• 全国中文核心期刊
  • 中国科技核心期刊
  • 美国工程索引(EI)收录期刊

2003 Vol. 14, No. 5

Display Method:
Neutron activation analyses on element composition of natural waters in China
GU Wei-zu, LU Jia-ju, CHEN Ting-yang, XU Qi-gao, Norman E. Peters
2003, 14(5): 535-541.
Abstract:
The element composition of natural waters including rainfall,river water and groundwater are tested by neutron activation analyses.The rainfall is sampled from 11 stations distributed in all main climate zones of this country with altitude from 5 m ASL to 3 659 m ASL,annual mean precipitation from 50 mm to 1 571 mm.The river water are sampled from 12 hydrometric stations of the main rivers of China,including inland rivers,island river and brooks of 3 representative catchments.The natural waters are sampled simultaneously.35 elements in rainfall,39 elements in river water and groundwater are found.Concentration of elements are grouped with level greater than 1 000 μg/L to that less than 0.01 μg/L.Many elements are found to be beyond the range of world fresh water concentration reported by Bowen i.e.,several elements much higher or lower than Bowen values.
Experimental study on pollutant transport in surf zone
TANG Jun, ZOU Zhi-li, SHEN Yong-ming, QIU Da-hong
2003, 14(5): 542-547.
Abstract:
Coastal and offshore areas,especially in mild sloping beaches,are extremely dynamic regions where the advection and diffusion of pollutants are more complicated due to the distortion and breaking of wave.The experiments of pollutant trans port for diverse wave cases in surf zone were carried out on the two gently sloping beach of 1:100 and 1:40 slope.The pollutant extension areas at different times for diverse incident wave cases were provided.The movement range and direction of pollutants under the action of regular and irregular waves,diverse wave amplitude cases were provided and investigated.The distribution tendency and direction for pollutant transport in surf zone were also provided and studied in this paper.It is indicated that,in surf zone,the movement direction of pollutants is mainly along shore,almost independent of incident wave direction,and that the movement state of pollutants is influenced by incident wave cases and quite complicated for diverse wave cases,and different from the pollutant movement under the action of pure current.
Impacts of river wastewater unsaturated filtration on its offshore soil and groundwater quality
LIANG Bin, WANG Chao, WANG Pei-fang, QIAN Jin, ZHENG Xiao-ying
2003, 14(5): 548-553.
Abstract:
A mathematics model forecasting the impacts of river wastewater unsaturated filtration on its offshore soil and groundwater quality is established based on the analysis of the river wastewater unsaturated filtration and the transportation mechanism.The implicit difference method and the time-center difference formats are performed in the disperse equations,which have obtained good effects.The conservative pollutant Cl- and non-conservative pollutant nitrite of river wastewater are taken as examples to study the model parameters of the transportation and transformation of the unsaturated filtration pollutants in the soil and groundwater.Finally the model is verified by the field data of Xucun and Huangqiao's cross sections in Xuzhou,Jiangsu province.The result shows that the calculated data agrees with the measured data.
A new method for parameter identification in water environment model
YANG Xiao-hua, YANG Zhi-feng, LI Jian-qiang
2003, 14(5): 554-557.
Abstract:
In this study,a new method,Gray Code Hybrid Accelerating Genetic Algorithm (GCHAGA),and its detailed steps are developed to identify water environment model parameters.With the shrinking of searching range,the method gradually directs to optimal result by the excellent individuals obtained by gray code genetic algorithm (GCGA) embedding with simplex searching operator and simplex algorithm.Further,the convergence and global optimization of the GCHAGA is discussed theoretically and practically,and its high precision on global optimization is ascertained over such parameters as river transverse diffuse coefficients model.Compared with the GCGA and the conventional optimization methods,the GCHAGA remarkably improves convergence speed and calculation accuracy.It proves a good nonlinear optimal method that can search both global solution and fractional one in greater probability,and could be applied to various water environment optimization issues.
Water quality variation in Lingding sea influenced by Pearl River delta and Hong Kong sea area
PANG Yong, LI Xue-lin, LONG Jiang
2003, 14(5): 558-562.
