Outflow loads were measured using three kinds of watersheds: a forest area (F), an agricultural area without a pig (A) and an agricultural area with many pig farms (P) by an automatic water sampler at intervals of 6 hr for 6 months. Each number of data is 720. From these data, some data (n=6, 12, 18, -----) were picked up using 4 methods: same interval, random, corresponding to discharge and notincluding any storms. Then, the mean of outflow loads were calculated using 4 methods: average by equation (4) (L_a), revise by flow rate by Eq.(5) (L_w), LQ method by L=aQ+b (straight type) Eq.(3) (L_q1) and LQ method by L=aQ^b (curved type) (L_q2).
Next, the values of mean X, standard deviation δ and mean squared error e² were calculated, and squared error ratio E and range ratio R were obtained by Eq.(1) and (2).
Results: 1) LQ method is better than the method of average and revise by flow rate.
2) In the case of NO₃-N load by the LQ method, the squared error ratio E is smaller than 10% for the agricultural area when the number of picked up data (n) is larger than 18. In the forest area, it is smaller than 5% when n equals 6 as shown in Fig. 3.
3) A small difference exists between the results calculated by the LQ equation of the straight type and that of the curved type. In the case of a small number of data (n=6), the value of E calculated by the curved type in an agricultural area (A) became large as shown in Fig. 3.
4) In the case of SS, the value of E were so large that it would be impossible to use LQ equation for calculating the outflow load as shown in Fig. 5.

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Sixty soil samples were taken from a plow layer within Shengyang Agriculture Univ. experimental field using the mesh sampling method. These samples were classfied as “BROWN EARTH” in the Chinese soil classification system. Soil-water retention tests were carried out to obtain the soil-water characteristic curves.
These soil-water characteristic curves were scaled by the following four functions with linear or nonlinear regression.
(1) h=Σ[a_k (1-s^k)]/s, (2) s= [1+ (ah) ⁿ] ^-m, (3) s=ah^-b, (4) θ=ch^-d where h is suction, s the degree of saturation, θ is volumetric water content, a, b, c, d, m, n are constants.
The major results are as follows.
(a) Functions (2), (3) and (4) were suitable to estimate these soil-water characteristic curves for Brown Earth.
(b) Function (4) was the most useful function for applying the scaling technique to practical problems.
It is because the volumetric water content (θ) could be directly calculated instead of its function.
(c) It was found that the relationship between cumulative probability and scaling factors were approximately log-normal and normal distribution.
(d) Scaling factors that were obtained from functions (1)-(4) were not equal to each other, but had a strong correlation to the lineal or exponential functions.
(e) These scaling factors can be mainly determined by bulk density or porosity, soil texture and the degree of saturation before a test.
The greater the bulk density, the content of soil particle size of <0.01 mm and the degree of saturation in soil sample before test, or the smaller the content of soil particle size of> 0.25 mm, the smaller the scaling factors became.
(f) In the same suction, the water content estimated from soil-water characteristic curves using the scaling technique was smaller than it from soil-water characteristic curves obtained by the normal method of least squares.

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We have some subjective consciousness on how people living in rural areas consider their surrounding landscape and living space. The purpose of this investigation is to classify various rural types of landscape, to see the differences in consciousness in localities for rural landscape, and detect consciousness for their hometown by use of a questionnaire.
In conclusion, the rural landscape for residents can be summarized into 12 types of images according to a case study. Furthermore, there are some different preferences in each local place of the investigated areas for rural landscape, which are caused by natural features and experience with farming. Generally, rural residents have a desirable image of their hometown, which they see as being with peaceful nature as well as being with both traditional and good local human relations. However, it is found that some differences of consciousness for hometown exist between old residents and new ones. Namely, the former has a comparatively dominant image of local human relations, the latter has that of peaceful nature.

