Abstract: When shallow-water is flowing around a shore or solid wall,often occurs a periodic flow phenomenon due to separation,vortex gener ation and shedding.This paper proposes a parameterized local vortex model and an algorithm aimed at modeling the transportation of newly-generated vortices in a background flow field as well as their interactions,which have been used to numerically simulate the lateral oscillations of flows near the dam site in Three-Gorge reservoir.
Abstract: The charact eristic of groundwater flow changed appa rently under high-temperature situations.The normal Darcy's law is not admissible at high-temperature situations.The reason is that the existence of tempera ture-gradient has direct and indirect effect on the flow of water body.In this paper,the theory of thermodynamics is used to solve the macro-balance equati on of momentum of fluid phase.Then the modified equation of motion for high-tem perature situation is presented.The modified equation can be used in practical problems,such as the usage of geothermal resources in China,the transport of groundwater with high-temperature found recently in the world.
Abstract: In order to study the effect of soil mulching with transparent polyethylene film upon the soil temperature regimes with variou soil water content a numerical one dimensional model has been developed.Optical properties of the cover was considered and the effect of soil water movement on soil temperature distribution was ignored.The ability of the model to predict the temperature regimes of the mulched soil under different soil water content was tested.The calculated results agree well with the observed data.It was shown that the temperature regimes are significantly influneced by the polyethylene film.The model is used to calculate the soil heating by the transparent polyethylene film mulched in the area which inputs the data of meteorology information.
Abstract: With the hypothes is of parallel plate model for local aperture regions,the apertures are generat ed by using the statistical methods according to a certain aperture distribution,and the numerical simulations are performed for saturated seepage flow and unsaturated seepage flow in the fracture.The mechanism of both saturated seepage flow and unsaturated seepage flow is the difference of water pressure potential.For the unsaturated seepage flow,the pressure of wetting phase(water) is less than the pressure of nonwetting phase(air) everywhere in the field.The water flow is mainly in the large apertures for saturated seepage flow.On the contrary,the water flow is mainly in the little a pertures for unsaturated seepage flow.
Abstract: According to the demand of decision support system and real-time water allocation for Huoquan Irrigation District,this paper presents a stochastic prediction model for yearly discharge and a real-time prediction model for monthly.The case study indicates that the AR(p) model is appropriate for yearly discharge and the precision of monthly model is also satisfied.
Abstract: The 3-D vis ualization of debris simulation can not only improve the representation of debris process,but also is very helpful for discoverying the macrorules controlling debris flowing and so can lay good foundation for providing later deeply analysing policy.In this paper,two systems are introduced.One is a system for debris simulation based on particle model(DEBRIS),developed by our department,the other is the well-known RS-GIS integrated raster GIS-ERDAS.Based on detailed data structure analysis of both systems,a 3-D dynamic visualization policy is designed and realized.
Abstract: In the foun dation of traditional forecasting flood methods,the neural network technology is adopted to forecast flood transfer history with high sediment percentage.Using the neural network method,the intelligent models are setup,and the recognition mechanism of flood with high sediment percentage is explained.The least mean square method is adopted to train intelligent models and through the neural network thinking flood water level,the discharge and sediment percentage are forecasted.There are very important value and far-reaching significance to study the theory and technology of forecasting the flood with high sediment percentage.
Abstract: Based on the statistics of the hist orical typhoon data,the general features,active periods,original scenes and active regions,and the intensity and natural life of tropical storms(typhoon)in the west-north part of the Pacific were analyzed.The main factors to cause serious typhoon disasters were discussed,and then the variation yearly,variation monthly,landing locations of typhoons landed in Chinese inshore regions were analyzed st atistically.Finally,a few of well-known landed typhoons and their caused disasters and loss were introduced briefly.
Abstract: This paper presents the comprehensive framework of complex flod forecasting system and uses neighborhood matrix to manage the network relationship of the interaction of models and data.The framework of flood for ecast system includes flood database,forecasting models,database integrity platform and model manager.The neighborhood matrix reflexes temporal dependence of flood forecast models,by traveling the neighborhood matrix we can get the model chain and data chain of the forecast system.
