Abstract: A perfect water quality monitoring system has been built in China during 50 year's effort After many years,we have collected a great deal of water quality data.The China water environment information database was finished in 2001.It includes water quality testing records in 1990s of 160 important water quality stations.The database,maintenance system and in formation system based on Web GIS have made water quality data being shared.In this paper,the prime water quality situation of every big river area are analyzed based on these original data.The probable situation of water environment can be reflected by the statistics,such as water quality class and primary water pollution type.The results show that water environment situation of China is not optimistic,water pollution is serious,and the river area in North China such as Yellow River and Liaohe River are,especially,seriously polluted.
Abstract: The RNG turbulence model considering the buoyancy effect is used to establish a mathematical model of obstructed round buoyant vertical jets in static ambient.The hybrid finite analytic method with stagged grid is used to solve this model With the concept of concentration correction factor,the effect of the disc to improve the near field dilution of buoyant jet is confirmed.Meanwhile,the H/D,H is vertical distance of disc from jet exit section and D is disc diameter,primarily affects the concentration distribution behind the disc.It is found that the range of Froude number,in which normal round flowing occur,decreases quickly while H/D <1.When the plate is near the port,jet can be easily reverberated by the plate,and when the plate is far from the port,the round flow after the plate will bifurcate out of the range of Froude number.The two steps to control flow pattern and improve dilution on the axial near the plate are proposed also.
Abstract: Based on a series of numerical calculations,the behavior of flow field in obstruct ed round buoyant vertical jet is summarized and analyzed.Based on the axial line velocity distribution,the flow after the disc can be divided into three regions:i e recirculation region,transitional region and self similar region.The laws of the length of recirculation region varying with Froude number F0,port diameter D/d and the distance H/d of the disc from the port are got.The velocity distribution charts in cross sections and the least length from the disc needed for reaching self similar area in different Froude number under three different conditions of H/D=1,D/d=2,6 and H/D=3,D/d=2 are also obtained.And it is found that Froude number is the key factor to decide which flowing pattern in the field.The pressure distribution changing in the flow area for three kinds of flow patterns is analyzed and it is found that the magnitude and location of the third negative pressure center caused by the increase of Froude number are closely related to flow patterns.
Abstract: In this paper,The flux difference splitting(FDS) scheme is applied to two-dimension flow-pollutant numerical simulation.Some simplified models in ideal conditions are used to analyze the accuracy of FDS scheme.The model of steady point source discharge shows high accuracy.To reduce numerical diffusion in big concentration grades,a limited flux is added to the first order scheme so as to derive the second order scheme.The results of water quality discontinuities model prove that FDS second order scheme can catch discontinuities with so high resolution that it can accurately simulate big concentration grades or abrupt water quality jump.The successful application in water environment numerical simulation of Nantong section of Yangtze River ulteriorly validates the practical application ability of FDS scheme.
Abstract: ased on the universal k-ε turbulent model,we trace free surface with the volume of fluid(VOF) method for taking the character of distinct surface elevation,and establish a two-dimensional model of vertical plane turbulent jet discharged from bottom of shallow water.Many numerical simulation experiments are implemented for differential groups of water depth,velocity and width of jets and the whole flow field is analyzed.We find that the distribution characters of velocity vector field and that of surface elevation are corresponding.A self-preservation law of surface elevation distribution around jet axis is found and an empirical formula is established.Due to the surface retardation,the attenuation rate of velocity becomes quicker,which depends on water depth and jet width.
Abstract: The integrated system described in the paper combines the geographic information system software based on a vector data structure with a simulation model for non-point sources(NPS) pollution management.Territory is disaggregated into a series of irregular vector polygons for spatial modeling units of NPS through many map overlays such as land-use types,soil cover,subwatershed layers,and the case is studied in Suzhou creek,Shanghai.The structure,functions and database of the seamless integrated Suzhou creek NPS pollution management system are designed based on the COMGIS MapX,surfer software platform.At the end,the management system is developed.The integrated system can perform effectively the pollution loading estimation,the pollution index evaluation,the isoline output of unit pollution loading,and total quantity control of NPS pollution.Our integrated system is not only an available test of NPS professional software,but also an available probe of digital watershed environmental management.
Abstract: Many phenomenon and findings have demonstrated that heavy mental pollutants transport through the carrier of sediment.So,to describe the complicated process,it is very important to firmly grasp two important factors:sediment motion and its relationship with heavy metal pollutants transport.In this article,the present existing models on heavy metal pollutants transport are generalized and classified.Base on analysis of the interaction relationship between sediment and pollutants,a coupling model on heavy metal pollutants transport is obtained by combing environment chemistry and mechanics of sediment motion.The sediment motion and the dynamic process of heavy metal's adsorption and release are considered in the model.To prove the model's rationality,theoretical analysis and computational comparison are also conducted,the result shows that the model can describe the complicated procession properly.
