Journal of the Japan Society of Erosion Control Engineering
Online ISSN : 2187-4654
Print ISSN : 0286-8385
ISSN-L : 0286-8385
Volume 59 , Issue 2
Showing 1-14 articles out of 14 articles from the selected issue
  • Takahisa MIZUYAMA
    2006 Volume 59 Issue 2 Pages 1-4
    Published: July 15, 2006
    Released: April 30, 2010
    JOURNALS FREE ACCESS
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  • Takashi JITOUSONO, Etsuro SHIMOKAWA, Yukiyoshi TERAMOTO
    2006 Volume 59 Issue 2 Pages 5-12
    Published: July 15, 2006
    Released: April 30, 2010
    JOURNALS FREE ACCESS
    Abstract A deep-seated landslide occurred in the Harihara River basin on the western flank of Mt. Yahazu-lake, the Pliocene volcano, in Izumi City, Kagoshima Prefecture on July 10, 1997. This deep-seated landslide was caused by rising of groundwater level associated with heavy rainfall, the hydrogeomorphological formation of the underground area prone to storage of groundwater, and deeply weathered volcanic rocks. This study aimed to develop a method for potential site prediction of deep-seated landslide. Some indicators for ascertaining such sites were examined based on topographical and geological surveys, along with hydrological observations in four watersheds on the western flank of Mt. Yahazu-lake. It was ascertained that effective indicators for predicting potential site of deep-seated landslide were the patial distributions of gentle slopes, boundaries between aquifer and aquiclude, the change points of stream discharge, electric conductivity, and silica concentrations along a longitudinal stream, and the distribution of springs.
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  • Atsuhiko KINOSHITA, Masaharu FUJITA, Takahisa MIZUYAMA, Toyoaki SAWADA
    2006 Volume 59 Issue 2 Pages 13-20
    Published: July 15, 2006
    Released: April 30, 2010
    JOURNALS FREE ACCESS
    To evaluate the physiological impact of sediment flushing on fish, the prediction of the temporal variation in the dissolved oxygen concentration is very important. Previously, Kataoka et al. constructed a model that predicts temporal variation in the dissolved oxygen concentration after flushing in the Kurobe River. In this study, we made a model for a headwater stream.
    First, we examined the temporal variation in the concentration of dissolved oxygen at two sites in a headwater area subject to sediment flushing. Then, we modeled the results. We investigated the components of sedimentation in the dam and confirmed that the Fe2+ in the flushed sediment caused the decrease in the dissolved oxygen concentration. We postulated that, as the volume of the pool decreases with flushing, the concentration of dissolved oxygen decreases resulting from aeration decreases. Finally, we showed that when there are pools with sufficient volume, the decrease in the dissolved oxygen concentration caused by flushing is little downstream from the dam.
    Using the model, we were able to predict the temporal variation in the dissolved oxygen concentration after flushing in a headwater stream. We found that the decrease in the dissolved oxygen concentration caused by flushing is little downstream from the dam if there are sufficient large pools.
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  • Naomasa HONDA, Takenobu OKUMURA, Yasuyuki TADA
    2006 Volume 59 Issue 2 Pages 21-29
    Published: July 15, 2006
    Released: April 30, 2010
    JOURNALS FREE ACCESS
    The resistance value in simple penetration tests, i.e., the Nc-value, is useful for investigating sliding surfaces or the surface soil layer of a forest slope. However, the impact weight of 5-kgf, which is the conventional one used in the tests, is too great for accurately estimating the physical characteristics of soil within the surface soil layer when the soil layer is soft. This paper proposes a new type of impact weight for simple penetration tests that is variable from 1-kgf to 5-kgf in 1-kgf increments. Many simple penetration tests are conducted in order to estimate the effect of this weight on an actual forest slope. Experimental results provide a detailed description of the vertical distribution of the penetration resistance value within the surface soil layer. This is made possible by using lighter weights than the conventional one, especially the weights 2-kgf and 3-kgf ones. In addition, the penetration resistance value obtained with the 3-kgf weight is nearly equal to that with Hasegawa 's soil penetration test, but detail is improved further by using the 2-kgf and 1-kgf weights.
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  • Iwao Miyoshi, Yusuke Sakai, Kazuki Matsumura
    2006 Volume 59 Issue 2 Pages 30-36
    Published: July 15, 2006
    Released: April 30, 2010
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    Fukui storm which arose in July 2004, brought large damage in each place of Fukui prefecture, and killed 5 people. Kuratsukuri district of Miyama town has been also suffered from the disaster due to the sediment discharge from 3 rivers that confluent this district. In one of them named as Kuratsukuri River, the sediment discharge was trapped with Sabo and erosion control dams completely in the upper reaches. So the cause of disaster in Kuratsukuri River was thought as the bank collapse occurred in the down reaches near the town. It was recognized that the bank collapses occurred in regardless of land form and vegetation and the whole sediment volume yielded in down reaches were same as the upper reaches, from the field survey
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  • Yasuhiro DOI, Satoshi TAGATA, Takao YAMAKOSHI, Katsuo SASAHARA, Haruo ...
