Aquifer recharge from flash floods in the arid environment: A mass balance approach at the catchment scale

Estimation of the infiltration/natural recharge to groundwater from rainfall is an important issue in hydrology, particularly in arid regions. This paper proposes the application of The Natural Resources Conservation Service (NRCS) mass balance model to develop infiltration (F)–rainfall (P) relationship from flash flood events. Moreover, the NRCS method is compared with the rational and the Ф-index methods to investigate the discrepancies between these methods. The methods have been applied to five gauged basins and their 19 sub-basins (representative basins with detailed measurements) in the southwestern part of Saudi Arabia with 161 storms recorded in 4 years. The F–P relationships developed in this study based on NRCS method are: F = 39% P with R² = 0.932 for the initial abstraction factor, λ = 0.2. However, F = 77% P with R² = 0.986 for λ = 0.01. The model at λ = 0.01 is the best to fit the data, therefore, it is recommended to use the formula at λ = 0.01. The results show that the NRCS model is appropriate for the estimation of the F–P relationships in arid regions when compared with the rational and the Ф index methods. The latter overestimates the infiltration because they do not take λ into account. There is no significant difference between F–P relationships at different time scales. This helps the prediction of infiltration rates for aquifer recharge at ungauged basins from monthly and annual rainfall data with a single formula.     

Advanced differential interferometry synthetic aperture radar techniques for deformation monitoring: a review on sensors and recent research development

This paper reviews the advanced differential interferometry synthetic aperture radar (A-DInSAR) techniques, with two major components in focus. First is the basic concepts, synthetic aperture radar (SAR) data sources and the different algorithms documented in the literature, primarily focusing on persistent scatterers. In the second part, the techniques are compared in order to establish more linkage in terms of the variability of their applications, strength and validation of the interpreted results. Also, current issues in sensor and algorithm development are discussed. The study identified six existing A-DInSAR algorithms used for monitoring various deformation types. Generally, reports of their performance indicate that all the techniques are capable of measuring deformation phenomena at varying spatial resolution with high level of accuracy. However, their usability in suburban and vegetated areas yields poor results, compared to urbanized areas, due to inadequate permanent features that could provide sufficient coherent point targets. Meanwhile, there is continuous development in sensors and algorithms to expand the applicability domain of the technology for a wide range of deformable surfaces and displacement patterns with higher precision. On the sensor side, most of the latest SAR sensors employ longer wavelength (X and P bands) to increase the penetrating power of the signal and two other sensors (ALOS-2 PALSA-2 and SENTINEL-1) are scheduled to be launched in 2013. Researchers are investigating the possibility of using single-pass sensors with different look angles for SAR data collection. With these, it is expected that more data will be available for various applications. Algorithms such as corner reflector interferometry SAR, along track interferometry, liqui-InSAR, and squeeSAR are emerging to increase reliable estimation of deformation from different surfaces.     

Hydrochemical model and probable pollution in the water of Euphrates River (Qaem–Falluja)

The study of hydrochemical models and probable pollution in Euphrates River from Qaem–Al-Falluja was performed through regime observation in ten water points. The hydrochemical properties of Euphrates River waters are determined by using the analysis results of 21 physico-chemical variables during the water year (2008). The interpretation of the hydrochemical phenomena is achieved in accordance with the statistical results of Polynomial Regression Statistic, calculating the coefficient of variation among the physico-chemical components of the water terminating by 14 models. The results of monitoring during the water year 2008 indicate a pollution case by SO₄ and Cd in Ramadi and downstream stations; TDS, Mg, Na, Cl, Mn, and CO₂ in Ramadi station; TDS, Ca, Na, Cl, and Fe in Baghdadi station; and Ca and H _T in Qaem station and Mg in Obaydi station. The research suggests the best locations for hydrochemical monitoring as continuous hydrologic stations used for the long-term monitoring. These stations are in Qaem city as inlet location and Al-Baghdadi and Ramadi cities terminating in Falluja city as outlet location. Furthermore, daily record system is recommended for the other stations in each city to complete the regime observation of Euphrates water type. From the configuration approach of hydrochemical models with the pollution phenomena, there are potential point sources of pollution such as municipal effluent pipes and reused water from mining process for building materials in the first sector of river, which extends between Qaem and Haditha dam. Also groundwater seepages and springs discharge of mineralized water mixed with sewage water from cities act as potential point sources of pollution on the river water in the second sector extended between Haditha and Ramadi scheme. The third sector of the river is affected by all reasons in the first and second sectors as well as the effectiveness of agricultural activities throughout drainage canals and irrigation projects extended between Ramadi and Falluja cities.     

