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1.
Mahleb Anissa Hadji Riheb Zahri Farid Boudjellal Rania Chibani Abdelmohcen Hamed Younes 《Geotechnical and Geological Engineering》2022,40(8):4217-4230
Geotechnical and Geological Engineering - Soil erosion is one of the major environmental problems in the Middle East and North Africa (MENA) region. Favoured by the harmful effects of climate... 相似文献
2.
Regional soil erosion risk mapping in Lebanon 总被引：10，自引：0，他引：10
Soil erosion by water is one of the major causes of land degradation in Lebanon. The problem has not yet been treated in detail although it affects vast areas. This study elaborates a model for mapping soil erosion risk in a representative area of Lebanon at a scale of 1:100,000 using a spatial database and GIS. First, three basic maps were derived: (1) runoff potential obtained from mean annual precipitation, soil-water retention capacity and soil/rock infiltration capacity; (2) landscape sensitivity based on vegetal cover, drainage density and slope; and (3) erodibility of rock and soil. Then two thematic maps were derived: potential sensitivity to erosion obtained from the runoff potential and landscape sensitivity maps, and erosion risk based on the potential erosion and erodibility maps. The risk map corresponds well to field observations on the occurrence of rills and gullies. The model used seems to be applicable to other areas of Lebanon, constituting a tool for soil conservation planning and sustainable management. 相似文献
3.
Soil and bedrock distribution estimated from gully form and frequency: A GIS-based decision-tree model for Lebanon 总被引：2，自引：1，他引：1
Torrential rainfall and relatively sparse vegetation in the Mediterranean region result in the development of gully systems and land degradation, notably on lands with specific types of soil and bedrock. This paper proposes a decision-tree model to predict the distribution of soil and bedrock susceptible to gully erosion (white Rendzinas and marly rocks) from the form and frequency of gullies. The study area is located in Lebanon and the model is linked to GIS. V-fold cross-validation of the pruned model indicates that gully features including cross-section size and shape, network frequency, types of meandering, and catchment area can explain 80% of variance in soil/rock properties. The overall accuracy of the soil/rock map was estimated to be ca. 87%. The proposed model is relatively simple, and may also be applied to other areas. It is particularly useful when information about soil and rock obtained from conventional field surveys is limited. 相似文献
4.
Artificially enhancing recharge rate into groundwater aquifer at specially designed facilities is an attractive option for increasing the storage capacity of potable water in arid and semi‐arid region such as Damascus basin (Syria). Two dug wells (I and II) for water injection and 24 wells for water extraction are available in Mazraha station for artificial recharge experiment. Chemical and stable isotopes (δ2H and δ18O) were used to evaluate artificial recharge efficiency. 400 to 500*103 m3 of spring water were injected annually into the ambient shallow groundwater in Mazraha station, which is used later for drinking purpose. Ambient groundwater and injected spring water are calcium bicarbonate type with EC about 880 ± 60 μS/cm and 300 ± 50 μS/cm, respectively. The injected water is under saturated versus calcite and the ambient groundwater is over saturated, while the recovered water is near equilibrium. It was observed that the injection process formed a chemical dilution plume that improves the groundwater quality. Results demonstrate that the hydraulic conductivity of the aquifer is estimated around 6.8*10?4 m/s. The effective diameter of artificial recharge is limited to about 250 m from the injection wells. Mixing rate of 30% is required in order to reduce nitrate concentration below 50 mg/l which is considered the maximum concentration limit for potable water. Deuterium and oxygen‐18 relationship demonstrates that mixing line between injected water and ambient groundwater has a slope of 6.1. Oxygen‐18 and Cl? plot indicates that groundwater salinity origin is from mixing process, and no dissolution and evaporation were observed. These results demonstrate the efficiency of the artificial recharge experiments to restore groundwater storage capacity and to improve the water quality. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
5.
The groundwater along the eastern escarpment of the Dead Sea shows a variety of chemical compositions with EC values ranging
between 500 and a few thousand μS/cm. In this article the different groundwaters were correlated to the aquifers from where
they originate and the water–rock interactions were elaborated at. It was found that the start of intercalations of Permo-Triassic
and Jurassic rocks in the area and the basaltic dykes and sills are the sources, which cause a drastic increase in the salinity
of the water. These rocks contents of residual evaporites, contact metamorphism products, sills, dykes and secondary altered
mineral assemblage of plagioclase-, pyroxenes- and Fe-, Mn- minerals cause also drastic changes in ionic ratios, saturation
indices and groundwater types. Fresh groundwater flows entering the area become, gradually, after a few kilometres highly
salinized and of earthalkali type with prevailing chloride and sulfate instead of being bicarbonate waters. 相似文献
6.
This paper predicts the geographic distribution and size of gullies across central Lebanon using a geographic information system (GIS) and terrain analysis. Eleven primary (elevation; upslope contributing area; aspect; slope; plan, profile and tangential curvature; flow direction; flow width; flow path length; rate of change of specific catchment area along the direction of flow) and three secondary (steady‐state; quasi‐dynamic topographic wetness; sediment transport capacity) topographic variables were generated and used along with digital data collected from other sources (soil, geology) to statistically explain gully erosion field measurements. Three tree‐based regression models were developed using (1) all variables, (2) primary topographic variables only and (3) different pairs of variables. The best regression tree model combined the steady‐state topographic wetness and sediment transport capacity indices and explained 80% of the variability in field gully measurements. This model proved to be simple, quick, realistic and practical, and it can be applied to other areas of the Mediterranean region with similar environmental conditions, thereby providing a tool to help with the implementation of plans for soil conservation and sustainable management. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
7.
