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This study aims to estimate artificial recharge of groundwater by using remote sensing technology, geographical information systems, and groundwater surveys. This study is part of the King Fahd project for rainfall and runoff water harvesting, within the premises of Alilb Dam in Diriyah to the west of Riyadh. Digital elevation models were obtained with the help of aerial photography from the year 2007. These models were used to delineate watershed. Average rainfall was calculated using isoheytal method, and the area of each of the storage lakes was measured using SPOT 5 satellite images from 2007. Fluctuations in groundwater levels, evaporation, and infiltration rates were used to determine the water balance for the purpose of estimating of artificial recharge. Artificial recharge rates were found to surpass natural recharge from rainfall. Recharge wells caused a reduction in the effect of evaporation on storage lakes and helped in supplying water to the groundwater reservoir. Moreover, 80% and 86% of the rainwater was found to be available for artificial recharge in Alilb at 2005 and 2007, respectively. The study recommends the establishment of strategic projects for water storage using artificial recharge wells, an increase in the number of monitoring wells around the dams, and the monitoring of hydrochemical changes in groundwater both before and after the artificial recharge. It also recommends the erection of a weather station in the northwest of Wadi Hanifa. 相似文献
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Fawzy F. Basta Ayman E. Maurice Bottros R. Bakhit Kamal A. Ali William I. Manton 《Journal of African Earth Sciences》2011,59(2-3):227-242
The ophiolitic metabasalts (pillowed and sheeted dikes) of Wadi Ghadir area, Eastern Desert, Egypt, were analyzed for their major, trace and rare earth elements, Nd and Sr isotopes and the chemistry of their plagioclase, amphibole and chlorite was also reported. Geochemically these rocks range from tholeiitic basalt to basaltic andesite. The generally low MgO, Cr and Ni and high Zr contents are consistent with derivation of these rocks from an evolved magma. The high TiO2 contents (mostly between 1.76% and 2.23%) classify Wadi Ghadir ophiolitic metabasalts as MORB ophiolite. The chondrite-normalized REE patterns of most samples display small LREE-enrichment with (La/Yb)n ranging from 1.44 to 2.56. The MORB-normalized spider diagram shows variable LILE abundances, which are either similar to or enriched relative to MORB, and most samples display small Nb depletion. The abundances of some LILE (Ba, Rb and K) as well as Na and Si were modified by post-magmatic seafloor hydrothermal alteration. Enrichment of the least mobile LILE (Th & U) indicates that Wadi Ghadir ophiolitic metabasalts are akin to C (contaminated)-MORB. These geochemical characteristics are similar to BABB modified by contamination.Wadi Ghadir metabasalts have low initial Sr ratios (0.7010–0.7034) which are similar to those of MORB, while their εNd(t) values (+7.7–+4.5) are either more or less positive than the value of depleted mantle (DM). The more positive εNd(t) values indicate DM source for these basalts, while the less positive εNd(t) values reflect the involvement of slightly older component in Wadi Ghadir ophiolite. We suggest that the parent magma of metabasalts was contaminated by slightly older material, most probably oceanic-arc crustal rocks, which caused enrichment in LREE, and by analogy LILE, but did not significantly affect Nd isotopic systematics or modify Sr isotopes.Such contaminated MORB character also revealed by other ophiolitic metavolcanics in the Central Eastern Desert, contrasting the N-MORB character of the Gerf ophiolite in the South Eastern Desert. Moreover, the present work suggests the increase of the degree of contamination of the ophiolitic metabasalts from south to north in the Central Eastern Desert. 相似文献
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Ayman N. Qadrouh José M. Carcione Ahmed M. A. Salim Zuhar Zahir Tuan Harith 《Arabian Journal of Geosciences》2016,9(5):413
Thin and relatively thin anelastic layers (compared to the signal wavelength) generally represent hydrocarbon reservoirs, where the rock is a sandstone or a source rock saturated with brine, oil and gas. The study of the seismic response of these layers is important to detect the hydrocarbons on the basis of the reflection and transmission coefficients and the wave velocity and attenuation properties. Different seismic experiments (source-receiver configurations) can provide useful information to characterise its properties. In this work, we consider varying thicknesses and Q values of the layer and analyse the reflection and transmission coefficients. Moreover, we obtain spectrograms of surface seismic profiles and vertical and horizontal well profiles (VSP and HSP, respectively) to analyse their frequency content with offset due to variations of the attenuation properties of the layer. In addition, we compare the effects due to NMO stretching and intrinsic attenuation related to the low-frequency shadows (LFS) observed in real data after stacking, since LFS can have several causes. Ambiguity is present in this case, indicating that non-stretch NMO is required, otherwise an offset mute of the data may remove useful information regarding the intrinsic (physical) loss. 相似文献
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Ensemble smoothing of land subsidence measurements for reservoir geomechanical characterization 
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下载免费PDF全文 Domenico Baù Massimiliano Ferronato Giuseppe Gambolati Pietro Teatini Ayman Alzraiee 《国际地质力学数值与分析法杂志》2015,39(2):207-228
Geomechanical models are often used to predict the impact on land surface of fluid withdrawal from deep reservoirs, as well as investigating measures for mitigation. The ability to accurately simulate surface displacements, however, is often impaired by limited information on the geomechanical parameters characterizing the geological formations of interest. In this study, we employ an ensemble smoother, a data assimilation algorithm, to provide improved estimates of reservoir parameters through assimilation of measurements of both horizontal and vertical surface displacement into geomechanical model results. The method leverages the demonstrated potential of remote sensing techniques developed in the last decade to provide accurate displacement data for large areas of the land surface. For evaluation purposes, the methodology is applied to the case of a disk‐shaped reservoir embedded in a homogeneous, isotropic, and linearly elastic half space, subject to a uniform change in fluid pressure. Multiple sources of uncertainty are investigated, including the radius, R, the thickness, h, and the depth, c, of the reservoir; the pore pressure change, Δp; porous medium's vertical uniaxial compressibility, cM, and Poisson's ratio, ν, and the ratio, s, between the compressibilities of the medium during loading and unloading cycles. Results from all simulations show that the ensemble smoother has the capability to effectively reduce the uncertainty associated with those parameters to which the variability and the spatial distribution of land surface displacements are most sensitive, namely, R, c, cM, and s. These analyses demonstrate that the estimation of these parameters values depends on the number of measurements assimilated and the error assigned to the measurement values. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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A simplified fatigue-life model is proposed for assessing the seismic inelastic rotational capacity of steel connections. First relations are developed for rigid steel connections under lateral loading. Next this is extended to account for the effects of the welded steel moment frame (WSMF) connections of the so-called pre-Northridge type. The seismic fatigue theory is validated against experimental results. The experiments were conducted under increasing ductility amplitudcs until the onset of fracture. Miner‘ rule was used to convert the test results to given an equivalent constant amplitude cyclic fatigue life. Satisfactory agreement is obtained when comparing the experimental observations with the theoretical predictions. 相似文献
