Use of temperature profiles and stable isotopes to trace flow lines: Nagaoka area, Japan     

Salem Zel-S  Taniguchi M  Sakura Y 《Ground water》2004,42(1):83-91

In this study, we use borehole temperature data and stable isotopes to delineate the flow system and estimate the effect of urbanization in the Nagaoka area of Japan. Temperature profiles were measured four times in observation wells during the period 2000-2001 and compared with those measured in the same wells during the period 1977-1983 (Taniguchi 1986). Water was sampled in both observation and pumping wells during the same period. The temporal and spatial variability in temperature indicate clearly the effect of urban warming and heavy pumping on the ground water system. Urban warming caused higher temperatures recently as compared to the older values, and pumping caused induced recharge from the river to the ground water. The stable isotope data show the ground water flow system is divided into shallow, intermediate, and deep systems, and that land use and infiltration rate are affecting the shallow flow system.  相似文献   

A dripper-TDR method for in situ determination of hydraulic conductivity and chemical transport properties of surface soils     

Salem A. Al-Jabri  Jaehoon Lee  Anju Gaur  Robert Horton  Dan B. Jaynes 《Advances in water resources》2006

Field determined hydraulic and chemical transport properties can be useful for the protection of groundwater resources from land-applied chemicals. Most field methods to determine flow and transport parameters are either time or energy consuming and/or they provide a single measurement for a given time period. In this study, we present a dripper-TDR field method that allows measurement of hydraulic conductivity and chemical transport parameters at multiple field locations within a short time period. Specifically, the dripper-TDR determines saturated hydraulic conductivity (K_s), macroscopic capillary length (λ_c), immobile water fraction (θ_im/θ), mass exchange coefficient (α) and dispersion coefficient (D_m). Multiple dripper lines were positioned over five crop rows in a field. Background and step solutions were applied through drippers to determine surface hydraulic conductivity parameters at 44 locations and surface transport properties at 38 locations. The hydraulic conductivity parameters (K_s, λ_c) were determined by application of three discharge rates from the drippers and measurements of the resultant steady-state flux densities at the soil surface beneath each dripper. Time domain reflectometry (TDR) was used to measure the bulk electrical conductivity of the soil during steady infiltration of a salt solution. Breakthrough curves (BTCs) for all sites were determined from the TDR measurements. The K_s and λ_c values were found to be lognormally distributed with average values of 31.4 cm h⁻¹ and 6.0 cm, respectively. BTC analysis produced chemical properties, θ_im/θ, α, and D_m with average values of 0.23, 0.0036 h⁻¹, and 1220 cm² h⁻¹, respectively. The estimated values of the flow and transport parameters were found to be within the ranges of values reported by previous studies conducted at nearby field locations. The dripper TDR method is a rapid and useful technique for in situ measurements of hydraulic conductivity and solute transport properties. The measurements reported in this study give clear evidence to the occurrence of non-equilibrium water and chemical movement in surface soil. The method allows for quantification of non-equilibrium model parameters and preferential flow. Quantifying the parameters is a necessary step toward determining the influences of surface properties on infiltration, runoff, and vadose zone transport.  相似文献   

Analytic signal approach and its applicability in environmental magnetic investigations   总被引：1，自引：0，他引：1  

Ahmed Salem  Dhananjay Ravat  T. Jeffrey Gamey  Keisuke Ushijima 《Journal of Applied Geophysics》2002,49(4):787

We investigate the analytic signal method and its applicability in obtaining source locations of compact environmental magnetic objects. Previous investigations have shown that, for two-dimensional magnetic sources, the shape and location of the maxima of the amplitude of the analytic signal (AAS) are independent of the magnetization direction. In this study, we show that the shape of the AAS over magnetic dipole or sphere source is dependent on the direction of magnetization and, consequently, the maxima of the AAS are not always located directly over the dipolar sources. Maximum shift in the horizontal location is obtained for magnetic inclination of 30°. The shifts of the maxima are a function of the source-to-observation distance and they can be up to 30% of the distance. We also present a method of estimating the depths of compact magnetic objects based on the ratio of the AAS of the magnetic anomaly to the AAS of the vertical gradient of the magnetic anomaly. The estimated depths are independent of the magnetization direction. With the help of magnetic anomalies over environmental targets of buried steel drums, we show that the depths can be reliably estimated in most cases. Therefore, the analytic signal approach can be useful in estimating source locations of compact magnetic objects. However, horizontal locations of the targets derived from the maximum values of the AAS must be verified using other techniques.  相似文献   

