Two-dimensional numerical modeling of dam-break flows over natural terrain using a central explicit scheme     

Jaswant Singh  Mustafa S. Altinakar Yan Ding 《Advances in water resources》2011,34(10):1366-1375

A two-dimensional (2D) numerical model has been developed to solve shallow water equations for simulation of dam-break flows. The spatial derivatives are discretized using a well-balanced explicit central upwind conservative scheme. The scheme is Riemann solver free and guarantees the positivity of the flow depth over complex topography if the Courant number is kept less than 0.25. The time integration is performed by Euler’s scheme. The model is verified against analytical results for water surface elevation and discharge for three benchmark test cases. A good agreement between analytical solutions and computed results is observed. The property of well-balancing in still water over an uneven bottom is also confirmed. The model is then validated by simulating a laboratory experiment in which a dam break flow propagates over a triangular obstacle. The model performance was found to be satisfactory. A dam break laboratory experimental test case on a frictionless horizontal bottom is also simulated for 2D validation of the model, and good agreement between simulation and the experimental data is observed. The suitability of the proposed model for real life applications is demonstrated by simulating the Malpasset dam-break event, which occurred in 1959 in France. The computed arrival time of the flood wave front and the maximum flow depths at various observation points matched well with the measurements on a 1/400 scale physical model. The overall performance indicates that this model can be applied for simulation of dam-break waves in real life cases.  相似文献   

Spatial Variation of Haloacetic Acids in Indoor and Outdoor Desalinated Household Drinking Water in Kuwait     

Humood F. Al‐Mudhaf  Mustafa I. Selim  Aleksander M. Astel  Abdel‐Sattar I. Abu‐Shady 《洁净——土壤、空气、水》2011,39(9):833-843

The present study reveals spatial variability of haloacetic acids and the basic physiochemical properties of drinking water samples through visualization based on the Kriging algorithm and hierarchical cluster analysis. Both projection and statistical method contributed to the logical classification of the indoor and outdoor water samples collected from various governorates covering more than 95% of the residential areas in Kuwait. Clustering of the variables led to the formation of several significant clusters corresponding to the effect of chlorine concentration and its residence time on the formation potential of chlorinated acetic acid derivatives in desalinated drinking water as well as to the total ionic composition of water samples and to the effect of the formation of brominated acetic acid derivatives. Clustering of samples, both indoor and outdoor, indicated that all of governorates located in the northern part of Kuwait are supplied with water containing high concentrations of chlorinated acetic acid derivatives, whereas significantly lower amounts of chlorinated or monobrominated acetic acids were found in water samples in the central and southern parts of the country.  相似文献   

Mineral Content of Bottled and Desalinated Household Drinking Water in Kuwait     

Humood F. Al‐Mudhaf  Mohammad N. Al‐Hayan  Mustafa I. Selim  Abdel‐Sattar I. Abu‐Shady 《洁净——土壤、空气、水》2011,39(12):1068-1080

Three hundred and twenty‐two samples of desalinated household water were collected from 99 sampling locations that covered 95% of Kuwaiti's residential areas. Seventy‐one brands of bottled water were collected from Kuwaiti markets. The water quality parameters that were studied included pH, electrical conductivity (EC), total dissolved solids (TDS), F^?, Cl^?, Br^?, , , , , , , , and the major macronutrients Na⁺, K⁺, Ca²⁺, and Mg²⁺. The analysis yielded a large range of results for most of these parameters, with differences in some cases exceeding 10‐fold. With a few exceptions, the results were found to comply with US‐EPA and WHO standards. Only the water in two brands of bottled water was acidic (pH < 6.5). The TDS was found to be higher than the US‐EPA regulated value in 4 and 3% of the household samples and bottled water brands, respectively. The fluoride levels were generally higher in bottled water than in household water. However, the household water that was produced by the Doha desalination plant and some of the European brands of bottled water were the best samples studied in terms of their quantity of Ca²⁺, Mg²⁺, and Na⁺ compared with the DRI values for those substances. EC and TDS were positively correlated with , , Na⁺, K⁺, Ca²⁺, and Mg²⁺ for household water but only with Ca²⁺ and Mg²⁺ for bottled water.  相似文献   

