Abstract: The salinizing process of Bosten lake is attributed to the human-activities and the climatic process in the past several decades.Based on the relation between the lake's salinity and the salt budgets,a meaningful equation expressed with the factors of water volumes,slinities and evaporation etc.is studied to gain insight into the mechanism of the salinization process.With the analyses of the data from 1960 to 1999,the salt mixing ratio is introduced for evalutating the unavailable data,and the effect of each factor on the lake's salinazation is discussed quantitively.The limitations of the lake's salinity also are calculated in theory in several cases,Bosten lake,with 1.1 g/L at the rest salinity state,is a slightly salt lake rather than a fresh one.
Abstract: The ecological revetment engineering can protect river ecosystem health well,and is used widely in the channel revetment.The flexible vegetation is a main kind of engineering materials in the ecological revetment engineering,because it grows quickly and can be easily planted and constructed.In this study,36 samples of turf and reinforced turf were tested,and the vegetation's hydraulic roughness was calculated.The experiment proves that the hydraulic roughness of the turf used in revetment ranges from 0.020 to 0.090.The roughness depends on the different categories of soil,period of growth and way of reinforcement.The data proves that the roughness of reinforced turf is higher than the turf generally.
Abstract: Based on the characteristics of erosive storm and soil sheet erosion in the Loess area,the transportation system of the steady siltladen flow is used to simulate runoff and sediment generation from upper slope.The hydraulic characteristics of the silt-laden flow in different gradient grassplots and the mechanism of its reducing sediment are analyzed.The results show that the Froude number Fr of the different gradient grassplots with the overland flow increases with the increase of the gradient,and the silt-laden flows of all treatments are laminar and tranquil.The roughness coefficients decreases with the increase of the gradient.There is a negative relationship between the grassland retention of the sediment and the gradient.And for the same gradient,grassplots reduce more sediment at the initial than final stage of the runoff generation.The sediment produced from grassplots has significantly greater mean diameter and proportion of the large particle (> 10 μ m) than that flowing into the grassplots under the same gradient condition.
Abstract: A direct method for actual evapotranspiration (AET) measurement is presented,that is,the compensatory lysimeter method with three cylinders.By using this method,the evapotranspiration loss over water surface and aquatic macrophytes can be measured directly without destroying reed's living conditions.Experimental test was carried out in Zhalong wetland from 2004 to 2005 (during reed growing time in the middle of May-Oct.).The primary analysis results are as follows: (1) the average AET over reed belt of the two years is 812.1 mm and the average evaporation over water surface (Ew) is 433.9 mm; (2) the AET of reed belt reaches its maximum in June or July every year,while the maximum of Ew appears in May;and (3) the ratio of AET to Ew varies markedly in different months,and the average ratio in reed growing season is 1.87.By the observed data,a multi-regression equation of AET for Zhalong reed belt is established.It can serve as a useful tool for water resource planning and management of wetland.
Abstract: For lack of the theoretical calculation method at present,the skew bridge backwater is simulated in adopting circle pier and embank uncompressing river through hydraulic models.With the change of skew angle,the change of backwater is analysis.The model experiment indicates the immanence law of the change of the height of backwater around the skew bridge.The calculation formula for the correct coefficient of the skew bridge backwater height is given through the regress analysis.Considering interaction of piers,the calculation formula for skew bridge backwater height is deduced based on the flow character of the skew bridge and theory of trail flow.
Abstract: The flow experiment of wide,shullow and steopflume in the paper indicates that the resistance loss of shallow supercritical flow in the steep channel is more than that of the general open flow.The author analyzes the flow momentum distribution in wide and steep channel,and finds that when the ratio B/h< 40 and the discharge is larger(hk> 1.04 m),the flow momentum lateral distribution at the end of steep channel presents a saddle profile which has stronger stability,but when the ratio B/h > 40 and the discharge is smaller (hk < 1.04 m),the momentum lateral distribution presents a elliptical profile which has weak stability and can't restrain the boundary disturbance Based on intervenient method,an new adjusting work is done through the submerged triangle wing.It can effect ively restrain the progressive minor disturbance,named Domino effect and get satisfied effect.The author further discusses the controlling mechanism and the main factors,and obtains some designable principle and the dimensionless geometric factor k of submerged triangle wing for engineering.
Abstract: By analyzing the 2-D river-network numerical model,a generic 2-D river-network numerical model is brought forward.In this mode,the 2-D river-network is combined with the several cells which include "tree like" river cell,"ring-like" river cell,and "cross-like" river cell.By disposing these cells,1-D river-network coupling with 2-D can be easily simulated,and a soft system about generic 2-D river network's numerical model is built.Derivation and realization of the "tree-like" cell calculation model shows that the method is very valuable and can be applied to the large-scale simulat ion of 1-D and 2-D river network.