Impacts of wastewater irrigation in arid and semi arid regions: case of Sidi Abid region,Tunisia     

Salem Bouri  Habib Abida  Hafedh Khanfir 《Environmental Geology》2008,53(7):1421-1432

Impacts of irrigation with treated wastewater effluents on soils and groundwater aquifer in the vicinity of Sidi Abid Region (Tunisia) are evaluated. The groundwater aquifer was monitored by several piezometers, where monthly water levels were registered and groundwater salinity was evaluated. This resulted in characterizing the spatial and temporal evolution of the hydrochemical and hydrodynamic properties of the aquifer, showing thereby the impact of artificial recharge. Piezometric maps for pre-recharge and post-recharge situations were developed and a comparison study of both piezometric situations was considered. The piezometric evolution map showed a generalized rise of the piezometric level in the vicinity of the irrigation zone. The extent of recharge was shown to increase with time as the groundwater level increase, which was localized in the vicinity of the irrigation area, reached more extended zones. Several groundwater samples were withdrawn from wells and piezometers and analyzed. Examining the corresponding physical and chemical parameters showed an increase in the concentrations of nutrients (28 mg/l for NO₃ and 3.97 mg/l for NH₄) in the groundwater aquifer below the irrigation zone, which confirms again the infiltration of treated wastewater effluents. The evolution of soil salinity was examined through chemical analysis of soil samples. Electric conductivities of soils were generally shown to be less than 4 mS/cm while the irrigation water has an electric conductivity that may reach 6.63 mS/cm. This might be explained by the phenomenon of dilution and the capacity of soils to evacuate salts downward.  相似文献   

Shallow subsurface temperature in the environs of El-Nubaria canal,northwestern Nile Delta of Egypt: implications for monitoring groundwater flow system     

Zenhom El-Said Salem  Osman M. Osman 《Environmental Earth Sciences》2016,75(18):1241

  相似文献   

Geochemical and Mineralogical Studies of the Mylonite Xenoliths and Monzogranite Rocks at Wadi Abu Rusheid,South Eastern Desert,Egypt: Insights on the Genesis of Mineralization     

Mohamed Salem KAMAR 《《地质学报》英文版》2021,95(5):1551-1567

Abu Rusheid area lie in the south of the Eastern Desert of Egypt and comprises (1) ophiolitic mélange, consisting of ultramafic rocks and layered metagabbros in metasedimentary matrix (2) cataclastic group, consisting of protomylonites, mylonites, ultramylonites and silicified ultramylonites (3) monzogranites (4) pegmatite pockets, quartz veins and post-granite dykes. Focus on the monzogranites and the xenoliths of mylonite rocks from the geochemical and mineralogical points of view introduces a new view about the genesis of the related mineralization. Geochemically, the monzogranites have a metaluminous character and were crystallized under moderate water-vapor pressure around 3 kb and temperatures of 750–800°C. The monzogranites are altered along strike-slip faults exhibiting propylitic, with slightly sodic metasomatism and record high radioactive measurements. The average uranium and thorium (U and Th) contents in fresh monzogranites, mylonite xenolith and altered monzogranites are (7.3, 21.20), (40.36, 94.82), (60.34 and 347.88 ppm), respectively. These high radioactivities are attributed to the presence of kasolite, uranothorite, cerite, fluorite, zircon, apatite and columbite. The mylonite xenolith is higher in radioactivity than the surrounding fresh monzogranites, reflecting U and Th enrichment before emplacement of the monzogranites, then the latter were subjected to right lateral strike-slip faulting with producing hydrothermal solution rich in Th and U.  相似文献   

Gravity contributions to the understanding of salt tectonics from the Jebel Cheid area (dome zone, Northern Tunisia)     

Imen Hamdi-Nasr  Mohamed Hédi Inoubli  Abdelhamid Ben Salem  Saïd Tlig  Abdelbaki Mansouri 《Geophysical Prospecting》2009,57(4):719-728

