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71.
Groundwater resources assessment using integrated geophysical techniques in the southwestern region of Peninsular Malaysia 总被引:2,自引:0,他引:2
Mohamed S. E. Juanah Shaharin Ibrahim Wan Nor Azmin Sulaiman Puziah Abdul Latif 《Arabian Journal of Geosciences》2013,6(11):4129-4144
Combined geophysical techniques such as multi-electrode resistivity, induced polarization, and borehole geophysical techniques were carried out on volcano-sedimentary rocks in the north of Gemas as part of the groundwater resource’s investigations. The result identifies four resistivity units: the tuffaceous mudstone, tuffaceous sandstone, the tuff bed, and the shale layer. Two types of aquifer systems in terms of storage were identified within the area: one within a fracture system (tuff), which is the leaky area through which vertical flow of groundwater occurs, and an intergranular property of the sandy material of the aquifer which includes sandstone and tuffaceous sandstone. The result also reveals that the aquifer occupies a surface area of about 3,250,555 m2 with a mean depth of 43.71 m and a net volume of 9.798?×?107?m3. From the approximate volume of the porous zone (28 %) and the total aquifer volume, a usable capacity of (274.339?±?30.177)?×?107?m3 of water in the study area can be deduced. This study provides useful information that can be used to develop a much broader understanding of the nature of groundwater potential in the area and their relationship with the local geology. 相似文献
72.
The presence of natural voids and cavities in subsurface karstic limestones causes severe problem for civil engineering and environmental management.The presence of such features hinders the extension of urbanizations particularly in the new metropolitan.The eastern part of Saudi Arabia contains various types of karstic limestone,sinkholes,solution cavities and voids.In this context,geophysical methods particularly electrical resistivity technique is used as a cost-effective solution for investigating subsurface caves,voids,and shallow weathered zones.2-D electrical resistivity data sets have been acquired along seven profiles in the new urbanization at Al Hassa area.Data processing has been carried out taking into consideration the response of synthetic models,which simulates physical models of the most common karstic features in the area.The results are very useful to determine the extension of shallow weathered zones and to locate different cavities underneath them.The hard limestone bedrock can also be detected and traced along the surveyed profiles. 相似文献
73.
Norazlina Ab Halim Faradiella Mohd. Kusin Khairul Nizam Mohamed 《International Journal of Environmental Science and Technology》2018,15(4):733-742
This study was carried out to determine the concentration of heavy metals (Cd, Ni, Pb, Cr, Ni and Zn) in ordinary Portland cement (OPC) produced from the co-processing with hazardous waste in comparison with OPC produced using natural raw materials. The results showed that the concentration of heavy metals in cement produced from natural raw material was in the order of Zn > Pb > Cr > Ni > Cu > Cd. Zn and Cd were the highest and the lowest concentrations, respectively, in cements produced from the co-processing activity. The difference between heavy metals concentrations in OPC produced with and without co-processing was found to be statistically significant. The concentration of heavy metals in the cement produced is generally factory dependent. The human risk assessment associated with the heavy metals for non-carcinogenic and carcinogenic risks has been evaluated. The calculated hazard index (HI) and total lifetime cancer risks (LCR) were lower than the acceptable threshold reference values, HI < 1 and LCR < 1 × 10?4, respectively. Thus, it is anticipated that there is no potential of non-carcinogenic and carcinogenic risks for both adult and children. However, the findings indicated that there is a need for regulatory monitoring. The exposure pathway for both non-carcinogenic and carcinogenic risks are both in the order of ingestion > dermal > inhalation. 相似文献
74.
Hatem A. Ewea Nassir S. Al-Amri Mohamed A. Dawoud Amro M. Elfeki 《Natural Hazards》2018,94(2):801-817
Forecasting and monitoring extreme floods in arid regions like Saudi Arabia (SA) are a big challenge for engineers and hydrologists. It is difficult to derive reliable flood estimates at any site without adequate flood measurements. Therefore, envelope curves were developed for reliable estimates of flood peaks. Relaying on recorded flood events in SA, Francou–Rodier approach is used to develop the Regional Maximum Flood (RMF) for some wadis and for SA as a whole. A total of 3121 flood events in 32 arid basins of sizes varying from 99 to more than 4500 km2 are collected and analyzed. Results show that established regional coefficients (K) range between 2.76 and 5.5. The RMF formula for the Saudi regions is Q?=?251 A0.45. The flood-frequency analysis showed that the Log-Pearson Type III is best. The extreme observed floods for the envelope curve for K?=?5.5 accommodate floods of recurrence interval ranging between 1000 and 100,000 years. The study results provide more realistic runoff peaks for a design of flood protection works for SA watersheds and for the similar environment. Consequently, it is recommended to use the developed envelope curves and models for efficient, safe and precise hydraulic structures design in SA. 相似文献
75.
