFL formation, thickness and length were positively correlated, and the ratio of IFL thickness to length exhibited a positive exponential correlation to recharge rate. After IFL formation, the central position of the simulated IFLs migrated laterally in the direction of groundwater flow at a velocity less than the range of applied recharge rates and greater than the groundwater flow velocities. The time required for the IFL to reach a minimum thickness, or IFL degradation, exhibited a positive exponential correlation to recharge rate. The Dupuit-Ghyben-Herzberg solution used to model coastal freshwater lens thickness was tested against the physically modeled IFLs and deemed invalid. A correction factor and modified solution are provided to predict IFL thickness, providing motivation for future analytical and numerical studies on inland variable-density groundwater systems in arid regions globally.
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In 1962 Rachel Carson warned of the consequences of man's pollution in her book Silent Spring, a book that some feel marks the real beginning of our environmental awareness. Silent Spring told of the consequences of our increasing pesticide use to birds. Almost 30 years after her warning, the western Arabian Gulf experienced its "silent spring" when approximately 100,000 to 250,000 waterbirds died, along with millions of other organisms, due to the massive oil spill that resulted due to Gulf war. The magnitude of our environmental problems has continued to grow during the last thirty years to a point where even the "doomsday" environmentalists could hardly have envisioned back in 1962. It seems the death of yet uncounted thousands of humans was not sufficient for Saddam Husain. His desire for power and infamy led him to unleash environmental war on mankind. At the end of the Gulf war he set ablaze the oil fields of Kuwait and released more oil into the sea than had been spilled at any time throughout history. These actions were despicable and an affront to civilized man. A quality environment should be a right of all mankind, and to wage war by deliberately polluting the earth cannot be tolerated.
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Satellite observations were used to test the validity of previously identified favourable conditions for the formation of freshwater lenses, identify additional potential occurrences, and model modern potential recharge in the Raudhatain Watershed (3696) in northern Kuwait. Favourable conditions include infrequent yet intensive precipitation events, drainage depressions to collect the limited runoff, and presence of conditions (e.g. high infiltration capacity) that promote groundwater recharge and preservation (e.g. underlying saline aquifer) of infiltrating groundwater as freshwater lenses floating over saline aquifer water due to differences in density. Specifically, the following field and satellite-based observations were noted for the Raudhatain Watershed: (1) Over ~30 precipitation events were identified from the Tropical Rainfall Measuring Mission precipitation data (1998–2009); (2) slope is gentle (2 m/km), and the surface is largely (80%) covered by alluvial deposits with high infiltration capacities (up to 9 m/day); (3) no flows and long-term ponding were reported at the watershed outlet or detected from Landsat thematic mapper images; (4) infiltration is high based on increases in soil moisture content (from an advanced microwave scanning radiometer) and vegetation index following large precipitation events; and (5) freshwater lenses that overlie highly saline [total dissolved solids (TDS): >35 000] unconfined aquifers underlying the watershed are absent in the southern regions, where infiltrating fresh water mixes with the less saline groundwater (TDS: <10 000). Twenty potential locations (size: 1 to 75 km2) for freshwater lens development were identified in northern Kuwait, and continuous rainfall–runoff models (Soil Water and Assessment Tool) were applied to provide a first-order estimation of the average annual recharge in the watershed (127 × 106 m3) and freshwater lenses (8.17 × 106 m3). Results demonstrate the settings for enhanced opportunities for groundwater recharge, outline the amounts of and preservation conditions for the groundwater feeding the freshwater lenses, and highlight potential applications and locations of freshwater lenses in similar settings elsewhere in the Arabian Peninsula and beyond. Copyright © 2013 John Wiley & Sons, Ltd.
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The recognition that urban groundwater is a potentially valuable resource for potable and industrial uses due to growing pressures on perceived less polluted rural groundwater has led to a requirement to assess the groundwater contamination risk in urban areas from industrial contaminants such as chlorinated solvents. The development of a probabilistic risk based management tool that predicts groundwater quality at potential new urban boreholes is beneficial in determining the best sites for future resource development. The Borehole Optimisation System (BOS) is a custom Geographic Information System (GIS) application that has been developed with the objective of identifying the optimum locations for new abstraction boreholes. BOS can be applied to any aquifer subject to variable contamination risk. The system is described in more detail by Tait et al. [Tait, N.G., Davison, J.J., Whittaker, J.J., Leharne, S.A. Lerner, D.N., 2004a. Borehole Optimisation System (BOS) – a GIS based risk analysis tool for optimising the use of urban groundwater. Environmental Modelling and Software 19, 1111–1124]. This paper applies the BOS model to an urban Permo–Triassic Sandstone aquifer in the city centre of Nottingham, UK. The risk of pollution in potential new boreholes from the industrial chlorinated solvent tetrachloroethene (PCE) was assessed for this region. The risk model was validated against contaminant concentrations from 6 actual field boreholes within the study area. In these studies the model generally underestimated contaminant concentrations. A sensitivity analysis showed that the most responsive model parameters were recharge, effective porosity and contaminant degradation rate. Multiple simulations were undertaken across the study area in order to create surface maps indicating areas of low PCE concentrations, thus indicating the best locations to place new boreholes. Results indicate that northeastern, eastern and central regions have the lowest potential PCE concentrations in abstraction groundwater and therefore are the best sites for locating new boreholes. These locations coincide with aquifer areas that are confined by low permeability Mercia Mudstone deposits. Conversely southern and northwestern areas are unconfined and have shallower depth to groundwater. These areas have the highest potential PCE concentrations. These studies demonstrate the applicability of BOS as a tool for informing decision makers on the development of urban groundwater resources.