Abstract: The current methods for hydrological forecasting are divided into two classes, i.e. the process-driven model and the data-driven model. The process-driven model is based on the conception of hydrology, with which the discharge forecasting can be performed by simulation of the runoff variation and river channel evolution. The advances of process-driven models in medium- and long-term forecasting mainly concentrate on the modification of the precipitation and runoff models of river basins, so that the models can meet the requirement of the medium- and long-term forecasting. While, the data-driven model, without requirement of the analysis of the physical mechanics, is fundamentally a black-box model with an objective of identification of the optimal mathematical relationship between inputs and outputs. Among all the data-driven models, the linear regression model is the most commonly used. Owing to the introduction of some new forecasting methods into hydrological forecasting, such as the artificial neural network model, the nonlinear time-series analysis model, the fuzzy mathematic model, the grey system model, and so on, and the improvement of the capability of data acquisition and calculation, the data-driven model has drawn wide attentions in hydrological forecasting.

Abstract: An experimental study was performed of the influence of concrete parameters on the deposition effect in repairing of concrete cracks with the electrodeposition method, the parameters including the rate of weight increase, the rate of surface coverage, and the rate of crack closure. Under the experimental condition, some conclusions were drawn: the rates of weight increase and crack closure increased with the water-cement ratio, but the rate of surface coverage inversely varied with the water-cement ratio; the three parameters increased with the decrease of the thickness of the concrete cover; the rates of surface coverage and crack closure increased with the decrease of the crack width,but it was not clear whether the rate of weight increase varied with the crack width or not.

Abstract: An introduction was given to the principle of the VOF method in the simulation of interface variation in two-phase flows.Some works for improvement of the calculation precision and the effect of interface reconstruction of the VOF method and some research results were summarized. Finally, it was pointed out that the VOF method could be widely applied to numerical simulation of multi-dimensional flow fields if some theoretical improvements were made.

Abstract: The continuity of flooded region was analyzed by use of the expansion operator in mathematical morphology,and the discrete elevation data of flooded region were obtained by GIS lattice data.Based on the calculated result,the water depth distribution and flooded region were computed by the principle of volumetric method.

Abstract: A model test in an organic glass flume with a scale of 1∶100 was performed to demonstrate the generation and evolution of piping in embankment foundation with different depths of cut-off wall.The area of sediment outflow caused by piping was obtained by photo reproduction,and the local cross-sections of samples after the occurrence of piping were observed and measured with colored sediment taken as tracers.Thus,the piping-induced failure of two-layer foundation was verified as that: mass flow firstly appears in the upper weakly permeable layer,and then underground erosion and scouring gradually occur from downstream to upstream between the serviously and weakly permeable layers.Moreover,the quantitative relationships among the depths of hanged cut-off wall,the density of foundation soil,and the piping evolution were also derived from tests.

Abstract: In allusion to the serious leakage occurring in the Xibing dam body after water impoundment, the causes of leakage were analyzed, with emphasis on the measures for seepage control adopted for treatment of inter-layer defects, such as boring from the top toward the bottom of the dam body and placement of grout holes perpendicular to the joint face In consideration of the objectives of the project, special requirements of construction were put forward, including prolonging low-concentration grouting to ensure the sufficient grouting in small pores, avoiding the adoption of batch-type grouting to improve the grouting efficiency, and without setting the upper limit of the time and total amount of grout filling in single holes The survey of the dam after grouting shows that there is no leakage from the original seepage points, demonstrating the good effect of construction

Abstract: The minimum ecological flux of rivers for seven hydrological control sections in the Haihe River Basin was calculated by use of the minimum flux method based on river geomorphology.The method determined the critical flux by consideration of both breakpoint on the water level-river width curve and the maintenance of the original habitat(mainly including average water depth,average velocity,et al) to a certain extent.The results show that the average minimum ecological flux of the seven control sections is 5.84?m~3/s,which accounts for 5.8%-10% of the long-term average value,and that under the minimum ecological flux,the ratio of river width is 43%?70%(the average value being 61%),the average water depth is 0.24?0.59?m,and the flow velocity is 0.24?0.34?m/s.The calculated results are in accordance with those previously obtained and recognized at aboard.By extrapolation of the calculated results according to the similarity principle,the minimum ecological flux of other rivers in the Haihe River Basin can be obtained as well.