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From 1989, we have carried out experimental studies for estimating the compressive strength of concrete by non-destructive methods. In this paper, the non-destructive methods used to estimate the strength are as follows.
(a) Rebound method (rebound number by the Schmidt hammer N type);
(b) Penetration method (penetration depth using the Pin tester);
(c) Resonant frequency method (dynamic modulus of elasticity); and
(d) Pulse velocity method (ultrasonic pulse velocity).
The compressive strength estimated by these methods was compared with the measured compressive strength from cylindrical and beam specimens. As a lot of data on the strength has not been used and the concrete with a wide range of strength has not been made, it was difficult to estimate the reliable compressive strength by these non-destructive methods. Up to now, the results obtained are as follows.
(1) Among the non-destructive methods, the Pin tester method gave the closest estimation to the measured strength but this method took a great amount of time to measure the penetration depth and left small holes that needed to be repaired on the concrete surface.
(2) The estimation from the Schmidt hammer method disperses frequently because the surface hardness of concrete is greatly affected by the surface conditions such as moisture content or surface roughness.
(3) The pulse velocity method is promising to estimate the strength of concrete because unskillful people can use it easily.
(4) The most promising combination is the ultrasonic pulse method in conjunction with rebound method because this combination gives a higher correlation between the measured strength and that estimated and these method have no restriction with respect to the shape of specimens and structures.

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In 10 plots differing in land utilization, surface soils were sampled every four seasons from 1990 to 1991 and 6 items including 18 factors which may affect the formation and stabilization of soil aggregate were examined.
As a result of this research, using a canonical correlation and time series analyses, the following results were obtained:
1) Factors concerned with items for aggregate and three phases of soil did change with alterations in land use.
2) Biological activity of soil, aluminium content and organic matter content in soil had an influence on the formation and stabilization of soil aggregate.
3) It seems very probable that seasonal changes in the degree of aggregation and mass diameter of aggregate was caused by the biological activity in the soil, which changed remarkably with temperature. Therefore, application of organic matter and inorganic matter, including Al, in spring may be successful in forming and stabilizing the soil aggregate.

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The effect of soil water potential on transpiration under saline water irrigation is experimen tally investigated. The laboratory experiment is carried out in a growth chamber with temperature and relative humidity maintained at 30°C and 40%, respectively. The saline water with 6 different salt concentrations is continuously irrigated for 12 hr into 6 root-boxes, in which dune sand is uniformly packed and soybean plants are being grown. Transpiration rate is determined from the water balance in each root-box. The experimental results show that the transpiration rate ratio (the ratio between the transpiration rate under saline water irrigation and the transpiration rate under freshwater irrigation) decreases exponentially with as the soil water potential decreases which is caused by an increase in the salt concentration in the irrigation water. An experimental formula describing a high degree of correlation between the soil water potential and transpiration rate ratio is obtained. Furthermore, the applicability of the experimental formula is examined under various conditions of both matric and osmotic potentials in the growth chamber under the same meteorological conditions. The weighted mean soil water potential in the root-box is estimated using the modified Gardner's formula. The estimated transpiration rate with saline water by using the weighted mean soil water potential in the empirical formula is in good agreement with measured one. The results of the study suggest that the developed formula can be applied in estimating the transpiration for water management in the arid regions.

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Salt accumulation process associated with water uptake by plant roots is numerically solved by using the method of characteristics for solving convection-dispersion equation and the implicit finite difference method for solving Richards' equation. Root water uptake under a saline condition is assumed to be expressed by the root contact model of Herkelrath et al.(1977). The laboratory experiments are performed under a controlled-environment to test the validity of the proposed numerical method. Experimental results show that the transpiration rate under saline water irrigation decreases compared with that under freshwater irrigation. The calculated profiles of soil water content and salt concentration are in good agreement with the measured data. The numerical methods are also applied to the computation of the salt accumulation process due to the water uptake from the saline water fixed at the bottom boundary. It is demonstrated that the numerically predicted salt accumulation process agrees well with the experimental one and, that the shape of salt concentration profile is quite similar to that of root density profile.

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The present paper addresses a method for estimating the hourly snowmelt discharge mountainous catchment, using hourly data of temperature and duration of sunshine at a measuring sta situated at a low altitude.
The proposed method is applied to estimation of the hourly snowmelt discharge in the Toppu R catchment, located in the Mashike Mountains of West Hokkaido. In this study, a time series of estimated hourly snowmelt discharges were in good agreement with the observed ones.
Characteristics of the present study are summarized as follows:
(1) The method is built in the underlying physical processes from the snowmelt on the surface of snow deposit to the snowmelt through both overland and channel phases of the river. The delay time of snowmelt water passing through the snow deposit is much longer in early snowmelt season, because the snow depth is large. The present approach can estimate the snowmelt discharge at the bottom of snow deposit, using the runoff distribution function model which allows the time of concentration to vary with the depth of snow.The hourly response of a river basin to snowmelt was solved by kinematic wave routing for overland flow as well as channel flow.
(2) The peak discharge and time to the peak of the computed hydrograph compare favorably with those of the observed one for a one-month melting season.
(3) The snowmelt routine developed herein is simple to transfer spatiallydistributed snowmelt to the runoff model, which makes use of hourly air temperature at the measuring site, lapse rate and hourly radiation amount estimated from the duration of sunshine. The method is especially useful to estimate the hourly snowmelt amount in a mountainous catchment in situations where data on sites are not sufficient.
The present method is proposed as alternatives for hourly snowmelt discharge analyses.

