In the aerodynamic method, if the constant flux layer is under the conditions of neutral stability, then the wind profile in the layer can be written as u= (u_*/k) ·ln {(z-d)/z₀} over a tall canopy, in which u is the wind velocity at elevation z, u_* is the friction velocity, k is von Kármán's constant, d is the zero-plane displacement height and z₀ is the roughness length.
The above d is usually chosen as a fraction of canopy height or by the selection of a value which forces the above canopy neutral wind profile to be semi-logarithmic. In this paper, these methods of determining the value of d were examined by using wind profiles measured under the conditions of neutral stability and the friction velocity measured by the eddy correlation method.The results obtained are summarized as follows:
1) The value of d ought be determined with the value of k.
2) If the value of d was determined by the former method, then the friction velocity, u_*, which was obtained from the above equation, could not always be estimated with high accuracy.This result is mainly because the value of d depends on the wind velocity.
3) If wind velocities were measured with high accuracy, then the appropriate value of d could be determined by the latter method.If they were measured with cup anemometers over a field, however, then u_* could not always be estimated with high accuracy by the use of d determined with the latter method.

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The purpose of this paper is to clarify the correlation between a percolation pattern (the closed and the open system percolation) and ions of Fe and Mn in downward seepage water in a stratified paddy field model with sand or gravel under the plowsole.The stratified soil model column composed of 3 layers was used.
The following results were obtained.
(1) In the case of low drain depths (about 90 cm from the surface), layers of the closed system percolation (surface soil and plowsole, kuroboku soil) became low DO (about 2 ppm) and reduced layer, and Fe and Mn ions were detected in downward seepage water in the model column. However, the layers of the open system percolation (subsoil, sand or gravel) became high DO (about 6 ppm) and oxidized layer, and these ions (Fe and Mn) were not detected.From these results, it was concluded that the illuvial horizon occurred at the upper border of the subsoil.
(2) In the case of high drain depths (about 20 cm from the surface) in the same column, all layers became the closed system percolation, low DO and reduced layers after about 90 days, but subsoil was poor organic layer.Mn ion in seepage water in the subsoil was detected as a decrease in Eh values and then Fe.Also it was recognized that the downward removal of the peak concentration point of these ions in the downward seepage water was slow in the subsoil, and that the removal was influenced by percolation rate.
(3) It was recognized that correlation between the detection depths of these ions in the downward seepage water and these concentration in layers was high over the experiment, as well as the removal of these ions from the illuvial horizon was very slow.
Judging from the above, it is clear that the percolation pattern is a very important factor to the removal of soluble ions that correspond to oxidized and reduced states.

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An optimization model for irrigation canal controls is developed that designs the upstream discharge boundary condition so as to minimize the duration of flow transient from one steady state to another.Discussions are, however, limited to those on increasing discharge release at the upstream end.
Flow dynamics are incorporated in the model as the time-dependent equations of state which result from piecewise integrating the partial differential equations of unsteady flow by means of the cubic spline interpolations.The upstream discharge is taken as a control variable, and its allowable minimum and maximum values are prescribed to serve as the constraints.Minimization of the duration of flow transient is achieved by that of the functional expressed in terms of the deviations of the state and control variables from their final (targeted) steady state values.Because of the constrained control variable, the condition for minimizing the functional is derived resorting to the Pontryagin principle of maximum.The principle then requires to timewise solve the two sets of the ordinary differential equations with respect to the state and adjoint variables.In operation of the model, these equations are solved by a numerical iterative procedure to find an approximately optimum manner of the upstream discharge release.
A typical control manner, ON-OFF control which can be represented by time?dependent functions with only one parameter to be optimized, are considered to make some demonstrative optimization examples.The model is operated under the ON-OFF controls to conclude that this strategy, which is rather preferable in engineering practices, is the very one which brings the optimum control when the process time is properly set up.