Seasonal changes and morphodynamic behavior of a high-energy mesotidal beach: case study of Charf el Akab beach on the North Atlantic coast of Morocco

The morphodynamic behavior of a mesotidal sandy beach was monitored during both calm and energetic conditions. Two years of seasonal surveys were carried out on Charf el Akab, a gently sloped beach in the North Atlantic coast of Morocco. The method of survey consisted of a 3D study of the beach morphological changes and provided 2 cm vertical accuracy. During the surveyed period, Charf el Akab beach underwent very energetic wave conditions, and the breaking wave height was of H _b ≥ 1.5 m. The beach is characterized by a nonpermanent swash bar and composed of well-sorted medium sand. The application of environmental parameters revealed a dissipative state with very low beach gradient which did not vary significantly over the studied period. Morphological changes consist of beach erosion and bar decay under high-energy waves, whereas the intertidal bar re-established and the beach recorded an accentuated accretion due to relatively fair weather conditions. The beach volume reveals a seasonal behavior; the sand accumulated during summer is dramatically removed during winter season. The range in beach sand volume from the most accreted to the most eroded conditions observed is about −5,493 m³. The average sand volume flux between surveys reaches −1 and 0.4 m²/day during peak erosion and accretion periods. The relationships between the wave forcing and the sand volume adjustments were examined. The sand volume change was found to be highly correlated (0.91) with the wave energy flux. The highest correspondence (0.95) was found between the sand flux rate and the wave energy flux. The wave forcing is expected to be the main factor governing beach morphodynamics at Charf el Akab site.     

Late Neoproterozoic alkaline magmatism in the Arabian–Nubian Shield: the postcollisional A-type granite of Sahara–Umm Adawi pluton, Sinai, Egypt

The Sahara–Umm Adawi pluton is a Late Neoproterozoic postcollisional A-type granitoid pluton in Sinai segment of the Arabian–Nubian Shield that was emplaced within voluminous calc-alkaline I-type granite host rocks during the waning stages of the Pan-African orogeny and termination of a tectonomagmatic compressive cycle. The western part of the pluton is downthrown by clysmic faults and buried beneath the Suez rift valley sedimentary fill, while the exposed part is dissected by later Tertiary basaltic dykes and crosscut along with its host rocks by a series of NNE-trending faults. This A-type granite pluton is made up wholly of hypersolvus alkali feldspar granite and is composed of perthite, quartz, alkali amphibole, plagioclase, Fe-rich red biotite, accessory zircon, apatite, and allanite. The pluton rocks are highly evolved ferroan, alkaline, and peralkaline to mildly peraluminous A-type granites, displaying the typical geochemical characteristics of A-type granites with high SiO₂, Na₂O + K₂O, FeO*/MgO, Ga/Al, Zr, Nb, Ga, Y, Ce, and rare earth elements (REE) and low CaO, MgO, Ba, and Sr. Their trace and REE characteristics along with the use of various discrimination schemes revealed their correspondence to magmas derived from crustal sources that has gone through a continent–continent collision (postorogenic or postcollisional), with minor contribution from mantle source similar to ocean island basalt. The assumption of crustal source derivation and postcollisional setting is substantiated by highly evolved nature of this pluton and the absence of any syenitic or more primitive coeval mafic rocks in association with it. The slight mantle signature in the source material of these A-type granites is owed to the juvenile Pan-African Arabian–Nubian Shield (ANS) crust (I-type calc-alkaline) which was acted as a source by partial melting of its rocks and which itself of presumably large mantle source. The extremely high Rb/Sr ratios combined with the obvious Sr, Ba, P, Ti, and Eu depletions clearly indicate that these A-type granites were highly evolved and require advanced fractional crystallization in upper crustal conditions. Crystallization temperature values inferred average around 929°C which is in consistency with the presumably high temperatures of A-type magmas, whereas the estimated depth of emplacement ranges between 20 and 30 km (upper-middle crustal levels within the 40 km relatively thick ANS crust). The geochronologically preceding Pan-African calc-alkaline I-type continental arc granitoids (the Egyptian old and younger granites) associated with these rocks are thought to be the crustal source of f this A-type granite pluton and others in the Arabian–Nubian Shield by partial melting caused by crustal thickening due to continental collision at termination of the compressive orogeny in the Arabian–Nubian Shield.     

Cosmological Axially-Symmetric Viscous Fluid Interacting with the Gravitational Field

The problem of cosmological axially-symmetric viscous fluid interacting with the gravitational field has been investigated. Exact solution have been obtained for the pressure and density of the fluid. Physical interpretation of the solutions regarding the expansion factor, acceleration components and reality condition have been made. This revised version was published online in July 2006 with corrections to the Cover Date.     

Le graben de l'Anti-Atlas occidental (Maroc) : contrôle tectonique de la paléogéographie et des séquences au Cambrien inférieur

In the Moroccan western Anti-Atlas, the combined extensive tectonic events with a long-term sea-level rise is the main factor on building vertical stacking transgressive–regressive sequences. In the Ait Abdallah-Boussafene axis, the subsidence processes, relayed by a brutal platform tilting generated an elongated NE–SW graben. This is an evidence of the persistence of the Anti-Atlasic rifting process during the last part of the Lower-Cambrian succession.     

The particular “rammed earth” of the Saadian sugar refinery of Chichaoua (XVIth century,Morocco): mineralogical,chemical and mechanical characteristics

This work focuses on the building material used in the Saadian sugar refinery of Chichaoua (about 70 km southwest of Marrakesh). The study involved a classification of different types of rammed earth, followed by their mineralogical characterization based on optical microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). These studies are complemented by chemical investigations, X-ray fluorescence, and thermal analysis (DTA and TGA). The results demonstrate the use of two types of earth for the realisation of rammed earth, the first one non-plastic, -grained with added lime, the other one of low plasticity, and fine grained without addition of lime. Mechanical tests on site and in laboratory how at the first type of material exhibits great strength, exceeding the values known for rammed earth.