Abstract: Considering the influences of sea ice thermodynamic factors on the ice conditions,such as thickness,concentration,a sea ice thermodynamic-dynamic model is established based on the smooth particle hydrodynamics (SPH).In this sea ice model,the numerical diffusion in the traditional methods of the finite difference method (FDM) and the particle-in-cell (PIC) is avoided,while the ice edges can be modeled with high precision when the thermodynamics is introduced into the sea ice numerical model of SPH.In this paper,the basic theory of SPH and the thermodynamic factors of sea ice are presented first.The governing equations of the sea ice thermodynamics-dynamics are addressed by the using the thermodynamics to calculate the ice thickness and concentration in the SPH numerical simulation of the sea ice dynamics With this current sea ice model,the sea ice in Bohai Sea is simulated in 48 hours,and the distributions of sea ice thickness and drifting velocity in the whole ice field are obtained Moreover,the ice thickness,the temperature in vertical direction and the other thermodynamic factors are also discussed in detail.With the numerical results above,it can be concluded that this sea ice thermodynamic-dy-namic model based on the SPH method is an effective numerical model,and can be applied well in the sea ice simulation of Bohai Sea.
Abstract: The microstructure of circumfluence and the characteristic of the mixing intensity on the cross-section of thermally stratified shear flow in curved flumes are studied experimentally.By the experimental investigation of the curved flumes with three different sinuosities of 45°,90° and 180°,the transition of the circumfluent structure on the cross-section from the stable stratification to mixing is explored.The four-circulation patterns of the secondary flow are first detected at the critical condition of the conversion of the stable stratification to mixing Moreover,the differences of three-circulation patterns of the secondary flow between stable stratification and mixing are also first discovered,and the reasons of difference between two situations are investigated In addition,the change process of the mixing intensity along the curved flumes is obtained.
Abstract: Human activities,including the construction of the Three Gorges Dam,Gezhouba Dam and other river training projects,are changing the river environment and stream habitat in the Yangtze River in China.As a result,the aquatic organisms,especially,the rare species and fishery fishes with economic value are affected.This paper studies the changing characteristics of the river that affect the aquatic community habitat,such as substrate,water depth,water temperature,water velocity,water quality,etc.Chinese Sturgeons,an anadromous species mainly live in the Yangtze River,are endangered by the construction of dams and other hydraulic projects.Habitat suitability indices for the chinese Sturgeon are proposed and calculated.Based on the research on the main eco-factors influencing growth and reproduction of the species,ten aquatic eco-factors are analyzed for the habitat suitability indices,including water temperature,water depth,substrate,water velocity,sediment concentration,and egg-predatory fishes.The stream habitat for the Chinese Sturgeon is assessed with the model,which integrates these eco-factors.The model is validated by its application to 12 groups of data,and a habitat saitabllity index model for Chinese Sturgeon is presented.
Abstract: This paper proposes an integrated approach for the spatial variation in water quality based on the multivariate statistical analysis,i.e.,the cluster analysis (CA) and the discriminant analysis (DA),aimning at identifying the spatial similarity and differences between sampling sites and optimizing the monitoring network.The main procedures of this approach include: (1) checking the normality of all parameter's distribution with the kurtosis and skewness tests,then log-transforming the original data of all parameters,(2) grouping the sampling sites based on CA which was performed on the standardized log-transformed data,and (3) recognizing the discriminant parameters based on DA which can account for most of the expected spatial variation in water quality.The proposed approach is applied to deep bay water control zone in northern Hong Kong,and the results demonstrate that: (1) the distribution of original data is improved after log-transformation,and all parameters are close to the normal distribution; (2) the sampling sites are classified into 3 clusters at (Dlink/Dmax)×100 < 25,i.e,the low,moderate,and highly polluted.Moreover,the later two clusters belong to the nutrient and heavy metal pollutions,thus the domestic wastewater,livestock pollution,industrial pollution and surface runoff should be controlled; (3) in backward stepwise DA on the original data,only seven discriminant parameters (pH,NH3-N,NO3-N,F.coil,Fe,Ni and Zn) in spatial variation are identified and the correct assignations are 90.65% for three cluster sites; and (4) based on spatial variations in water quality,it is possible to optimize the monitoring strategy in future with only one of 3 sampling sites and seven discriminant parameters,which can decrease the number of sampling stations and corresponding costs.
