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1.
Based on geomorphologic and hydrogeologic characteristics of its territory, Lebanon is divided into three provinces: the West Lebanon province, the Bekaa province, and the East Anti-Lebanon province. These provinces are subdivided into smaller hydrogeologic units, the basins and subbasins. Significant features used in the subdivision are faults, relief, anticlinal axes, river channels, and water divides. Recharge to groundwater is a percentage of the intake area, the percipitation rate over this area, and the infiltration rate of outcropping rocks. The amounts of recharged water over the three provinces are 1609, 914, and 19 Mm3, respectively. Discharge is surface water from springs and water wells along the Lebanese coast. The discharge from the Lebanese rivers exceeds 3700 Mm3/year, an appreciable amount of which comes from natural springs. The quantity of groundwater pumped by wells or flowing into neighboring countries and to the sea as submarine springs, may exceed 800 Mm3/year.  相似文献   
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 Chemical data are used to clarify the hydrogeological regime in the Mafraq area in northern Jordan, as well as to determine the status of water quality in the area. Groundwater from the shallow aquifer in the Mafraq area can be divided into two major groups according to geographical locations and chemical compositions. Water in the basaltic eastern part of the study area is characterized by the dominance of chloride, sulfate, sodium, and potassium, whereas waters in the limestone aquifers in the west are dominated by the same cations but have higher concentrations of bicarbonate. Stable isotopes show that the shallow aquifers contain a single water type which originated in a distinct climatic regime. This water type deviates from the Global Meteoric Water Line (MWL), as well as from the eastern Mediterranean meteoric water line. The waters are poor in tritium, and thus can be considered generally older than 50 years. Chemical mass balance models suggest that water is moving from the west towards the north of the study area. This suggests that waters from the different basins are separated from each other. Degradation of water quality can be attributed to agricultural fertilizers in most cases, although the waste-water treatment plant at Khirbet es Samra is a contributor to pollution in the southwestern part of the study area. Received: 20 August 1997 · Accepted: 3 February 1998  相似文献   
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The bank infiltration (BI) technique may be a viable option if the local climate, hydrological, and geological conditions are conducive. This study was specifically conducted to explore the possibility of using BI to source the polluted surface water in conjunction with groundwater. Three major factors were considered for evaluation: (1) investigation on the contribution of surface water through BI, (2) input of local groundwater, and (3) water quality characteristics of water supply. Initially, the geophysical method was employed to define the subsurface geology and hydrogeology, and isotope techniques were performed to identify the source of groundwater recharge and interaction between surface water and groundwater. The physicochemical and microbiological parameters of the local surface water bodies and groundwater were analyzed before and during water abstraction. Extracted water revealed a 5 %–98 % decrease in turbidity, as well as HCO3 +, SO4 ?, NO3 ?, Al, As, and Ca concentration reduction compared with those of Langat river water. However, water samples from test wells during pumping show high concentrations of Fe2+ and Mn2+. In addition, amounts of Escherichia coli, total coliform, and Giardia were significantly reduced (99.9 %). Pumping test results indicate that the two wells (DW1 and DW2) were able to sustain yields.  相似文献   
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Bank infiltration (BI) is one of the solutions to providing raw water for public supply in tropical countries. This study in Malaysia explores the use of BI to supplement a polluted surface-water resource with groundwater. Three major factors were investigated: (1) contribution of surface water through BI to the resulting abstraction, (2) input of local groundwater, and (3) water-quality characteristics of the resulting water supply. A geophysical method was employed to define the subsurface geology and hydrogeology, and isotope techniques were performed to identify the source of groundwater recharge and the interaction between surface water and groundwater. The physicochemical and microbiological parameters of the local surface-water bodies and groundwater were analyzed before and during water abstraction. Extracted water revealed a 5–98 % decrease in turbidity, as well as reductions in HCO3 ?, Cl?, SO4 2?, NO3 ?, Ca2+, Al3+ and As concentrations compared with those of Langat River water. In addition, amounts of E. coli, total coliform and Giardia were significantly reduced (99.9 %). However, water samples from test wells during pumping showed high concentrations of Fe2+ and Mn2+. Pumping test results indicate that the two wells used in the study were able to sustain yields.  相似文献   
8.
