Abstract: A watershed drainage network generation model (WDNGM)is developed in the Three Gorges watershed on the basis of the hillslope flow modeling approach and the shortest flow course method for ‘filling sink',using the digital elevation model (DEM).The Xmanjiang model is improvedfor development of a watershed hydrological model characterizing the Three Cxmges watershed.Basedon the hydraulic dynamic theory,a flood routing model of the river channel pattern reservoir in the Three Cxmges,considering the water project operation influences,is established and fully coupled with the watershed hydrologic model.On the GIS platform,a real-time flood forecasting system is developed by integrating the watershed hydrological model,the flood routing model and the WDN GM in the Three Cprges watershed,which its functions are advanced and complete.This system has been installed and test operated by the reservoir control center of Three Gorges Company.
Abstract: To counter the contradictions among the electricity generation, flood control and navigation in the Three Gorges Project (TGP) operation, the flood risk and the benefit of generation and shipping in different impounding schemes is studied, the reservoir water sediment regulation multi-purpose decision model is developed by the relationships between the flood risk, generation and shipping benefit, in order to study its optimum impounding time and mode, and a weighted balance mode is applied to decide an optimum impounding scheme.The results can be used for the TGP operation.
Abstract: Since the 1970s,the water fluxes from the Yellow River into the sea have declined significantly.The formauve cause for this is dealt with in this study.Based on the data of precipitation,measured and "natural" runoff, water diversion and the areas of erosion control measures over the drainage,the relationship between the water fluxes and the influence of changing precipitation and human activities are studied.The Yellow River basin can be divided into some different water source areas.The change in precipitation over different runoff source areas has different effect on the water flux.The water diversion from the river forms a "lateral branch water cycle system",which increased intensively and resulted in significant decline in the water flux.Since the 1960s,the erosion control measures have been practiced over the drainage basin,leading to a decrease in the water flux into the sea.A multiple regression equation is established for estimating the change in water fluxes caused by the changes in precipitation,water diverlion and erosion control measures.
Abstract: There are some sediment transport capacity model for soil erosion and transport from overland flow.These sediment transport rate are used in steady sediment transport.The soil erosion and sediment transport model for overland flow is developed in the paper.The physical-based sediment transport equations are derived from the assumption that the sediment transport capacity can be determined by a dominant variable such as flow discharge,flow velocity, shear stress,stream power,unit stream power.The coefficients of the model are computed by experimental data.The sediment transport capacity models are applied to different rainfall intensity and slope.The results indicate that the unit stream power model gives better simulation sediment loadfor small rainfall intensity.The shear stress model simulates sediment load more satisfactorily for large rainfall intensity.
Abstract: Based upon the theory of river mechanics, thermodynamics and late research results on the mechanism of ice jam, this paper presents a synthetic and dynamic mathematic model for river ice-jmn sunulation, characterized by ice-water coupling, which describes formation, evolution and evolvement of river ice-jam, The model is validated by the measurement data on the Hequ section of the Yellow River.
Abstract: Based on the analysis of the traditional kinetics mechanism about mixing and the comparison of the relat ive magnitude of macroscopic and microscopic mixing time, a new kinetics mechanism on mixing in turbulence is presented.The speed of macroscopic mixing is controlled by eddy diffusion, and the speed of microcosmic mixing is controlled by molecular diffusion.The mixing process is dominated by macroscopic mixing.The Euler number can be used as the cont rol parameter that determines the mixing efficiency.The mixing tests are conducted in three reactors of different volumes to verify the practicality of this index.
Abstract: On the base of quality balance equation, the two-dunension ecological dynamic model is established, which could simulate the core process-ecological dynamic process of eutrophication in the water body with cxunplex boundary.Considering not only the hydrodynamic conditions but also the chemical, physical and ecological changes, the model gives the more detailed information of eutrophication.The model is used to describe the distributing situation of chlorophyll, total phosphorus and total nitrogen concentrations in the Geheyan reservoir.The results calculated by the model are consistent with the results monitored in the Gehevan reservoir.
Abstract: Geochemistry of phosphorus in sediments cores of the Taihu Lake which is a large shallow lake in China is studied by sequential extraction method.There is an abrupt change of both the chemical fraction characteristic of phosphorus and the other physicochemical properties of sediment,such asp H,Eh,LOI and water content at the depth 5 cm to 15 cm in the sediment cores.No significant correlation between the concentration of phosphorus in interstitial water and the bio-available phosphorus in the sediment.Hydrodynamics and aquatic vegetation may be the major factors controlling the geochemistry of phosphorus in the large shallow lake.