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A method for estimating the distribution of annual maximum acceleration values at two sites, which are different from each other in seismic activities, located in the western part of the Chubu District in Japan, is presented. Using two sets of seismicity data in other historical times and linking the estimators from them, these distribution curves are obtained as extreme ones with upper bound limits. The exceedance probabilities of the peak acceleration in t years are also obtained.
Subsequently, the optimum acceleration and probability of failure of the structure during service life are calculated with the aid of the minimum cost criterion, under the assumption that the structure is in one of two states after each earthquake, failure or no failure. Namely, the design values are automatically determined considering the initial construction cost and expected failure cost, related to the degree of importance of the structure and its circumferences lying around. In particular, it has been shown that the optimum probability of failure is individually constant irrespective of the duration of service life of the structure within the range of actually existing expected failure cost values, given the local seismicity and cost values.

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The purpose of this paper is to clarify the correlation between the percolation pattern and soil horizon differentation to oxidation and reduced layers. The soil of a paddy fields that had open system percolation was used in this investigation. The stratified soil model column is composed of Kuroboku soil sampled disturbedly from plow and plowsole layer and composed of yellowish-brown loam sampled undisturbedly from subsoil in the paddy field. In the experiment, DO, pressure head in seepage water, air entry value and Eh were measured at short intervals in the vertical plane, and then, the drainage level was controlled by the soil column. Velocity of the model was about 50 mm/d and that of the other model was about 100 mm/d.
As a result of this observation, the following information was obtained.
1) In the case of a low drainage level (about 70 cm), surface soil became the closed system percolation, low DO (1 ppm level), and reduced layers. Both plowsole and subsoil became the open system perco) ation, high DO (6 ppm level), and oxidized layer.
2) In case of a high drainage level (about 20 cm) in the same column, all layers became a closed system percolation, low DO soon, but became reduced layers after about 80 days.
Judging from the above, it is clear that the open system percolation caused penetration of air into the layer and produced oxidized layer. The closed system percolation caused separation of air from the layer and produced a condition of reduced surroundings. When the activation of microbes was poor, the advance of reduced condition became slow, but the closed system percolation finally brought about a reduced layer.

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The purpose of this paper is to clarify the correlation between the percolation pattern and soil horizon differentiation to oxidized and reduced layers. The model had three layers of the plow layer (Kuroboku soil) of paddy field that is managed yearly by using feritilizer. The stratified soil model column was composed of the Kuroboku soil. The model layers were composed of plow layer (puddling state), plowsole and subsoil (compacted).
In the experiment, DO, pressure head in seepage water, air entry value and Eh were measured at short intervals in the vertical plane, and then, the drainage level was controlled by the soil column. Velocity of the model was about 50 mm/d and that of the other model was about 100 mm/d.
As a result of this observation, the following information was obtained.
1) In the case of a low drainage level (about 90 cm), plow layer and plowsole became a closed system percolation, low DO (1 ppm level), and reduced layers. Subsoil became an open system percolation and high DO (7 ppm level), and oxidized layer.
2) In the case of high drainage level (about 25 cm) in the same column, all layers became a closed system percolation, soon reverting to a low DO, but later becoming reduced layers after about 20 days.
Judging from the above, it is clear that the open system percolation produced an oxidized layer though microbe activation was maximum. The closed system percolation produced a reduced layer at almost a quater of the time required in the inorganic stratified soil column model reported in the previous paper. Therefore, the open system percolation was seen as a necessary and sufficient condition for formation of an oxidized layer. The closed percolation was necessary for a reduced layer. However, it was not a sufficient, and promotion power of reduction is necessary for closed percolation to be a sufficient. The development of reduced layers depends on strength of the promotion power.