Community-scale simulations were performed to investigate the risk to groundwater and indoor air receptors downgradient of a contaminated site following the remediation of a long-term source. Six suites of Monte Carlo simulations were performed using a numerical model that accounted for groundwater flow, reactive solute transport, soil gas flow, and vapour intrusion in buildings. The model was applied to a three-dimensional, community-scale (250 m × 1000 m × 14 m) domain containing heterogeneous, spatially correlated distributions of the hydraulic conductivity, fraction of organic carbon, and biodegradation rate constant, which were varied between realizations. Analysis considered results from both individual realizations as well as the suite of Monte Carlo simulations expressed through several novel, integrated parameters, such as the probability of exceeding a regulatory standard in either groundwater or indoor air. Results showed that exceedance probabilities varied considerably with the consideration of biodegradation in the saturated zone, and were less sensitive to changes in the variance of hydraulic conductivity or the incorporation of heterogeneous distributions of organic carbon at this spatial scale. A sharp gradient in exceedance probability existed at the lateral edges of the plumes due to variability in lateral dispersion, which defined a narrow region of exceedance uncertainty. Differences in exceedance probability between realizations (i.e., due to heterogeneity uncertainty) were similar to differences attributed to changes in the variance of hydraulic conductivity or fraction of organic carbon. Simulated clean-up times, defined by reaching an acceptable exceedance probability, were found to be on the order of decades to centuries in these community-scale domains. Results also showed that the choice of the acceptable exceedance probability level (e.g., 1 vs. 5 %) would likely affect clean up times on the order of decades. Moreover, in the scenarios examined here, the risk of exceeding indoor air standards was greater than that of exceeding groundwater standards at all times and places. Overall, simulations of coupled transport processes combined with novel spatial and temporal quantification metrics for Monte Carlo analyses, provide practical tools for assessing risk in wider communities when considering site remediation.  相似文献   
9.
Continual expansion of population density, urbanization, agriculture, and industry in most parts of the world has increased the generation of pollution, which contributes to the deterioration of surface water quality. This causes the dependence on groundwater sources for their daily needs to accumulate day by day, which raises concerns about their quality and hydrogeochemistry. This study was carried out to increase understanding of the geological setup and assess the groundwater hydrogeochemical characteristics of the multilayered aquifers in Lower Kelantan Basin. Based on lithological data correlation of exploration wells, the study area can be divided into three main aquifers: shallow, intermediate and deep aquifers. From these three aquifers, 101 groundwater samples were collected and analyzed for various parameters. The results showed that pH values in the shallow, intermediate and deep aquifers were generally acidic to slightly alkaline. The sequences of major cations and anions were Na+ > Ca2+ > Mg2+ > K+ and HCO3? > Cl? > SO42? > CO32?, respectively. In the intermediate aquifer, the influence of ancient seawater was the primary factor that contributed to the elevated values of electrical conductivity (EC), Cl? and total dissolved solids (TDS). The main facies in the shallow aquifer were Ca–HCO3 and Na–HCO3 water types. The water types were dominated by Na–Cl and Na–HCO3 in the intermediate aquifer and by Na–HCO3 in the deep aquifer. The Gibbs diagram reveals that the majority of groundwater samples belonged to the deep aquifer and fell in the rock dominance zone. Shallow aquifer samples mostly fell in the rainfall zone, suggesting that this aquifer is affected by anthropogenic activities. In contrast, the results suggest that the deep aquifer is heavily influenced by natural processes.  相似文献   
10.
Laminated, dolomitised marine limestones within a transgressive fluvio-lagoonal-carbonate platform sequence at Gara Sbaa in the Kem Kem region of south eastern Morocco yield well preserved marine fishes and crustaceans. A rarer terrestrial component includes delicate fern fronds, insects and a lizard. Sedimentological structures and stratigraphic context indicate initial shallow waters with in a carbonate lagoon with benthic microbial mats followed by deepening. High precision dating has yet to be accomplished, but a Late Cenomanian or Early Turonian age is indicated on the basis of faunal and sequence-stratigraphic considerations. The fish assemblage has affinities with mid-Cretaceous ichthyofaunas in South America and Lebanon, including taxa in common at generic level.  相似文献   
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