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In rotational paddy fields, a breaking of plowsole is commonly practiced to avoid the wet injury of upland crops during their growths.As the breaking of plowsole affects more or less the managing practices in restored paddy fields, it is necessary to estimate the effect brought by the practice in order to determine the introduction of the plowsole breaking.
In this paper, a method for estimating the effect of the breaking of plowsole on avoiding the wet injury of soybean plants on their seedling emergence on the basis of probability by using long?-term precipitation data is reported.In addition, the results obtained by the application of the estimation method to the reported cases in other papers are reported.
The devised estimation method is made up of following steps:
(1) The amount of precipitation causing wet injury differs dependent on the cases where the drainage is improved or not improved by the breaking of plowsole.Therefore, each of the precipitation is computed by assuming a water balance model, and the ones thus obtained are referred as the standard precipitation.
(2) The summed amounts of precipitation observed for a given period of before and after the assumed planting dates in past years are compared with those of the standard precipitation determined in such a way as described in (1).
(3) The summed number of days (N) arising wet injury in the cases where the breaking of plowsole are not practiced are computed on the basis of the results obtained in (2).
(4) The rate of the number of days that can be avoided wet injury by the plowsole breaking is obtained through dividing the N by the sum of assumed planting days being possible to seed. Making this value n, the reciprocal 1/n is approximately regarded as a probability year with the effect of the practice. When the 1/n is less than 10, namely in the case where wet injury is judged to arise with the probability of more than once in 10 years if the breaking of plowsole is not practiced, the effect of the introduction of plowsole breaking is judged to be significant.
This estimation method was applied to the fields of the cases reported in other papers.The results obtained showed that the 1/n values were in the range of 4-8, so that it was considered that the effects of the introduction of plowsole breaking on avoiding the wet injury of soybean plants on their seedling emergences in these fields were significant.

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Flexural test of brittle material have been usually carried out by third-point loading of a rectangular beam.The modulus of rupture is usually estimated by Navier's formula assuming symmetric loading. But, as the results of an elastic analysis and of a photoelastic study, it was reported by the authors that Navier's formula was not so exact and an asymmetric loading usually takes place in this test.The objectives of this paper are to propose an elastic analysis method of beam subjected to asymmetric load and to define the effect of degree of asymmetry on the modulus of rupture.Stress of a beam subjected to asymmetric load was estimated by superposing the stress for symmetric load on that for inversely symmetric load.Numerical results obtained indicated that the value and the position of the maximum horizontal normal stress axmax at the lower face of the beam varied depending on the degree of asymmetry of load.The value of σ_xmax for asymmetric load was greater than that for symmetric load, and it varied within 20%.But it varied only 2% when cracking appeared within middle sixth-point.If Navier's formula is used, the value of the modulus of rupture estimated by the third-point loading is 75-89% of that obtained by the central loading. This result corresponds to that reported by flexural test.

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As silica fume has the properties such as pozzolanic reaction, micro-filler effect and ball-bearing effect like fly ash, it is very useful to improve the consistensy and strength development of concrete.However, the concrete mixed with silica fume needs a chemical admixture such as the superplasticizer because it shows a low consistency with the content of silica fume.
In the absence of a chemical admixture, it was shown that the optimum mixing percentage of silica fume is about 5%judging from the consistency and compressive strength of mortar.To get the more economical mixing percentage of silica fume, an air entraining agent was used to the mortar mixed with silica fume.It was found that this agent can improve the consisitency of mortar mixed with silica fume but has the defect reducing the compressive strength to a large extent.
Nextly we used the superplasticizer to improve the consistency, the strength development of mortar and concrete mixed with silica fume.In the case of mortar it was shown that the 1.2% superplasticizer gives the maximum mixing percentage of silica fume 30%without reducing the compressive strength.Then, the density, pulse velocity, dynamic modulus of elasticity and compressive strength of concrete mixed with 30%silica fume and 1.2%superplasticizer were measured. As a result, the superplasticizer greatly improved the consistency and the compressive strength of concrete especially after the age of 28 days.

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Farmland consolidation is done at many paddy fields in Hokkaido.It promotes independent setting of irrigation and drainage canals, conversion of fields into multi-purpose ones and reduced set-aside of rice paddy.So landuse has been of two types.One is paddy field and the other is upland field.We call this situation “Baraten”.As the environment of paddy fields changes considerably because of new varieties and techniques of water management, the role of water management changes to keeping a matched water requirement rather than maintaining an absolute requirement.As a result, it is impossible to calculate gross water needs by the water requirement rate method using net water requirements.We therefore researched the role of water requirement corresponding to new farming techniques from recent investigations.We studied a method of calculating lot-management water requirement and delivery water requirement considering intermittent irrigation, meteorological conditions and reduced set-aside of rice paddy.

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In a settlement area redevelopment project, farmers will get non-agricultural lots as ones usable for residence.Therefore, methods to put a land readjustment project into practice as soon as possible is an important subject to realize the aim of the Settlement Area Redevelopment Law and to solve technical problems of planning.
In this paper, after classification of the technical ploblems in terms of succession of (1) procedure and (2) evaluation, we clarified the meaning of them.On basis of examination of project areas which made technical consideration, we made some proposals on a lot substitution technique needed in the settlement area redevelopment project.
As a case study area, sellected was K-settlement area, Kakogawa, Hyogo Prefecture, principal features of which are technical consideration on succession of evaluation.On land conversion of the new settlement area, unique techinical considerations by K-settlement area have been made on evaluation and foundation works to solve the problems.