Abstract: The analys is of the change of trace element content in the upper part of Bore-YA indicat es that the content of B and the ratio of B/Ga,Sr/Ba and Cl/Br are sensitive in dicators of paleo-water salinity.The Bore-YA palaeo-salinity index curve shows,several one-hundred-scale salinity fluctuations occurred in this a rea in the last several thousand years,and they are probably relevant to sea-water inundations and recessions resulted from concurrent sea-level fluctuations.The fact indicates that trace elements in sedimental strata in the coastal area are good proxy for conventional sea-level changing indicators.
Abstract: The main technology scheme based on the Intranet environment of the informati on system of prophase achievement for the middle route South-to-North water transfer project is introduced.The system development and management method,network building,development environment and tools etc. are described.Some key techniques for the similar system development are discussed.
Abstract: Water resource value is the foundation of water resource continuous utilization.The traditi onal water conservancy project economy a ssessment was manacled by the idea of "water resource are taken unexhausted and expensed unexhausted",so there was a complete lack of taking into account water resource itself value,brought the water conservancy project economic assessment into a fuzzy result or a feasibility conclusion with deviation.This text brings water res ource themselves value into the water conserv ancy project economy appraise in two asp ects:the influences of water resource value on supply-requirement contradiction at waters upply area and water conserv ancy project economy benefits,the result declares that consideration or no consid eration water resource themselves value can bring into tremendous influence on a nalytical results,even may-be bring opposite conclusion comparison with intrinsic conclusion.
Abstract: The food yield per unit water is an important index,which indicate the efficiency of the irrigation water use and status of food production.Based on the calculation of food yield per unit water in every provinces,analysis of the regional conditions and actuality of water resources development and utilization,it is shown that the potential of food produce rely mainly on increasing food yield per area and improving irrigation water use,and the irrigation area can be moderately developed in the areas with abundant water resources and land resources.
Abstract: Based on the univ ersal water surface eva poration coefficient formula obtained from numerous experimental data and extens ive evaporation investigations of different types of water regions in China,a formula of additional evaporation loss from cooling ponds caused by waste heat rejection is recommended and compared with that used currently.
Abstract: This paper mainly introduces the complement,the condition and the use of applying the way of pollutant discharged trade to reduce the nonpoint source pollution,especially discusses the way to reduce the phosphorus pollution in Tai Lake.It is considered that the pollutant discharged trade is one of the effective ways which solves the pollutant in Tai Lake nourishment.
Abstract: The development of groundwater vulne rability concept is such a continu ously enriched,perfected and developed course which is from simple to complex,from considering inner factors merely to considering inner and outer factors comprehensively,and from divergence to agreement.Correspondingly,the assessment methods are from qualitative description by using maps to quantitative express by using mathematical model.The existing problems of groundwa ter vulnerabi lity assessment are put forward,and the present situation of research is discussed,and it points out that it is a hopeful research direction to assess the groundwater vulnerability by using the gray system theory,the fuzzy mathematical theory,the AHP method and the GIS techniques at last.
Abstract: The spatial variability of soil hydraulic properties is one of the most important factors which have great effects on soil water and solute movement.The experimental study on spatial variability of soil hydraulic properties since 1970s have been rev ie wed in this paper,and the experimental results have also been analyzed.It can be seen that there is a good relation between the correlation scale of the soil hydraulic properties and the field scale of interesting,the probability density function for parameters of soil hydraulic properties are normal distribution and lognormal distribution,etc..All the results are valued for analyzing the behavior of solute or contaminant transport in aquifers as well as the risk monitoring of field soil regime.
Abstract: Some advanc ements of application and studies of non paramer ic statistic approach have been made in the system of hydrology and water resources.Those include three aspects:(1)hydrology frequency analysis,(2)forecasting of hydrology and water resources,and(3) simulating of hydrology and water resources.In this paper,the state of a pplications and studies of non-parametric statistic approach have been introduced.Finally,some trend and directions for future studies are presented.