Eutrophication-induced changes to benthic faunal activities are problems of significant ecological impact, affecting global
nutrient budgets as well as local trophic connections. We address the question of how nitrogen loads to estuarine embayments
alter the bioturbation activities of benthic fauna. Specifically, we related local benthic activities to calculated local
nitrogen concentrations for 22 northeastern US estuaries. These local nitrogen concentrations were derived from the calculated
nitrogen loading for the embayment together with the spatial distribution of the local flushing time. Our results showed a
maximum bioturbation rate at intermediate nitrogen concentrations or a “hump-shaped” pattern of response. This behavior was
evident in all embayments that had a range of concentrations including low, intermediate, and high values. Embayments where
sampling did not include this full range did not show this behavior. This work provides methods and guidance to help managers
make decisions concerning the effects of nitrogen loading on the activities and well-being of benthic fauna in coastal embayments.
The novelty of this approach lies in identifying the response of bioturbation to nitrogen loading in many systems, without
costly and time-consuming speciation of benthic fauna, and also in rapidly identifying embayments and aquatic areas with vulnerable
fauna. These results are ecologically significant in supporting the hypothesis that benthic organism abundance and activity
will peak at mid-levels of nitrogen due to the interplay of food availability and oxygen levels, noting that the critical
levels of these factors differ among water bodies. 相似文献
76.
The Sinai Peninsula constitutes an important district of the Egyptian lands where it forms a triangular portion in northeastern Egypt. The southern Sinai metamorphic complexes are the northern uppermost part of the Arabian–Nubian Shield revealing the upper and middle crust from the East African Orogeny, in which they tectonically evolved. The Feiran–Solaf metamorphic complex (FSMC) of Sinai, Egypt is one of the highest grades metamorphic complexes of a series of basement domes that trends NW and crops out throughout the Arabian–Nubian Shield. The main aim of the present study is to apply the geospatial technology and to represent the capability of the geospatial technology to estimate the combined influence of lithology and structure studies, and to construct the lithological and structural maps of FSMC. Furthermore, detailed structural analysis is carried out to reveal the different ductile and brittle deformational events and proposed the tectonic evolutionary model for the study area. Mainly geospatial technology and structural analysis software have been used to go well with the aim of the present study. Developing specific image processing of satellite images and structural analysis were succeeded to discriminate the various lithological rock units, and the geological structural features of the FSMC, using geographic information system tools to construct the different thematic maps, were extracted. The present detailed investigations of the enhanced satellite images, structural analysis, and field verification reveal that the FSMC reached its present tectonic setting through more than four deformational phases concluding that the Pan-African Najd Fault System continued in Sinai and was reactivated during Red Sea tectonics as indicated by the dextral shear zone (Rihba) bordering the northern side of the FSMC. 相似文献
77.
Usama Massoud Fernando Santos Mohamed A. Khalil Ayman Taha Abbas M. Abbas 《Hydrogeology Journal》2010,18(3):699-710
The integration of geophysical data with direct hydrogeological measurements can provide a minimally invasive approach to characterize the subsurface at a variety of resolutions and over many spatial scales. The field of hydrogeophysics has attracted much attention during the last two decades. In this domain, the geophysical data inverted to geophysical models are interpreted in terms of the hydrogeology to serve as a basis for the definition of hydraulic models in the areas of interest. The hydraulic conductivity (K) value measured in a reference borehole has been combined with the electrical conductivity obtained from nearby geo-electromagnetic sounding data in the Cenomanian (Upper Cretaceous) aquifer, central Sinai, Egypt. The resulting relation was interpreted with Dar Zarrouk parameters to infer the transmissivity variations at other vertical electrical sounding locations, where K values are unknown. Coincident transient electromagnetic data have been adopted to increase accuracy while interpreting the aquifer geoelectrical properties. The results indicate that the transmissivity values in the aquifer of interest vary from 2,446 to 9,694 m2/day, and K varies from 12.9 to 57.0 m/day throughout the studied area. 相似文献
78.
79.
80.
Ahmed Barakat Christian Marignac Marie-Christine Boiron Mohamed Bouabdelli 《Comptes Rendus Geoscience》2002,334(1):35-41
The gold showings at Bleida are hosted in Late Pan-African N50–80 °E quartz–hematite–chlorite 1 tension lenses that are related to the activity of major sinistral sub-east–west thrusts. Ores result from three superimposed stages of fluid migration. Gold occurs in microcracks offsetting the earlier minerals. Fluids evolved from COHN compositions with a saline component to boiling aqueous fluids. Pressure and temperature decreased from 50 MPa and 300 °C to less than 4 MPa and 150 °C. Thus, the gold showings at Bleida were formed in a typical geothermal (epithermal) setting, likely controlled by the Late Pan-African magmatism. To cite this article: A. Barakat et al., C. R. Geoscience 334 (2002) 35–41 相似文献