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On a settlement area redevelopment project (SARP), technical troublesome difficulties are there in the land evaluation of the new residential area, because of relation in interest of landowner.Y area, in Matumoto-si, Nagano prefecture, having been carried out in a landconsolidation project for green district development, but not in a SARP, has made unique considerations in land evaluation.The area, having been converted non-agricultural zone in the urbanization control area, is different from usual type which convert the zone in the urbanization promotion area. Hence, applyed was analogas lot substitution technique to one for a SARP which converts the new settlement area in the urbanization control area, and needed was solution of the similar technical problems as ones which are common to a SARP.Distinctive feature of Y area is application of the land value appraised accordig to highway frontage in evaluation of lot, which method is used in a land readjustment project, and in this paper, we examind on the lot substitution technique for a SARP with reference to the case.

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Exchange and consolidation of lands under the Agriculture Promotion Areas Act is anticipated as a project for controlling land use in urban fringe.Actually, only two cases have beenrealized since the project's establishment.We analyzed these two cases (Niitsu City and Ogaki City) to clarify conditions for realization of the project.
The results may be summarized as follows:
1.One of the necessary conditions for realization is a concrete plan for large urban development and proper management of Agriculture Promotion Areas.
2.The method of land exchange must be compatible with the behavior of landowners.For example, in less urbanized regions, the area of exchanged lots is equal.On the other hand, in more urbanized regions, the price is equal.
3.The weight of tax on land exchange influences the motivation of landowners and local governments.
4.Generally, a hamlet self-government organization is expected to mediate the interests of landowners.But, when urbanization weaken its function, the local government staff has to be a substitute.

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This paper presents the results of a study of a strategic management for estimation of the water demand in a paddy field throughout the operation period of the water management forecasting system developed by the authors using fuzzy inference methodology.
On water management practice in a paddy field, the administrator uses a certain strategy to either increase or decrease the amount of water demand, taking into account not only previous day's water demand and environmental conditions, such as the growing stage of the rice, daily average temperature and weather, but also the change in the farm management practices, requirements of the farmers and so on.This process is mostly influenced by intuitional and creative judgement of the administrator.In order to grasp the structure of strategy, index W which can measure grade of the strategy in quantity was newly introduced into the forecasting system.This was achieved by applying the idea of Truth Value of Fuzzy Set.Then the property of W value was searched using the results obtained from the system operation in the field. Moreover, the mechanism ofinferring W value was studied using the Neuro Network, and it was confirmed that this model is useful for estimating the most suitable management strategy.
Based on this fundamental study, the authors developed a new type of system with a function inferring suitable management strategy using the Neoru Network as a sub-system within the water management forecasting system.As a result of operation in the paddy field, it was observed that the new type of system can estimate water demand of paddy fields with a better correlation to the actual water demand, in comparsion with the old forecasting system.

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A simple real-time system for forecasting flood water level at a retardation pond of a drainage pump station is presented.In this system, a lumped runoff model composed of two tanks is adopted.One of the tanks is a non?linear storage representing runoff from urban areas, while the other tank is a linear storage used for runoff from rural areas.This system is called the Lumped Tank Model system (LTM system).The runoff coefficients and storage heights for both tanks are estimated iteratively, using Kalman filtering and the difference between estimated and observed water levels of the retardation pond as the criterion.
The performance of the LTM system is compared with that of the system adopting a simplified version of the Diffusive Tank Model (DTM) called SDTM system.Comparison of the two systems was performed using the floods of July, 1972 and July, 1986 in the Ogura basin.The results show that the LTM system has almost the same level of accuracy in forecasting flood level as the SDTM system and requiring much less computing time.Because of the equal level of accuracy and computational efficiency, the application of LTM system should be preferred.

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This paver is concerned with the experimental study of interfacial settling properties of suspended sediments (SS) in Quiescent sea water.
Experiments using the settling column were performed in which sea bed sediments, initial SS concentration, and salinity of sea water were varied, while settling height, pH, and temperature of sea water were held constant.
The results suggest that the interfacial settling properties of SS were dependent on sediment type, SS concentration, and salinity.In particular, the effect of initial SS concentration on the interfacial settling properties was revealed to a great extent.The interfacial settling of SS decreased markedly with increasing initial SS concentration, and then approached a constant value at a specific initial SS concentration, thereafter held constant.However, the effect of salinity in the region of 1.3-4.4% on the average velocity was very small.
An equation of interfacial settling velocity of SS was derived on the basis of the two-phase flow theorem of a fluid-sediments system.Comparison of the theoretical values of the mean interfacial settling velocity of SS with the experimental data showed a good agreement and proved the validity of the derived equation.

