Abstract: Aimed at the rainfall-runoff tracing using inorganic ions,the experimental study is conducted in the Chuzhou Hydrology Laboratory with special designed experimental catchments,lysimeters,etc.The various runoff components including the surface runoff,interflow from the unsaturated zone and the groundwater flow from saturated zone were monitored hydrometrically.Hydrochemical inorganicions including Na+,K+,Ca2+,Mg2+,Cl-,SO42-,HCO3-+CO32-,NO3-,F-,NH4-, PO42-,SiO2 and,pH,EC, 18O were measured within a one month period for all processes of rainfall,various runoff components and groundwater within the catchment from 17 boreholes distributed in the Hydrohill Catchment,few soil water samples were also included 1The results show that:(a)all the runoff components are distinctly identifiable from both the relationships of Ca2+ versus Cl-/SO42-,EC versus Na+/(Na++Ca2+)and,from most inorganic ions individually;(b)the variation of inorganic ions in surface runoff is the biggest than that in other flow components;(c)mostions has its lowermost concentration in rainfall process but it increases as the generation depths of runoff components increased;(d)quantitatively,ion processes of rainfall and groundwater flow display as two end members of that of other runoff components;and(e)the 18O processes of rainfall and runoff components show some correlation with that of inorganic ions.The results also show that the rainfall input is not always the main source of inorganic ions of various runoff outputs due to the process of infiltration and dissolution resulted from the preevent processes.The amount and sources of Cl- of runoff components with various generation mechanisms challenge the current method of groundwater recharge estimation using Cl-.
Abstract: Serious flood occurred in the extremely-heavy Meiyu episode over the Yangtze and Huaihe Valleies in 1931.The disasters and death toll were the highest of Meiyus in recent 121 years(1885-2005).The characteristics of precipitation,the abnormal changes and the influence factors of atmosphere and ocean are studied.Some of the important influence-factors can be seen in the winter of last year or about 2-6 months before the extremely heavy Meiyu in 1931.So that these factors can be considered to be used for the long-range weather predictions.
Abstract: The changes of water resources and theirs influence on environment are key points for arid researches.This paper mainly focuses on the evolvement of Manas lake in Xinjiang,which is based on the remote sensing images from 1972 to 2004 integrated with measured topographical data in 1999 and other materials from 1950s.The results of this research show that(1) Manas lake is a part of old Manas lake group and it is not a migratory lake;(2)there are two periods of the lake evolvement in the past 50 years:from 1949 to 1999/2001 and from 1999/2001 to nowadays,which are respectively corresponding to negative and passive evolvement process of Manas lake;(3)the trend of Lake change is synchronous to the change of Manas river's runoff;and(4)the main driving forces for the lake evolvement in the past 50 years are human activities and climate change.
Abstract: Based on the snow vertical temperature profiles measured during CHINARE2003 Arctic Expedition,the temperature distribution in snow is described by using one-dimension thermal transfer equation,and the effective thermal diffusion coefficients and thermal sources.The zero thermal source is defined as the snow without water.The evaluation method of the water content in snow is set up with the known physical parameters of snow and ice.The relation of water content and the snow temperature,and the water content distribution with time and space are given.
Abstract: The discharge data of the source area of the Yangtze River are analyzed through the Mann-Kendall test.The results reveal that the annual discharge has a weak decreasing trend during 1956-2000,but has a significant decreasing trend from 1980-2000.The annual air temperature has a significant increasing trend within the basin,while the precipitation has a decreasing trend.The consistent change of discharge and precipitation,and no obvious variation of the relation between precipitation and runoff within the basin,suggest the discharge decease during the 1980-2000 period is mainly caused by the reduction of precipitation,and the increase of ice melt,and does did not offset the reduction by reason of the regional warming.The spring discharge has an increasing trend from 1956-2000,which may be attribute to the early startup period and strengthening of snow or ice melting.
Abstract: Based on the systemic analysis method and the preferred plane theory in rock-soil mass,the concept of storage and movement effect of water on rock-soil preferred structural plane is put forward,and its application is studied.The following conclusions can be drawn.Firstly,there are different kinds of structural planes in rock-soil,and the stability and infiltration problems of rock-soil can be induced by the structural planes.Secondly,after confirming the preferred structural plane,preferred location and preferred depth of well,the finding out of underground water can be ensured.Thirdly,the water emerging in underground engineering has close relation with the structural plane.But only when the structural plane possesses some preferred index,such as time,dimension,it can lead to water-emerging.Finally,the interaction of water and preferred planes can induce the sliding of slope and infiltration destruction of dykes.
