The real-time operation of reservoir is carried out based on available information on the inflow hydrographs, the status of reservoir-storage volume and the outflow release rates. The proposed operating procedure is concieved as a system comprising of three fuzzy scopes, namely, inflow hydrograph, storage volume and inflow discharge. The knowledge data base on the inflow hydrograph is extracted from the past flood records using recognition thechneques. According to the combination of sub-spaces, the release in rule base is optimized through dynamic programming and the real release is decided through fuzzy inference theory.

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For building database of irrigation intake water, especially for paddy-fields, data structure must be made clear. The authors collected printed or manuscript irrigation data of 326 points in Kinu and Kokai River basins. 142 points of them have some measured data. By the analysis of these data, following points come to be clear. 1) Irrigation facilities are historical structure. Therefore random additional information cannot be negligible. Database must have some variable length data structure. 2) Some structures have multi-names. Synonym dictionary must be prepared.

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This paper presents hydrosperic disaster estimation by means of expert system. This system make a diagnosis of the type and potential of disaster using the information of topographical and geological features. The present system can be performed by the personal computer. A knowledge representation method is based on production rules. The certainty factors associated with them. The example of the actual disasters is analyzed by this system.

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Concept of river-basin-database is discussed for runoff analysis. Two kinds of satellite data and the national digital land information are utilized. MOS-1 data and the national digital land informtion are rearranged into unified format files to represent a river basin in detail spatially. NOAA-AVHRR data are collected as a time series data to analyse a variation of snow field in spring. The basins of the Kamafusa dam and the Tadami River are selected as test fields.

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Most of radar hydrogists in Japan have spent a lot of money and time to read and arrange many magnetic tapes recorded by weather radar. A standard format is proposed to share the data file observed by weather radar. We suggest a RAF1 and a RAF2 radar data formats for sequential and random access files. Two systems for the standard file format are also introduced.One is a database system using the RAF2 file format. The other is an image processing system which could treat the data from the database system as image pixels to trace the movements of the rainfall areas.

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This paper deals with the numerical simulation method concerning the two-directional multi-layered flow by use of the curvilinear orthogonal coordinate system and its verification through the numerical experiment of stratified flows in a reservoir. Starting from the hydrodynamic principles, the mathematical models are deduced by making use of the integral technique with respect to the control volumes derived from the geometrical features in the flow field. The numerical simulation method with use of the models is developed by means of the finite difference technique in terms of the staggered schemes. The results obtained through the proposed procedures in a reservoir are agreed with the past experiences and usefulness of the procedures is successfully verified.

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The properties of turbulence induced by oscillating a grid vertically have been investigated by means of both numerical analysis and turbulence measurement. The turbulent field generated by an oscillating-grid is in the equilibrium between the diffusion and the dissipation of turbulent energy, and it is homogeneous in the horizontal direction. The vertical distributions of turbulent energy k, its dissipation rate ε, eddy viscosity and a characteristic length scale have been calculated by using the k-ε turbulence model. The turbulent energy and the energy flux in the vertical direction have been measured. Their vertical distri-butions agree well with the calculated results. The values of k and ε at the origin of a vertical axis of coordinates, which have been evaluated by fitting these experimental results to the calculated ones, have been related with the hydraulic conditions.

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In computational fluid dynamics, various boundary conditions are used, and some of them have required special treatments. Free surfaces, density interfaces, and open boundaries encountered in hydraulic numerical analysis are those examples. On the basis of a deformable-cell method, in which cells dividing the incompressible fluid can deform according to the movingboundaries, most boundary conditions are considered on a “generalized boundary equation, ” and they can be treated in a unified manner. The density stratified shear flow at a river mouth is simulated nu-merically by this method, and each boundary is shown to behave as expected.

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In the recent years, some accurate methods for calculation of linear advection term have been developed and performance of some of them on nonlinear cases have also been attempted. In this paper, the split operator approach and the characteristic method were adopted for the calculation of nonlinear advection term. The computational method was proposed from a combination of the upwind difference and the 6-point scheme resulting into a scheme which has proved to give accurate solution for 1-D Burger's equation. Its application to practical cases such as hydraulic bore etc. is also straightforward and accurate.

