Assessing sustainability of groundwater resources on Jeju Island,South Korea,under climate change,drought, and increased usage   总被引：2，自引：0，他引：2  

Aly I. El-Kadi  Suzanne Tillery  Robert B. Whittier  Benjamin Hagedorn  Alan Mair  Kyoochul Ha  Gi-Won Koh 《Hydrogeology Journal》2014,22(3):625-642

Numerical groundwater models were used to assess groundwater sustainability on Jeju Island, South Korea, for various climate and groundwater withdrawal scenarios. Sustainability criteria included groundwater-level elevation, spring flows, and salinity. The latter was studied for the eastern sector of the island where saltwater intrusion is significant. Model results suggest that there is a need to revise the current estimate of sustainable yield of 1.77?×?10⁶ m³/day. At the maximum extraction of 84  % of the sustainable yield, a 10-year drought scenario would decrease spring flows by 28 %, dry up 27 % of springs, and decrease hydraulic head by an island-wide average of 7 m. Head values are particularly sensitive to changes in recharge in the western parts of the island, due to the relatively low hydraulic conductivity of fractured volcanic aquifers and increased groundwater extraction for irrigation. Increases in salinity are highest under drought conditions around the current 2-m head contour line, with an estimated increase of up to 9 g/L under 100 % sustainable-yield use. The study lists recommendations towards improving the island’s management of potable groundwater resources. However, results should be treated with caution given the available data limitations and the simplifying assumptions of the numerical modeling approaches.  相似文献   

Hydrochemical assessment of a deep Jordanian aquifer     

A. R. Awad  S. A. Taqieddin  A. S. Al-Homoud  E. A. Barakat 《Environmental Geology》1997,30(3-4):198-208

 This paper was mainly initiated to estimate some parameters of the quality and hydraulics of water in the vicinity of a proposed dam site in Jordan. The assessment of the chemical character was carried out to examine the suitability of the groundwater for domestic, municipal, industrial or irrigation use. Also, the anticipated problems associated with the quality of the reservoir water were delineated. Pumping tests were conducted at some wells that were drilled within the dam site zone and drawdown-time curves were constructed, by means of which the transmissivity and storage coefficients were assessed using two different methods. Total dissolved solids and electrical conductance were also measured and the relationship between them established. In addition, sodium ion concentrations at different piezometric tip elevations were measured in a number of wells that were previously drilled inside the dam site zone. This data indicates that the water quality as expressed in terms of total dissolved solids, electrical conductance, and sodium ion concentration limits do not comply with internationally recommended standards. The usage of this water for usual domestic purposes is therefore not viable, while the utilization of this water for irrigation purposes is very restricted. Received: 1 September 1995 · Accepted: 2 April 1995  相似文献   

Geochemistry of granitic rocks,the eastern desert,Egypt     

H. Kotb  M.M. Aly  M.M. Hassan  M.S.S. Holyle 《Precambrian Research》1982,16(4):A29

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Simplified Regression Model to Predict the Strength of Reinforced Sand with Waste Polystyrene Plastic Type     

Aly Ahmed 《Geotechnical and Geological Engineering》2012,30(4):963-973

A proposed regression model was developed based on experimental data using regression analysis method to predict the strength of sand reinforced with strips of waste polystyrene plastic type. Three different variables were studied to investigate the behavior and strength of reinforced sandy soil with waste plastic strips. These are the content, size and aspect ratio of plastic strips. For this purpose, a series of unconfined compression and splitting tensile tests were conducted on unreinforced and reinforced sand specimens. Test results showed that using strips of waste plastic polystyrene type improved the strength of the tested soil. Increasing content of waste plastic has a more significant effect on the enhancement of splitting tensile strength compared to the enhancement of compressive strength. Content, size and aspect ratio of waste plastic strips have significant effects on the improvement of strength. Utilization of such waste plastic type, which polystyrene, in this way will help in reducing the quantity of solid waste as well as reducing the cost of ground improvement. Results showed that multiple linear regression models can accurately predict the strength of sand reinforced with waste plastic strips within the range of the studied variables in this paper. Consequently, using such regression models will save time as well as reduce laboratory costs.  相似文献   

Ocellar lamprophyre dyke bearing mineralization,Wadi Nugrus,Eastern Desert,Egypt: Geology,mineralogy and geochemical implications     

M. E. Ibrahim  G. M. Saleh  N. A. Dawood  G. M. Aly 《中国地球化学学报》2010,29(4):383-392

The ocellar lamprophyre dyke (ENE-WSW) is recorded at Wadi Nugrus, Eastern Desert, Egypt. It cuts porphyritic biotite granites and varies in thickness from 0.5 to 1.5 m and up to 3 km in length. The lamprophyre dyke has been altered, and it is characterized by porphyritic and panidiomorphic textures with plagioclase, olivine, and augite constituting the porphyritic phase in a fine groundmass of the same composition. Rutile, titanite, apatite, fluorite, graphite, calcite, allanite, autunite and Fe-Ti oxides are accessory minerals. Kaolinite, chlorite and epidote are secondary minerals. Carbonitization and hematitization are common. Rounded to sub-rounded porphyritic and zoned ocelli with radiate or brush-like shapes are generally common and represent physical traps for mineralization. The ocellar features are interpreted to represent the late stage of magmatic segregation or magmatic crystallization involving two immiscible magmatic liquids.  相似文献   