    2006 Volume 59 Issue 2 Pages 37-42
    Published: July 15, 2006
    Released: April 30, 2010
    JOURNALS FREE ACCESS
    Authors surveyed the sediment runoff actually occurring in the Miyakejima Island after 4 years have passed since the volcanic eruptions lastly occurred. The survey was carried out by repeating measuring the freeboards of sedimen control dams newly installed in the rivers. Topographic surveys of cross sections of the rivers were also carried out it the two rivers. As a result, it was confirmed the tendency that sediment runoff still persists in the rivers where the mon volcanic ash deposited at the time of the last eruptions. Observing the quality of the runoff sediment, it can be classifrec into the two types, that is, scoria and fine sediment. The result of the topographic surveys in the two rivers, one is the scoria-runoff-river and the other is the fine-sediment-runoff river, showed that the source of the scoria was the sedimen in the riverbed, while that of the fine sediment was the sediment consisting of the river banks and rill ditches. The scoria-runoff-river has abundant erodible scoria on the riverbed still now, while the fine-sediment-runoff river has solic lava bed such that riverbed erosion will no longer occur.
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  • Ambika DHAKAL, Satoshi TSUCHIYA, Okihiro OHSAKA
    2006 Volume 59 Issue 2 Pages 43-48
    Published: July 15, 2006
    Released: April 30, 2010
    JOURNALS FREE ACCESS
    This research aims to study the sediment delivery estimation models for upland mountainous catchments, which are subject to soil erosion, and sediment delivery to downstream areas every year. A method that combines the Universal Soil Loss Equation (LISLE) and sediment delivery ratio (SDR) model and use Geographic Information System (GIS) techniques to estimate soil loss and sediment delivery at the watershed scale was applied to Higashi-gouchi catchment, a forested mountainous catchment located at the upper part of the Ohi River basin. Many landslide sites are present in the catchment. The USLE was used to estimate mean annual soil loss. Required GIS data layers for the input included rainfall, soil characteristics, elevation and land use. The value of the dam sediment for the study area was calculated from the sediment data deposited in the Ikawa dam. The estimated sediment delivery for the study area in 1997 varied from 14799 to 25487 m3 corresponding to the model applied, while the value of the dam sediment was obtained as 25008 m3 based on the Ikawa dam sediment. The result obtained from the SDR model developed by Vanoni showed an encouraging correspondence with the dam sediment. Further study applying the method for the whole Ikawa dam catchment extending the analysis for several years will be done to clarify whether the method can be used for catchments of larger scale and for the long term.
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  • Yasuyuki HIRAKAWA, Hiroshi SUWA, Katsuyuki FUKUDA, Noriyuki KOBAYASHI
    2006 Volume 59 Issue 2 Pages 49-54
    Published: July 15, 2006
    Released: April 30, 2010
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  • Yoji Chida, Okichika Kurokawa
    2006 Volume 59 Issue 2 Pages 55-58
    Published: July 15, 2006
    Released: April 30, 2010
    JOURNALS FREE ACCESS
    A variety of sabo facilities have already been and will be built to reduce sediment related disasters. And also it is said that the establishment of a warning and evacuation system that is called nonstructural measure, is very important to mitigate disasters. In this case, dissemination of information is one of the important things. In 2003, Hokuriku region was damaged severely by floods of heavy rain accompanying typhoon and by an earthquake. It was reported that a small-scale community broadcasting FM played an important role in dissemination of information during the disaster. The effectiveness and application of the measure in Sabo field are given in this paper.
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  • Takao YAMAKOSHI
    2006 Volume 59 Issue 2 Pages 59-63_2
    Published: July 15, 2006
    Released: April 30, 2010
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  • Hajime NISHIKAWA, Toshihiro HASHINOKI
    2006 Volume 59 Issue 2 Pages 64-72
    Published: July 15, 2006
    Released: April 30, 2010
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  • [in Japanese], [in Japanese], [in Japanese], [in Japanese]
    2006 Volume 59 Issue 2 Pages 73-77_2
    Published: July 15, 2006
    Released: April 30, 2010
    JOURNALS FREE ACCESS
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  • [in Japanese], [in Japanese]
    2006 Volume 59 Issue 2 Pages 78-79
    Published: July 15, 2006
    Released: April 30, 2010
    JOURNALS FREE ACCESS
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  • [in Japanese]
    2006 Volume 59 Issue 2 Pages 80-87
    Published: July 15, 2006
    Released: April 30, 2010
    JOURNALS FREE ACCESS
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