Abstract: Based on a review of current methods for calculation of the shadow price in broad-sense, a nonlinear dynamic input-output optimal model was proposed for calculation of the shadow price of water resources. The specific method and process of the model were given to calculate the shadow price of water resources of China, and data of 1949-2050 were derived by use of 1999's input-output table of water resources of 33 sectors in China. It is shown that the shadow price theory is applicable for analysis of water price.

Abstract: Based on an analysis of causes and basic characteristics of drought in north and south areas of China,it is pointed out that drought in north areas,such as the Yellow River Basin and the Huaihe River Basin,was characterized by the severe systematic demand-supply contradiction resulted from the shortage of water resources,and successive drought disasters intensified by hot and dry weather,and that drought in south areas was characterized by the occurrence or successive occurrence of dry years due to hot and dry weather and the seasonal water shortage induced by their geographic and climatic features and insufficient water supply capacity.Furthermore,the harmfulness of drought disasters was briefly introduced,and some drought-resisting measures,including administrative management measures,technical measures,rural drought-resisting measures,urban drought-resisting measures,and emergency measures,were proposed.

Abstract: Distribution laws and variation characteristics of the precipitation and temperature in the area above the Longyangxia Reservoir on the upper Yellow River were analyzed with the climate data obtained since 1956. Based on the relationships between the natural runoff at the Tangnaihai Station and the temperature and precipitation at each gauging station, a natural runoff calculation formula was established. With the formula, the influence of climate variation in the upper Tangnaihai region since the 1990s on the inflow of the Longyangxia Reservoir was calculated, and the sensitivity of runoff at the Tangnaihai Station to climate variation was analyzed. The results show that the average annual temperature in the 1990s is about 0.5 higher than the perennial average value,and increases by 0.7-0.8 as compared with that of previous decades,that the annual rainfall of this region is much less than the long-term average value,and especially, the maximum reduction of rainfall is up to 15.8% in Maqu district, that the natural annual runoff in the 1990s decreases by 43.710~8?m~3 as compared with that of previous decades, and 20.2% of which is induced by climate variation, and that the variation of rainfall is of great influences on the inflow of the Longyangxia Reservoir as compared with the variation of temperature.

Abstract: Some local artificial boundaries for 2-D anti-plane wave motion were summarized, including the viscous boundary,paraxial axial approximation boundary, Higdon boundary, superposition boundary, transmitting boundary, and viscous-spring boundary. The advantages and disadvantages of the above boundaries and their relationships were discussed, and the precision and applicability of the boundaries were compared. Finally, some advances in the research of the stability of local boundaries, especially high-order boundaries, were introduced.

Abstract: The rationality of setting of a guide wall on the curved section of the discharge trough was verified by model tests for several practical projects.The method for engineering design is introduced as follows: the guide wall is generally set along the axis of the curved section,starting from the beginning of the curved section;its length can be equal to or a little longer than that of the axis of the curved section,and the height of the wall can be determined as 1.0-1.1 times of the height of the discharge channel bottom to be lifted;with a reinforced concrete structure usually adopted,the rectangular section is suitable for the guide wall,and the top of the wall should be constructed in forms of trapezium or hemicycle so that water can flow over it.

Abstract: A new method was presented to analyze 1-D water-mass tracer test data and further to determine the water quality parameters of rivers under the condition of instantaneous injection of tracers. By fitting of the top part of t ~(1/2) c-t curve with the parabolic equation, formulas for calculation of the maximum value and corresponding time of the parabolic equation with the coordinates of three points on the curve were derived, and then, with the formulas derived, a formula for calculation of the average flow velocity of different river sections was constructed. Based on the above work, the formulas for calculation of the longitudinal dispersion coefficient and discharge parameter were also derived by concentration-time data transformation. Theoretical derivation and examples of calculation show that the approximate fitting method of the parabolic equation is of such advantages as low requirement for the number of test data, simple process of calculation, and simultaneous calculation of three water quality parameters.

