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[in Japanese]
1995 Volume 8 Issue 1 Pages
1-2
Published: January 05, 1995
Released on J-STAGE: October 22, 2009
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[in Japanese]
1995 Volume 8 Issue 1 Pages
3-6
Published: January 05, 1995
Released on J-STAGE: October 22, 2009
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[in Japanese]
1995 Volume 8 Issue 1 Pages
7-12
Published: January 05, 1995
Released on J-STAGE: October 22, 2009
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Brutsaert Wilfried
1995 Volume 8 Issue 1 Pages
13-18
Published: January 05, 1995
Released on J-STAGE: October 22, 2009
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Seizo TAKEBAYASHI, Goro YASUDA
1995 Volume 8 Issue 1 Pages
19-37
Published: January 05, 1995
Released on J-STAGE: October 22, 2009
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Economic appraisal guidelines and methodologies in Japan for river projects are compiled. The scope of the appraisal system in the whole range of social cost-benefit elements is delineated. Then, available nonmarket goods valuation techniques are discussed. We find that some of these techniques will be useful to aid the realization of the holistic appraisal of river projects although more accumulation of empirical studies in Japan is needed to assess how far these techniques should be incorporated into the appraisal system. The criterion of the assessment should be whether decrease of the allocative inefficiency can be expected more than the increase of the x-inefficiencies caused by the surveys. Some supplementary discussion on empirical use of nonmarket valuation techniques in overseas countries is also made.
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Kazuhisa CHIKITA
1995 Volume 8 Issue 1 Pages
38-48
Published: January 05, 1995
Released on J-STAGE: October 22, 2009
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Sediment discharge generated from snowmelt was observed in the Ikushunbetsu River, Hokkaido (basin area: 60.0 km2) in April 1993. Continuous records of water discharge, Q and suspended sediment concentration, Cs exhibit synchronous time variations at a station along a river channel and a downstream increase in sediment discharge (Qs=Q·Cs) between two stations. The sediment suspended over 90 % of water depth consists of more than 95 wt.% of silt (3.91<d≤62.5 μm) and clay (d≤3.91 μm). Sources of the fine suspended sediment were identified by comparing grain size distributions of some sediment samples taken along the river channel, being supplemented by mineralogical analysis. It is concluded that the sediment discharge is generated by the fluvial erosion of weathered soils deposited on a side gorge slope, and the amount of eroding sediment is approximately proportional to the fluvial shear stress.
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Jiusheng LI, Hiroshi KAWANO
1995 Volume 8 Issue 1 Pages
49-56
Published: January 05, 1995
Released on J-STAGE: October 22, 2009
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An approximate model for simulating infiltration under sprinkler irrigation was developed. The model, which took account of the nonuniformity of both water application and initial soil water content, was verified by field experiments and then was used to study the spatial soil water distribution under sprinkler irrigation. It was found that the effect of water application uniformity on the uniformity of soil water content is not important for the studied sandy soil. The influence of water application uniformity on deep percolation was also examined and showed that deep percolation decreases significantly as water application uniformity increases for the uniformity less than 85%, however, increasing water application uniformity becomes ineffective for decreasing deep percolation when the uniformity exceeds 85%.
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Tosiyuki NAKAEGAWA, Taikan OKI, Katumi MUSIAKE
1995 Volume 8 Issue 1 Pages
57-66
Published: January 05, 1995
Released on J-STAGE: October 22, 2009
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There are two main objectives in this study, in which one is to develop a methodology for estimating the evaporation from macro-scale hydrologic grid that corresponds to basin-scale or GCM grid scale, and the other to carry out basic sensitivity analysis using bulk method. Macro-scale evaporation formulas, into which the subgrid-scale distribution of related physical equations can be incorporated, are derived from ordinary estimation formulas of evaporation by an areal integration. The sensitivity of the subgrid-scale distributions of surface soil moisture and temperature on the evaporation estimation is examined. The major obtained conclusions are as follows: (1) The estimated values of evaporation are dependent not only on the effect of the distribution but also on other factors and can either be lager or smaller than those values obtained without considering the effect of distribution, (2) The evaporation values are different when different types of distributions with the same mean and variance are employed.
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Shuichi IKEBUCHI, Kenjiro SHO, Hiroshi MIYAI
1995 Volume 8 Issue 1 Pages
67-78_1
Published: January 05, 1995
Released on J-STAGE: October 22, 2009
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There are some historical information on water level of Lake Biwa in Edo Era. In this paper we restore annual maximum values of water level and areal thirty days precipitation of Lake Biwa in order to introduce those historical and paleoflood information in flood frequency analyses. In addition to change of reference level at gage station, effects such as dregging of outlet river at Lake Biwa and expansion of flow capacity at outlet weir are considered in the estimation of water level of Lake Biwa. The hydrological data on flood peak from the year 1718 to 1911 reproduced with those historical data and the systematic observed data since the year 1912 are compared qualitatively with the paleolimnological data of Lake Biwa.