Abstract: First,the widely used Rayleigh-Model founded by predecessor is introduced and its merits and drawbacks are pointed out.Having noticed its drawbacks and made some assumptions and simplifications,the following two models are deduced based on basic law of hydraulics and Rayleigh fractional principle: (1) the differential equation model for the stable isotope composition that varies with time in static water body,which discloses the relationship among stable isotope composition in static water body,the fractional factor and the evaporation rate,and (2) the differential equation model for stable isotope composition that varies with time and space of the kinetic water body in the river,which describes the quantitative relations among the flowing river water's hydrogen and oxygen's stable isotope composition,the fractionation factor,the fluid velocity and flux.In the end,the inner link among these three models is presented through the mathematical deduction.The proposal of these models makes it possible to simulate the river water's stable isotope composition quantitatively and gives help to interpret more objectively and more sufficiently the information included in the stable isotope data of water.
Abstract: The sulfur isotopic (δ34S-SO42-) composition of the water in Wujiang river and its catchment area was measured during high-flow period.The average SO42- concentration is 0.48 mmol/L.The river water δ34S values range from -11.5‰ to 8.3‰,whereas the δ34S values of mainstream show only a narrow range and exhibit negative values from -6.7‰ to -3.9‰.The isotopic composition of surface water allows distinguishing the contribution due to the weathering rock and atmospheric precipitation,and the spatial variation in δ34S over the catchment area is obvious.The average SO42- concentration is higher in the upper part of the river than in the lower regions,while the average δ34S value is lower.The upper river shows a three end 2 member mixing between rainwater SO42-,SO42- from oxidation of pyrite in coal and the sulfide deposits.In the lower reaches,the samples lie mainly on the isotopic mixing trend between the evaporitic SO42- and rainwater SO42-,the contribution of SO42- from oxidation of pyrite is less.The SO42- export flux of Wujiang river is 172×1010 g/a,of which the high-flow period export flux accounts for 80%.the relative contributions from the oxidation of pyrite in coal,the oxidation of sulfides deposits,the rainwater SO42- and the evaporitic SO42- are 50%,25%,20% and 5%,respectively.The erosion rate of carbonate by sulfuric acid is 35.1 t/km2/a (17.5 mm/ka) and the consumption rate reducing CO2 is 3.66×105 mol/km2/a approximately.
Abstract: A method for calculating design tide levels is presented for the planned projects in the area where tide levels are hard to measure Firstly,a short-time tide process at the planned project site,that it is more than a month,is obtained by means of the tidal current numerical calculation.Secondly,the synchronization correlation analyses are carried out.By comparing the tide levels at the site with those at a nearby harbour or tide station with long-term measured data,the regressione quations are established.Finally,the design tide levels at the harbour or tide station are calculated by using the method of Code of hydrology for Sea Harbour,and the design tide levels at the site are obtained through the regression equations.The results show that the method proposed in the paper is reasonable and feasible.
Abstract: The wave flume used in this laboratory experiment is 12 meter long with a cross-section 0.5 m wide and 0.7m in height.The Experiments were conducted to investigate the generation of internal solitary waves (ISW) in a two-layered free surface fluid system.The experimental control conditions include the thickness ratio between the upper and lower fluid H1/H2,step depth η0,and density ratio.The internal waves are thus generated with various waveform types Given positive potential energies,an elevation-type ISW is followed by an anticlockwise overturning motion at the interface; on the other hand,an ISW of depression-type is generated by clockwise motion.The inappropriate configuration in the flume will produce wave fluctuations without period.
Abstract: This paper presents the results of a series of laboratory experiments on internal solitary wave in a two layer fluid system.The int ernal solitary waves (ISWs) of variable amplitudes and types were experimentally arranged from several physical variables,including the different layer thickness ratios H1/H2,the interface differences η0,and the density ratios ρ1/ρ2.The wave flume used in this experiment is 12 meter long with a cross section 0.5 m wide and 0.7m in height.Five ultrasonic probes placed at equidistance record the interface fluctuations.The data collection and processing were carried out through control software,Multi Nodes Data Acquisition System (MNDAS).This paper reports physical properties related to wave propagation.By comparing the relationship between nonlinear parameter and characteristic wave frequency,experimental results agreed well with the KdV and mKdV solutions.