Abstract: The ergodic hypothesis will become invalid in a small domain.Therefore,the modified covariance functions of aquifer parameters are evaluated from the ensemble average,and an improved numerical model is developed based on the K-L (Karhunen-Loeve)expansion and chaos expansion.This study analyzes the impact of the domain scale on groundwater flow. The results show that the investigation scale causes the change of the eigenvalue and eigenfunction series,and the investigation scale impacts the total head,water content and velocity in different degree.The variances of total head and velocity increase as the investigation scale increases,and the mean of total head,velocity and water content are scaled independent.
Abstract: This paper analyzes the erosion efficiency of floods in the lower Yellow River during the storage periods of the Sanmenxia reservoir and the Xiaolangdi reservoir The results indicate that,when the discharge is less than 4 000 m3/s,the erosion efficiency of the total sediment in the downstream of the dam increases with the increasing of average flood discharge, while it maintains a constant value when the discharge is greater than 4000 m3/s. By investigating the erosion efficiency through the group sediment,we find that the decrease of the erosion efficiency of the fine sediment load is higher than the in creae of the erosion efficiency of the coarse one,which may be the crucial reason why the erosion efficiency of the total sediment load does not increase with the increase of the average flood discharge any more when the discharge is greater than 4000m3/s. The supply of the fine sediment load from the riverbed is the major factor affecting the erosion efficiencies of the total sediment load. It is suggested that the average flood discharge during the storage periods of the Xiaolangdi reservoir should be controlled at about 4000 m3/s to obtain the highest erosion efficiency. We can make good use of the limited water resources and improve the drainage capacity of the channel in the Lower Yellow River.
Abstract: In order to use the Palmer drought severity index method(PDSIM)in the real-time large scale drought survey,the Palmer modified drought index(PMDI)of daily model is developed based on the further modification of the PDSIM by Liu Wei-wei etc.(2004).After the initial parameters adjustments of 556 weather stations scat ered in China,the countrywide daily PMDI calculation system is established.The results of one yearcs operation show its validity,and it can describe in time the large scale drought situation and its evolvement.
Abstract: In order to estimate the influence of the initial field error on the river simulation,the governing equation is developed by the small perturbation method in this paper.The analytical solution to the equation is derived according to the form of the seiche wave.The theoretical result shows that the initial field error is equivalent to an extra numerical wave imposed on the simulated river.The numerical wave exists as standing wave,whose length is four times of the simulated river length.Its period can be estimated by the Merian formula,where the friction impact can be neglected.The error wave disappears quickly, which reveals the strong dissipation of the velocity field.The analysis is validated by a numerical simulation in a natural river.
Abstract: A 2-D mathematical model is applied in the paper.By the calculating of the distorted models and the undistorted model of the circumfluence,the effect of the distortion ration on the flow is analyzed.The flow dynamic axis in the distorted models is smoother than that in the undistorted model,while the flow horizontal gradient in the distortion model is smaller than that in the undistorted model.The results of the elementary analyses are provided.
Abstract: The river network structure changes much with the development of urbanization in the coastal area of Southeast China.As a result,a series of ecological problems such as the flood and waterlogging disaster,drought and the deterioration of water quality occur.We take the Southeast Yin plain area in the coastal areas of East Zhejiang province as an example in this paper.With the support of GIS technique,and the aerial pictures as main information resources,the changes of river network in the study area are discussed by analyzing the change of river structure due to urbanization adopted measurement,the statistics of river gradation and the map overlaying.Besides,the correlation between the urban expansion and the river network evolution is studied,and the trends of river structure changes under the present urbanization in the study area are qualitatively forecasted.Based on these,the measures to avoid the trends are discussed,that is,the existing riverways should be reserved as much as possible in the course of urbanization,especially the small and medium river channels.The restoration of river network structure and functions should be attached much importance so as to improve the urban water quality and water environment.The study will provide reference for the protection of river network during urbanization in the coastal area of Southeast China.
