Morphed block-crack preferential sedimentation in a reservoir bed: a smart design and evolution in nature

Abstract

A pedological study of the reservoir bed of Al-Khoud Dam, Oman, revealed an unusual sedimentation pattern which evolved into an intricate composition of silt blocks surrounded by vertical cracks and horizontal layers filled with a “proppant” sand. The discovered soil morphology reflects the complex topology of water motion (infiltration–seepage–evaporation) through the sand-filled cracks/layers and blocks during both the rare flood events and ensuing periods of ponding, and the long, intervening dry periods. These naturally formed soils demonstrate an ability to preserve a large quantity of water inside the silty blocks at depths of 0.5 to 1.5 m, despite the high temperature and dryness of the topsoil. The hydrological optimality and “smartness” of these soils is attributed to the unique block-crack system. Natural, lush vegetation was found in adjacent zones of the reservoir bed, and acted as a footprint of the shallow “fractured perched aquifer”. Planted “ivy” (Convolvulaceae) in the vertical face of one pedon showed intensive growth without irrigation. Soil moisture content data confirmed the hydrological immobility of water in the blocks if not depleted by transpiration. The novel phenomena reported unveil the possible alteration of soil heterogeneity for optimization of the soil–water system in arid zone soils.

Editor D. Koutsoyiannis; Associate editor F.F. Hattermann

Citation Al-Ismaily, S.S., Al-Maktoumi, A.K., Kacimov, A.R., Al-Saqri, S.M., Al-Busaidi, H.A., and Al-Haddabi, M.H., 2013. Morphed block-crack preferential sedimentation in a reservoir bed: a smart design and evolution in nature. Hydrological Sciences Journal, 58 (8), 1779–1788.     

基于Ecopath模型的孟加拉国孟加拉湾海域营养结构和能量流动分析

依据现有研究提供的信息,在孟加拉国孟加拉湾（BoB）新划定的超过90 000 km²的海域基于Ecopath方法利用2016年7月至2017年6月的数据构建了该生态系统的营养通道模型。对食物网中营养级从1（主要生产者和碎屑）到3.45（鲨鱼）的各功能群之间的营养相互作用进行评估,所研究的共19个功能群被认为代表了其中所有的营养级。大多数消费者的生态营养转换效率（EE）超过0.80;表明这是一个被高度利用的生态系统,并且从低营养级到高营养级有较高的能量转换效率。此外,整个生态系统的净效率（0.0018）和能量转换效率（11.12%）标志着当前这一"正在发展中的生态系统"已趋向成熟。生态系统的冗余度（64.6）和聚合度（35.4）也表明了这一生态系统的稳定性。因此,本研究认为这一海域具有显著的后备力量面对压力情况并有能力快速恢复到初始状态。     

Investigation on crude oil penetration depth into soils

The main objectives of this paper are to study crude oil migration as a toxic fluid, its rate of penetration, and its consequences for eventual treatment. To achieve these objectives, an experimental model was designed comprising two separated columns, filled with soil and other rock types to simulate a real case scenario. Crude oil penetration depth versus time was recorded by taking soil samples whereas water samples were collected from the wet system to analyze the penetrating liquid. The results show that penetration depth was greater in the wet system during the early stages rather than in the dry system. However, with time, penetration becomes more developed in both systems. Overall penetration in the final stage was found to be significantly higher in the dry system. In addition, it was observed that during crude oil migration in dry system, chromatographic separation of crude oil components has occurred obviously. The obtained results reveal that immediate treatment must be performed in both systems but particularly in the wet system, due to its higher initial penetration rate.     