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The characteristics of heat balance and thermal environments in the different land use in summer were compared experimentally under the same meteorological conditions. It was shown that the paddy field acted as a sink of heat in the crop-growing season. In this season, the characteristic of heat balance in the asphalt area compared with those in the paddy and non-irrigated potato fields, was that the divisions to sensible heat in the afternoon and to thermal radiation component at night were high. The surface temperature has reached over 50°C in the asphalt area and in the non-irrigated bare field, while it has never exceeded 27°C, 30°C and 35°C in the paddy field, the potato field and irrigated bare filed, respectively. These results showed that the thermal environment can be moderated by irrigation and vegetation, and that this effect is remarkable by vegetation.

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It is important to determine the type of internal storm structure for the design of rainfall in the planning of drainage systems, water resources and so on. However, the formulation of this structure has not been performed. Several studies which have focused on rainfall distribution itself did not deal with the internal storm structure of the rainfall.
This paper discusses the characteristics of the internal structure of heavy rainfall of several durations (T=6, 12, 24 and 48 hours). This analysis leads to studies of the optimal planning of drainage facilities for which the design of rainfall is used as input into the system.
Rainfall data, with a minimum threshold of 70 mm per day, observed at the Kyoto Meteorological Observatory for 45 years were used in the analysis. The internal storm structure, including maximum rainfall over given durations, number of peaks, position of peaks and autocorrelation of hourly rainfall, was examined. In addition, a theoretical formula was derived in order to estimate the probability distribution of rainfall of longer duration from that of shorter duration. The results obtained are summarized as follows:
1) Half of the heavy rainfall events observed consisted of storms with a single peak, and those with less than 3 peaks accounted for 96% of the whole pattern.
2) There was a highly positive correlation between maximum T-hour rainfall (T=6, 12, 24 and 48 hours) and maximum I-hour rainfall. This correlation was more evident in a 3-hour moving average series than the observed series, and in a rainfall series of a shorter duration than that of a longer duration.
3) The peak positions were evenly scattered within a fixed duration although a slightly high concentration was observed at 0.4 T and 0.8 T (T=duration).
4) The Gamma distribution fitted in well with the hourly distribution of the amount of rainfall over the above threshold, resulting in a skewed type of shape parameter h>1.
5) The series of hourly rainfall sequences correspond to the Markov process and, using this result, rainfall distribution of a longer duration can be estimated from the known distribution of hourly rainfall.

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This paper proposes a model for design storm rainfall with several peaks. It was applied to the observed rainfall patterns of which the characteristics were analyzed by using data observed in Kyoto and Hikone. The results obtained are summarized as follows:
1) More than half of the heavy rainfall events observed consisted of storms with a single peak, and those with less than 2 peaks accounted for 90% of the whole event.
2) A new model for design storms with 2 peaks was shown by utilizing Sherman's intensity curve for a single peak storm. This model has 4 parameters.
3) These unknown parameters were determined by solving non-linear simultaneous equations by the Newton-Raphson, Regula Falsi and Continuation methods, for example. In addition, a simplified 3-parameter model instead of a 4-parameter one turned out to be useful when an optimal combination of 4 parameters was difficult to identify.
4) The model was applied to all the rainfall patterns of 2 peaks observed in Kyoto and proved to be useful and practical.

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Ever since Burmister's paper appeared regarding elastic analysis of a multilayered axisymmetric half infinite body, research on the structural design of a flexible pavement have been widely carried out. Corresponding to the elastic analysis, surface loading test of several types have also been tried as regards this type of pavement. These tests are expensive and very time consuming, and it is not easy to test the various conditions of the pavement system. Mechanical properties of subgrade soil generally depend on water content, dry density and other conditions. If we use a small cylindrical pit, it is easy to carry out a plate loading test for the various conditions of subgrade soil. However, there exists no analytical solution regarding on elastic body in a cylinder. The objective of this paper is to introduce a simple analytical solution for a single elastic body restrained in a cylinder, and apply the numerical results on the plate loading test in the cylindrical pit. Distributions of load intensity were given by the Fourier-Bessel expansion, and the solution of stresses and displacements obtained were expressed by infinite series with Bessel functions and an hyperbolic one. On the other hand, repeated plate loading tests using two cylindrical pits of different sizes were performed. Using experimental and numerical deflections of loading plate, the method to evaluate the values of Poisson's ratio and of modulus of deformation of compacted soil in the pit was proposed.