Changes of freshwater-lens thickness in basaltic island aquifers overlain by thick coastal sediments   总被引：1，自引：1，他引：0  

Kolja Rotzoll  Delwyn S. Oki  Aly I. El-Kadi 《Hydrogeology Journal》2010,18(6):1425-1436

Freshwater-lens thickness and long-term changes in freshwater volume in coastal aquifers are commonly assessed through repeated measurement of salinity profiles from monitor wells that penetrate into underlying salt water. In Hawaii, the thickest measured freshwater lens is currently 262 m in dike-free, volcanic-rock aquifers that are overlain by thick coastal sediments. The midpoint depth (depth where salinity is 50% salt water) between freshwater and salt water can serve as an indicator for freshwater thickness. Most measured midpoints have risen over the past 40 years, indicating a shrinking lens. The mean rate of rise of the midpoint from 1999–2009 varied locally, with faster rates in highly developed areas (1.0 m/year) and slower rates in less developed areas (0.5  m/year). The thinning of the freshwater lenses is the result of long-term groundwater withdrawal and reduced recharge. Freshwater/salt-water interface locations predicted from measured water levels and the Ghyben-Herzberg principle may be deeper than measured midpoints during some periods and shallower during other periods, although depths may differ up to 100 m in some cases. Moreover, changes in the midpoint are slower than changes in water level. Thus, water levels may not be a reliable indicator of the amount of freshwater in a coastal aquifer.  相似文献   

Recovery of thorium (IV) from leached monazite solutions using counter-current extraction     

A.M.I. Ali  Y.A. El-NadiJ.A. Daoud  H.F. Aly 《International Journal of Mineral Processing》2007

A flow sheet was developed to recover thorium from Egyptian monazite sands. The results of a detailed investigation on the extraction and stripping of thorium in the hydrous oxide are obtained after alkaline dissolution followed by leaching with alkaline carbonate solutions. This cake was dissolved in 4 M HNO₃ and thorium was extracted selectively by a counter-current extraction system using a mixer–settler contactor and Aliquat-336 in kerosene as extractant. The results show that 2 h of continuous operation are necessary to reach the steady state condition for the process. The extraction efficiency is found to be 80% and the stripping efficiency is 82%.  相似文献   

Rotational evolution of a symmetric gyrostat with visco-elastic bars around the center of mass in a circular orbit     

Samy Ahmed  El-Hafiez Aly 《Celestial Mechanics and Dynamical Astronomy》1987,40(3-4):225-231

The motion of a gyrostat in a circular orbit in a Newtonian field of force is considered. The gyrostat has four homogeneous viscoelastic bars attached to it. Rotation of the symmetric rotor inside the rigid body is statically and dynamically balanced. Bending deformations of the bars, accompanied by dissipation of energy, are the cause of the evolution of the system's rotational motion. Approximate equations describing this evolution are derived, together with averaged equations in Andoyer variables.  相似文献   

Identifying variably saturated water-flow patterns in a steep hillslope under intermittent heavy rainfall   总被引：5，自引：0，他引：5  

Aly I. El-Kadi  Jill D. Torikai 《Hydrogeology Journal》2001,9(3):231-242

The objective of this paper is to identify water-flow patterns in part of an active landslide, through the use of numerical simulations and data obtained during a field study. The approaches adopted include measuring rainfall events and pore-pressure responses in both saturated and unsaturated soils at the site. To account for soil variability, the Richards equation is solved within deterministic and stochastic frameworks. The deterministic simulations considered average water-retention data, adjusted retention data to account for stones or cobbles, retention functions for a heterogeneous pore structure, and continuous retention functions for preferential flow. The stochastic simulations applied the Monte Carlo approach which considers statistical distribution and autocorrelation of the saturated conductivity and its cross correlation with the retention function. Although none of the models is capable of accurately predicting field measurements, appreciable improvement in accuracy was attained using stochastic, preferential flow, and heterogeneous pore-structure models. For the current study, continuum-flow models provide reasonable accuracy for practical purposes, although they are expected to be less accurate than multi-domain preferential flow models. Electronic Publication  相似文献   

Non-linear earthquake-response analysis of long-span cable-stayed bridges: Theory     

Aly S. Nazmy  Ahmed M. Abdel-Ghaffar 《地震工程与结构动力学》1990,19(1):45-62

The non-linear dynamic analysis of three-dimensional long-span cable-stayed bridges when subjected to seismic loading is formulated. All possible sources of non-linearity, such as cable sag, axial force-bending moment interaction in bridge towers and girders and change of geometry of the whole bridge due to large displacements are considered in the analysis. Both cases of uniform and multiple-support seismic excitations are considered in the non-linear formulation of the problem. A tangent stiffness, iterative procedure is utilized to capture the the non-linear seismic response. The non-linear equations of motion are solved using a step-by-step integration technique in the real displacement coordinate space as well as in the modal coordinate space to save computational time.  相似文献