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The horizontal cross-sections of a meandering channel flow were visualized using fine particles as tracers. Picture films were digitized and processed by the computer to obtain two-dimensional distributions of velocity vectors.
In this paper, the methods of flow visualization and picture processing beside with the significance of the method are described. The results obtained by the method are discussed and observed vortices are related with the large scale vortices observed by the aerial photographs of the flood flow.

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The horizontal cross-sections of the uniform open channel flow was visualized and twodimensional velocity distribution in each cross-section was obtained by picture processing.
Two-dimensional pattern recognition method was introduced into the obtained velocity data. Two-dimensional patterns of vorticity distributions was proposed to detect the typical arrangement of vortex motions.
Ensemble averaged pattern of two-dimensional distribution of velocity vectors, x- and zcomponents of velocity vectors, vorticity and two-dimensional divergence around the detected points were shown. Based on these patterns, mechanism of sweeps and ejections, and onedimensional methods to detect these events were examined.

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The method of an for unsteady to flow is developed. A large number of graphic data are compressed small enough to display the flow for long period. Applying this method for wave-current combined flow over rigid ripples, the spacial profile of Reynolds' stress -u'v' is appeared like the visualization. Superimposing the mean velocity profile, the negative-production of the turbulent energy can be understood visually.

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A digital image analysis method for velocity measurements was developed. Velocities were estimated by tracking four succesive tracer-particle image data. The method was applied to vertical velocity distributions at an abrupt drop and good agreements with those measure by a current meter were obtained. The errors in velocity estimations were discussed and the following results were obtained:
1) the error falls within 2% if the length/pixel is as small as 0.5mm/pixel, and an interval time of input image data is 0.03sec.
2) the combination of a length/pixel and interval time of input image data is reccomended so as to exceed more than 10 pixels for practical accuracy.
3) the error for estimating the center of gravity of the tracer is not affected by setting a threshold level and a thickness of slit light.

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A non-contact and simple method of quantitative measurement of alluvial channel bed configuration during its initial formation and development stages under running water has been devised. The information of the bed configuration obtained by the use of a laser-light sheet and ultra-sonic sounder is undergone the image processing by the use of an electronic computer. The time-and spatial variations of the bed configuration can thereby be obtained with no interruption of water flow.

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Two-dimensional water-surface flow structure at a right-angled open-channel confluence is investigated by applying an image processing technique. In this study, the correlation method is used to obtain instantaneous velocity distributions. From the successive twodimensional velocity distributions, unsteady features of a saparation bubble at the confluence for different discharge ratios and the Reynolds numbers are investigated.The result shows that the separation bubble is distorted into two or three groups of vortices at low frequency and a distorted vortex-group moves downstream at a speed of about halfof the main-stream velocity. Turbulent characteristics obtained by the correlation method agree well with the results by point measurements near the water-surface.

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The aim of this research is to develop new techniques for tracking particles in fluid. They consist of three elements, as follows. In the first part, a method to make microcapsules which are filled with pure water and covered with thin film of polystyrene was developed. Their mean specific gravity and mean diameter were 1.0046 and 673μm, respectively. In the second part, a new method was proposed to objectively determine the threshold of brightness, which separates particel-images from background. Finally, a new algorithm is now under development for tracking particles. It is composed of Kalman's filtering theory to predict location and brightness of each particle in the next frame and χ²-test to evaluate the probability that a pair of particle-images in the successive frames are the same one.

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To investigate the unsaturated water percolation property, the soil temperature at more than ten levels was measured automatically. Warm/Cold pure water was applied on a lysimeter as an artificial rainfall once a week. The computer controlled system to measure the soil temperature and other physical parameters has been developed. Furthermore, the timesaving data analysis system, including file transmission between the terminal computer and host one, usage of a convenient computer graphic software, and so on, has been adopted. Comparing the measured time variations of soil temperature with the calculated ones given by a simple heat transfer model, the percolated depth of the rain water was evaluated.

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Hydraulic experiments on alluvial bed have various conditions to be controlled and produce many data to be measured and processed. These laborious works compelled us to approach laboratory automation that faciliates the execution of a large number of runs and observations under wellcontrolled conditions. A personal computer control' system of discharge and water surface slope that made it feasible to conduct experiments under complicated unsteady conditions is explained. A traverser measurement system with a sand surface detector and a water level guage improved to be compatible to personal computers was applied to a few kinds of experiments very successfully.

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