Environmental assessment of soil,groundwater, and surface water quality in the south of the Riyadh,Saudi Arabia     

Abeer. Sh. Salman  Ali Al Dosari  Faisal K. Zaidi  Oumar Allafouza Loni 《Arabian Journal of Geosciences》2017,10(22):490

To understand the impact of the influence of treated wastewater, a study was undertaken in the downstream side of Wadi Hanifa in the southern part of Riyadh City in Saudi Arabia. Chemical elements from 17 groundwater samples, 9 surface water samples (treated wastewater), and 14 soil samples were analyzed. Water facies analyses showed that both groundwater and surface water belong to the SO₄-Cl class. However, the groundwater is characterized by high salinity (average value of 3547 mg/l), which may be result of the greater rock-water interaction and limited rainfall recharge. The NO₃ values are also high in the groundwater samples (average value of 40 mg/l) and are mainly attributed to the agricultural practices in the study area. The surface water samples (treated wastewater from the plant) shows an average salinity value of 1232 mg/l and is better suited for irrigation purposes. Heavy elements analyzed in the soil samples show high concentrations of all the elements except Mn and Ni as compared to their background concentration. Enrichment factor and index of geoaccumulation calculated from the soil samples indicate that they are severely enriched with respect to Cd and Se. The spatial distribution maps were prepared based on kriging interpolation technique to estimate the concentrations of the analyzed elements at unknown locations. The treated wastewater in the study area is better suited for agricultural and domestic activities as compared to groundwater.  相似文献   

Rangeland hydrology and erosion model (RHEM) enhancements for applications on disturbed rangelands   总被引：2，自引：0，他引：2       下载免费PDF全文

Osama Z. Al‐Hamdan  Mariano Hernandez  Frederick B. Pierson  Mark A. Nearing  C. Jason Williams  Jeffrey J. Stone  Jan Boll  Mark A. Weltz 《水文研究》2015,29(3):445-457

The rangeland hydrology and erosion model (RHEM) is a new process‐based model developed by the USDA Agricultural Research Service. RHEM was initially developed for functionally intact rangelands where concentrated flow erosion is minimal and most soil loss occurs by rain splash and sheet flow erosion processes. Disturbance such as fire or woody plant encroachment can amplify overland flow erosion by increasing the likelihood of concentrated flow formation. In this study, we enhanced RHEM applications on disturbed rangelands by using a new approach for the prediction and parameterization of concentrated flow erosion. The new approach was conceptualized based on observations and results of experimental studies on rangelands disturbed by fire and/or by tree encroachment. The sediment detachment rate for concentrated flow was calculated using soil erodibility and hydraulic (flow width and stream power) parameters. Concentrated flow width was calculated based on flow discharge and slope using an equation developed specifically for disturbed rangelands. Soil detachment was assumed to begin with concentrated flow initiation. A dynamic erodibility concept was applied where concentrated flow erodibility was set to decrease exponentially during a run‐off event because of declining sediment availability. Erodibility was estimated using an empirical parameterization equation as a function of vegetation cover and surface soil texture. A dynamic partial differential sediment continuity equation was used to model the total detachment rate of concentrated flow and rain splash and sheet flow. The enhanced version of the model was evaluated against rainfall simulation data for three different sites that exhibit some degree of disturbance by fire and/or by tree encroachment. The coefficient of determination (R²) and Nash–Sutcliffe efficiency were 0.78 and 0.71, respectively, which indicates the capability of the model using the new approach for predicting soil loss on disturbed rangeland. By using the new concentrated flow modelling approach, the model was enhanced to be a practical tool that utilizes readily available vegetation and soil data for quantifying erosion and assessing erosion risk following rangeland disturbance. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Model-based imputation of missing data from the 122 Cities Mortality Reporting System (122 CMRS)     

Paula Moraga  Al Ozonoff 《Stochastic Environmental Research and Risk Assessment (SERRA)》2015,29(5):1499-1507

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A macroseismic study of the Taldy-Sai caravanserai in the Kara-Bura River valley (Talas basin,Kyrgyzstan)     