Rania S. MABROKE Osama M. EL-HUSSEINY Abd El-Naem F. A. ZIDAN Al-Azab TAHOUN Ashraf SULOMA 《海洋湖沼学报（英文）》2019,(1):313-320
This study was conducted to evaluate the ef fect of replacing soybean meal(SBM) by low protein ?oc meal(LPFM; 24% CP) in tilapia diets on growth performance, feed utilization and ?sh chemical composition. Three isonitrogenous and isocaloric diets were formulated; control diet(C; without LPFM),FM 25(25% of SBM protein was substituted by LPFM) and FM 50(50% of SBM protein was substituted by LPFM). Nine 55 l circular plastic tanks were stocked by 12 ?sh to form three experimental groups.No dif ferences in tilapia performance were observed between the control and the FM 25 diet. Chemical composition of ?sh did not dif fer signi?cantly among treatments except for protein and selenium contents where the highest values were recorded in the control treatment. The highest mineral content was recorded in ?oc collected from the control tanks, while calcium content showed its highest value in ?oc collected from FM 50 e ? uent. These data indicate that replacing soybean meal with LPFM up to 25%, had no negative ef fect on growth performance and potentially may improve the system sustainability. Meanwhile, the adverse ef fect of more inclusion of LPFM in tilapia diet may be attributed to the higher content of ash. In other word,minerals seem to cause more energy utilization in ?sh fed ?oc meal since it is needed to maintain osmotic homeostasis. 相似文献
8.
Mabroke Rania S. El-Husseiny Osama M. Zidan Abd El-Naem F. A. Tahoun Al-Azab Suloma Ashraf 《中国海洋湖沼学报》2019,37(1):313-320
This study was conducted to evaluate the effect of replacing soybean meal (SBM) by low protein floc meal (LPFM; 24% CP) in tilapia diets on growth performance, feed utilization and fish chemical composition. Three isonitrogenous and isocaloric diets were formulated; control diet (C; without LPFM), FM 25 (25% of SBM protein was substituted by LPFM) and FM 50 (50% of SBM protein was substituted by LPFM). Nine 55l circular plastic tanks were stocked by 12 fish to form three experimental groups. No differences in tilapia performance were observed between the control and the FM 25 diet. Chemical composition of fish did not differ significantly among treatments except for protein and selenium contents where the highest values were recorded in the control treatment. The highest mineral content was recorded in floc collected from the control tanks, while calcium content showed its highest value in floc collected from FM 50 effluent. These data indicate that replacing soybean meal with LPFM up to 25%, had no negative effect on growth performance and potentially may improve the system sustainability. Meanwhile, the adverse effect of more inclusion of LPFM in tilapia diet may be attributed to the higher content of ash. In other word, minerals seem to cause more energy utilization in fish fed floc meal since it is needed to maintain osmotic homeostasis.
相似文献9.
Noamen Rebai Hammadi Achour Rochdi Chaabouni Rania Bou Kheir Samir Bouaziz 《Earth Science Informatics》2013,6(4):187-198
Morphotectonic analysis using geomorphic indexes has been developed as a basic tool to identify recent tectonic deformation in specific areas.This study was undertaken to develop an integrated quantitative geomorphic analysis of tectonic activity in the North–south axis, central of Tunisia. Different geomorphic indexes, including elongation ratio (E), drainage basin asymmetry (Af), hypsometric integral (Hi), Valley floor width-to-height ratio (Vf), mountain front sinuosity (Smf), and stream length gradient index (SL) were calculated. The relationships between the calculated indexes, their correlations and their significance (based on p-values) were also investigated.. Using the hierarchical cluster analysis based on Ward’s method, these indexes were classified into three classes describing the relative, different effect of tectonics in each fault segment. The higher deformation is concentrated in the NE-SW Boudinar fault, followed, in order of decreasing activity, by Goubrar, Gouleb, and Majoura normal faults. This pattern of variation in the relative degree of tectonic activity is consistent with field evidence. 相似文献
10.
Seawater intrusion into the shallow aquifer in the Syrian coast, north of Latakia (Damsarkho, Ras Ibn Hani) and south of Tartous
(Al Hamidieh, Ein Zarka) was studied using hydrochemical and isotopic techniques. The electrical conductivity (EC) distribution
map north of Latakia revealed that mixing in this area is the consequence of a frontal intrusion of seawater within the fresh
groundwater aquifer which, in turn, results from intensive pumping since the 1960s which has lowered the water table inland
below sea level. In Ein Zarka, south of Tartous, in contrast, the EC distribution revealed that seawater intrusion is due
to local up-coning as a result of intensive pumping. The deuterium and oxygen-18 relationship is that of a mixing line with
a slope of 5.55, indicating an intrusion between freshwater and seawater. In addition, the relationship between oxygen-18
and chloride reveals that the mixing has a dominant role compared to evaporation process. The mixing ratios are estimated
to be between 6 and 10% north of Latakia, while they do not exceed 3% south of Tartous. A tritium model was applied to compute
the “mean transit time”, which is estimated to be around 10 years, on average, to reach the equilibrium that existed originally
between the fresh groundwater and seawater, provided that severe pumping is completely halted and the aquifer is naturally
recharged by rainfall and deep percolation of irrigation water, thereby allowing the restoration of the hydraulic gradient.
This paper is dedicated to the memory of Dr. Y. Yurtsever. 相似文献