Contamination of diuron in coastal waters around Malaysian Peninsular

The use of antifouling paints to the boats and ships is one among the threats facing coastal resources including coral reefs in recent decades. This study reports the current contamination status of diuron and its behaviour in the coastal waters of Malaysia. The maximum concentration of diuron was 285 ng/L detected at Johor port. All samples from Redang and Bidong coral reef islands were contaminated with diuron. Temporal variation showed relatively high concentrations but no significant difference (P > 0.05) during November and January (North-East monsoon) in Klang ports (North, South and West), while higher levels of diuron were detected during April, 2012 (Inter monsoon) in Kemaman, and Johor port. Although no site has shown concentration above maximum permissible concentration (430 ng/L) as restricted by the Dutch Authorities, however, long term exposure studies for environmental relevance levels of diuron around coastal areas should be given a priority in the future.     

Intraplate uplift: new constraints on the Hoggar dome from the Illizi basin (Algeria)

Zones of anomalously high topography within continental interiors, distant from active plate boundaries, are interpreted as being either dynamically supported by viscous flow in the underlying mantle or influenced by plate tectonics. Constraining the models of their genesis requires accurate data on the timing and dimensions of such features. New apatite fission‐track and thermal maturity data from the Illizi Basin in Algeria quantify the magnitude and timing of kilometre–scale uplift and exhumation of the northern flank of the Hoggar swell in North Africa. The findings of this study, integrated with previously published thermochronological data, confirm that long‐wavelength regional uplift occurred during the Cenozoic extending over a distance in excess of 1500 km from north to south. The uplift, centred on the Hoggar Massif, significantly impacted the flanking Illizi and Tim Mersoï basins. The combination of thermal history modelling and regional stratigraphic observations indicates that the onset of exhumation of the Illizi Basin likely occurred during the Eocene, broadly coincident with magmatism on the Hoggar Massif to the south and the onset of tectonic shortening in the Atlasic belt to the north.     

Identification and mapping of clay minerals in the region of Djebel Meni (Northwestern Algeria) using hyperspectral imaging,EO-1 Hyperion sensor

Applied in Djebel Meni (Northwestern of Algeria), this research highlights the results obtained from the supervised classification using the Spectral Angle Mapper (SAM) algorithm, through introducing the spectral signatures of illite, kaolinite, and montmorillonite, via Jet Propulsion Laboratory (JPL) spectral library. These results were compared to the ones of the SAM classification, which use spectral signatures obtained by the Sequential Maximum Angle Convex Cone (SMACC) endmembers extraction algorithm. This implies the ability to detect and identify any object present on the Earth’s surface, whether its nature is mineral, vegetal, or human made, from hyperspectral imaging. By extracting the spectral signatures with the SMACC algorithm and matching them to the current signatures of JPL spectral library, comparing spectral signatures with another is not an easy task. Indeed, for a better comparison and a more appropriate interpretation in the use of the SAM classification, the results obtained were very relatively convincing because, regarding very strong similarities. It appears also that the signatures extracted with SMACC occupy the same areas as those of the JPL spectral library. This method of detection and identification of any present object on the Earth’s surface is rather conclusive.     

Stabilization of desert sands using municipal solid waste incinerator ash

This paper presents experimental results on the use of incinerator ash in stabilizing desert sands for possible use in geotechnical engineering applications. The incinerator ash was added in percentages of 2, 4, 8, 10 and 12%, by dry weight of sand. Laboratory tests such as compaction, unconfined compression, shear box and hydraulic conductivity were performed to measure the engineering characteristics of the stabilized material. The results showed substantial improvements in unconfined compressive strength and shear strength parameters (c and φ). Thus, incinerator ash can be used to improve the shear strength characteristics of desert sands. The permeability of the sand–incinerator ash mixture was relatively low.     

Comparison of the growth and biomass production of six acacia species in Riyadh, Saudi Arabia after 4 years of irrigated cultivation

The growth and biomass production of six acacia species were studied in the field for 4 years. The species used were Acacia asak, A. negrii, A. seyal, A. karroo, A. ampliceps, and A. stenophylla. The first three species are indigenous while the others are exotic. The results showed both A. ampliceps and A. asak with 100% survival while all A. negrii died. Acacia ampliceps attained the greatest height, diameter, relative growth rate and above-ground biomass while A. asak had the least. Height and diameter growth of acacia species decreased between warm and cold periods of the year.