A.M. Korjenkov  K.Sh. Tabaldiev  Al.V. Bobrovskii  Ar.V. Bobrovskii  E.M. Mamyrov  L.A. Orlova 《Russian Geology and Geophysics》2009,50(1):63-69

We report a macroseismic study of a ruined medieval building, a small caravanserai located along the caravan way from the Talas valley to the Chatkal and Fergana valleys in Kyrgyzstan. The ruins document several events in which the caravanserai was destroyed, apparently during earthquakes, and was rebuilt or repaired. The earliest earthquake occurred soon after the building was put up, about 400 years ago, according to radiocarbon dating of charcoal, and another event shook the area between 400 and 50 years BP. After being damaged in the ultimate earthquake, in the middle of the 20th century, the building was eventually abandoned.  相似文献   

Impact of the Use of Reclaimed Water on the Quality of Groundwater Resources in the Jordan Valley,Jordan     

Mustafa Al Kuisi  Taiseer Aljazzar  Thomas Rüde  Armin Margane 《洁净——土壤、空气、水》2008,36(12):1001-1014

The use of reclaimed water and its impact on groundwater quality in the middle and southern parts of the Jordan Valley are investigated. The chemical analyses indicate that nitrate and bacteriological pollution is widespread, and thus, seriously affects groundwater use. During the study, 365 water samples were collected from wells and springs to determine the water chemistry and the extent of nitrate pollution. Three hydrochemical facies are identifed, i. e., (Ca–(Mg)–Na–HCO₃), (Ca–Na–SO₄–Cl) and (Ca–Na–Cl). The change of facies is accompanied by a gradual increase in the groundwater total dissolved solids (TDS), which is mainly controlled by evaporates and carbonates dissolution in the aquifer matrix. Water analyses indicate that the shallow aquifer in the study area is affected by non‐point pollution sources, primarily from natural (manure) and chemical nitrogen (N)‐fertilizers and treated wastewater used for agriculture. The concentration of nitrate in the groundwater ranges from 10 to 355 mg/L. Considerable seasonal fluctuations in groundwater quality are observed as a consequence of agricultural practices and other factors such as annual rainfall distribution and the Zarqa River flow. The noticeable levels of total coliform and Escherichia coli in the northern part of the study area may be attributed to contamination from the urban areas, intensive livestock production, and illegal dumping of sewage. Heavy metal concentrations in all samples were found to be significantly lower than the permissible limits for drinking water standards.  相似文献   

The water balance of the Dead Sea: an integrated approach     

Radwan A. Al‐Weshah 《水文研究》2000,14(1):145-154

The Dead Sea is the lowest spot on Earth. It is a closed saline lake located in the middle of the Jordan Rift Valley between Lake Tiberias and the Red Sea. Its major tributaries are the Jordan River itself and the Dead Sea side wadis. The Dead Sea has a unique ecosystem and its water has curative, industrial and recreational significance. The level of the Dead Sea has been continuously falling since the early 1930s at an average rate of 0·7 m per year. The water level, as of February 1998, is about 410·9 m below mean sea level. In this paper, a water balance model is developed for the Dead Sea by considering different hydrological components of this water balance, including precipitation, runoff, evaporation and groundwater flow. This model is calibrated based on historical levels of the Dead Sea. Different scenarios are investigated, including the proposed Dead Sea–Red Sea Canal. This project is supposed to halt the shrinking of the Dead Sea and restore it to pre‐1950 levels in the next century. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   

Impacts of Anthropogenic Land Use Changes on Nutrient Concentrations in Surface Waterbodies: A Review   总被引：1，自引：0，他引：1       下载免费PDF全文

Madjid Delkash  Furat A.M. Al‐Faraj  Miklas Scholz 《洁净——土壤、空气、水》2018,46(5)