Detailed gravity measurements integrated with geological data were computed to constrain the mechanisms that were active during the emplacement of the Triassic evaporite-bearing folds of Jebel Cheid from the salt-dome zone in the Atlassic region. The gravity analysis consists in mapping the contrasting gravity responses: complete Bouguer anomaly, residual anomaly and derivative maps; the main results display a positive amplitude gravity anomaly as the response of Triassic evaporite bodies and important NE–SW-trending features at the boundaries between the Triassic outcrops and their enveloping strata. In contrast with gravity calculations of a salt dome structure usually resulting in negative gravity anomaly models, the Jebel Cheid clearly expresses a positive gravity anomaly; furthermore, this result is supported by synthetic gravity interpretation.  相似文献   

A New Inner Heliosphere Proton Parameter Dataset from the <Emphasis Type="Italic">Helios</Emphasis> Mission     

David Stansby  Chadi Salem  Lorenzo Matteini  Timothy Horbury 《Solar physics》2018,293(11):155

In the near future, Parker Solar Probe and Solar Orbiter will provide the first comprehensive in-situ measurements of the solar wind in the inner heliosphere since the Helios mission in the 1970s. We describe a reprocessing of the original Helios ion distribution functions to provide reliable and reproducible data to characterise the proton core population of the solar wind in the inner heliosphere. A systematic fitting of bi-Maxwellian distribution functions was performed to the raw Helios ion distribution function data to extract the proton core number density, velocity, and temperatures parallel and perpendicular to the magnetic field. We present radial trends of these derived proton parameters, forming a benchmark to which new measurements in the inner heliosphere will be compared. The new dataset has been made openly available for other researchers to use, along with the source code used to generate it.  相似文献   

Impact of Lithofacies and Structures on the Hydrogeochemistry of the Lower Miocene Aquifer at Moghra Oasis,North Western Desert,Egypt     

Abdelazeem  Maha  Salem  Zenhom E.  Fathy  Mohamed S.  Saleh  Maha 《Natural Resources Research》2020,29(6):3789-3817

Natural Resources Research - The Moghra Oasis is one of the major Egyptian desert-reclamation projects. Understanding the hydrochemistry of the Moghra aquifer is an onus to properly plan and manage...  相似文献   

Paleo-Tsunami deposits on the Red Sea beach, Egypt     

El-Sayed Mohamed Salem 《Arabian Journal of Geosciences》2009,2(2):185-197

The characteristics of the recent tsunami deposits threw light on some sources of deposition on the beach of the Red Sea. The studied area is delineated by latitudes 25°6′ N and 25°9′ N and longitudes 34°50′ E and 34°53′ E; it covers an elongate area of about 12 km² along the Red Sea coast, North Marsa Alam City (4 km). The area is bounded by Wadi Asalay to the north and Wadi Sifayn from the south. For evaluation of the area, a lot of information allows us to interpret the conditions prevailing during deposition of the sediments especially at the coast. To achieve the target, five wells were drilled to study core samples, well logging measurements, and 69 vertical electrical sounding stations were carried out. The studied area and adjacent areas were geologically surveyed to note geological features related to Paleo-earthquakes. From geological and geophysical studies, the dominant rock types at the western portions of the studied area are sandstone, sandy clay, clay, clayey sandstone, and gravels; at the middle portion of the studied area, the rocks are hard, but the eastern side of the area, especially at the beach of the Red Sea, several cycles of depositions of coral reefs occurred with intercalations of clastic deposits such as clay, sand, sandstone, conglomerate, gravels, pebbles, and a lot of fossils and shell fragments. The rocks are characterized by heterogeneous properties and ill-sorted. The area includes large numbers of faults due to highly tectonism of the area. The results indicated that the area has lateral variation of sediments. The carbonate rocks at the beach contain clastic fragments, and carbonate blocks are included within clastic rocks. With increasing the distance from the beach to the west, the sediments are less heterogeneous. The beach of the Red Sea was subjected to Paleo-tsunami waves due to highly Paleo-seismic activity inside the Red Sea and left their signature in geological column especially at the beach. The observation of some geological features such as Paleo-liquefaction and landslides indicate that the area subjected to strong earthquakes related to rifting of the Red Sea.  相似文献