Abstract:
An unsteady water quality and hydrodynamic model for river networks was employed in computing the amount of pollutants passing through the four east outlets in Pearl River delta into Lingding sea.The computed area is about 2000 square kilometers.Based on the verified model and the long series of the water quality data observed of 1985-1995 in the four east outlets,the amount of pollutants into Lingding sea are calculated and its variations are analyzed.The main conclusions are that the main pollution factors are COD and NH4,and the main pollution outlet is Humen.The 2-D hydrodynamic and water quality model is used to calculate the water quality in Lingding sea area which is influenced by Pearl River delta and Hong Kong pollutant.The model is calibrated and verified with the real data.The main conclusion are as follows: (1) If the water quality in east outlets is satisfied with the desired function and the water quality in Lingding sea can not reach the desired function.(2) The pollutant discharged by Hong Kong only influence Shenzhen bay even though in unfavorable hydrological conditions.(3) The water quality is higher in northwest of Lingding sea because the along shore flow is toward northwest.(4) If the pollu tion accidentlly occur in east outlets,the influenced area is at middle area in Lingding sea.
Study on non-equilibrium sediment transport in the sandy river erosion
LIU Jin-mei, WANG Guang-qian, WANG Shi-qiang
2003, 14(5): 563-568.
Abstract:
The flume experiments on the mobile sand bed are made in this paper.The frequent group initiation of bed material is found to occur by the turbulent sweep.The sand-wave movement is also observed.According,two physical models of the bed material exchange in different levels are presented to prove the coarsening of surface bed material makes the recovering distance much longer than that for the condition of uniform bed material,and thus greatly effects the non-equilibrium sediment transport process.The new boundary condition considering the coarsening of the surface non-uniform bed material is obtained.Lots of non-equilibrium sediment transport process in different hydraulic and bed material conditions are calculated by the new lognitudinal-vertical 2-D mathematical model of non-equilibrium sediment transport considering the coarsening of surface bed materiel.Finally,the experiential expression of the recovering coefficient of sediment concentration is discussed.
Analysis of near-bed sediment motion
LIU Qing-quan, ZHOU Ji-fu, SHU An-ping
2003, 14(5): 569-575.
Abstract:
Based on the experimental data obtained by using two-phase measuring technique,this paper analyzes the fluctuating features and mechanism of sediment movement near the bed in water-sediment flow.The special mechanism of sediment movement in the near-bed layer is found in that sediment particles have very intense non-turbulent fluctuation near the bed,resulting in fluctuating stress,which will greatly influence sediment movement.From this point of view,a systematical knowledge on the physical process of sediment particles being raised in water flow is presented.Some problems and insufficiencies existing in traditional theories are discussed,from which a new basic model of sediment entrainment is suggested.Using the two-phase flow theory,the mechanism of sediment entrainment are analyzed in detail.Finally,the profile of sediment concentration are investigated by the theory of momentum equilibrium of particle movements in vertical direction.It is demonstrated that,besides the gradient of sediment concentration,the gradient of fluctuating velocity intensity of particles is also a significant diffuse force,which further gives a reasonable explanation for the mechanism of two types of profiles of sediment concentration.
Vortex structures of round turbulent jets in cross-flow
LI Wei, JIANG Guo-qiang, ZHANG Xiao-yuan
2003, 14(5): 576-582.
Abstract:
The vortex structures of round turbulent jets in cross-flow with different velocity-ratio were investigated by using the PIV in this paper.It is found that the vortex structures include the Kelvin-like vortexes in shear-layer of jet,the cross-flow separation vortex pair,the horseshoe vortex system in upstream bottom region of jet and the wake vortexes.Through analysis of evolvement mechanism of vortex structure and topology,the two separation lines in the nearfield of the jets are obtained :one of them is the separation line of the cross-flow and another is the line of shear vortexes around the jet to enter cross-flow separation vortexes.Ultimately,the separation vortex pair enter and mix with the jet at far field to form the counter-rotating vortex pair in the jet body.
Influence of the tunnel crossing the Yellow River in South Water to North Project on flow and sediment movement
YU Ming-hui, FAN Bei-lin, YU Wei-qing
2003, 14(5): 583-587.