Increased population leads to land use (LU) changes from natural to urban and agricultural LU. These disturbances not only decrease the natural treatment potential but they also worsen surface water quality (SWQ). The aim of this review is to assess studies about impacts of anthropogenic LU changes on levels of nutrient concentrations in surface waterbodies, highlighting the important parameters needed for an integrated simulation. The results reported in the literature are not always fully consistent. These contradictory results can sometimes be explained by field measurements under different climatic conditions, different features of landscapes, air deposition rates on ground surfaces, and groundwater flow interactions with surface water. Integrated modelling has been suggested to overcome these inconsistencies. Physical‐based and empirical models are the most popular approaches for LU‐SWQ studies. Generally, anthropogenic LU such as agricultural and urban areas usually enhances nutrient concentrations much more than natural lands such as forest and barren. Developing sustainable metropolitan areas instead of rural areas, establishing high‐standard wastewater treatment plants, and practicing efficient fertiliser application would ameliorate the poor nutrient conditions in SWQ. Riparian vegetation, grassed swales, and construction of artificial wetlands as buffer zones are the most promising natural water quality control measures.  相似文献   

Aquifer Treatment of Sea Water to Remove Natural Organic Matter Before Desalination          下载免费PDF全文

Abdullah H. A. Dehwah  Samir Al‐Mashharawi  Kim Choon Ng  Thomas M. Missimer 《Ground water》2017,55(3):316-326

An investigation of a sea water reverse osmosis desalination facility located in western Saudi Arabia has shown that aquifer treatment of the raw sea water provides a high degree of removal of natural organic matter (NOM) that causes membrane biofouling. The aquifer is a carbonate system that has a good hydraulic connection to the sea and 14 wells are used to induce sea water movement 400 to 450 m from the sea to the wells. During aquifer transport virtually all of the algae, over 90% of the bacteria, over 90% of the biopolymer fraction of NOM, and high percentages of the humic substance, building blocks, and some of the low molecular weight fractions of NOM are removed. Between 44 and over 90% of the transparent exopolymer particles (TEP) are removed with a corresponding significant reduction in concentration of the colloidal fraction of TEP. The removal rate for TEP appears to be greater in carbonate aquifers compared to siliciclastic systems. Although the production wells range in age from 4 months to 14 years, no significant difference in the degree of water treatment provided by the aquifer was found.  相似文献   

The structural inventory of a small complex impact crater: Jebel Waqf as Suwwan,Jordan          下载免费PDF全文

Thomas Kenkmann  Sebastian Sturm  Tim Krüger  Elias Salameh  Marwan Al‐Raggad  Khalil Konsul 《Meteoritics & planetary science》2017,52(7):1351-1370

The investigation of terrestrial impact structures is crucial to gain an in‐depth understanding of impact cratering processes in the solar system. Here, we use the impact structure Jebel Waqf as Suwwan, Jordan, as a representative for crater formation into a layered sedimentary target with contrasting rheology. The complex crater is moderately eroded (300–420 m) with an apparent diameter of 6.1 km and an original rim fault diameter of 7 km. Based on extensive field work, IKONOS imagery, and geophysical surveying we present a novel geological map of the entire crater structure that provides the basis for structural analysis. Parametric scaling indicates that the structural uplift (250–350 m) and the depth of the ring syncline (<200 m) are anomalously low. The very shallow relief of the crater along with a NE vergence of the asymmetric central uplift and the enhanced deformations in the up‐range and down‐range sectors of the annular moat and crater rim suggest that the impact was most likely a very oblique one (~20°). One of the major consequences of the presence of the rheologically anisotropic target was that extensive strata buckling occurred during impact cratering both on the decameter as well as on the hundred‐meter scale. The crater rim is defined by a circumferential normal fault dipping mostly toward the crater. Footwall strata beneath the rim fault are bent‐up in the down‐range sector but appear unaffected in the up‐range sector. The hanging wall displays various synthetic and antithetic rotations in the down‐range sector but always shows antithetic block rotation in the up‐range sector. At greater depth reverse faulting or folding is indicated at the rim indicating that the rim fault was already formed during the excavation stage.  相似文献   

Application of a mixture distribution of extreme values to earthquake magnitudes in Iraq and conterminous regions     

Khalid J. Fahmi  Jamal N. Al Abbasi 《Geophysical Journal International》1991,107(2):209-217

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