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The assessment of water quality environment in broad watersheds requires the sufficient understandings of landuse pattern in study areas.The landuse pattern in broad areas can not be analyzed so easily.In this research, the application of satellite remote sensing data (Landsat TM data) to the recognition of landuse pattern was studied and the relation between the area ratio of arable land and the concentration of nitrate nitrogen in the river water in 53 watersheds of Hokkaido was studied;the test areas were Konsen area, Kushiro area and Tokachi area.This research resulted as follows.
1) The accuracy of landcover classification was fairly good, comparing with the landuse statistics of eight counties around study watersheds.
2) The correlation analysis was carried out.The coefficients of correlation were higher than 0.8 in most of the areas.
As a conclusion of this research, the landcover ratios calculated from Landsat TM data are useful for the research on the assessment of water quality environment in broad watersheds.

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“The land consolidation model project for the 21st century typed agriculture”, which will generate 176 thousand yen per hectar in all project life, should be initiated mainly by land improvement districts by means of close land use coordination with the relevant organizations. According to this plan, core farmers would classify into 40 percent individual farmers and 60 percent farmers' association.Labour hours for rice cultivation per year should be cut down to 21 hours from the present 44 hours, and the rice cost per 60 kg will be 9.8 thousand yen, a decrease of 40 percent. “Agricultural land accumulation projects for core farmers” will be expected to raise 59 thousand yen.Both projects should contribute to boost agricultural productivity, promote agricultural structure improvement policy, consolidate farming management, and reduce farming payments.
Land consolidation projects should be promoted more from the view point of promotion of an agricultural structure improvement policy.Therefore, 3 new concept projects, (1) an urgent land consolidation project, (2) a simplified land consolidation project and, (3) a sustainable land consolidation project, are advocated.

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To complete comprehensive model for water quality analysis is generally difficult.The model should be made by purpose, limiting the range of its adaptation.
In this paper, practical method of water quality diagnosis in Kibagata-Lake was discussed.Improvement of water quality by pouring clear water was under planning there.
The two models which were called mass balance model and pollutant diffusion model in this paper, and which had separate purpose, were prepared to diagnosis effect of the project.The former model treated Kibagata?Lake as one pond, and calculated required discharge of clear water to satisfy water quality standard for paddy fields.The reaching rate and removal rate coefficient were determined based on observed date.In the latter model, Kibagata?Lake was divided by 50m interval to simulate plane flow and diffusion.Using this model, distribution of water quality according to location of pouring clear water were compared.
This paper focused on whole procedure of analysis.By combining results of two analysis, the improvement planning of water quality could be diagnosed with enough accuracy on practical use.

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With the physical properties of aggregates used in Miyazaki prefecture investigating, and with the mean value of Miyazaki aggredgate comparing with the mean values of all Kyushu and all Japan aggregates, it revealed that the aggregates used in Miyazaki prefecture are by no means inferior to latters.
Physical properties, alkali silica reaction, compressive strength of concrete mixed with Portland blast-furnace slag cement B, Young's modulus, Poisson's ratio and length change ratio, of coarse aggregates used in Miyazaki which have been deemed to be not good quality and have not been used positively as a material for concrete, were investigated byexperiment.
Assuming a farm pond of water for irrigation and other, a predictive simulation of internal temperature in concretes mixed with the coarse aggregates of poor quality was carried out using a threedimensional finite element heat transfer model, and a preventive method of thermal crack and its availability were examined.

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The recession of a lowflow hydrograph during a period without rain represents the total effect of watershed features and geological characteristics. Thus, the analytical results on the lowflow recession characteristics give effective information forwater resources planning.
Lowflow recession curve characteristics from the perspective of analysis and construction of the recession curve, and these application are reviewed, then problems for topics are posed in this paper.
First, an expressional form of the recession curve, and the estimation and analysis of recession constant are summarized, second, the characteristics and construction of the master recession curve are treated, and finally, the synthesis for the predictionof lowflow runoff is examined through geology, geography, and watershed features.
Moreover, since papers presented before 1968 had been reviewed, only papers presented after then are included in this paper.

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[in Japanese]

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