Abstract: The effect of phosphorus on the assimilable organic carbon (AOC) and the bacterial regrowth potential (BRP) in deionized water with necessary nutrients addition is studied.It is shown that phosphorus would become the limiting factor on bacterial regrowth when its concentration is low enough.At the same time,pilot-scale drinking water treatment processes are used to treat the raw water and the effect of phosphorus on the biological stability of the treated water was studied.It was shown that after 50μg/L PO43--P was added to the treated water,the AOC of the treated water increased 55% and the BRP increased 123%.This indicated thatphosphorus was the limiting nutrient of bacterial regrowth in the treated water.Because the conventional drinking water treatment processes could effectively remove phosphorus from raw water,the results got in the experiment indicated the possibility and feasibility of ensuring the total phosphorus(TP) in drinking water less than 5 μg/L to restrict microbial regrowth in drinking water distribution system in China.
Abstract: The main problem of regional water environment is the water environmental capacity which is involved in some comprehensive factors of economy,society and environment and related to the object that the sustainable development comes true.In the paper,the DYNAMO language and system dynamic are used to model and simulate water environmental capacity,at the same time,some alternatives are brought forward through controlling some parameters.The perfect scenario of water environment capacity in Changchun city is introduced based on adjusting policy parameter such as technologic investment,public consciousness of saving water,water price and so on,which provides scientific basis for realizing the sustainable development of Changchun.
Abstract: The fractal theory is used to study systematically the fractal character of the river basins of China in this paper.Some significant conclusions are drawn as follow: (1) The fractal character exists objectively in the river basins of China.(2) The fractal dimensions of the river basins of China are calculated.The box dimension of the whole river basins of China is 1.4189, and that of the exorheic region of China is 1.4305, etc.(3) The box dimensions of river basins in plain regions of China are larger than those in mountain regions.(4) The box dimension of the whole river basins of China is different from the average dimension of all its parts.The more the parts of the river basins, the larger the difference between the box dimension of the original river basins and the average fractal dimension of all parts.
Abstract: Guided by the theories on energy flowing and materials exchange within Soil-Atmosphere-Plant Continuant(SPAC),retrieval models of key hydrological parameters were established in the Yellow River Basin based on remote sensing technique.The precipitation andevapotranspiration were derivedfrom the meteorological satellite GMS5 and Fengyun-2 meteorological satellite data.A precipitation model is calibrated and tested with the ground observed data;meanwhile,the evapotranspiration result is verified with the lame aperture scintillometry.
Abstract: The concept of ecological water requirement is presented,and the essential principles and the estimation method for ecological water requirement are discussed.The framework is demonstrated by an application to the Weihe River basin,which ecological water requirement is estimated as 39.80×108m3.Some prospects of this field are also presented.
Abstract: According to the ecological appropriate theory, the logarithm normal distribution model between the growth of natural vegetation and the depth of groundwater was established.Based on the model, the quantitative method for ecological water requirement of natural vegetation in arid area is proposed, by using the remote sensing technique to divide the area in the light of different ecological vegetation and the spot tested data of vegetative physiology demand.As an example, the ecological water requirement of natural vegetation in Heihe River basin is computed. Compared with the other related researches, the result is rational.The method is reasonable and can be used in other arid area.
Abstract: The paper analyzes two main types of irrigation control which are based on sensing soil moisture or calculating water requirement, and discusses their application to micro-irrigation.As a synthesis of them, a new micro-irrigation control model with self learning ability is proposed.This model enhances calculating precision, because it eliminates the open loop control error, excludes the difficulties arising from rain and deep drainage, and facilitates evaluation of the crop coef ficient.A greenhouse status coefficient is introduced for calculating the water requirement of greenhouse irrigation.Though soil moisture sensors are adopted, their distribution density is quite low, and the control failure arising from lag of measure is avoided.The new model shows a large-scale application prospect.
Abstract: To overcome the shortage of available data analyzing methods which needs supplement test to be applied in the case of non-conservative tracer, some suitable transformation are conducted on the analytical solution describing onedunension river strewn water mass tracer test under the condition of instantaneous injection of non-consemative tracer and two linear regression equations are deduced in the paper.With application of cmxelation coefficient extreme method to the equation with two independents, the,quation estunating average velocity of stream is derived.And with application of linear regression method or linear-schematic method to the linear equation with one independent, the values of two linear constants may be estimated and based on the results of the estunat,d values of the two linear constants, the values of longitudinal dispersion coefficient and first reaction rate k may be calculated.The main appliration steps of the method is illustrated with an example.
Abstract: The permeability coefficient of unconfined aquifer in the underground research facilities (URF) at CIRP's test field was obt ained by Hvorslevr's slug test which seems to be an only appropriate option that in the condition of thin aquifer, poor water quantities, limited space for ongoing test of nuclides migration, we can not adopted any pumping test ot injection test.The aquifer medium is made of loam.The bot tom of URF is 6 meters higher than the bottom of the aquifer.The impulse capacity of the test was so small that we can neglect the impact on test results from the south of the aquifer.The aperture of bore hole for test designed was closed to the inner diameter of well pipe theref or the influence of the structure of bore hole on test results was reduced.Comparison of the results of laboratory test (4.1×10-4~8.2×10-4cm/s) in which undist urbed soil column was used and the permeability coefficients result acquired by the slug test (4.72×10-4, 6.58×10-4cm/s) was same in magnitude.