Abstract: A comparative analysis is performed on the suitable range for the coefficients of the wind speed function in Dalton's formula and its influences on the simulated result of water surface evaporation It is shown that there is a wide range of values suitable for the coefficients of the wide speed function, and that satisfactory results can be obtained even though one of the coefficients equals to zero In combination with the research result on water surface evaporation at home and abroad in recent years, the wind speed function in Dalton's formula is improved A segmented function with three steps is proposed to act as the wind speed function As a result, not only does the new function accord with the physical nature of effect of wind speed on water surface evaporation, but also greatly reduce the error in fitting of the spatial-temporal regularity of water surface evaporation, and the accuracy of simulation is greatly improved

Abstract: The result of mullen experiments on geomembrane with different nicks shows that there are great differences in the strengths between damaged geomembrance and undamaged geomembrane under liquid pressure.The maximum stress of damaged geomembrane decreases as the depth of nicks increases,however,the maximum strain does not follow the same regularity.Without change of the diameter of holding aperture and thickness of geomembrane,the development of the damage to geomembrane results in the decrease of tangential deformation modulus and the secondary exponential decline of the mullen strength under the same stress level.

Abstract: In consideration of non-uniform distribution of water resources, insufficient water supply capacity, and day-by-day aggravation of unbalance between water supply and water demand in Jiangsu Province, it is necessary to popularize water-saving irrigation techniques for paddy planting. In this paper, three kinds of water-saving irrigation techniques and the popularization mode of "demonstration in districts-demonstration expansion-popularization in large areas-general popularization" were introduced, and the effect of popularization of the techniques was summarized. Three-year popularization of the techniques from 1998 to 2000 shows that the total area of water-saving irrigation is up to 4.18910~6?hm~2, the volume of water saving is more than 12?480 million m~3, the total output of rice is increased by 2?550 million kg, and the input-output ratio reaches 1103. The results demonstrate the effectiveness of technique popularization in water saving, output increase, and benefit improvement.

Abstract: A control strategy for single-neuron fuzzy self-adaptive controllers was designed by combination of fuzzy control with neural control. The strategy made full use of the nonlinear approximation of fuzzy logic and the self-adaptability of neural control. The application of the strategy to the simulation of operation process of mixed flow generating units at a hydropower station in two cases shows that the control strategy is of good dynamic performance and adaptability as compared with the conventional PID control system.

Abstract: An introduction was given to the application of optical-fibre sensors to seepage monitoring of the earth dam at Xikeng Reservoir from aspects of system structure, arrangement of monitoring points, selection of optical-fibre sensors, and software design. The analysis of the monitoring results shows that the system meets the requirement for precision and reliability in seepage monitoring, and that the system has good performance in resistance to thunderbolts and disturbances as compared with conventional instruments.

Abstract: By introduction of the control theory, synergetic theory and dissipation structure theory into the water resources system, a multidimensional critical water resources regulation and control theory was developed According to the research method for the complex system, in which the qualitative study was combined with the quantitative integration, a multidimensional critical regulation and control model was established for the Yellow River Basin water resources Through a case study with the developed model, the optimal allocation of water resources of the Yellow River Basin was realized, and the rationality of the present model and theory was verified

Abstract: The level of research was commented from aspects of causes of durability degradation, study on components of which the durability was degraded, and durability evaluation and service life prediction for structures Some problems for further study were also discussed

Abstract: The trend and some issues of urban water resources development and utilization in China were discussed. It is emphasized that urban water supply will be the key point of water resources development and utilization in future, that the domestic and eco-environmental water demand will increase rapidly, and that the shortage of water resources will promote the effective utilization of water resources and the transfer of the part of water for agricultural utilization into cities. Accordingly, the mode of water resources development and utilization will change, and the safety of water supply, water sources, and urban flood control will become more and more important. Based on the above thoughts, the whole country was divided into six areas. The strategies for urban water resources development and utilization of different areas were discussed according to their natural condition and current situation of water resources and social economy, and the some solutions were put forward.

Abstract: An introduction was given to some key problems about grout enriched vibrated RCC(GEV-RCC),including the experimental method for GEV-RCC,the optimization of mixing-ratio,the grouting method,and the reasonable amount of grout to be added.The research shows that the fluidity apparatus for cement grout proposed in this paper can reflect the rheological properties of cement grout,and can be applied to field test for optimal determination of the mixing-ratio of GEV-RCC and quality control.Simulation test performed on GEV-RCC by use of three different grouting methods under different grouting ratios shows that it is an effective measure to determine reasonable grouting method and mixing-ratio for GEV-RCC.

