Abstract: The problems of three aspects,properties of sediment particles,characteristics of sediment motion in polluted waters,such as,sediment motion in the sewage oxidation pond and in river mouths,and transport-transfor mation of heavy metal pollutants,non-degradable organic matters,nutritional sustances and oil pollutantin natural waters,were discussed in this paper.According to these discussion,it is necessary to using environmental sciences,such as,water environment chemistry,environmental geochemistry and hydrochemistry,and hydraulic sciences,for example,hydraulics and mechanics of sediment motion to study the problems in aquatic environment.
Abstract: The assessment models for water environmental health risk analysis and its application are shortly intruduced in this paper.The application example shows that the assessment models can both quantitatively describe the harm of the environmental pollution on public health and give the pollution risk order for the environmental pollutants.The environmental health risk assessment(EHRA)is not included in the environmental assesment for the time being in China.It is pointed out that the EHRA should be included in the environmental assessment.
Abstract: The first,the structure of river water quality model is established.The second,the distribution mixed coefficient numerical inverse formulas are derived for one dimensional unsteady diffusion convective equation both in time and frequency domain.Finally a numerical test result and analysis conclusion are given.
Abstract: All the characteristichs of root-shoot relation system were induced in the paper, and the control and simulation modle of the system was established according to its mechanisms at the level of organism under the frame of integrity ideas. The test results of the modd show that it can not only be used to study the root-shoot relationship under different soil water regimes, but also regulate and control crop growth or schedule irrigation.
Abstract: A finite difference method for solving Richards' Equation in one dimension is presented, and the calculated results agree well with the observed data. The method is an implicit iterative scheme with a hyperbolic sine transform for the matrio potential.The infiltration in a range of soils for sand, silt loam and clay can be simulated in a few seconds on a personal computer with errors of only a few percent in the amount of soilwater. The beaviour of infiltration in unsaturated soil is divided into three phases: before ponding time, after ponding time and recession.
Abstract: This Paper gives an analysis of operation characteristics of Sihu Drainage System, sets up a NLP/DP/LP model structure of operation planning for the system,and presents an optimal model of operation planning for the system. The model consists of nonliear programming, dynamic programming and linear programming, which can carry out different optimal function of the system.
Abstract: Based on the river dynamics,a model of stage forecast for scouring and silting channel is developed by using hydrology method and the sediment rating curve.The model is usable for the channel without backwater effect and with the better sediment rating curve.A example is also given.
Abstract: The philosophy and algorithm of wavelet network model of chaotic phase space are introduced,then its applicable for hydrology is discussed.It is reasonable and superior to use this model in medium-and long-term hydrologic prediction.At last application of the model in the long term daily runoff prediction of the Jinsha River is shown.
Abstract: A forecast model of fuzzy pattern recognition with neural network is developmed in this paper. This makes a break through to the topologic structure of neural network. The Fuzzy Pattern Recognition Model developed by Chen Shouyu is used as the stitulation function of hidden nodes. On the basis of Error Back Propagation Algorithm(BP Algorithm),the model learning method is developed. An middle-and-long term runoff forecast example is given at last.
Abstract: Hangjiahu Region Locates in the south region of Taihu Basin,and consists of low-lying lands,paddy fields surrounded with dikes and a densely river networks.Serious damages were caused by flood and water logging in recent years.The models for Hangjiahu river-network runoff yield and routing of flood are developed by the Canadian one dimension hydrody namic model(1-DM)according to the principles of Saint Venant equations.Based on the historical hydrological data in the past two years,the model is rated and can be used to study the regulation rules of key projects and pump stations in the Hangjiahu Region.It is concluded that the Canadian 1-DM can be used to solve the problems related to flood proofing and water logging control in Hangjiahu Region.
Abstract: In this paper, a simulating method is introduced into drought study. By use of this technique, the author analyze the rule of regional drought, i. e. temporal and spatial distribution of agriculture drought on the area, discuss the process of drought developing, assess the possible loss of crop product. The result shows this method is a useful tool for drought study.
Abstract: Based on comprehensive studying on the regime of Jinci Spring, Taiyuan city,the main factors that affect the flow of Jinci spring were analyzed.The model for simulating flow of Jinci Spring was established by using method of time series analysis.Finally,the karst water resources of the spring basin can be managed by means of management curve of water discharge from coals mine.
Abstract: Three monthly rainfall-runoff models,namely the statistical model,Belgium model and Xinanjiang model,were applied to several basins in North China. The simulation result indicated that the statistical model can better reflect the response of catchment out put to its input,the modified Xinanjiang model can better describe the runoff characteristics of semi-arid region and the simulated result was better fitted to the measured runoff.As for the Belgium model,a prelinminary application showed that the fitted result was worse than the Xinanjiang model.
Abstract: The wells field near by a river is a common way to exploit the groundwater resource that is an important part of water resources.The groundwater management models based on hydraulic model,such as two-dimensional flow model,sat uratedly three-dimensional flow model and saturated-unsat urated flow model,are efficient tools to evaluate the groundwater resources in the case.The two-dimensional flow model,in which the adjacent river of that field is supposed to penetrate through aquifer completely,and the saturatedly three-dimensional flow model,in which the river can be treated as real case,are more popular.The groundwater resource calculated by the two-dimensional flow model,though the model prevails on the groundwater exploration of our country,must be more than the real resource from aquifer.In order to protect the environment and keep a forever use of the water resources,the saturatedly three-dimensional flow model,even saturated-unsaturated flow model,will be employed in the future.