Abstract: The division of reservoir flood season is a multi dimension time series cluster quest ion of the unknown number of cluster,so the cluster methods are in demanded to hold the capacities of dealing with multi-dimension,time series and cluster validity.But no one can meet all these needs.Therefore,based on the fuzzy C-means cluster method and the compact and separate cluster validity function,a dynamic fuzzy C-means clustering method and corresponding cluster validity function based time are put forward,and a set of self-contained modeling steps is taken coupling the two methods above.There is a complex nonlinear optimal question in the model,and the regular optimal method is very difficult to solve it.By using the real coding based accelerating genetic algorithm to solve it is very effect ive and can overcome the initialization value sensitivity difficulty from the regular iterative optimal method used for the fuzzy C-means cluster.Its test and application results show that it is very effective.
Abstract: The paper presents an improved real allocation based accelerating genetic algorithm (RAGA) and its application to optimal feeding reservoir group operation,which overcomes the shortcoming of dynamic plan in the reservoir group operation,such as "dimension difficulty" or the problems of obtaining global optimum solution.The local search is embedded into RAGA to accelerate its convergence and enhance its global optimization ability.According to the water conservancy contact among reservoirs,an algorithm frame is designed base on RAGA and an idea of water supply strategy interval is put forward.To reveal its outstanding characters,the algorithm is contrasted with optimization by reservoir turns based on the dynamical planning in the optimal operation of the two reservoirs in series.The results show that it is reasonable and feasible and its convergence is quite fast,which proves its advantages of the computing speed and global optimization.
Abstract: The multi-reservoir flood control is typical multi-object decision making problem with the uncertainty.There are many uncertain factors in the course of the flood control.D-S An evidential reasoning approach is proposed to evaluate the project of multi-reservoir flood control.By using this method to combine the uncertain evaluation information,the problem is converted into a certain decision making problem.The arithmetic step for evidence reasoning is presented.Finally,example shows that this method is efficient and practical.
Abstract: In allusion to the conflict in solving the precision and constringency speed in genetic algorithm,this paper advances a kind of a new genetic algorithm for self adaptation,symmetry and congruity.Taking GeHeYan reservoir for example,this paper sets up the most suitable optimal model for reservoir hydraulic power operation,which has got satisactory achievements.The result indicates that the new coupling model avoids blindness of network seeking excellence,so as to achieve the most suitable planned integration effect,improve effectively forecast precision and speed,and expand new approach for setting up long or middle term load forecast model.
Abstract: Not only have hydraulic uncertainty and hydrologic uncertainty influence on dynamic risk of diversion,but also construction scheduling of dam body and its finishing duration.The integrated risk between hydraulic,hydrologic uncert ainty and the construction scheduling uncertainty should be analyzed.The paper puts forward the risk analysis model for the costruction scheduling and the risk analysis model for construction diversion on the assumption that the construction scheduling is affirmable.Thus the Monte-Carlo method is used to simulate the integrated risk of construction diversion system considering hydraulic,hydrologic uncertainty and the construction scheduling uncertainty The case study shows that the research of inte grated risk model for construction diversion system and its analytical method are reasonable and effective.
Abstract: A kind of new technique,3-D fluorescence spectroscopy (TDFS),is used to analyse the phytoplankton of Shenzhen Dongjiang water source project.It is found that there are abundant algaes in the water through all the pipe line.The chlorophyll-a concentration is between 10.71 and 16.43 μ g/L,and the algae biomass vanges from 72.92 to 1 375×104/L.TDFS can basically identify the species and quantity of algaes in water.There is distinct interconversion between fluorescence intension with chlorophyll-a concentration and the algal biomass.Furthermore,different kinds of dissolved organic matters and their concentration can be identified with TDFS method.
Abstract: The advances in control and environmental risk management of industrial effluents and municipal sewage in developed countries and China are reviewed in the paper.Compared with the developed countries,the chemical monitoring is now the only tool used in China for the control of discharges which mainly relies on a few parameters such as COD,and this approach is unable to regulate the discharges with complex mixtures of toxic organics Ecotoxicity assay can be used for the same time to supply the gap to control the release of toxic organics effectively based on the requirements of environmental risk management.Toxicity identification evaluation for identifying the key toxicants causing the ecotoxicity are a core of reducing the environmental risk of discharges.The discussion and prospects are also described for the application of ecotoxicity assay to the control and environmental risk management of discharges in China.
Abstract: The dissolved organic matter (DOM) in natural waters consists of a large number of organic compounds.This paper review the characteristic and measurements of DOM firstly,shows the laser induced fluorescence measurements at monitoring of DOM in water,and discusses in detail the spectral fluorescent signature technique and using Raman scattering as an internal standard to normalize the fluorescence intensity of DOM.Finally,the calibration method of DOM with fumic acid is showed,and many influence factors like temperature,salinity,pH value,fluorescence saturation and fluorescence quenching are discussed.