Abstract: In order to detect the aquatic organic pollutants in the Huaihe river and assess their impacts on human health and local economy,a series of methods including the concentration analysis,the health damage and the economical loss are con ducted.The river analysis method is to find out the semi volatile organic chemicals(SVOC)from the water samples of the surface water in the Jiangsu reach of Huaihe river. Results show altogether there are thirty three SVOCs,while the concentration levels of some polyaromatic heterocycles(PAHs)and substituted benzenes are relatively high. Al these chemicals are in the list of USEPA's Priority Pollutants.Then,a new method for predicting the probability of disease and mortality,supposed to occur due to these kinds of toxic Priority Pollutants,is put forward.The economical losses caused by them and ratios of the costs of GDPs are calculated. Result shows that the economical losses from GDPs of 2002 and 2003 are 0.876-2.22 and 0.684-2.25,respectively.Then some suggestions on how to reduce the losses of this kind are advanced.
Abstract: The algalbloom prediction models are constructed by using the decision trees to qualitatively predict bloom timing and use the nonlinear piecewise regression to quantitatively predict bloom intensity.The traffic light systems are used as the indicator for degree of algal bloom.Liuhai-lake in Beijing city is used an example.The constructed model indicates that the water inflow,the temperature and total phosphorus are the most impact factors on the algalbloom in Liuhai-lake.The concentration of Chl-a<30 μg/L is labeled as green,30 μg/L60 μg/L as red.When water inflow Q>79.0×104m3 or Q<79.0×104m3 and water temperature<13.4℃,the indicator is green;when Q<79.0×104m3, water temperature T>13.4℃,the indicator is yellow;and when Q<38.7×104m3,water temperature>23.25℃,TP>0.13 μg/L,the indicator is red.The model is test by an independent dataset from the same area,the predicted blooming time error rate and the error of predicted bloom intensity are presented in the paper.The model has great advantages to deal with the common problem in algal-blooms.It's more accurate when the limiting factor is changing.And the structure is understandable and easy to interpret.
Abstract: On July 20,2004,the underwater irradiance was measured and the water samples were collected at 9 sampling sites in Wuli lake ecological demonstration project.The concentrations of total suspended mater(TSM),organic suspended matter(OSM),inorganic suspended mater(ISM),chlorophyll a(Chla),dissolved organic carbon(DOC)and absorption coefficients of total particles,phytoplankton,nonalgal part icles and chromophoric dissolved organic matter(CDOM)were mea sured and calculated TSM,Chla and DOC are in the range of 5.1-38.7 mg/L,25.5-86.4μ/L,7.43-8.74 mg/L,respectively.The ecological demonstration project can signif icantly decrease the concentrations of TSM and Chla TSM,Chla of type region decrease by 53.4%,33.0% and TSM,Chla of Ⅲ type region decrease 77.4%,65.0% relative to type region,photosytheically available radiation(PAR)diffuse at enuation coefficients range from 1.81 to 4.93 m-1,and the corre sponding euphotic depths range from 0.93 to 2.54 m PAR diffuse attenuation coefficients of Ⅱ and Ⅲ type region decrease by 42.2%,52.8%,respectively,and the corresponding euphotic depths increase 73%,112%,respectively. Absorption coefficient of CDOM at 440 nm(ag(440)),absorption coefficient of nonalgal particles at 400 nm(ad(440))and absorption coefficient of phytoplankton at 440 nm(aph(440))are in the range of 0.79-1.31 m-1,0.41-2.22 m-1 and 0.73-2.12m-1 The relative contribution of pure water(aw)to total absorption coefficient(a)integrated over the range of PAR(400-700 nm)is less than 15%.The relative contributions of CDOM(ag),nonalgal particles(ad)to total absorption coefficient (a)are in the range of 18.16-40.28%,14.40-37.88%,respectively.The relative contributions of phytoplankton(aph) to total absorption coefficient(a)is the biggest,ranging from 31.05 to 45.28%.Based on the regression analysis between PAR attenuation coefficients,euphotic depths,secci disc and main light attenuators and the relative contribution of every component,phytoplankton and organic suspended solid play a main role in regulating the attenuation of light in ecological demonstration project in Wuli lake However,the roles of phytoplankton and nonagal particles in regulating the attenuation of light are almost equal to type region of the periphery of ecological demonstration project.
Abstract: According to the importance of storage state and the operation policy of reservoir or reservoir-group for satisfying the water requirements of regional water-supply system,the regional drought identification procedure,which is taken as the key judgment parameters,the sum of the initial time-period storage of reservoir and the inflow within the period,and the goal water requirement of water-supply system are proposed.The procedure indicates the drought and non-drought status of the water-supply system by the positive and negative sign of the difference of the above two key parameters.To make the comprehensive analysis of the characteristics of the regional drought,such as the distribution pattern of the drought and non-drought duration, the transfer probabilities,the recurrence interval of drought,etc.,we,from various research aspects,take a real water-supply system as example.Both the simulating and statistical method and probability analysis method are applied to the drought duration study.Meanwhile,the distinction of the traits and the computing results of two methods and their causes are pointed out.