Abstract: According to some previous results,the relationships among three common incipient motion conditions are deduced.Considering these relationships,dozens of incipient motion conditions are united,and K of all kinds of formulas is otained commonly from 3.37 to 7.86.This result is helpful to select appropriate incipient equation.Based on this research,the comparison study is made between pebble factual data in outdoors flume of Hanqiwei in Minjiang,1965,and calculation results of parts of classic formulas.This result is also useful to select appropriate incipient equation in Dujiangyan,Minjiang.
Abstract: How does the long and deep buried diversion tunnel influence the water temperature in an important question related to downstream aquatic organisms.A 3D numerical temperature model for diversion tunnel is established by combining the k-ε model and the energy transport equation.The model is tested with the prototype observed data.The water temperature of the diversion tunnel of Jinping second cascade to be built is predicted and it shows that the increase of the water temperature through the tunnel is not obvious due to the big flow rate,short retention time and large diameter of the tunnel.As the actual full size data is used to build up the computational zone including the concrete lining zone and the action between temperature and velocity field is taken into account,the model can accurately simulate the temperature field and provide scientific reference for the design of hydropower stations and protection of aquatic organisms.
Abstract: The problem of bulky memory requirement and low efficiency in calculation of unsteady flow with finite element method(FEM) has troubled the engineers for long time.It also restricts the applications of FEM to fluid dynamics The method of time-splitting and FEM were combined to solve the 2-D shallow water equations.The row-indexed sparse storage mode was used to store the sparse coefficient matrix,and the preconditioned bi-conjugate gradient method was used to solve the huge linear system.The results are satisfactory both in memory and efficiency The problem has been solved to a certain extent.
Abstract: A new division of ice engineering sub areas is set up based on the ice physical and mechanical parameters distributions in Bohai.The characteristic of the division shows that the load on the vertical structures with same diameter or width is equal in a same division area.Therefore,the new division index becomes the product of a uniform ice sheet design thickness and peak compressive strength at different return periods.To obtain these physical and mechanical parameters,we use history data to set up the expressions of a uniform ice sheet or ice sample temperature,salinity and density with air temperature,water temperature,ice period and ice thickness.Then ice porosity is obtained Later ice peak compressive strength is calculated by using the experimental relationship of Bohai ice peak compressive strength and porosity.At last,the ice sheet physical and peak compressive strength distributions at different return periods in Bohai are developed from ice sample results.The new ice engineering sub-areas at different return periods are obtained with the help of the new division index.The new ice sub-areas in return periods of 25-,50- and 100-year are given as samples.
Abstract: The article studies the Muskingum method,its advantages of the hydrodynamic models and the way to calculate the lake-saving.And a numerical model that can reflect effection of the lake-saving is established,which is validated by using the observed data of the Jingjiang River and the Dongting Lake in 1996 and 1997.The result indicates that the model is suitable to deal with lake-saving.At the end,the article studies the complexities of lake-saving in calculating complex river systems.
Abstract: This paper deals with water cycle and identifies its remarkable changes in the Yellow River basin.The water cycle provides an essential foundation for scientific assessment and rational development of regional water resources.The changes of water cycle elements depend closely on climate variations and human activity impacts.Based on the careful investigations of the influences resulting from climate change and human activities,the author describes the water cycle changes in the Yellow River basin,and suggests in this paper that the adoptive measures should be employed to adopt climate change influence through deeper and better understanding of the relationship between water cycle and climate change trend and predict it.The human activity impacts could scientifically controlling water resources development by enhancing water management.All in all,the targets should maintain renewability of natural water resources system in the Yellow River basin.
Abstract: The simulation experiment was carried out in Taihu Laboratory for the lake ecosystem research from May 8 to June 24 in 1999.In order to find the distribution of light intensity and variation of primary productivity due to the increase of total suspended matter caused by water flow,the attenuation law of underwater light intensity,the relationship between the diffuse attenuation coefficient,the light euphotic depth and the total suspended matter,and the effects of light on primary productivity were studied.The results show that the light intensity attenuated as the depth increased,showing the good negative index correlation under not only the immobile condition but also weak and strong water flow.From immobile condition to weak and strong water flow,the diffuse attenuation coefficient increases from 1 m-1 to 2 m-1 and 4 m-1,and euphotic depth decreases from 4 m to 2 m and 1 m.There are a good linear correlation between diffuse attenuation coefficient and total suspended matter as well as euphotic depth.Under immobile condition,the maximum primary productivity was recorded between 0.4 m and 0.6 m due to light inhibition at surface water shined by strong light.Under other circumstance,the maximum primary productivity was recorded between 0 m to 0.2 m due to the increase of the total suspended matter caused by water flow.