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The applicability of roughness coefficients based on the experiments to actual reclaimed farmland is examined by runoff analysis. To evaluate the validity of these runoff analysis, discharges were observed not only at the end of the whole catchment area, but also at the field lot, located on the way of the runoff process. On flood routing, the basin model of the field lot is considered to be composed of a large number of unit blocks which have the same area as the lysimeter used in the runoff experiment, and that of the catchment area is composed of several such field lots in accordance to the drainage system. Using the kinematic wave model, hydrographs of the field lot and catchment area were estimated, and comparisons between the observed and calculated values were made, respectively. The results showed that the experimentally based roughness coefficients could explain satisfactorily the runoff hydrographs of both the field lot and the catchment area.

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Discharge just before a rainfall event, antecedent precipitation evapotranspiration index, and result of cylinder intake rate test are developed to evaluate rainfall loss in a kinematic wave model. Infiltration parameters obtained from such methods and the experimentally based roughness coefficients were taken into the prediction model, and runoff analyses of three experimental catchments were made respectively. The results obtained were as follows. The experimentally based roughness coefficients can give good prediction of the runoff characteristic of the actual catchment area. The good predictions in the peak discharge show that, the methods of estimating sorptivity with antecedent precipitation evapotranspiration and/or the result of cylinder intake rate test are useful for the prediction of runoff discharge. One of the reasons for taking the final infiltration rate between 1/3-2/3 of saturated hydraulic conductivity, can be explained by the relationship between the rainfall pattern and the sampling interval of rainfall data.

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It is well known that the outflow loads of N (nitrogen) and P (phosphorus) from paddy fields during the puddling and transplanting season are large. For three years, the authors made close investigations to clarify the characteristics of the nitrogen and phosphorus effluents.
The results are summarized as follows: When the puddling and transplanting season (15 days) is divided into three periods of 5 days each, the highest concentrations of N were found in the early days of the first period, this is the period when farmers allow irrigation water to flow in pudding. One reason for the highest concentration in this period is that organic N and ammonia N in the paddy soils, are changed to nitrate when the soil is dried before puddling, because nitrate concentration is noted only in this period of the year. However, effluent loads were largest from the last days of the first period to second period, due to the very large drainage discharge during this period.
In the case of P, the highest concentration and largest effluent loads were both found in the second period. The PO₄-P concentrations were very low, so it seemed that almost all the P was absorbed by the soil particles in the drainage water. The high concentrations of P were made by the processes of paddling and transplanting, because the P concentration in the daytime were much higher than at night.
The characteristics of the effluent loads of N and P differ greatly. As the effluent loads of N and P are affected by the drainage discharge, it is possible to reduce the effluent loads of N and P from paddy fields by correct irrigation water management.

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Penman equation is the calculation process by which potential evapotranspiration is estimated using air temperature, humidity, wind velocity and duration of sunshine. These elements are observed at meteorological stations.
In this paper, we have described the calculation process of the Penman equation in detail by using the observed data and actual values as much as possible as a guide when calculating the potential evapotranspiration using the Penman equation.
Also, we have shown a program of the Penman equation written in BASIC, which agrees fairly well with the calculated example.

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We propose some ideas for easy calculation of the Penman equation.
(1) Wind velocity at 2m height is necessary in the Penman equation. However, wind velocity measurement heights at meteorological stations vary considerably. So we come up with a simple equation to convert wind velocity at the various heights to 2m height values.
u₂=u_H · log (200)/log (100 · H)
u₂, u_H: wind velocity at 2m and Hm height (m·s^-1)
(2) To save manhours for data processing, we have provided approximate equations to account for declination δ and the distance from the earth to the sun, as the number of days from 1 st. January, J.
δ=23.45 cos {0.966 (J-173)}
d/d=1.0000+0.01676 cos {0.977 (J-186)}
d, d: real and average distance to the sun These equations are provided to reduce errors occurring during summer time, or during irrigation periods. The approximate error is zero during the summer solstice (J=173), or aphelion (the farthest day to the sun, J=186).
(3) Different kinds of sunshine recorders are used. Old solar cell-type sunshine recorder indicates the long duration of sunshine. To modify the observed hours recorded by it and bring it into par with the values observed using a standard sunshine recorder, or rotary-type, we have come up with the following next conversion equation.
Y=-0.00302 X³+0.101X²+0.207X
X, Y: Duration of sunshine by old solar cell-type, and rotary-type sunshine recorder value.

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