Abstract: Each winter,ice jam may form on rivers in cold regions,causing many problems with its effects on the increasingly wet perimeter and blocking cross.Ice formation has the potential for causing the stage in the river to rise and suddenly catas-trophic flooding.Break ice jams often occur suddenly and induce severe flooding with little warning.It is important to mitigate the stages due to the evolution of ice jam.This paper provides analyses and discussion of ice jam stages with variation in ice discharge and initial flow depth and velocity in straight and curved channels based on the data from the experiment and the field observations at the Hequ gauge station of the Yellow River.
Abstract: As an important ecological infrastructure of an urban area,whether a river system can work normally mainly depends on its structure and patterns,while the latter can be improved through the urban river system planning.By calculating and comparing the major indexes such as γ and α etc.of the spatial structure of a city's key river system before and after planning,we can find the changes of the structure and patterns of the river system,judge the rationality of the planning,and expose the essence of river system planning on improving the spatial structure of the local rivers and increasing the connectivity of the river system network.Taking Taicang's river system planning as an example,we calculate the γ and α and some other indexes of the current and planned river system.The results show that the indexes includingγandαincrease,which means that the structure and patterns of Taicang's river system are improved.The results of the four water-diversion areas show that the lower the value of the indexes of the current river system,the higher increasing range of the indexes of the planned river system,and there is remarkable spatial differece among the four areas.So once a river system plan of a city is worked out,the scale of the urban area should be considered firstly,and the next is the diversion-area scale.
Abstract: The size and structure of neutral networks must be predefined if the standard backpropagation neural network architecture is used for trainin. On the contrary,the initial network of cascade correlation(CC)is composed of the input layer and output layer while the hidden unit is inserted into the network one by one.The principle of CC is presented in this paper,and the monthly streamflow in the Lasa river is forecasted by using the CC and the BP models.The result shows that the CC model only needs to run five times while the BP model needs 70000 times to reach the same precision.The efficiency of the CC model is much higher than that of the BP model Another conclusion is that the network size of a CC model is smaller than that of the BP mode.
Abstract: In the course of light reflection,light refraction,light absorption and light scattering,not only its intensity but also its polarized state are changed,so the polarized state,a kind of information,can be used in the remote sensing. Water polarized reflectance data from the three reservoirs in Changchun city were collected with a kind of bi-directional reflectance detection instrument.The specialties of this instrument lie in its ability to measure the polarized reflectance of targets at various zenith viewing angles,incidence light zenith angles and azimuth angles with band A(630~690nm)and band B(760~1100nm).Hence,the analysis,according those characteristics,listed above is done.It is found that the polarized phenomena are an important characteristic of water. This study on polarized reflectance of water not only helps to find a new way for polluted water detection,but also provides a theoretical basis for the further research on polluted water polarized light remote sensing.
Abstract: The agricultural non-point source pollution(AGNSP)caused by soil erosion is a key pollution source of the water quality deterioration.The paper reviews in detail the research progresses in the AGNSP caused by soil erosion for the past 20 years,including the pollutant transport processes,the affecting factors,the prediction models,and the control measures,etc. This paper also proposes the key research fields of the AGNSP in China,including the effect of erosion process on the agricultural pollutant movement and the water quality,the prediction model of AGNSP.We have worked out the standard indicator systems of the different pollutant risk-assessment.
Abstract: The riverine carbon transport is closely related to the processes of terrestrial erosion-deposition.This paper firstly reviews two different kinds of terrestrial erosion(the mechanical and chemical weathering mechanisms),discusses their respective roles in providing carbon to the river,and compares the differences between the monsoon and non-monsoon drainage basins in flux and the characteristic of the riverine carbon transport.Then it makes a summary of the terrestrial carbon deposition and points out several potential land-origin carbon traces including dam capture,deposition happening in floodplain,estuary and near-shore area,and terrestrial carbon precipitation.It is necessary to pay more attention to the terrestrial carbon deposition, and set up clear mechanisms of different types of carbon deposition and their respective contributions to world terrestrial carbon sink,because the captive effect of terrestrial environment relative to the terrestrial erosion is unclear.In addition,we should further explore direct or indirect impacts of human activities on the processes of terrestrial erosion-deposition and the riverine carbon cycle.