Abstract: In this paper,we firstly,introduce the present research situations about ecological water deman,develop and analyze theoret ically,a new method for calculating the ecological water demand,combining the ecological economy theory based on sustainable development.According to the ecological value theory,the ecological values for different ecological water demand are confirmed.The relationship between ecological value and the economic value of water resources is used to confirm the ecological water demand.A case is used to show the concrete steps of this method The ecological water demand confirmed by this method fit with actual conditions,and can be used to study the ecological water demand theory during environment construction.In this method,the ecological system and the economy system are combined together by water resources.And this method has significance for studying the water resources utilization in the condition of sustainable development.
Abstract: With the increasing awareness of the importance of ecological and environmental protection,the concept of ecological water demand has been disputed among numbers of researchers mainly from the field of ecology,hydrology and water resources.In this paper,the concepts related to different aspects of the ecological water protection are discussed,including ecological water demand,the existing ecological water,the ecological water use,the ecological water shortage,the ecological eater consumed and ecological water returned.Two general relationships between the concepts are also described.It is noted that the concept ecological water demand is proposed for the ecological protection or rehabilitation as well as water resources development and utilization.While the ecological water shortage must be the most direct factor for water resources allocation if we take into account the ecosystem and environment health.The ecological water shortage can be determined based on the estimation of ecological water demand and the assessment of existed ecological water,and may be the base of ecological water use.The procedure of water resources allocation for the ecosystem is as follows.At first,the ecological object must be defined rationally according to the field investigation.Then the ecological water demand,existing ecological water can be estimated,and the ecological water shortage can be obtained.Based on the ecological water shortage and the feasibility of ecological water use,the schemes of ecological water allocation can be settled.
Abstract: This paper aims at obtaining the furthest assurance of the unitary of interstitial geohydrology succession(IGS) types in discrete voxels,improving on the defect of multi-types of current simulating discrete voxels,and consequently,enhancing the operability of parameter evaluation and the precision of simulated result in the stimulating process of groundwater current 3D finite-difference.Considering spatial discontinuity and thickness asymmetry of IGS in the nature,this paper studies IGS 3D spatial discrete techno-course based on geographic information system(GIS) and put forward the implementary method with IGS anomalous hexa-voxels.It can not only keep the type unitary of IGS anomalous hexa-voxels to the utmost extent,but also make full use of GIS spatial analysis and data auto-extraction functions,extract rapidly the spatial coordination of all calculating labels and all kinds calculating parameters,therefore,greatly shorten the time need in geohydrology model spatial dispersion and relative data file management,and increase the simulating effectiveness for a given period of the groundwater 3D finite-difference.
Abstract: In this article,the relationship between the three existing forms of carbonate and pH value is studied at different temperatures and CO2 pressures in an open underground water system while activity is taken into consideration.We find that the value of pH0 decreases with the increase of temperature and tends to a stable value at a given CO2 pressure and the value of pH0 decreases with the increase of the CO2 pressure at a given temperature when CO2 pressure changes in the range of 10～105Pa and the temperature changes in the range of 0～30℃.However,no matter how the temperature and CO2 pressure of the underground water change,pH0=7.92～8.60.These conclusions reflects the actual conditions of the underground water and can be better used for the review of water analysis data.
Abstract: As a new kind of technology,the virtual reality is more and more recognized by geographical industries in recent years.In this paper,several key points on the application of virtual reality to valley simulation are discussed based on the construction of Dujiangyan virtual-reality system,including multilevel terrain construction,fluid simulation,scene roaming controlling,multi-subject switching,project simulation and database connection,the research of all these aspects would be significant to the virtual reality application to valley simulation.
Abstract: Based on the 3S technology and the soil erosion equation revised by us,the soil loss amount and areas to be harnessed in the upstream of Longchuanjiang River of the Yangtze River were numericaly simulated and quantitatively analyzed.The calculated results are as following:(1) The soil erosion amount in 1998(drought year) was 840069.19 t,the erosion area was 2293.7841 km2,the soil erosion amount in 1999(water-logged year) was 8 90 182.6 t,the erosion area was 2 293.784 1 km2,the sum of the strong,heavy and violent erosion areas in 1999 were obviously stronger than that of 1998.(2) Soil erosion area over middle degree in 1999 was 35.2% of total area,meanwhile it was 26.0% in 1998.(3) The areas to be managed rapidly in classification sizes of prevention strength in 1999 and 1998 respectively occupied 16.27% and 14.63% of the watershed area.(4) The modeled results are similar to the observation value on the spot,which indicats that the method can be applied to soil erosion research of the red earth and monsoon region of Southwest China and it is accurate,convenient and practical.
