Measurement of monthly evapotranspiration from grass by a nonweighing lysimeter in the Tottori sand dunes, 1972 and 1973, showed maximum daily mean values of 6.1 mm/day in June, 1972 and 6.7 mm/day in August, 1973 and 3.5 mm/day and 3.6 mm/day in annual average, respectively. The relationship between evapotranspiration and solar radiation represented a “loop effect” due to thermal lag behind radiation.The liner relationship was obtained by use of solar radiation weighted according to air temperature.The potential evapotranspiration was estimated by the routine meteorological data (1952-1975) based on the air temperature method, the solar radiation method, the combination method and the pan evaporation method.The prediction methods were calibrated against the measured evapotranspiration, 1972 and 1973.The results obtained from the solar radiation method, the combination method and the pan evaporation method represented similar seasonal patterns of the maximum values in August and of the dip in June due to the rainy season, while, with the air temperature method, the maximum values occurred in July and the values in June were larger than in May.It is felt that the combination method and the solax radiation method offered the best results for predicting potential evapotranspiration.The pan evaporation method and the air temperature method may be graded next, since the accuracy of estimates by the former could be influenced by siting, and since the latter includes only two factors such as air temperature and maximum bright sunshine hours.

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In building up a water quality management system for the Yamada River Basin, the following procedures are important.
1) urderstanding the water pollution characteristics of the basin
2) water quality modeling and parameter estimation
3) predicting the quality of water in the future maintaining
4) planning measures for water quality
In this paper, we discuss the trial estimation of predicting the future quality of the Yamada River, using the water quality model presented in the last paper.
Secondly, supposing some measures for cutting the pollution load which would be produced in the basin in the future, we estimated the improvement in water quality by putting certain measures into practice.

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Sediment of storage dams has long been and still is a most urgent problem to be solved. Thus, sediment trap efficiency is revaluated here by collecting and analysing data of storage dam sediment, mainly in relation to storage capacity index. Comprehensive studies on sediment budget throughout Japan, in relation to each sediment index, are also conducted. The main results are summarized as follows:
1) For the relation between C/I ratio and sediment trap efficiency E_T, more or less different distribution from the center curve by Brune and Dendy is indicated as is shown in Fig.4. The following equation is obtained as an experiential equation.C is storage capacity (m³), I is average annual inflow (m³), and E_T is sediment trap efficiency (%).E_T=100×0.96^0.25logC/I
Since close agreement between observed and calculated values by this equation is obtained, this equation can be considered applicable as an equation for estimating sediment trap efficiency for each storage capacity.
2) Comprehensive studies on sediment budget in Japan are made through rough estimations on production and run off sediment by relating specific sediment deposition of storage dams and sediment index of sediment trap efficiency E_T to drainage areas.
Consequently, it can be assumed that approximately 1/3 of sediment produced in mountainous regions is trapped in storage dams and the other approximately 2/3 is stored in mountainsides and riverbeds and then supplied to down basins resulting in environmental changes due to production and runoff of sediment with their concomitant merits and demerits.

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Cracking within a mass concrete structure is caused mainly by a nonhomogeneous temperature field owing to cement hydration and ambient temperature.
Therefore, the analysis of this temperature field is necessary for crack protection.
Here, this analysis was made by a finite element method which is a very convenient tool for solving field problems.
In part (I), the F.E.M.analysis was applied to the unsteady state temperature field of a real structure and its accuracy was investigated.
The result was satisfactory except for small changes in the daily temperature.The efficiency of this analysis has been proved.

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The fundamental properties of volume-change of normally consolidated clays are discussed by theoretical considerations and experimental results.
The equation for the relationship between effective stresses and volumetric strain is derived by assuming superposition of strain due to isotropic compression and dilatancy.Both triaxial CU and CD Tests were carried out using Kaolin and CF Clay containing a less clay fraction than Kaolin.
The experimental results of Kaolin are shown to be in good agreement with the predicted values from the derived equation.As for CF Clay, the equation is of no use for the latter half of shearing. Since it was found from CU Test results that constants of CF Clay in the equation vary during shear, a modified equation is proposed.
Furthermore, a graphical method is presented for predicting volume changes from CU Test results. This method can be regardless of variations in the constants of the equation, and good agreement is found between the predicted and observed values for both clays.

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[in Japanese]

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In this paper, the results of experiments on the influence of the strain rate e on shearing properties of compacted clay (T-clay) and clayey silt (N-clay) are shown.
The compressive strength (σ₁-σ₃) _f and pore pressure at failure Δu_f increase with an increment in the consolidation pressure σ_3c' but the influence of the strain rate ξ on (σ₁-σ₃) _f and Δu_f is hardly detectable.
The stress path of compacted soils is similar to that of overconsolidated clay.The strain rate ε has an influence on the stress path of T-clay but none on that of N-clay.
The components of cohesion and internal friction on shearing resistance change with strain;namely, the component of cohesion is mainly at small strain and that of internal friction is mainly at large strain but strain rate ε has littl influence on these components.
In conclusion, the strain rate e has little influence on the shearing properties of compacted cohesive soils.

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Reconsideration of land for the planning of suburbs shows the necessity of knowing all physical land conditions and the cultural-historical background of an area.Therefore it is important to develope a system for grasping and representing land conditions to plan an area properly rapidly and at low cost.
Definition of Digital Land Condition (DLC) map is given and the concept of Complex Scene, which is areal pixel-sets in MSS data represented on a DLC map, is described.
Finally the methods for recognizing and discriminating Complex Scenes are described.In brief, the characteristics of Complex Scenes are grasped quantitatively by the attributes of thier histograms (density level, mean, standard deviation, kurtosis, skewness etc.) and are then classified by the Matching or Linear discriminant function etc.

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The effect of pressure dissipation with orifices can be applied to an accurate and convenient means of pressure control in closed conduits.In this application, it is necessary to avoid cavitation.
From the viewpoint of dividing the required amount of pressure dissipation among multiorifices, hydraulic experiments and considerations were made on the characteristics of orifices.
The results are as follows:
1) When orifice diameter to pipe diameter ratio β is within the range of 0.2≤β≤0.6, incipient cavitation index σ_i and critical cavitation index σ_c are given in the following equations respectively.
σ_i=4.5β+0.5
σ_c=3.3β
2) When the value of cavitation index σ is greater than that of critical cavitation index σ_c, the recovery of pressure is achieved at 4D-5D and pressure fluctuation in downstream is small.Where, Dis pipe diameter.
3) When two orifices at intervals of 5D are arranged in series and each cavitation index of these orifices is σ>σ_c, the value of pressure dissipation for each orifice can be estimated by Gardel's equation.
4) When two orifices are arranged in series, orifice diameter to pipe diameter ratio of the orifice settled in upstream should be a little smaller than that in downstream. After this condition is satisfied, each orifice has much the same degree of safety against cavitation occurrence.

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