Abstract:
The tunnel is one of the ways to cross the Yellow River in South Water to North Project.This paper has calculated and analyzed the influence of the project on the flood flow,sediment movement and river bed deformation,which is only referred to the tunnel method,using the 2D-horizontal unsteady numerical model and in the flood process once per 10000 years.It has been proved that there is little influence of the tunnel on flow and sediment movement in the flood process.
Investigation of different models to describe soil particle-size distribution data
LIU Jian-li, XU Shao-hui, LIU Hui
2003, 14(5): 588-592.
Abstract:
Particle-size distribution (PSD) is the most fundamental soil physical property,which has a distinct impact on other physical properties such as soil hydraulic properties.As an input parameter for various simulation models,the accurate description of PSD is of vital importance to the reliability of simulation results.In the present study,five empirical models,i.e.,the log-normal distribution,the cubic spline,the logistic growth,the modified logistic growth and the van Genuchten models,are employed to describe the cumulative particle-size distribution data from laboratory experiments,an international database and literature publications.Results indicate that optimal agreements between measured and predicted values are obtained through the modified logistic growth model while the most frequently used log-normal model produces relatively poor agreements.Furthermore,the other three empirical models are in between the aforementioned two models in terms of prediction accuracy.Similar results are obtained in additional application of these models to estimate soil water retention characteristics using a fractal approach.
Sensitive analyses of parameters in unsaturated soil hydraulic conductivity model
LI Yi, SHAO Ming-an, WANG Wen-yan, WANG Quan-jiu
2003, 14(5): 593-597.
Abstract:
This paper analyses the sensitivities of the parameters in the unsaturated soil hydraulic conductivity model developed by Shao Mingan.The sensitivity degrees of unsaturated soil hydraulic conductivity to different parameters are calculated by using the laboratory measured data to compare the influence of parameters on soil unsaturated hydraulic conductivity.The results show when the linear function is adopted to express the relation of average moisture of soil profile and moisture of wetting front,the sensitivity of parameters are much higher than the other parameters in Shao's unsaturated hydraulic conductivity model.
Pumping test in the fracture-karst aquifer in Zhangji well field in Xuzhou
QIAN Jia-zhong, WU Jian-feng, ZHU Xue-yu, DONG Hong-xin, LI Gen-yi
2003, 14(5): 598-601.
Abstract:
Based on the assignments in the phase of detailed reconnaissance in Zhangji well field in Xuzhou,as well as its characteristics of hydrogeology,the new technical requests and working methods for the pumping test in Zhangji well field is proposed.The results of the tests show that the new technical requests and working methods not only satisfy with the request of numerical calculation for the evaluation of groundwater,but also fit for the situation of electrical webs and wells,in addition saves the outlays.In the meantime,the conclusions are important value for the evaluation and ministration of groundwater resources in the large-type well fields.
Study of determining geomorphologic unit hydrograph by means of probability density functions of path length and slop
RUI Xiao-fang
2003, 14(5): 602-606.
Abstract:
The instantaneous unit hydrograph (IUH) was interpreted as the probability density function (PDF) of water drop travel time in the basin by Rodriguez-Iturbe et al and Gupat et al.As the water drop travel time in the basin equals to proportionality of the water drop path length to its velocity,a new method for determining IUH is suggested by means of the PDFs of path length and velocity of water drop based on law of the probability theory.The PDF of the water drop path length can be viewed as the width function,and the PDF of water drop velocity is transformed by the PDF of slop.Otherwise,the analytical equation of slop PDF is derived by the principle of maximization information entropy.Technical support of the new method is of the digital elevation model.The example watershed given in this paper is located at Hubei province,China,and the simulation accuracy is satisfactory.
New model for multi-step prediction and its application to flow prediction
WEI Feng-ying
2003, 14(5): 607-611.
Abstract:
Based on the analysis of annual maximum flows between 1951 and 2001 in Tongguan,Huayuankou and Lanzhou,a new model for the multi step prediction is proposed in the paper.The model is well available for continuous multi step pre diction and anomalous extreme values.The example,applying the model to the multi step prediction of independent sample during 1995-2001,results show that the tendency of variation for every year can be predicted skillfully by the model.The variation for the flow during 2002-2005 is also predicted.
Problems on flood forecasting in the semi-arid region
CHEN Yu-lin, HAN Jia-tian
2003, 14(5): 612-616.