Abstract: Dujiangyan Water Resources project,constructed in 256 B.C,is one of the oldest water resources projects which are still functional in the world.Recently,due to lack of maintenance of project's infrastructure,deterioration of the ecological environment and excessive industrial and agricultural expansions in its surrounding areas,the existing traditional water resources development model can no longer be able to adapt to the current and future demands of Dujiangyan irrigation area.Therefore,under the guidance of sustainable development principles and with a clear objective and a complete framework in mind,a new strategic framework for Dujiangyan water resources development is presented,together with its associated enforcement measures and an evaluation system,to push Dujiangyan Irrigation Area's progress toward sustainable development.
Abstract: In the irrigation area which adopts the flow measuring instrument,there are inevitably a lot of error in the process of measuring and calculating the water because of the section measured or person factors.Some illogical phenomena occur now and then.For example,sometimes the water measured on the upriver station is more than the lower station,and sometimes the water calculated between the stations is more or less obviously inaccurate.By using the revised simplex method of the linear planning theory,a model for adjusting water is proposed to adjust water of the illogical measuring stations and increase the precision of the statistics of allocated water and allocation regulation.Through application to Weishan irrigation area,it is shown that the model has a good effect.The decisive method in theallocation regulation of irrigation area realizes transformation from the practical qualitative analysis to the scientific quantitative analysis.So water management becomes more scientific.
Abstract: This paper introduces in detail the thought and way of long term forecast of water regime of reservoirs,based on the method of step regression and optimization of predictors,to reduce the error of prediction to the minimum.The way was effective for long term forecast of water regime of several reservoirs in the past.Forecast for the three hydraulic plants in the North East region of China is illustrated in detail and flow prediction for the June-September flood period in this region is part icularly suggested in this paper.We think that this method is practical for long termprediction for water regime of reservoir.
Abstract: One of the problems that an insurance agent wants to solve is how to carry out the flood disaster insurance loss estimation swiftly and efficiently for policyholders.According to the actual condition of insurance company,this paper investigates synthetic effects of the suffered body due to disaster,factors leading to the disasters and environment forming them,then brings forward a formula for the flood disaster insurance loss estimation ratio,so that a model for estimating flood disaster loss insurance is established.The factors,such as ground overload capacity related to the flood suffered body and the vulnerability of environment forming disaster,can be concerned and digitalized using the remote sensing and geography information system.The model is used to estimate the flood disaster loss insurance happened to the special economical zone of city Shenzhen.The result indicates that application of the model leads to the higher precision of all kinds of estimated objects.
Abstract: In the flood insurance,the sample information gotten doesn't accord with the theory requset for the statistical sample.So the Bayesian approach is used,namely according to premium confirmed by priori information,claim frequency and expected claim size are adjusted and corrected combining the new claims sett lement record.Thus premium can be est imated correctly and suits actual risk level.And an example is used to check the feasibility of Bayesian approach.The method and conclusion of the paper can afford reference for project research and business of flood insurance.
Abstract: Knowledge of atmospheric water vapor are related to many aspects such as rainstorm forecast,preventing and managing of droughts and floods,protecting and improving of ecology and environment and so on.Now these knowledge are scattered in every branch of meteorology,and there is not theory framework about atmospheric water.From the viewpoint of earth water science,the branch of atmosphere water is short of.We suggest that a branch of atmospheric hydrology should be established to fill the theory gap.Atmospheric hydrology is knowledge systems on researching exist,motion,change,effect and utilize of atmospheric water.
Abstract: MODIS(MODerate-resolution Imaging Spectroradiometer) is the newest generation of remote sensing techniques.Compared with the data obtained from other single remote sensing platforms such as NOAA and LandSat,the MODIS data have many advantages,for example,it is free and has higher temporal resolution(0.5 day),spatial resolution(250 m) and spectral resolution(36 spectral channels,ranging between 0.4 and 14 Lm).For the moment,the application of MODIS in hydrology and water resources is just at the beginning.This paper summarized the applications of the MODIS data in different aspects of hydrology and water resources,such as flood disaster monitoring,glacier or snow distribution,precipitation estimation,vegetation changes survey,soil moisture simulation,evapotranspiration calculation,hydrological modeling,and water quality control.It is expected that MODIS would be a very powerful tool for researches and applications in hydrology and water resources.