Spatial information of soil hydraulic conductivity and performance of cokriging over kriging in a semi-arid basin scale   总被引：1，自引：0，他引：1  

Mustafa Basaran  G. Erpul  A. U. Ozcan  D. S. Saygin  M. Kibar  I. Bayramin  F. E. Yilman 《Environmental Earth Sciences》2011,63(4):827-838

Unlike the studies in small parcels by systematic measurements, the spatial variability of soil properties is expected to increase in those over relatively large areas or scales. Spatial variability of soil hydraulic conductivity (K _h) is of significance for the environmental processes, such as soil erosion, plant growth, transport of the plant nutrients in a soil profile and ground water levels. However, its variability is not much and sufficiently known at basin scale. A study of testing the performance of cokriging of K _h compared with that of kriging was conducted in the catchment area of Sarayköy II Irrigation Dam in Cank?r?, Turkey. A total of 300 soil surface samples (0–10 cm) were collected from the catchment with irregular intervals. Of the selected soil properties, because the water-stable aggregates (WSA) indicated the highest relationship with the hydraulic conductivity by the Pearson correlation analysis, it is used as an auxiliary variable to predict K _h by the cokriging procedure. In addition, the sampling density was reduced randomly to n = 175, n = 150, n = 75 and n = 50 for K _h to determine if the superiority of cokriging over kriging would exist. Statistically, the results showed that all reduced K _h was as good as the complete K _h when its auxiliary relations with WSA were used in cokriging. Particularly, the results of the “Relative Reduction in MSE” (RMSE) revealed that the reduced data set of n = 75 produced the most accurate map than the others. In this basin-scaled study, there was a clear superiority of the cokriging procedure by the reduction in data although a very undulating topography and topographically different aspects, two different land uses with non-uniform vegetation density, different parent materials and soil textures were present in the area. Hence, using the statistically significant auxiliary relationship between K _h and WSA might bring about a very useful data set for watershed hydrological researches.  相似文献   

Spectrophotometric Determination of Gold (III) after Liquid–Liquid Extraction and Selective Pre‐concentration with a Novel Dibenzo‐18‐Crown‐6 Derivative     

Volkan N. Bulut  Celal Duran  Zekeriya Biyiklioglu  Mehmet Tufekci  Mustafa Soylak 《Geostandards and Geoanalytical Research》2011,35(4):471-483

A selective and sensitive method for the extraction and spectrophotometric determination of gold with N,N′‐6,7,9,10,17,18,20,21‐octahydrodibenzo[b,k][1,4,7,10,13,16] hexaoxacyclo‐octadecine‐2,13–diylbis(2‐chloroacetamide) (ODBOCA) is described. The ODBOCA–Au(III) complex was extracted from a slightly acidic aqueous solution (pH 5) into a chloroform layer and then the absorbance of the extract was measured using a UV–Vis spectrophotometer with 1.0 cm quartz cells at 540 nm. An enrichment factor of 200 was achieved. In the chloroform medium at 540 nm, the molar absorptivity and Sandell’s sensitivity were 4.12 × 10³ l mol^?1 cm^?1 and 0.048 μg cm^?2, respectively. Beer’s law was obeyed in the range of 0.5–15 μg ml^?1 in the measured solution. The relative standard deviation for ten replicate samples at the 1.0 μg ml^?1 level was 3.0%. The limit of detection, based on 3s, was 0.5 μg l^?1 in the original sample. The effects of pH, ligand concentration and shaking time were studied. The ratio of the metal ion to ligand molecules in the complex was found to be 1:2 according to the Job Method. The effects of interference by a number of metal ions were investigated. The method was verified with certified reference materials and spiked tests, and quantitative recovery values were obtained. The method was fast, accurate, selective and precise, and was applied to the determination of gold in water and ore with good results.  相似文献   

Study of radon in soil gas,trace elements and climatic parameters around South Kordofan state,Sudan     

Hajo Idriss  Isam Salih  Abdulaziz S. Alaamer  M. Y. Abdelgalil  Salih Ali Salih  Amna M. Hasan  Mohammed A. ELtahir  Mustafa M. O. Ahamed 《Environmental Earth Sciences》2014,72(2):335-339

