Abstract: This paper discussed issues that water resources are faced with the global change studies,as well as the due important position of the water resources in the a ssemble program of global change studies.This paper at tempts also to discuss some relevant technical issues in water resources planning and management in implementation of the principle for water resources sustainable development.
Abstract: This hydrodynamic model is founded by S.Q.Wang for predicting the fluvial processes in the reservoirs and the river channel.The new formulas of flow resistance and sedimentt ransport are used in the model and the characteristics of hyperconcentration and nonuniformity of sediment are considered in the model.This model is verified by using observed data from 1960 to 1988 in the Sanmenxia Reservoir and the lower Yellow River.It is successfully applied to predict the processes of aggradation and degradation of the Xiaolangdi Reservoir and the lower Yellow River for various schemes.
Abstract: The flow field is simulated by using 2-D vertical unsteady fluid dynamic equations,in which a κ-ε urbulent model is employed.Based on the flow field,concentration distribution is computed by solving a quasi-3-D concentration equation in the near area of 6-point waste-water discharged in the deep water in Qiantangjiang river.Compared of the surveyed fields,the computational results are reasonable.
Abstract: To probe into the motion laws of Oncomelania in channel flows,the paper investigates the threshol d velocity of Onco melania st icking to the boundary of channel by means of experimentals in flume; two formule for the threshold velocity are derived based on the theories of river mechanics and biomechanics and the elements which effect on the threshold velocity have been analyzed.The results show that,because of the eminent biological adsorptive power,the treshold velocities for Oncomelania with open operculum and sticking to the boundary of channel are statistically much great than that for Oncomelania with close operculum and justlying on the channel bed,however,the theshold velocities scatter whthin wide limitas.
Abstract: In this paper,the SMAR (Soil Moisture Accounting and Routing) Model is briefly reviewed with a special addressed on it srevision-the distributed and flexible time-intervals model which were made during this study course.The auto-optimisation technique of the model parameters,the flow routing method and the real-time updating theory which were employed in the developed system are discussed.The features,menu system,and basic requirements of the developed system are briefly introduced.As one case study,the application results of the system in the Three-Gorges catchment on the Yangtze River are presented and discussed.
Abstract: Hydrological factors of formation of large flood in the lower tidal reach of the Yangtze River are analyzed,and change trend of large flood is revealed.Obtained conclusions are:(1) Formation of large flood in the river reach is very complex; (2) Occurrence frequency of large flood in the river reach has been increasing since 1900; (3) The mean value of the peak stage has been rising since 1975; and (4) Above the charct eristics of occurrence of large flood in the river reach are primarily affected by human activity and rise of sea level.
Abstract: Chaotic and stochastic behaviors of natural phenomena are fully diffirent.It is the foundation for simulation and prediction of flood flows to distinguish the behavior of a system which will generate them from their stochastic behavior.This paper deals with the identification of these two behaviors froma time series of flood flows and based on the analysis principle of chaos.The results show that the time series of flood flows at Pinshan station are characteristic of chaotic behavior,that is,a strange attractor may exist.Such a strange attractor has fractal dimension,positive Lypunov exponent and Kolmogorov entropy.Therefore,the complex phenomena of flood flows may result from the evolution of an inherent non-linear dynamic system.
Abstract: Firstly,based on the theory of runs distribution in one-dimensional random process,the theory of run distributions in multi-dimensional random processes is presented in this paper.Here,random processes are classified in four types:(1) Processes are independent on spatial and temporal scales; (2) Processes are independent on spatial scale and correlated on temporal scale; (3) Processes are corre-lated on spatial scale and independent on temporal scale; (4) Processes are correlated bot hon spatial and temporal scales.Secondly,the statistic method is used to test the accuraucy of developed runs theory.Finally the results from the application of runs theory to Yellow River historial droughtevents reappear characters show that return period of annual drought event taking place in middle reach and lower reach of the Yellow River at the same time is 5.78 years,return period exceeding one year is 7.76 years,and exceeding three years is 110 years etc.
Abstract: The paper deals with optimal operation of conjunctive-use system composed of reservoir and aquifer.Considering distributed parameter characteristic of the system,a general response function is used to couple physical model and optimization model,then a decomposition-coordination approach is established based on hiera rchical structure and complex in teractions of the system.Finally,the approach is applied to the reservoir-aquifer conjunctive use system in Xingtai distinct,and follows a satisfactory results.
Abstract: The steamline curve ratio in the bucket of a spillway gradually changes in the flow direction,but the wall curve ratio changes in the point of contact of the bucket suddenly.To coordinate the streamline curve ratio with the wall curve ratio,the definition of the curve ratio in the point of contact of the bucket is replenished,it is supposed that the curveratio in the vicinity of the point of contact of the bucket is a linear relation,the gravity and centrifugal force and the development of the boudary layer are taken into account,the pressure for mulas in the bucket of a spillway is developed.With the help of the testing data,the validity and reliability about the formulas is verified.
Abstract: The Sacramento Model has many parameters with complex relation ship.The reasonable physics region of parameters should be determined in order to calibrate effeciently.The parameters of the Sacramento soil moisture model are classified as 5 categories based on the main overall effect that they can have on soil moisture state and runoff response,and the method of initial parameter estimate is described by hydrograph analysis and basin's physical characteristics.The practical experiences were stated in a application example of parameter optimization.
Abstract: Caoe River basin is one of the richest river basins in water resources along the shore of East China Sea,and is one of the rivers with the most frequent flood disasters.This paper is focused on the effects of water-resource projects on terrestrial and aquatic environment,especially on the carrying capacity of water environment.It has evaluated the importance of these water-resource projects in utilization of the nature water resources.It also pointed out how to prevent the sideeffect of those projects.It provides impo tant data for scientific research in the following a spects.(1) The water-resource projects influence the distribution of runoff in space and time and balance the runoff among different seasons.The suspension load,sediment discharge,and sediment flux have all been reduced by 10% to 20% in the down river of the reservoir.(2) These projects have protected the natural botanical zone a round the reservoir,changed the local climate,and improved eclolgical structure and functions of the local farmland.They also influenced the growth of aquatic organism which increases the productions of fishing and other aquatic products.(3) These water-resou rceprojects have both positive and negative effets on the carrying capactity of water environment.They increased the carrying capacity during drounght season while decreasing it dring flood season.The tendency of balancing the carrying capacity of water environment among different seasons plays an imporant part in improving environmental quality.
Abstract: The river flood control hydrological information system in Yi-Shu-Si rivers basin is an important part of the flood control decision support system.This paper introduces mainly design characteristics for the flood control hydrological information system,including openness of the system auto-adaptability of processing hydrological information,graphic expression of hydrological information,figure roamming,synthetical showing of hydrological information,combining the windows,overlapping of graphic,dialoging for man and computer,the historical flood information retrieval,drawing on screen and its in correspondence with plotting instrument and so on.
Abstract: Cold-atom fluorescence is a sensitive method of determining mercury.However,bigerrormay occure if it is not operated reasonably.This paper discusses and tests repeatedly the treatment method of standard series during the test,the cortrol of the blank value of the reagent and the quality guarantee of alined curve.The methods for obtainning reliable data are also studied.
Abstract: In this paper,various models for analysis of seepage flow in fractured rock masses are systematically summarized and studied.Bases on the seepage mechanism,the merits、demerits and applied conditions of these models are illuminated.In addition,their application circum stance in engineering is stated.Above all,the continuum-discrete coupled model which takes advantages of both equivalent continuumm odel and discrete fracture model has the most vast vistas for engineering applications.