Abstract: A summary was made of the advances in research at home and aboard on sediment initiation(including the loose sediment and newly sedimentary soil),the initiation model,and some affecting factors.The thoughts of and results from different research works in this area were compared,and some problems existing were listed.Owing to the complexity of cohesive soil and the different parameters adopted in different research works,the initiation models of cohesive soil,which have been developed in former research works,are of great differences. The factors affecting the initiation of cohesive soil mainly lie in the physical factors,geomechanical parameters,and chemical characteristics.It is considered that,in the further study,the emphasis should be placed on the undisturbed cohesive soil,and that manipulated soil tests should be performed to find the relationship between each affecting factor and the shear stress of initiation,to analyze the mechanism of cohesive soil initiation and its affecting factors,and further to determine the physical model.Thus,the inherent law can be found by information accumulation of enough soil samples from great amount of flume tests.

Abstract: The significance of application of the aesthetics principle to hydraulic structure design was analyzed from the angles of improvement of the aesthetical value of hydraulic structures and promotion of water-related tourism.Based on the architectural aesthetics principles,the characteristics of hydraulic structures,the case study on practical projects,and some pervious experiences,the rule that beauty comes from harmony was discussed,and it is indicated that to keep harmony within hydraulic structures and with natural environment and humanistic landscapes is important in hydraulic structure design.Case study shows that the introduction of aesthetics principles into hydraulic structure design is of great significance to prevention of unpleasant hydraulic structures and improvement of the economic,social and environmental benefits of hydraulic structures.

Abstract: According to in-situ monitoring data, the displacement of rock slope varies with time, and the variation of air temperature is doubted to be one of the influencing factors. Through the calculation of the temperature and displacement fields for the rock slope of the powerhouse of the Geheyan Hydropower Station, it is found that the influence of air temperature on the displacement of the slope is only in the range of several millimeters, while the fluctuation of measured displacement is in the range of several centimeters; besides, the fluctuation of calculated displacement is annually changed, while the variation of measured displacement shows no obvious periodicity. Therefore, the variation of air temperature is not the main factor affecting the displacement of the slope. Moreover, some regularities about the displacement varying with air temperature are also found through calculation: the variation of displacement lags behind that of air temperature for 35-75 days; the influence of air temperature on rock mass can reach a depth of 10 m; the steady temperature of rock mass is about 17?℃, etc.

Abstract: From an analysis of some difficulties occurring in the design of several hydraulic structures and the advantages of the reinforced concrete finite element method(RCFEM),it is concluded that RCFEM is necessary,applicable,and effective for design and analysis of hydraulic structures.Based on a discussion of some key problems in structural design,such as the constitutive relationship,element model,crack model,material strength,and load determination,the calculation principle,which should be followed in hydraulic structure design with RCFEM,is presented.

Abstract: The GPR and high-density resistivity method were used to investigate the three leakage points occurring at the same altitude on the back slope of a reservoir dam by setting of three longitudinal measuring lines on the top of the damThe result shows that the loose structure of the dam body mainly characterized by the horizontal loose layers is the cause of formation of the leakage pointsMeanwhile,the distribution and characteristics of the loose belts were identifiedThe detection result was in good agreement with the reality, and it was also verified in excavation

Abstract: An introduction was given to the principle,scope of application,and characteristics of the vacuum grouting method and impact-echo method.Some research works and achievement about improvement of the common grouting technology by adoption of better grouting materials and techniques in famous universities abroad were presented.In consideration of the fact that the common grouting technology will be widely used in domestic bridge construction,it is concluded that the improvement of grouting materials and techniques is of applicable value in practical projects.

Abstract: A random vibration analysis model of arch dam-foundation interaction was developed by combination of the pseudo-excitation algorithm with FE-BE-IBE time domain procedure. The effects of traveling waves on random seismic responses of arch dams can be conveniently included. To verify the accuracy of the presented model, the Monte-Carlo method was employed to calculate the seismic responses of a concrete arch dam model. The result shows that the traveling wave affects the dynamic response of arch dams with an amplitude of 10%-20% , and that the lower velocity of traveling wave results in the concentration of pseudo static stresses on the boundary of arch dams. Therefore, the traveling wave effect is of great influences on the dynamic response of arch dams.