Abstract: Boundary layer is separated due to the barrier along the flow border line, thus the circulating flow is strengthened and the flow pattern is deteriorated.It is a common phenomenon in the project of water conservancy, searoute and power station.From the theory of boundary layer control, the size of circulating region in the dwvrr strewn of the barrier can be reduced by using the method of "sucking-spouting" water, which sucks part of the discharge in the upstream of the convex barrier and spouts it in the downstremn of it.The results of tests in the 50 cm width flume show that the method of "sucking-spouting", water is very effectme.
Abstract: The fractal geometry theories were adopted to study the relations between porous media permeability and its microst ructure from the physical mechanism of its microstructure formation and Darcy's law.Furthermore the function between saturate porous media permeability and the fractal dimension was established with the viewpoint that soil(or rock) is fractal in a statistic sense.The morphological details was studied and the fractal dimensions was gained by the scanning electron microscope, which verified the function.Compared the permeability values predicted by the model with the measured values, a good agreement was obtained.The results demonst rate that the model is precise in predicting the porous media hydraulic parameters.
Abstract: This article makes a qualitative analysis on the water price issue in the project of watertransfer between regions according to the cost division of the whole-cost pricing method,drawing an analogy between this issue and the "bubble method" in pollution-discharge management,and gives a general framework for economic analysis in detailed research.The analysis proves that the water-transfer has a full-scale impact on each part of the two regions water resource cost.If the quantity of the water-transfer is appropriate,the water resource costs of the two regions would be more close each other,and the whole cost is decreased and very similar to the change of the cost of pollution control resulting from the trade of pollution-discharge rights.The water resource connection between the two regions by the water-transfer project changes the water cost division.The surplus water in the region that exports the water now has opportunity costs,because it can be traded to other region and the water-transfer leads a water supply pattern adapting to the water demand in the two regions,the turnover rate of water will be increased and the water cost will be decreased.The time factor demonstrates its importance here.The analysis indicates that when the potential property rights of water resource become full ones that can be traded because of theproject of watertransfer between regions, the efficiency of water resource deployment will be improved,which is consistent with the Coase theorem.The income of the region of inputting water in short-run is different with that in long run.
Abstract: On basis of the mathematical model for electrolyte diffusion in flow with a pulse input,a velocity measuring system for sheet flow is designed by analyzing the influences of flowing water on solution transport and its electrical property.A operation system is written with Visual Basic for automatically data collection,velocity estimation and parameter analysis.The flume experimental data indicated that the velocity values estimated with this advanced system agreed well with those from the volumetric method which demonstrates the feasibility of the methodfor velocity measurement of velocity in sheet flow.This method and system can also be used in other related fields.
Abstract: An extensive review of eutrophication models for lakes and reservoirs is presented.In general,there are three basic approaches to modeling the eutrophication,that is,single limited nutrient factor models,the interrelated models for phytoplankton to nutrients and eco-dynamic models.These models have been widely used to simulate and predict the behavior of enriched water bodies.The basic thesis,the applied scopes and distinctive advantage and disadvantage of each type of model are discussed.This will be beneficial for researchers to comprehensively understand each type of model and determine the sound method for integrated management of their objective water bodies.Also the promising modeling methods and developing trend of eutrophication models are introduced.
Abstract: The ecological models play very important roles in lake eutrophication research and ecosystem management.Most of the eutrophication models have been developed since the 1960s when the eutrophication of lakes around the world drew the attention of environmentalists.Since that time,the models have evolvedfrom comparatively simple,single-layer,single-segment,single-constitute,and zero-dimension models to complex,multi-layer,multi-segment,multi-constitute,and three-dimensional models.Based on four categories of the eutrophication models,namely,very simple regression models,simple nutrient budget models,complex water quality-ecological-hydrodynamic models and structural dynamic models,the paper analyses the development and characteristics of these models and discusses the existing problems and development trends in the lake eutrophication models.
Abstract: In ancient China, the Chinese people had made special achievments and contributions in many fields of hydrologic science including hydrologic cycle, runoff, silt, water-silt relation as well as for their observations, records and their rationalization.More than 2000 years ago, the Chinese people described the hydrologic cycle by using "circle concept" which is completely coinsided with the scientific definition used nowadays.The records about historic hydrology including literatures and carving marks of extraordinary high or low water levels along river banks or on the river beds, provide not only the evidence of historic floods or low stages but also specially important data for planning and design of large scale hydraulic and hydropower projects in China.