This study was conducted primarily to measure and map radon activity concentration in soil gas and to understand the effect of geology and lithology and meteorology on radon concentration. Portable radon meter has been used for the measurement of soil gas radon at 30 different locations around Uro and Korn area in eastern Nuba Mountain South Kordofan State. The results indicate that the activity concentrations of ²²²Rn in soil gas fall within the range of 20–1,359 Bq/m³ with geometric mean of 102.80 Bq/cm³. The obtained data show that samples around Uro have anomaly of ²²²Rn concentrations than the sample around Korn. The reason could be attributed to differences in the geological structure, lithology and climate parameters. GIS predicative map has shown that the elevated levels of radon concentration were measured in North study area. Upon comparing the results with global data, it was found that the obtained values are far below the reported range of India, Slovenia, Portugal and Syria. However, the range of ²²²Rn concentrations in the soil observed in this study is significantly high relative to similar data reported from Libya. The regression analysis has shown that no correlation was noted between radon concentrations, climatic parameters and trace element.  相似文献   

Determination of heavy metals in sediments of the Ergene River by BCR sequential extraction method     

Ali Sungur  Mustafa Soylak  Selehattin Yilmaz  Hasan Özcan 《Environmental Earth Sciences》2014,72(9):3293-3305

Utilizing the sequential extraction procedure (acid soluble, reducible, oxidizable, and residual) proposed by The European Community Bureau of Reference (BCR), the trace metals present in the sediments of the Ergene River, Turkey, were determined. The sediment samples were collected from 10 sampling sites and analyzed to identify the concentrations of cadmium, cobalt, chromium, copper, manganese, nickel, lead and zinc. The flame atomic absorption spectrometer was used for metal determination. The validation of the results was checked by the analysis of the BCR-701 standard reference material. The relationship existing between the sediment characteristics and metal fractions was identified using the correlation analysis. Hierarchical cluster analysis was performed to find out the grouping of the sampling sites based on the similarities of the heavy metals in the bioavailable fraction. When the extractable amounts of heavy metals are considered, the quantity of the mobile fractions (viz., acid soluble, reducible, and oxidizable) of the heavy metals is observed to be higher when compared with that of the immobile fraction (residual). This might be caused by the anthropogenic sources. Besides, it was statistically discovered that the organic matter, pH and clay contents could influence the bonding of the analyte metals in various forms. The cluster analysis revealed three clusters of the sampling stations, with group I (S5-8) and group II (S3, S4 and S9) showing higher environmental risks. The risk assessment code indicated that the highly mobile soluble fractions of Mn, Zn, Cd and Co created a high environmental risk which could result in negative impacts on the aquatic biota.  相似文献   

Runoff and sediment yield modeling by means of WEPP in the Bautzen dam catchment,Germany     

Mustafa Al-Mukhtar  Volkmar Dunger  Broder Merkel 《Environmental Earth Sciences》2014,72(6):2051-2063

Soil erosion by water is one of the most widespread forms of soil degradation in Europe. There are many undesirable consequences of soil erosion due to water such as loss of water storage capacity in reservoirs and transfer of pollutants from farmland to water bodies. The objectives of this study were to calibrate and validate the Water Erosion Prediction Project watershed model (WEPP 2012.8) in the Bautzen dam catchment area with monthly and daily single events for runoff and sediment yield. This is to our knowledge the first study using WEPP in Germany. The catchment (310 km²) was subdivided into small sub-catchments with an area of <260 ha as recommended in WEPP. A sensitivity analysis revealed that the runoff is highly sensitive to the effective hydraulic conductivity in Bautzen, whereas the sediment yield is highly sensitive to rill erodibility, critical shear stress, and to the effective hydraulic conductivity as well. All these parameters were initially calculated using WEPP’s built-in equations and parameters, which, however, produced very poor results for both runoff and sediment yield. Therefore, the model was calibrated for 2 years (2005–2007) and validated for another 2 years (2008–2009) against monthly measurements, in addition to 14 daily single events from the calibration period and 2010. The monthly results were compared with the monthly measurements on the basis of a continuous simulation. Results of calibration and validation periods show a satisfactory performance of WEPP with a determination coefficient R ² above 0.6 and Nash–Sutcliffe efficiency coefficients above 0.50 for runoff and sediment yield. Thus, the model could be used to simulate runoff and sediment yield, and used in scenario studies in the Bautzen dam catchment area.  相似文献   