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Line-based modified iterated Hough transform for automatic registration of multi-source imagery 总被引：1，自引：0，他引：1
Image registration aims at combining imagery from multiple sensors to achieve higher accuracy and derive more information than that obtained from a single sensor. The enormous increase in the volume of remotely sensed data that is being acquired by an ever-growing number of earth observation satellites mandates the development of accurate, robust, and automated registration procedures. An effective automatic image registration has to deal with four issues: registration primitives, transformation function, similarity measure, and matching strategy. This paper introduces a new approach for automatic image registration using linear features as the registration primitives. Linear features have been chosen because they can be reliably extracted from imagery with significantly different geometric and radiometric properties. The modified iterated Hough transform (MIHT), which manipulates the registration primitives and similarity measure, is used as the matching strategy for automatically deriving an estimate of the parameters involved in the transformation function as well as the correspondence between conjugate primitives. The MIHT procedure follows an optimal sequence for parameter estimation that takes into account the contribution of linear features with different orientations at various locations within the imagery towards the estimation of the transformation parameters in question. Experimental results using real data proved the feasibility and robustness of the suggested approach. 相似文献
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The seismic performance of timber bridge substructures is not well established, particularly when compared to concrete highway bridges. This paper presents a dual experimental‐computational modelling program to investigate the seismic behaviour of typical braced timber bridge pile bents. For this purpose, a prototype timber bridge was used to develop a near‐full‐size physical model that was used for shaking table experiments and quasi‐static reversed cyclic loading tests on the laboratory strong‐floor. A non‐linear force‐displacement computational modelling study was also undertaken as a companion effort to the experimental investigation. On the basis of the experimental study, seismic vulnerability analysis was conducted for this kind of timber bridge principally with shaking in the transverse direction. In this analysis, a simplified fundamental mechanics‐based approach was employed from which fragility curves were derived. The study showed that braced timber pile bents have considerable strength and deformability capability. Nevertheless, they are not immune from earthquake damage. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
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Increased use of digital imagery has facilitated the opportunity to use features, in addition to points, in photogrammetric applications. Straight lines are often present in object space, and prior research has focused on incorporating straight–line constraints into bundle adjustment for frame imagery. In the research reported in this paper, object–space straight lines are used in a bundle adjustment with self–calibration. The perspective projection of straight lines in the object space produces straight lines in the image space in the absence of distortions. Any deviations from straightness in the image space are attributed to various distortion sources, such as radial and decentric lens distortions. Before incorporating straight lines into a bundle adjustment with self–calibration, the representation and perspective transformation of straight lines between image space and object space should be addressed. In this investigation, images of straight lines are represented as a sequence of points along the image line. Also, two points along the object–space straight line are used to represent that line. The perspective relationship between image– and object–space lines is incorporated in a mathematical constraint. The underlying principle in this constraint is that the vector from the perspective centre to an image point on a straight–line feature lies on the plane defined by the perspective centre and the two object points defining the straight line. This constraint has been embedded in a software application for bundle adjustment with self–calibration that can incorporate point as well as straight–line features. Experiments with simulated and real data have proved the feasibility and the efficiency of the algorithm proposed. 相似文献
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The present work deals with meandering and bank erosion of the River Nile of Egypt and its environmental impact between Sohag and El-Minia, Egypt. The study depends on using Landsat imagery acquired on 1987–2000 and field observations. Field observations, remote sensing, and GIS analysis and sinuosity index were used in this study to investigate river meandering and the associated processes of erosion of river bank and islands, deposition of sediments and formation of new islands. The analysis of Landsat imagery revealed the migration of river course with time and space. Some islands disappear completely in the study area whereas new islands appear in other places. The lateral erosion on the river banks led to a decrease in agricultural lands bordering the river banks and decrease in the areas of the river islands which in turn reduces the agricultural production. Depositional processes create new floodplains on the convex sides of the river course and new islands and sand bars. Protection methods are recommended to protect the river bank from further movement and erosion. The present conditions of river meandering and the associated processes of erosion and deposition accelerated with human activities have its impact on the environment. The most prominent hazard problem is reduction of agricultural lands and loss of property as well as navigation problems. River control is recommended to weaken the secondary currents created by the river bends. It is recommended to regularly monitor the river banks and islands and measure the rates of erosion and deposition. Sand bars and subsurface islands should be monitored and identified with flash lights to mitigate navigation problems. 相似文献