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Tetsuo KOBAYASHI
1995 Volume 8 Issue 1 Pages
79-83
Published: January 05, 1995
Released on J-STAGE: October 22, 2009
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The most widely accepted model for the water vapor movement in soil under temperature gradients, proposed by Philip and deVries (1957), is critically examined. Many experiments made after their proposal have shown that the model is not necessarily satisfactory for explaining the results. However, no substitute for it has been proposed as yet. The present author asserts that the scale of soil pores is not larger enough compared to the mean free path of air molecules to be able to disregard the water vapor movement under the kinetic control in comparison with the diffusive transfer. It is shown that they can compare each other in soil pores of typical size; therefore, in reality, a cross between the two processes operates there. The driving force for the kinetic water movement is the deviation from equilibrium between gas and liquid (adsorption) phases caused by the gradient of temperature. Taking account of this mechanism, the basic features of the results of experiment on the present phenomenon can be consistently explained.
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Maurice O. NYADAWA, Shigeki KOBATAKE, Kazuhiro EZAKI
1995 Volume 8 Issue 1 Pages
84-92
Published: January 05, 1995
Released on J-STAGE: October 22, 2009
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Presented in this paper is a study clarifying any distinctions or similarities in trends of extreme value statistics of rainfall and discharges recorded at stations sampled all over a basin traversing three distinct climatic zones in Kenya. It is found that in Athi basin, difference in seasonal rainfall pattern affect general characteristics of intense rainfall more significantly than spatial variation of mean annual rainfall. Survey of flood potential of the basin revealed zones which are considered hydrologically homogeneous and heterogeneous cases.
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Maurice O. NYADAWA, Shigeki KOBATAKE, Kazuhiro EZAKI
1995 Volume 8 Issue 1 Pages
93-100
Published: January 05, 1995
Released on J-STAGE: October 22, 2009
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Tank Model found to be suitable for predicting daily discharges of tropical subbasins identified as having pronounced sluggish runoff response due to basin storage effect is presented in this paper. Runoff response in the objective basins is highly damped at the onset of rains resulting in hydrographs which are considerably lagging behind hyetographs of causative rainfall. This unique basin-storage characteristic is the reason for referring to the basins as “Hydrologically large”. Simulated hydrographs are in good agreement with observed hydrographs in most years considered, therefore, this study concludes that it is possible to predict daily streamflows in the study area using proposed Tank Model.
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Case Study in the Echi River Fan
Haruhiko HORINO, Tsugihiro WATANABE, Toshisuke MARUYAMA, Toshihiro AOK ...
1995 Volume 8 Issue 1 Pages
101-109
Published: January 05, 1995
Released on J-STAGE: February 10, 2010
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In a paddy field area which has some water sources (and/or intake facilities) such as dams, head works, spring ponds, small reservoirs and wells, how and how much water to be used from each source for irrigation is important from the view point of water management. In this paper, temporal water intake volumes from these sources were determined not only at the present irrigation plan, but also at the future, taking the Echi River Fan as a case study. This was carried out by minimizing the total cost of irrigation water using linear programming. The value obtained (optimum water intake volume from each source) was then compared with the actual one. Further, storage of groundwater at the optimum intake was estimated on the basis of a simple water budget. As a result, it was suggested that groundwater had advantages which should not be evaluated only by the cost, and that the upper limit of the water intake volume from the existing dam was about 130 Mm3. In addition, under the optimum intake conditions in the present plan, 65% of the water recharged into groundwater body from the paddy fields during the irrigation period, which was estimated to be 62-63 Mm3, was discharged and 30% of that was stored at the end of the irrigation period.
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[in Japanese]
1995 Volume 8 Issue 1 Pages
110-117
Published: January 05, 1995
Released on J-STAGE: October 22, 2009
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[in Japanese], [in Japanese]
1995 Volume 8 Issue 1 Pages
118-126
Published: January 05, 1995
Released on J-STAGE: October 22, 2009
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[in Japanese]
1995 Volume 8 Issue 1 Pages
127-133
Published: January 05, 1995
Released on J-STAGE: October 22, 2009
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[in Japanese]
1995 Volume 8 Issue 1 Pages
134-137
Published: January 05, 1995
Released on J-STAGE: October 22, 2009
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[in Japanese]
1995 Volume 8 Issue 1 Pages
138-141
Published: January 05, 1995
Released on J-STAGE: October 22, 2009
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[in Japanese]
1995 Volume 8 Issue 1 Pages
142-146
Published: January 05, 1995
Released on J-STAGE: October 22, 2009
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[in Japanese], [in Japanese]
1995 Volume 8 Issue 1 Pages
147
Published: January 05, 1995
Released on J-STAGE: October 22, 2009
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[in Japanese]
1995 Volume 8 Issue 1 Pages
148
Published: January 05, 1995
Released on J-STAGE: October 22, 2009
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