Abstract:
The characteristics of the semi-arid region are shortage of rainfall and the non uniformity of spatio temporal distribution.Conditions of catchment underlay differ from humid regions.It is difficult to forecast flood in the semi-arid region,which is non uniformity of infiltration capcity,computation of water content in surface soil,leakage calculation and non-unifority of rainfall.The preliminary methods for overcoming above difficulties are also discussed.
Study on the evapotranspiration simulation of sub-alpine forest area in Gongga Mountain
CHENG Gen-wei, CHEN Gui-rong
2003, 14(5): 617-621.
Abstract:
The Penman-monteith formula is applied to simulate the dynamic of evapotranspiration for naked land,Abies fabri forest and shrub-grass areas.The simulated results show that net radiation,air temperature and vegetation types are the predominant factors to control the dynamic of evapotranspiration.The evapotranspiration process modeled for naked land is similar to the observed evaporation of water surface.The higher values of evapotranspiration appear in April and September respectively owing to more sunshine and lower air humidity,while the lower values appear in July and August for great deal of rainy days.The simulated values of evapotranspiration of forest and shrubgrass areas are higher in growth period,or lower in non-growth period than that of naked land surface.The difference between these two kinds of land surface varies by ±25%.The simalated results show that the modified Penman-Monteith formula can be used satisfactorily in the hydrological cycle analysis for mountain regions with forest coverage.
A design risk model for the downstream slope for overtopped rockfill cofferdam during flood
HU Zhi-gen, HU Jian-ming, LI Yan-qun
2003, 14(5): 622-625.
Abstract:
The paper systematically discusses the relations of uncretainty between the current velocity head,design head of erosion protection of the downstream slope blocks,construction flood and sizes of diversion structure during operation of rockfill cofferdam,and analyzes the operational safety affecting cofferdam slopes.Based on the computational method for the worst flood discharge during overtopped rockfill cofferdam,a design overflow risk is measured by the probability that current velocity head of cofferdam downstream slope blacks exceeds its design erosion protection head.A computational method for design risk in overflow period of cofferdam is given by using the JC method of reliability theory,providing a theoretical rule of structural design,energy dissipation and erosion protection for overtopped rockfill cofferdam.
Application of the maximum entropy principle to risk analysis of economic benefits for water projects
LI Ji-qing, ZHANG Yu-shan, WANG Li-ping, JI Chang-ming
2003, 14(5): 626-630.
Abstract:
Adopting the method of arrangement analysis,this paper divides the general economic benefit system of water conservancy project into flood-control,power-generation and irrigation benefits subsystems,identifying their respective risk factors,establishing a risk analysis model of economic benefit based on the maximum entropy principle,and presenting the solving method.The paper analyzes the risk of general economic benefits in two ways : one way is to obtain the maximum entropy density function of the total benefit indices through a direct probability analysis of the identified factors of the system; the other way is to analyze the probability characteristic of subsystem benefit in advance,then combines the risks to examine the probability nature of the general system according to the idea of "risk tree".Finally,a practical example is provided to testify the feasibility and practicality of the model.
Design of water resources accounts:a case of integrated environmental and economic accounting
CHEN Dong-jing, XU Zhong-min, CHEN Ren-sheng
2003, 14(5): 631-637.
Abstract:
Based on concise introduction of the system of integrated environmental and economic accounting (SEEA) devel oped by United Nations,Zhangye prefecture,lying in Heihe catchment which is the second longest inland river in China,is studied to explain the compiling procedure of water resources accounts Water resources accounts include physical account,monetary account,allocation account of water depletion cost and integrated account in the paper.The results show that depletion cost of excessive water use is 197.93 million yuan,that net domestic product (NDP) deducting water depletion cost,EDP,is 3.56% less than NDP,and that water depletion cost accounts for 9.39% of traditionally net capital formation in Zhangye district in 2000.
Research on the produce function of the district flood control and water drain
HE Jun, FANG Guo-hua, GAO Shu-ming, TAN Wei-xiong
2003, 14(5): 638-642.