Geochemical and isotopic evolution of groundwater in the Wadi Watir watershed,Sinai Peninsula,Egypt     

Mustafa A. Eissa  James M. Thomas  Ronald L. Hershey  Maher I. Dawoud  Greg Pohll  Kamal A. Dahab  Mohamed A. Gomaa  Ashraf R. Shabana 《Environmental Earth Sciences》2014,71(4):1855-1869

The Wadi Watir delta in the Wadi Watir watershed is a tourist area in the arid southeastern part of the Sinai Peninsula, Egypt, where development and growth of the community on the delta are constrained by the amount of groundwater that can be withdrawn sustainably. To effectively manage groundwater resources in the Wadi Watir delta, the origin of groundwater recharge, groundwater age, and changes in groundwater chemistry in the watershed needs to be understood. Mineral identification, rock chemistry, water chemistry, and the isotopes of hydrogen, oxygen, and carbon in groundwater were used to identify the sources, mixing, and ages of groundwater in the watershed and the chemical evolution of groundwater as it flows from the upland areas in the watershed to the developed areas at the Wadi Watir delta. Groundwater in the Wadi Watir watershed is primarily from recent recharge while groundwater salinity is controlled by mixing of chemically different waters and dissolution of minerals and salts in the aquifers. The El Shiekh Attia and Wadi El Ain areas in the upper Wadi Watir watershed have different recharge sources, either from recharge from other areas or from different storm events. The downgradient Main Channel area receives groundwater flow primarily from the El Shiekh Attia area. Groundwater in the Main Channel area is the primary source of groundwater supplying the aquifers of the Wadi Watir delta.  相似文献   

Removal of cationic dye methylene blue (MB) from aqueous solution by ground raw and base modified pine cone powder     

Mustafa T. Yagub  Tushar Kanti Sen  M. Ang 《Environmental Earth Sciences》2014,71(4):1507-1519

The adsorption capacity of raw and sodium hydroxide-treated pine cone powder in the removal of methylene blue (MB) from aqueous solution was investigated in a batch system. It was found that the base modified pine cone exhibits large adsorption capacity compared with raw pine cone. The extent of adsorption capacity was increased with the increase in NaOH concentration. Overall, the extent of MB dye adsorption increased with increase in initial dye concentration, contact time, and solution pH but decreased with increase in salt concentration and temperature for both the systems. Surface characteristics of pine cone and base modified pine cone were investigated using Fourier transform infrared spectrophotometer and scanning electron microscope. Equilibrium data were best described by both Langmuir isotherm and Freundlich adsorption isotherm. The maximum monolayer adsorption capacity was found to be 129.87 mg g^?1 at solution pH of 9.02 for an initial dye concentration of 10 ppm by raw pine cone. The base modified pine cone showed the higher monolayer adsorption capacity of 142.25 mg g^?1 compared with raw pine cone biomass. The value of separation factor, R _L, from Langmuir equation and Freundlich constant, n, both give an indication of favourable adsorption. The various kinetic models, such as pseudo-first-order model, pseudo-second-order model, intraparticle diffusion model, double-exponential model, and liquid film diffusion model, were used to describe the kinetic and mechanism of adsorption process. Overall, kinetic studies showed that the dye adsorption process followed pseudo-second-order kinetics based on other models. The different kinetic parameters, including rate constant, half-adsorption time and diffusion coefficient, were determined at different physicochemical conditions. A single-stage bath adsorber design for the MB adsorption onto pine cone and modified pine cone has been presented based on the Langmuir isotherm model equation. Thermodynamic parameters, such as standard Gibbs free energy (ΔG ⁰), standard enthalpy (ΔH ⁰) and standard entropy (ΔS ⁰), were also calculated.  相似文献