Abstract:
This paper analyzes the features of the construction cost,running cost and output in the flood control and water drain section.The yearly benefits are random; the construction is the long-term acting and exhausted year by year.For making the produc function to be based on the actual cause and effect link,this paper advances to accumulate or average yearly bene fits to counteract the randomicity,then to calculate how much construction decrease in the corresponding period considering long-term acting.On this condition,the two kinds of the produce function are established.An example of the flood control and water drain produce function research in Jiangsu province is given.By the regression analysis the polynomial and power funce of the produce function are worked out.It shows that the flood control and water drain pay rate is very high after 1990 in Jiangsu province,and the running cost is more helpful to performance then construction cost.The accuracy and applicability of the method is verified by the example.
Flow measurement using concentrated salt water as non-radioactive tracer in sewage pump
GUO Jian-bin, ZHANG Qin-wu, WU Hai-bo, GUO Zhi-cheng
2003, 14(5): 643-646.
Abstract:
Taking account of the defects of routine measurements of water flow on sewage pump,the feasibility study about the method using as non-radioactive tracer was made from the theory and the practice.It was shown that the method was suitable for sewage measurement under the background of low salt density.The effects of exciting signals and temperature on results were observed.Then the revision method were proposed With the technique of data acquisition by computer,the accuracy and synchrony of this method were improved.
Indicators system for region sustainable water resources utilization and its assessing methods
SONG Song-bai, CAI Huan-jie, XU Liang-fang
2003, 14(5): 647-652.
Abstract:
This paper reviews the current state of indicators for sustainable water resources utilization and its assessing methods,analysis problems in establishing indicators for sustainable water resources utilization and evaluating methods.Finally,the authors probe into main contents and methods for sustainable water resources utilization.
Advances and main applications of lake optics research
ZHANG Yun-lin, QIN Bo-qiang, CHEN Wei-min
2003, 14(5): 653-659.
Abstract:
The main achievements of lake optics in recent several decades are simply presented,which include optical properties of lake water,the observation,transmission and calculation of underwater radiation.Research emphasis of lake optics are thoroughly expounded,including determination of absorption coefficient S of yellow substance,influence of UV-Bradiation on lake ecosystem,ecological effect of light,photochemical processes,calculation of lake primary production by the bio-optical model and analysis of restrictive factors for eutrophication and protection of lake eutrophication1.At last,the main applications of lake optics,such as calculation of lake primary production and Chl-a,demarcation of detection of suspended matter and water color remote sensing,are summarized.Moreover,the paper also points out research orientations,the gap between the level of lake optics reasearch in China and the worldcs advanced levels and researches required in China.
Advances in real-time irrigation operation
GU Shi-xiang, FU Hua, LI Jing
2003, 14(5): 660-666.
Abstract:
Irrigation real-time operation is an important mark of agriculture water management heading for intelligent,automation and modernization.Its future lies in synthesizing geographical information system,satellite remote sensing,global position system,computer,artificial intelligence,information technical,and agriculture irrigation,meteorology,system engineering,and improving the flexibility,reliability,and adaptability of irrigation operating.Meanwhile,it is faced with more difficulties such as the basic facilities backward,technical resources weak,and information process expensive,satellite transmission period longer,and so on.In order to promote development of irrigation water management research,this paper reviews the important advances and latest achievements in the research of real-time irrigation forecast,channel water dynamic allocation,field moisture monitor,computer assist decision support system and irrigation space information management.
Global climate change and its impacts
LEI Wen, Charles A. Lin
2003, 14(5): 667-674.
Abstract:
Governments and their citizens in different countries around the world are increasingly concerned with the potential impact of climate change on society and the environment.Society is also becoming increasingly vulnerable to severe weather events and climate extremes,which are projected to increase in frequency in a warmer world.It is thus important to understand recent changes in global climate and the occurrence of extreme events in the late 20th century,to better deal with projected climate change scenarios for the 21th century.This paper summarizes the results of climate change studies over different countries and regions.The results are based on scientific articles,reports and assessments already available in the literature.We first introduce regional climate variations in the late 20th century based on observations and analysis.We then discuss climate change scenarios based on the IPCC (Intergovernmental Panel on Climate Change) scientific report.Uncertainties in climate change projections and opinions of skeptics of human-induced climate change are also reviewed.Finally,the potential impact of climate change on society and the environment will be briefly addressed.
2003, 14(5): 675-676.
Abstract: