Updated on 2024/04/02

写真a

 
GOMI Takashi
 
Organization
Graduate School of Bioagricultural Sciences Department of Forest and Environmental Resources Sciences Professor
Graduate School
Graduate School of Bioagricultural Sciences
Undergraduate School
School of Agricultural Sciences Department of Bioenvironmental Sciences
Title
Professor

Degree 3

  1. Ph.D. ( 2002.5   ブリティシュコロンビア大学 ) 

  2. 修士 ( 1994.3   北海道大学 ) 

  3. 学士 ( 1992.3   北海道大学 ) 

Research Interests 1

  1. Watershed hydrology, Erosion control, Ecosystem management

Research Areas 3

  1. Environmental Science/Agriculture Science / Environmental agriculture  / 流域資源管理学

  2. Environmental Science/Agriculture Science / Environmental dynamic analysis  / 森林水文学

  3. Environmental Science/Agriculture Science / Environmental dynamic analysis  / 砂防学

Current Research Project and SDGs 2

  1. 流域の土砂や流木動態の評価と災害対策

  2. 森林管理と森林水循環の評価

Research History 5

  1. Tokyo University of Agriculture and Technology   Professor

    2016.10 - 2022.9

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    Country:Japan

  2. Tokyo University of Agriculture and Technology   Associate professor

    2009.9 - 2016.9

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    Country:Japan

  3. Tokyo University of Agriculture and Technology   Lecturer

    2007.10 - 2009.8

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    Country:Japan

  4. Kyoto University   Researcher

    2004.4 - 2007.9

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    Country:Japan

  5. ブリティシュコロンビア大学   地理学部   研究員

    2002.6 - 2004.3

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    Country:Canada

Education 3

  1. The University of British Columbia   Department of Forest Resources Management

    1998.1 - 2002.5

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    Country: Canada

  2. Hokkaido University

    1992.4 - 1994.3

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    Country: Japan

  3. Hokkaido University

    1988.4 - 1992.3

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    Country: Japan

Professional Memberships 6

  1. Geological Society of America

    2023.12

  2. 水文・水資源学会

    2010.4

  3. 応用生態工学会

    2010.4

  4. 日本森林学会

    2004.4

  5. 公益法人 砂防学会

    2004.4

  6. American Geophysical Union

    2000.8

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Committee Memberships 13

  1. 林野庁   令和5年度水源林造成事業評価技術検討会  

    2023.4   

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    Committee type:Government

  2. 神奈川県   令和4年度農林水産技術会議研究課題設定部会 委員  

    2023.1 - 2023.2   

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    Committee type:Municipal

  3. 経済産業省   環境審査顧問会  

    2022.10   

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    Committee type:Government

  4. 公益社団法人森林・自然環境技術教育研究センター   森林グリーンインフラ整備検証委員会  

    2022.7 - 2024.7   

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    Committee type:Other

  5. 経済産業省   再生可能エネルギー発電設備の適正な導入及び管理のあり方に関する検討会  

    2022.4   

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    Committee type:Government

  6. 神奈川県   水源環境保全・再生かながわ県民会議委員  

    2022.4   

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    Committee type:Municipal

  7. 林野庁   令和4年度水源林造成事業評価技術検討会  

    2022.4 - 2023.3   

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    Committee type:Government

  8. 日本森林技術協会   令和4年度山地保全調査(森林の水源涵養機能の評価・発信に関する調査)委員会  

    2022.3 - 2023.3   

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    Committee type:Other

  9. 林野庁   太陽光発電に係る林地開発許可基準に関する検討会  

    2022.1 - 2022.6   

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    Committee type:Government

  10. 環境省   環境影響審査助言委員  

    2021.4   

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    Committee type:Government

  11. 日本森林技術協会   令和3年度山地保全調査(森林の水源涵養機能の評価・発信に関する調査)委員会  

    2021.3 - 2022.3   

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    Committee type:Other

  12. 神奈川県   神奈川県水源林確保整備専門委員  

    2020.4   

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    Committee type:Municipal

  13. 日本森林技術協会   令和2年度山地保全調査(森林の水源涵養機能の評価・発信に関する調査)委員会  

    2020.4 - 2021.3   

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    Committee type:Other

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Awards 2

  1. 論文賞

    2020.9   水文・水資源学会   山地流域の水・土砂流出における空間スケールの影響(1)〜(3)

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    Award type:Award from Japanese society, conference, symposium, etc. 

  2. 森林学会賞

    2015.3   日本森林学会   森林施業による水流出プロセス・河川環境変化の評価とそのモデル化

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    Award type:Award from Japanese society, conference, symposium, etc. 

 

Papers 103

  1. The Mobility of Landslides in Pumice: Insights from a Flume Experiment Reviewed International coauthorship

    Rozaqqa Noviandi,Takashi Gomi,Hefryan S. Kharismalatri,Roy C. Sidle,Rasis P. Ritonga, Katsushige Shiraki

    Water   Vol. 14 ( 19 ) page: 3083   2022.9

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    Authorship:Corresponding author   Language:English  

    DOI: doi.org/10.3390/w14193083

  2. Runoff and erosion from three unpaved road segments in northern Vietnam Reviewed International coauthorship

    Nguyen Thi My Linh, Lee H. MacDonald, Takashi Gomi, Bui Xuan Dung

    Journal of Hydrology: Regional Studies   Vol. 51   page: 101625   2024.2

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    Authorship:Corresponding author   Language:English  

    DOI: https://doi.org/10.1016/j.ejrh.2023.101625

  3. A watershed-scale evapotranspiration model considering forest type, stand parameters, and climate factors Reviewed

    Shodai Inokoshi, Takashi Gomi, Chen-Wei Chiu, Yuichi Onda, Asahi Hashimoto, Yupan Zhang, Taku M Saitoh

    Forest Ecology and Management   Vol. 547   page: 121387   2023.11

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    Authorship:Corresponding author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: https://doi.org/10.1016/j.foreco.2023.121387

  4. Contrasting Patterns in the Decrease of Spatial Variability With Increasing Catchment Area Between Stream Discharge and Water Chemistry Reviewed International journal

    Tomohiro Egusa, Tomo'omi Kumagai, Tomoki Oda, Takashi Gomi, Nobuhito Ohte

    WATER RESOURCES RESEARCH   Vol. 55 ( 8 ) page: 7419 - 7435   2019.8

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:AMER GEOPHYSICAL UNION  

    Understanding how spatial variability in stream discharge and water chemistry decrease with increasing catchment area is required to improve our ability to predict hydrological and biogeochemical processes in ungauged basins. We investigated differences in this decrease of variability with increasing catchment area among catchments and among specific discharge (Q(s)) and water chemistry parameters. We defined the slope of the decrease in the variability with increasing catchment area as the rate of decrease in the standard deviation and coefficient of variation (delta(SD) and delta(CV), respectively), both of which are -0.5 for the simple mixing of random variables (random mixing). All delta(SD) and delta(CV) values of Q(s) were less than -0.5, while those of most water chemistry values were greater than -0.5, indicating that with increased catchment area the spatial variability of Q(s) decreased more steeply than for random mixing, while for water chemistry they decreased less steeply. delta(SD) and delta(CV) had linear relationships with both the spatial dissimilarity index and relative changes in parameters' mean values with increasing catchment area. It suggested that differences in delta(S)(D) or delta(CV) for Q(s) and water chemistry can be explained by the different spatial structures, where dissimilar values of Q(s) and similar values of water chemistry, respectively, are located close together in space. Differences in delta(SD) and delta(CV) according to Q(s) and water chemistry should significantly affect the determination of representative elementary area and therefore need to be considered when predicting representative elementary area from spatial variability of low-order streams.

    DOI: 10.1029/2018WR024302

    Web of Science

  5. Determinant factors of sediment graphs and rating loops in a reforested watershed Reviewed International coauthorship

    S. H. R. Sadeghi, T. Mizuyama, S. Miyata, T. Gomi, K. Kosugi, T. Fukushima, S. Mizugaki, Y. Onda

    JOURNAL OF HYDROLOGY   Vol. 356 ( 3-4 ) page: 271 - 282   2008.7

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    Sediment graphs and hydrographs were analyzed in a small, high-gradient reforested watershed in Mie Prefecture, Japan, which was instrumented to measure discharge and sediment transport. The study was conducted to recognize determinant factors on sediment graphs and hydrographs relationships, and corresponding rating loops using eight storm events that occurred in 2004. A cause-and-effect analytical approach was employed in the investigation of factors controlling individual hydrological events. The results showed that in a single event, the sediment peak preceded the peak discharge, following a clockwise hysteretic loop. The rating loops exhibited hysteresis with a greater suspended sediment concentration for a given discharge occurring on the rising limb rather than on the failing limb. Furthermore, the reduction in suspended sediment concentrations in a sequence of events and the falling limbs could mainly be associated with sediment exhaustion and contributions of throughfall and throughflow. We concluded that a combination of sediment availability, rainfall characteristics, soil water repellency, and contribution of different flow components control the variations in event-wise sediment graphs and rating loops in the study area. Understanding the relationship between controlling factors and sediment yield dynamics in the study area should greatly improve our understanding of sediment transport mechanisms and predictions in reforested watersheds, which should ultimately lead to better management of forest ecosystems. (C) 2008 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.jhydrol.2008.04.005

    Web of Science

  6. 根系効果の評価における模型斜面降雨実験の有効性 Invited Reviewed

    蓮沼佑晃・Rozaqqa NOVIANDI・岩佐直人・大高範寛・五味高志

    水利科学   Vol. 67 ( 6 ) page: 42 - 62   2024.2

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    Authorship:Last author   Language:Japanese   Publishing type:Research paper (scientific journal)  

  7. Vegetation Effects on Phosphorus Runoff from Headwater Catchments in a Cool-Temperate Region with Landslides, Northern Japan Reviewed

    Jun’ichiro Ide, Rikuto Naito,Yohei Arata, Ryoma Hirokawa,Izuki Endo, Takashi Gomi 4

    Forests   Vol. 15 ( 2 ) page: 229   2024.1

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    Authorship:Last author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: https://doi.org/10.3390/f15020229

  8. Satellite remote sensing model for estimating canopy transpiration in cypress plantation using in situ sap flow observations and forest inventory Reviewed

    Asahi Hashimoto, Chen-Wei Chiu, Yuichi Onda, Makiko Tateishi, Kenji Tsuruta, Takashi Gomi

    ISPRS Journal of Photogrammetry and Remote Sensing   Vol. 206   page: 258 - 272   2023.12

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    Authorship:Last author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: https://doi.org/10.1016/j.isprsjprs.2023.11.009

  9. 流域的視点を踏まえた森林科学と応用地形学 -森林植生と地形プロセスの相互作用とその時空間スケール- Invited Reviewed

    五味高志・猪越翔大・荒田洋平・小柳賢太・大平充

    地形   Vol. 44 ( 4 ) page: 149 - 186   2023.12

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    Authorship:Lead author   Language:Japanese   Publishing type:Research paper (scientific journal)  

  10. Stomatal ozone uptake of a Quercus serrata stand based on sap flow measurements with calibrated thermal dissipation sensors Reviewed

    Ryoji Tanaka, Chen-Wei Chiu, Takashi Gomi, Kazuhide Matsuda, Takeshi Izuta, Makoto Watanabe

    Science of The Total Environment   Vol. 888   page: 164005   2023.8

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: https://doi.org/10.1016/j.scitotenv.2023.164005

  11. Soil‐water response in a volcanic ash hillslope affected by fissures and microtopographic changes caused by the Kumamoto earthquake, in Japan Reviewed International coauthorship

    Yohei Arata, Takashi Gomi, Roy C Sidle, Hirotaka Saito, Gonghui Wang

    Hydrological Processes   Vol. 37 ( 8 ) page: e14947   2023.8

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: https://doi.org/10.1002/hyp.14947

  12. Spatiotemporal patterns in differences between the 137 Cs concentrations of forest and stream litters: effect of leaching Invited Reviewed

    Masaru Sakai, Mitsuru Ohira, Takashi Gomi

    Environmental Science: Processes & Impacts   Vol. 25 ( 8 ) page: 1385 - 1390   2023.7

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    Authorship:Last author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: https://doi.org/10.1039/d3em00236e

    Other Link: https://pubs.rsc.org/en/content/articlehtml/2023/em/d3em00236e

  13. 崩壊地の植被率の違いが炭素と窒素の河川流出に及ぼす影響に関する予備的検討 Reviewed

    井手 淳一郎, 野黒 大雅, 横山 陸, 荒田 洋平, 五味 高志, 遠藤 いず貴

    北方森林研究   Vol. 71   page: 67 - 70   2023.2

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: https://doi.org/10.24494/jfsh.71.0_67

    Other Link: https://www.jstage.jst.go.jp/article/jfsh/71/0/71_KJ00008740524/_article/-char/ja/

  14. A tree detection method based on trunk point cloud section in dense plantation forest using drone LiDAR data Invited Reviewed International coauthorship

    Yupan Zhang, Yiliu Tan, Yuichi Onda, Asahi Hashimoto, Takashi Gomi, Chenwei Chiu, Shodai Inokoshi

    Forest Ecosystems   Vol. 10   page: 100088   2023.1

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: https://doi.org/10.1016/j.fecs.2023.100088

    Other Link: https://www.sciencedirect.com/science/article/pii/S2197562023000039

  15. Ecological resilience of physical plant-soil feedback to chronic deer herbivory: Slow, partial, but functional recovery.

    Ohira M, Gomi T, Iwai A, Hiraoka M, Uchiyama Y

    Ecological Applications   Vol. 32 ( 7 ) page: e2656   2022.10

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1002/eap.2656

    PubMed

  16. Distribution of Radioactive Cesium in the Environment Around the Roadfrom the South Exit of Shinjuku to the Imperial Palace, Tokyo, Japan in 2020

    WATANABE Izumi, SEKIZAWA Kyoka, Oya Yuki, OZAKI Hirokazu, OHJI Madoka, GOMI Takashi

    Journal of Reconstruction Agriculture and Sciences   Vol. 2 ( 2 ) page: 28 - 42   2022.7

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    Language:Japanese   Publisher:Society of Reconstruction Agriculture  

    <p>In May 2020, street dust, bryophytes (mainly mosses) and Sumatran fleabane (Asteraceae family) were collected from the south exit of Shinjuku Station to the Imperial Palace, mainly along Route 20 in Tokyo and were analyzed radioactive cesium in an attempt to reveal the distribution of radioactive cesium around urban road sides environment. The highest concentration of radioactive cesium in this area at the time of the survey was 3,020 Bq kg<sup>-1</sup> dry weight of <sup>137</sup>Cs in street dust, suggesting the existence of potential hotspot areas in Tokyo. Among four types of samples analyzed, mosses rhizosphere soils, street dust, mosses, and shoot of Sumatran fleabane, in that order, showed the highest concentrations. The variability of concentrations varied among samples. Among the four types of samples, the roadside dusts, Sumatran fleabane, rhizosphere soil, and mosses showed the greatest variability, in that order. From these results, it was concluded that mosses and their rhizosphere soils accumulate radioactive cesium at high and stable concentrations and that their use for monitoring is effective. In the survey area, a peculiarly high concentration was found in front of Shinjuku Gyoen, and relatively high levels of radioactive cesium were also detected in Shinjuku 3-chome, Yotsuya Station overpass, and in front of Hanzomon. The roads at those sites were relatively narrow, suggesting that local geographical conditions may have played a role in the accumulation.</p>

    DOI: 10.57341/jras.2.2_28

    CiNii Research

  17. Understory biomass measurement in a dense plantation forest based on drone-SfM data by a manual low-flying drone under the canopy. Reviewed

    Zhang Y, Onda Y, Kato H, Feng B, Gomi T

    Journal of Environmental Management   Vol. 312   page: 114862   2022.6

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.jenvman.2022.114862

    PubMed

  18. Evaluating changes in catchment‐scale evapotranspiration after 50% strip‐thinning in a headwater catchment Reviewed

    Chen‐Wei Chiu, Takashi Gomi, Marino Hiraoka, Katsushige Shiraki, Yuichi Onda, Bui Xian Dung

    Hydrological Processes     2022.5

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    Publishing type:Research paper (scientific journal)   Publisher:Wiley  

    DOI: 10.1002/hyp.14611

  19. Seasonal variations of Cs-137 concentration in freshwater charr through uptake and metabolism in 1-2 years after the Fukushima accident

    Kengo Okada, Masaru Sakai, Takashi Gomi, Aimu Iwamoto, Junjiro N. Negishi, Masanori Nunokawa

    ECOLOGICAL RESEARCH   Vol. 36 ( 6 ) page: 935 - 946   2021.11

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:WILEY  

    Understanding the factors influencing Cs-137 concentrations in freshwater salmonids is crucial for reviving inland fisheries in polluted regions. We studied seasonal variations of Cs-137 concentration in charr (Salvelinus leucomaenis) through uptake and metabolism in forested headwaters at Fukushima and Gunma sites. Charr consumed both terrestrial and aquatic animals, and terrestrial prey was predated more in summer at both sites. The Cs-137 concentrations in litter, which is a dominant basal food resource of both forest and stream ecosystems, differed between forest and stream due to Cs-137 leaching effect on litter submerged in streams. The concentration difference in both litter and prey was greater at Fukushima site than at Gunma site. The estimated prey Cs-137 concentration at Fukushima site peaked in summer when terrestrial preys are most available, whereas it remained relatively constant at Gunma site because of the small difference of Cs-137 concentrations in between terrestrial and aquatic preys. The specific metabolic rate of charr was commonly changed with stream water temperature, greatest in summer, and lowest in winter at both sites. Because both prey Cs-137 concentrations and specific metabolic rates peaked in summer, the combination of uptake and metabolism at Fukushima site largely negated seasonal Cs-137 fluctuations in charr, whereas specific metabolic rate fluctuations could be the major determinant of charr Cs-137 concentrations at Gunma site. Our results suggested that Cs-137 concentrations in prey items, whose seasonality are varied due to initial Cs-137 fallout volume, were expected to be an important determinant for Cs-137 concentrations in charr.

    DOI: 10.1111/1440-1703.12266

    Web of Science

  20. Long‐term impacts of forest disturbances: Comparing cumulative effects of clearcut logging versus landslide on stream conditions and abundance of a headwater stonefly Scopura montana

    Mitsuru Ohira, Yu’usuke Watanabe, Takashi Gomi, Masaru Sakai

    Freshwater Biology   Vol. 66 ( 10 ) page: 2004 - 2015   2021.10

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    Publishing type:Research paper (scientific journal)   Publisher:Wiley  

    DOI: 10.1111/fwb.13811

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    Other Link: https://onlinelibrary.wiley.com/doi/full-xml/10.1111/fwb.13811

  21. Effects of Spatial Scales on Runoff/Sediment Transport in Mountain Catchments (4): Avenues for Prediction Improvement

    UCHIDA Taro, ASANO Yuko, HIRAOKA Marino, YOKOO Yoshiyuki, GOMI Takashi, MIZUGAKI Shigeru, NIWA Satoshi, KATSUYAMA Masanori

    JOURNAL OF JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES   Vol. 34 ( 3 ) page: 192 - 204   2021.5

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    Language:Japanese   Publisher:THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

    <p> To improve the prediction accuracy of numerical simulation models of water and sediment transport phenomena in mountainous catchments, we discuss extraction methods of the governing processes, and important site conditions and external forces affecting the governing processes. Results show a relationship between catchment area and water and sediment discharges, as derived from observations conducted at multiple locations within a catchment, can be typed according to differences in the spatial distribution of governing processes and controlling conditions. Elucidating relations between the catchment area and water and sediment discharges at multiple locations within the catchment might reveal the governing processes and controlling conditions of water and sediment transport phenomena. Based on these analyses, we discussed issues and approaches reflecting the observed information related to the spatial distribution of water and sediment discharge in the numerical prediction models. Results revealed (1) the importance of longitudinal observations at multiple streams in a catchment for ascertaining characteristics of the spatial distribution of water and sediment discharges. This study also clarified (2) the importance of cataloging spatial distribution of site conditions and, (3) processes that are and are not be expressible solely by topography, Furthermore, we argued (4) a method of modelling processes that cannot be determined solely by topography.</p>

    DOI: 10.3178/jjshwr.34.192

    CiNii Research

  22. A Review of SWAT Model Application in Africa

    Akoko George, Le Tu Hoang, Gomi Takashi, Kato Tasuku

    WATER   Vol. 13 ( 9 )   2021.5

  23. Topographic features and stratified soil characteristics of a hillslope with fissures formed by the 2016 Kumamoto earthquake

    Arata Yohei, Gomi Takashi, Sidle Roy C.

    GEODERMA   Vol. 376   2020.10

  24. Characteristics of landslides in forests and grasslands triggered by the 2016 Kumamoto earthquake

    Kenta Koyanagi, Takashi Gomi, Roy C. Sidle

    EARTH SURFACE PROCESSES AND LANDFORMS   Vol. 45 ( 4 ) page: 893 - 904   2020.3

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:WILEY  

    We examined the characteristics of landslides triggered by the 2016 Kumamoto earthquake (Mw = 7.0: focal depth=10.0 km) in forests and grasslands within two affected watersheds (Tokosegawa: 6.9 km(2) and Nigorigawa: 6.1 km(2)) in southwestern Japan. We identified 190 landslides using aerial photographs and analyzed their sizes by geographic information system (GIS). Field investigations were conducted to obtain landslide depth, volume and residual sediment for 38 selected landslides (21 in forests and 17 in grasslands). The minimum area of detected landslides in grasslands (400 m(2)) was smaller than in forests (1000 m(2)), probably because of reduced detectability of landslides under tree cover. The ratio of total area occupied by landslides for a given range of slope gradient in the watersheds increased from 3.2% on gentle grassland slopes (10-15 degrees) to 15.5% on steep (>45 degrees) slopes, whereas the maximum landslide-area ratio in forest sites (7.4%) occurred on relatively gentle slopes (25-30 degrees). Estimated landslide volume ranged from 27 to 9622 m(3), based on mean depth of each landslide measured around individual landslide scars. Moreover, the volumetric ratio of landslide deposit volume to total landslide volume exceeded 100% for 48% of the landslides within forests and 35% of the landslides within grasslands. Our findings show that land cover had extensive and recognizable effects on the characteristics of landslides and resulting in-channel sediment accumulations. Resetting sediment dynamics after earthquakes associated with different land cover distributions needs to be considered within watersheds. (c) 2019 John Wiley & Sons, Ltd.

    DOI: 10.1002/esp.4781

    Web of Science

  25. Assessing spatially distributed infiltration capacity to evaluate storm runoff in forested catchments: Implications for hydrological connectivity Reviewed

    Miyata, Shusuke, Gomi, Takashi, Sidle, Roy C, Hiraoka, Marino, Onda, Yuichi, Yamamoto, Kazukiyo, Nonoda, Toshiro

    Science of the Total Environment   Vol. 669   page: 148 - 159   2019.6

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER  

    We assessed spatial distribution of infiltration capacity under forest canopies to simulate runoff processes in a steep small catchment in Japan. High resolution LiDAR data were used to assess light availability to understory vegetation, which in turn was converted into an understory vegetation cover ratio. Spatially distributed infiltration capacities based on data from field rainfall-runoff experiments were incorporated into the TopoTube model using a relationship between infiltration capacity and vegetation cover. Effects of spatial distribution of infiltration capacity and its influence on hydrological connectivity and runoff processes were examined based on numerical simulations in the following three infiltration scenarios for seven natural storms: (1) spatially distributed infiltration capacity; (2) uniform infiltration capacity using the weighted mean of the spatial distribution in the drainage basin; and (3) uniform infiltration capacity using the arithmetic mean of field measurements. Although saturated subsurface flow dominated storm runoff in all simulations, Hortonian and saturated overland flow were significant for storm runoff response in smaller catchments (headwate

    DOI: 10.1016/j.scitotenv.2019.02.453

    Web of Science

    PubMed

  26. Gravel bar as an interface of ecological network

    GOMI Takashi, OHIRA Mitsuru

    Journal of the Japanese Society of Revegetation Technology   Vol. 44 ( 3 ) page: 489 - 493   2019.2

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    Language:Japanese   Publisher:JAPANESE SOCIETY OF REVEGETATION TECHNOLOGY  

    DOI: 10.7211/jjsrt.44.489

    CiNii Research

  27. Monitoring in Forest Hydrology and its Future

    JOURNAL OF JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES   Vol. 31 ( 6 ) page: 560 - 567   2018.11

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    Language:Japanese   Publisher:THE JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES  

    DOI: 10.3178/jjshwr.31.560

    CiNii Research

  28. Discovery of zero-order basins as an important link for progress in hydrogeomorphology

    Roy C. Sidle, Roy C. Sidle, Takashi Gomi, Takashi Gomi, Yoshinori Tsukamoto

    Hydrological Processes   Vol. 32 ( 19 ) page: 3059 - 3065   2018.9

  29. Effects of Spatial Scales on Runoff / Sediment Transport in Mountain Catchments (1) - A Review of Field Observations on Catchment Area and Properties

    ASANO Yuko, UCHIDA Taro, GOMI Takashi, MIZUGAKI Shigeru, HIRAOKA Marino, KATSUYAMA Masanori, NIWA Satoshi, YOKOO Yoshiyuki

    JOURNAL OF JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES   Vol. 31 ( 4 ) page: 219 - 231   2018.7

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    <p> Examining the patterns of spatial variability of runoff and sediment transport is necessary for understanding hydrologic and geomorphic processes in watersheds. Knowledge of water and sediment transport behaviors in various catchment areas can improve the process-based representation of numerical models. We reviewed the relations between drainage areas and various properties of runoff and sediment transport comprehensively, particularly addressing spatial-scale dependence and spatial heterogeneity. Results show that patterns of increases and decrease of water and sediment amounts occurred relative to the catchment area, although other properties showed no distinctive relation to catchment areas, partly because of a lack of measured data. Most earlier studies specifically examined either spatial-scale dependence or spatial heterogeneity. Properties such as peak specific discharge showing clear spatial-scale dependence should be controlled by mechanisms that change with the spatial scale. Properties such as specific discharge during base flow showed spatial heterogeneity. Results suggest that mechanisms controlling base flow did not change much with the spatial scale for the measured ranges of catchment areas. Heterogeneous properties of landscapes exerted strong effects on those properties.</p>

    DOI: 10.3178/jjshwr.31.219

    CiNii Research

  30. Effects of Spatial Scales on Runoff / Sediment Transport in Mountain Catchments (3) -Review for the Treatments of Numerical Models

    YOKOO Yoshiyuki, NIWA Satoshi, UCHIDA Taro, HIRAOKA Marino, KATSUYAMA Masanori, GOMI Takashi, MIZUGAKI Shigeru, ASANO Yuko

    JOURNAL OF JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES   Vol. 31 ( 4 ) page: 245 - 261   2018.7

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    <p> We reviewed the treatment of spatial scales in numerical models of runoff and sediment transport to elucidate current problems and to identify avenues for future research. We specifically examined the following questions: (1) Which spatial scale is used in existing modeling and how was it decided? (2) What spatial information was used? (3) Do the governing equations differ with spatial scale? Results show that the smallest spatial scale in distributed models was determined by the spatial resolution of spatially distributed information used in modeling, although lumped models were applicable at any scale. Some physical parameters used in modeling, aside from elevation, land use and vegetation cover, were not based on field-based information. Results demonstrate that the governing equations differ depending on locations within the watershed (i.e., hillslopes and channels) presenting different processes for runoff and sediment transport. Nevertheless, no report of the relevant literature describes a study with changed governing equations along with the changes in spatial scales. We also reviewed modeling studies of how we should treat the effects of spatial scale in runoff modeling, which revealed that they had reported minimum and the maximum spatial scales for lumping runoff mechanisms and the relative importance of spatial data used as input and parameters, although no attempts have been reported for a change in governing equations with spatial scale. We were unable to find similar studies of sediment runoff modeling. In summary, we suggest improvement of these findings and their use for modeling rainfall runoff and sediment transport mechanisms for better hydrological science.</p>

    DOI: 10.3178/jjshwr.31.245

    CiNii Research

  31. Effects of Spatial Scales on Runoff / Sediment Transport in Mountain Catchments (2) -Results from Intensively Studied Catchments

    ASANO Yuko, UCHIDA Taro, KATSUYAMA Masanori, HIRAOKA Marino, MIZUGAKI Shigeru, GOMI Takashi, NIWA Satoshi, YOKOO Yoshiyuki

    JOURNAL OF JAPAN SOCIETY OF HYDROLOGY AND WATER RESOURCES   Vol. 31 ( 4 ) page: 232 - 244   2018.7

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    <p> Findings for spatial patterns of runoff and sediment transport at selected observation sites were summarized to elucidate processes controlling scale dependence and spatial heterogeneity of their catchment areas. We selected Fudoji and Kiryu watersheds in Shiga for runoff generation and Tanzawa in Kanagawa and Saru watersheds in Hokkaido for sediment transport. Regarding runoff generation, variation of concentration of specific chemical species (i.e. silica) suggested various flow paths from weathered bedrock layer to soil layer in small catchments, although variation tapered with increased catchment area because of the mixing of several flow components. Sediment transport also varied spatially depending on the catchment characteristics. Variation tapered with increased catchment area. Moreover, increased storage components and decreased ratios of sediment source areas to the total catchment area for larger drainage areas decreased the sediment transport with catchment areas in some catchments. Landscape legacies of sediment supply, storage, and transport can contribute to increased sediment yields in larger catchments.</p>

    DOI: 10.3178/jjshwr.31.232

    CiNii Research

  32. Effect of canopy openness and meteorological factors on spatial variability of throughfall isotopic composition in a Japanese cypress plantation

    Xinchao Sun, Yuichi Onda, Akiko Hirata, Hiroaki Kato, Takashi Gomi, Xueyan Liu

    Hydrological Processes   Vol. 32 ( 8 ) page: 1038 - 1049   2018.4

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    Spatial variability of throughfall (TF) isotopic composition, used as tracer input, influences isotope hydrological applications in forested watersheds. Notwithstanding, identification of the dominant canopy factors and processes that affect the patterns of TF isotopic variability remains ambiguous. Here, we examined the spatio-temporal variability of TF isotopic composition in a Japanese cypress plantation, in which intensive strip thinning was performed and investigated whether canopy structure at a fine resolution of canopy effect analysis is related to TF isotopic composition and how this is affected by meteorological factors. Canopy openness, as an index of canopy structure, was calculated from hemispherical photographs at different zenith angles. TF samples were collected in a 10 × 10 m experimental plot in both pre-thinning (from July to November 2010) and post-thinning (from May 2012 to March 2013) periods. Our results show that thinning resulted in a smaller alteration of input δ18O of gross precipitation, whereas the changes in deuterium excess varied in both directions. Despite the temporal stability of spatial patterns in TF amount, the spatial variability of TF isotopic composition was not temporally stable in both pre- and post-thinning periods. Additionally, after thinning, the isotopic composition of TF was best related to canopy openness calculated at the zenith angle of 7°, exhibiting three different relationships, that is, significantly negative, significantly positive, and nonsignificant. Changes in meteorological factors (wind speed, rainfall intensity, and temperature) were found to affect the relationships between TF δ18O and canopy openness. The observed shifts in the relationships reveal different dominant factors (partial evaporation and the selection), and canopy water flowpaths control such differences. This study provides useful insights into the spatial variability of TF isotopic composition and improves our understanding of the physical processes of interception through canopy passage.

    DOI: 10.1002/hyp.11475

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    Scopus

  33. Cesium-137 contamination of river food webs in a gradient of initial fallout deposition in Fukushima, Japan

    J. N. Negishi, M. Sakai, K. Okada, A. Iwamoto, T. Gomi, K. Miura, M. Nunokawa, M. Ohhira

    Landscape and Ecological Engineering   Vol. 14 ( 1 ) page: 55 - 66   2018.1

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    We examined the cesium-137 (137Cs) contamination of river food webs in a gradient of initial fallout deposition (net density estimates 2.5–3.5 months after the Fukushima Daiichi Nuclear Power Plant accident in March 2011), in Fukushima Prefecture, Japan. Litter, aquatic insects, and salmonid fish were collected in five headwater stream reaches (watershed-average fallout density, 368.1–1398.4 kBq/m2) for the measurement of 137Cs concentration and stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) in June 2014. The stable isotope ratios suggested that the detrital food chain was a dominant energy pathway in rivers originating from a basal resource (litter) to primary (aquatic insects) and secondary (fish) consumers. The 137Cs concentration decreased with an increase in the trophic level, with the highest value for litter (10930 ± 5381 Bq/kg, mean ± SD), the lowest for fish (2825 ± 2451 Bq/kg), and the intermediate one for dominant (numerically and biomass-wise) detritivorous insect, Ephemera japonica McLachlan (4605 ± 1970 Bq/kg). 137Cs concentrations of three trophic levels were linearly predicted by the initial fallout amount of 137Cs. The evacuation of the gut contents of E. japonica during field experiments led to a reduction in their 137Cs concentration by approximately 50% within 1–2 day(s) without loss of body weight. This suggested that a substantial portion of 137Cs contamination of E. japonica was derived from highly contaminated fine solids deposited in depositional habitats at a disproportionately high density. Overall, the initial fallout amount of 137Cs was helpful in roughly predicting the contamination levels of headwater river-riparian ecosystems with the detrital food chain as a dominant energy pathway. Long-term monitoring of the dynamics and fates of 137Cs associated with fine organic and inorganic particulates appears important for better prediction of 137Cs contamination of food webs in forested headwater streams.

    DOI: 10.1007/s11355-017-0328-8

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  34. Evaluating 137Cs detachment from coniferous needle litter in a headwater stream: a litter bag field experiment

    Takashi Gomi, Masaru Sakai, Md. Enamul Haque, Kosuke Hosoda, Hiroto Toda

    Landscape and Ecological Engineering   Vol. 14 ( 1 ) page: 17 - 27   2018.1

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    This study examined 137Cs detachment from needle litter of Japanese cedar (Cryptomeria japonica) through leaching and decomposition in a headwater stream located 45 km from Fukushima Daiichi Nuclear Power Plant. We placed litter bags in pools and riffles and removed them after 4, 15, 75, 150, and 240 days. The 137Cs activity concentration in litter collected after 4 and 15 days was 48–72 % of the initial 137Cs activity concentration in litter. The 137Cs activity concentration in litter after 240 days in the pools decreased by 26 %, while that in litter of riffles decreased by 9 % compared with the initial 137Cs activity concentration. The dry weight of litter became 71 and 86 % of initial weight after 75 days, and from 32 to 51 % after 150 days. The decay coefficient of litter (k = 0.0060) in the riffles was 1.6-fold higher than that in the pools (k = 0.0037). The greater decrease in litter weight with longer submergence time was possibly associated with a combination of leaching and decomposition, in particular in litter that was submerged for 100 days in the water column. The difference in the rate of decomposition and 137Cs detachment from litter between the riffles and pools was due to the substrate and flow conditions at the litter bag sites. Examining the different patterns of 137Cs detachment from litter among channel morphologies is necessary for comprehending the mechanisms of 137Cs accumulation in aquatic biota. The findings of this study suggest that elucidating leaching and decomposition processes in litter of stream channels is important for understanding 137Cs dynamics in forested headwater ecosystems.

    DOI: 10.1007/s11355-017-0337-7

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  35. Tracing radioactive contamination of river basins for the development of effective mitigation measures

    Chihiro Yoshimura, Takashi Gomi, Kazumi Tanida

    Landscape and Ecological Engineering   Vol. 14 ( 1 ) page: 1 - 2   2018.1

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    DOI: 10.1007/s11355-017-0345-7

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  36. Hydrogeomorphic processes and scaling issues in the continuum from soil pedons to catchments Reviewed

    Roy C. Sidle, Takashi Gomi, Juan Carlos Loaiza Usuga, Ben Jarihani

    EARTH-SCIENCE REVIEWS   Vol. 175   page: 75 - 96   2017.12

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ELSEVIER SCIENCE BV  

    Understanding integrated hydrological phenomena in catchments is difficult because of the fragmented nature of soil physical and hydrological data, given these are typically derived from pedons or small plots. Runoff plot and lysimeter or pedon-scale studies do not capture the complexity of surface and subsurface flowpaths in hillslopes. Because pedon/plot scale results are not easily transferable to hillslope and catchment scales, theoretical and empirical approaches to quantify hydrological dynamics based on such 'point-scale' data tend to over- or underestimate parameters and fluxes. Unit area sediment flux measured during storms typically (but not always) decreases from small plots to hillslopes owing to sediment deposition and re-infiltration of overland flow in localized areas. At broader scales, re-entrainment of previously stored sediment complicates this generalization, as may the development of rill and gully systems, facilitated by overland flow concentration. Quantifying mass wasting and sediment interactions in channels presents different temporal and spatial challenges, and must be assessed at the catchment scale. Process-based scaling requires an over-arching integration of different hydro geomorphic concepts and approaches. Nested catchment studies, where processes are monitored at different scales, represent an opportunity to elucidate the diverse spatial and temporal patterns of water and sediment behaviour. The spatial scale dependence inherent in many pedology and catchment hydrology studies can be overcome by incorporating hydrogeomorphic, pedological, and connectivity concepts that demonstrate how soil hydraulic parameters, geomorphic controls, and water/sediment routing change from plot to hillslope to catchment scales. The resulting self-organization generates spatial and temporal dependencies and provides a paradigm to better understand, model, and assess management effects on water and sediment fluxes and pathways in the continuum from plots to catchments.

    DOI: 10.1016/j.earscirev.2017.10.010

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  37. The continuum of chronic to episodic natural hazards: Implications and strategies for community and landscape planning

    Sidle Roy C., Gallina John, Gomi Takashi

    LANDSCAPE AND URBAN PLANNING   Vol. 167   page: 189 - 197   2017.11

  38. Estimation of throughfall with changing stand structures for Japanese cypress and cedar plantations

    Sun Xinchao, Onda Yuichi, Kato Hiroaki, Gomi Takashi, Liu Xueyan

    FOREST ECOLOGY AND MANAGEMENT   Vol. 402   page: 145 - 156   2017.10

  39. Change in evapotranspiration partitioning after thinning in a Japanese cypress plantation Reviewed

    Xinchao Sun, Yuichi Onda, Kyoichi Otsuki, Hiroaki Kato, Takashi Gomi, Xueyan Liu

    TREES-STRUCTURE AND FUNCTION   Vol. 31 ( 5 ) page: 1411 - 1421   2017.10

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    Thinning resulted in evapotranspiration decrease and caused the relative contributions of each component to evapotranspiration to become very close.
    To increase the understanding of forest management to control water cycles, we examined the effect of 50% strip thinning on evapotranspiration (ET) and its partitioning into canopy interception (E (i)), tree transpiration (E (t)), and forest floor evaporation (E (f)) in a Japanese cypress (Chamaecyparis obtusa Endl.) plantation. Intensive measurements were employed to monitor each component of ET during the pre- and post-thinning periods. The results showed the annual E (t) was the dominant component of ET followed by E (i), whereas E (f) was the smallest component in both periods. Thinning has significant impact on the process of ET partitioning. In such that it decreased from 42.3 to 33.7% in E (i)/ET and from 45.0 to 34.9% in E (t)/ET, and increased from 12.7 to 31.4% in E (f)/ET on an annual scale. The relative contributions of each ET component to the whole ET became more or less the same after thinning. Additionally, the monthly E (i)/P (g) had relative stable values in both pre- and post-thinning periods, contributing significantly to the ET/P (g) during heavy rainfall conditions. After thinning, ET decreased by 21.4% from 629.3 to 494.8 mm during the growing season and by 20.4% from 979.8 to 780.1 mm at the annual scale, demonstrating that thinning results in an increase in water availability in the forested watershed. This study can improve the understanding of forest water budget in response to thinning and aid in development of appropriate forest management practices accordingly.

    DOI: 10.1007/s00468-017-1555-1

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  40. Effect of tree thinning and skidding trails on hydrological connectivity in two Japanese forest catchments Reviewed

    Manuel Lopez-Vicente, Xinchao Sun, Yuichi Onda, Hiroaki Kato, Takashi Gomi, Marino Hiraoka

    GEOMORPHOLOGY   Vol. 292   page: 104 - 114   2017.9

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    Land use composition and patterns influence the hydrological response in mountainous and forest catchments. In plantation forest, management operations (FMO) modify the spatial and temporal dynamics of overland flow processes. However, we found a gap in the literature focussed on modelling hydrological connectivity (HC) in plantation forest under different FMO. In this study, we simulated HC in two steep paired forest subcatchments (K2 and K3, 33.2 ha), composed of Japanese cypress (Chamaecyparis obtusa Endl.) and Japanese cedar (Cryptomeria japonica D. Don) plantations (59% of the total area) against a tree thinning intensity of 50% at different time. Additionally, construction of new skidding trails and vegetation recovery was simulated on five thinning-based scenarios that covered a 40-month test period (July 2010 - October 2013). As a future scenario, six check-dams located in the main streams were proposed to reduce sediment and radionuclide delivery. An updated version of Borselli's index of runoff and sediment connectivity was run, using the D-infinity flow accumulation algorithm and exploiting three 0.5-m resolution digital elevation models. On the basis of the pre-FMO scenario, HC increased at catchment scale owing to tree thinning and the new skidding trails. This change was more noticeable within the area affected by the FMO, where HC increased by 11.4% and 10.5% in the cypress and cedar plantations in K2 respectively and by 8.8% in the cedar plantation in K3. At hillslope plot and stream scales, the evolution in the values of HC was less evident, except the increment (by 5.4%) observed in the streams at K2 after the FMO. Progressive vegetation recovery after the FMO triggered a slight reduction of connectivity in all compartments of both subcatchments. Forest roads and especially skidding trails presented the highest values of HC, appearing as the most efficient features connecting the different vegetation patches with the stream network. The spatial and temporal evolution of HC over the five past scenarios correlated well with the observed changes in runoff yield, as well as with the available values of rainfall interception and throughfall before, during, and after the FMO. The simulation of the proposed scenario recommends the construction of check-dams as effective landscape features to somewhat reduce HC and thus to decrease the sediment and radionuclide delivery rates from the two subcatchments.

    DOI: 10.1016/j.geomorph.2017.05.006

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  41. Developing a food web-based transfer factor of radiocesium for fish, whitespotted char (Salvelinus leucomaenis) in headwater streams Reviewed

    Md. Enamul Haque, Takashi Gomi, Masaru Sakai, Junjiro N. Negishi

    JOURNAL OF ENVIRONMENTAL RADIOACTIVITY   Vol. 172   page: 191 - 200   2017.6

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    We developed a food web-based transfer factor (TFweb) to study contaminant movements from multiple prey items to a predator based on the dietary contributions of prey items with their respective contamination levels. TFweb was used to evaluate the transfer of Cs-137 into whitespotted char (Salvelinus leucomaenis) from the trophic structure of a stream riparian ecosystem in headwater streams draining a Japanese cedar forest. We also examined the applicability of this method by comparing sites with different contamination levels but similar surrounding environments in Fukushima and Gunma. All samples were collected from August 2012 to May 2013. The dietary contributions from both aquatic and terrestrial prey items to whitespotted char were analyzed using stable carbon and nitrogen isotope ratios. Cs-137 activity concentrations in char ranged from 704 to 6082 Bq kg(-1)-dry in Fukushima and from 193 to 618 Bq kg(-1)-dry in Gunma. Dominant prey taxa such as mayflies (Ephemera japonica), spider crickets (Rhaphidosphoridae gen. spp.), and freshwater crabs (Geothelphusa dehaani), each of them accounted for 3-12% of the fish diet, based on lower and upper estimates, respectively. TFweb ranged from 1.12 to 3.79 in Fukushima and from 1.30 to 4.30 in Gunma, which suggested bioaccumulation from prey items to predator. Widely used ecological parameters TFs by media-char and ITF by single prey -char showed high variability with both dilution and accumulation. TFweb is applicable for Cs-137 transfer in predator-prey systems with complex food web structures of stream-riparian ecosystems. (C) 2017 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.jenvrad.2017.02.020

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  42. Field estimation of interception in a broadleaf forest under multi-layered structure conditions Reviewed

    Yutaka Abe, Takashi Gomi, Norihisa Nakamura, Noriko Kagawa

    Hydrological Research Letters   Vol. 11 ( 4 ) page: 181 - 186   2017.1

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Japan Society of Hydrology and Water Resources  

    We performed a field experiment on throughfall, stemflow, and bamboo culm flow to estimate interception in a deciduous broadleaf forest with different stand structures by separately removing the overstory and understory vegetation. The study area is occupied by oak (Quercus serrata) and chestnut (Castanea crenata) with an understory of chino bamboo (Pleioblastus chino). We established three plots for vegetation control, including an overstory plot (removal of understory), a bamboo plot (removal of overstory), and a control plot (both overstory and understory remained). Throughfall amounts relative to precipitation were 61% in the control plot, 54% in the overstory plot, and 31% in the bamboo plot. Average stemflow in control and overstory plots was 3% of precipitation. The significant difference in throughfall for the bamboo plot may have been caused by the high density of understory vegetation. A large portion of intercepted water is transferred to the ground as bamboo culm flow in the understory beneath the canopy in the control plot and in the bamboo plot. Our experiment highlighted the significance of understory vegetation in altering hydrological processes from canopy to understory vegetation.

    DOI: 10.3178/hrl.11.181

    Scopus

  43. Fallout volume and litter type affect Cs-137 concentration difference in litter between forest and stream environments Reviewed

    Masaru Sakai, Takashi Gomi, Junjiro N. Negishi

    JOURNAL OF ENVIRONMENTAL RADIOACTIVITY   Vol. 164   page: 169 - 173   2016.11

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    It is important to understand the changes in the Cs-137 concentration in litter through leaching when considering that Cs-137 is transferred from basal food resources to animals in forested streams. We found that the difference of Cs-137 activity concentration in litter between forest and stream was associated with both litter type and Cs-137 fallout volume around Fukushima, Japan. The Cs-137 activity concentrations in the litter of evergreen conifers tended to be greater than those in the litter of broad-leaved deciduous trees because of the absence of deciduous leaves during the fallout period in March 2011. Moreover, Cs-137 activity concentrations in forest litter were greater with respect to the Cs-137 fallout volume. The Cs-137 activity concentrations in stream litter were much lower than those in forest litter when those in forest litter were higher. The Cs-137 leaching patterns indicated that the differences in Cs-137 activity concentration between forest and stream litter could change with changes in both fallout volume and litter type. Because litter is an important basal food resource in the food webs of both forests and streams, the Cs-137 concentration gradient reflects to possible Cs-137 transfer from lower to higher trophic animals. Our findings will improve our understanding of the spatial heterogeneity and variability of Cs-137 concentrations in animals resident to the contaminated landscape. (C) 2016 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.jenvrad.2016.07.030

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  44. Immediate change in throughfall spatial distribution and canopy water balance after heavy thinning in a dense mature Japanese cypress plantation Reviewed

    Kazuki Nanko, Yuichi Onda, Hiroaki Kato, Takashi Gomi

    ECOHYDROLOGY   Vol. 9 ( 2 ) page: 300 - 314   2016.3

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    This study revealed the influence of change in forest canopy structure by forest management practice for throughfall generation and canopy water interception process. Throughfall and stemflow were observed in a mature Japanese cypress (Chamaecyparis obtusa) plantation before and after thinning. Decreased stem density (from 2400 to 1300treesha(-1)) and basal area (from 107.6 to 60.4m(2)ha(-1)) resulted in an increase in the throughfall fraction (from 58% to 79%) and decreases in the stemflow fraction (from 14% to 8.6%) and the canopy interception loss fraction (from 27% to 12%). Thinning also decreased spatial variability in throughfall and smoothed temporal persistence of throughfall among sampling points or rainfall events. These results were supported by the change in the throughfall balance between direct throughfall and released throughfall. The proportion of direct throughfall of incident rainfall changed from 0.16 to 0.42 owing to an increase in canopy gap. The distribution ratio of released throughfall from intercepted rainwater by canopy changed from 50% to 64% because of a decrease in foliage; this led to lower water storage in the canopy (from 1.83 to 0.82mm), and thus less precipitation was needed to saturate the canopy. Consequently, the amount of throughfall increased and less precipitation was needed to stabilize the water flow path during the post-thinning period. This study contributes to knowledge of differential canopy wetting processes and spatiotemporal heterogeneity of throughfall distribution in response to specific silvicultural prescription. Copyright (c) 2015 John Wiley & Sons, Ltd.

    DOI: 10.1002/eco.1636

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  45. Different cesium-137 transfers to forest and stream ecosystems Reviewed

    Masaru Sakai, Takashi Gomi, Junjiro N. Negishi, Aimu Iwamoto, Kengo Okada

    ENVIRONMENTAL POLLUTION   Vol. 209   page: 46 - 52   2016.2

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    Understanding the mechanisms of Cs-137 movement across different ecosystems is crucial for projecting the environmental impact and management of nuclear contamination events. Here, we report differential movement of Cs-137 in adjacent forest and stream ecosystems. The food webs of the forest and stream ecosystems in our study were similar, in that they were both dominated by detrital -based food webs and the basal energy source was terrestrial litter. However, the concentration of Cs-137 in stream litter was significantly lower than in forest litter, the result of Cs-137 leaching from litter in stream water. The difference in Cs-137 concentrations between the two types of litter was reflected in the Cs-137 concentrations in the animal community. While the importance of Cs-137 fallout and the associated transfer to food webs has been well studied, research has been primarily limited to cases in a single ecosystem. Our results indicate that there are differences in the flow of Cs-137 through terrestrial and aquatic ecosystems, and that Cs-137 concentrations are reduced in both basal food resources and higher trophic animals in aquatic systems, where primary production is subsidized by a neighboring terrestrial ecosystem. (C) 2015 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.envpol.2015.11.025

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  46. Influence of strip thinning on nutrient outflow concentrations from plantation forested watersheds Reviewed

    Takehiko Fukushima, Rai Tei, Hiroyuki Arai, Yuichi Onda, Hiroaki Kato, Shimpei Kawaguchi, Takashi Gomi, Bui X. Dung, Sooyoun Nam

    HYDROLOGICAL PROCESSES   Vol. 29 ( 24 ) page: 5109 - 5119   2015.11

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    Nutrient concentrations in stream water, rainfall, throughfall, stemflow, surface flow and ground water were compared before, during and after strip thinning (intensive 50%) in plantation forested watersheds in Tochigi, Japan. Influences were evaluated comparing four thinning-applied and two reference basins for 1 year before, 6 months during and 1 year after the thinning. Results show that this strip thinning significantly increased dissolved total phosphorus, total phosphorus and dissolved organic carbon (0.01, 0.04 and 0.53 mg l(-1), respectively) during the thinning period and dissolved total nitrogen and total nitrogen (0.34 and 0.46 mg l(-1), respectively) after the thinning in stream waters relative to the unthinned basins. The increased phosphorus during thinning indicated ground disturbances by the strip thinning, with a concomitant increase in dissolved organic carbon. Changes in biotic and abiotic conditions resulted in increased nitrogen after the thinning, particularly in the dissolved pool. Changes in hydrological processes due to thinning, for example, a change in flow distributions (less high nutrient stemflow and more low nutrient throughfall) and an increase in water discharge in stream water, possibly weakened the direct influences of thinning on nutrient concentrations. Copyright (C) 2015 John Wiley & Sons, Ltd.

    DOI: 10.1002/hyp.10570

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  47. Effect of strip thinning on rainfall interception in a Japanese cypress plantation Reviewed

    Xinchao Sun, Yuichi Onda, Hiroaki Kato, Takashi Gomi, Hikaru Komatsu

    JOURNAL OF HYDROLOGY   Vol. 525   page: 607 - 618   2015.6

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    We examined the effect of strip thinning on rainfall interception (Et) in a 32-year-old Japanese cypress plantation in central Japan. Strip thinning was conducted in the catchment in October 2011; that removed 50% of the stems. The gross precipitation (Pg), throughfall (TF) and stemflow (SF) were monitored in a 12-m x 13-m plot before and after thinning. Et was calculated as the difference between Pg and the sum of TF and SF. The interception processes were illustrated using the revised Gash model with quantifying interception parameters. The results showed that the Gash model successfully predicted Et on a rainy-season basis in both pre- and post-thinning periods. Thinning altered the interception components whereas the largest part during and after rainfall accounted for similar proportion in both periods. Additionally, after thinning, the annual TF rate was increased from 61.4% to 73.0%, whereas the annual SF rate was decreased from 9.8% to 6.1%, and the annual E-i rate was decreased from 28.7% to 20.8%. The summarized findings of previous studies indicate that the degree of decline in the Ei caused by thinning is related to Pg and the thinning ratio. These results provide useful information for understanding the changes in interception processes induced by thinning, and for acquiring a more accurate forecast of the effects of forest management practices on water resources in the watershed. The response in rainfall partitioning to strip thinning can also help us to acquire an integrated understanding of the changes in canopy water balance under different forest practices. (C) 2015 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.jhydrol.2015.04.023

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  48. Characteristics of deep catastrophic landslides around the world Reviewed

    Takashi, Gomi, Kazutaka, Aoto, Marino, Hiraoka, Kyoko, Kikuchi, Tadanori, Ishizuka, Koji, Morita, Taro, Uchida

    Proceedings of INTERPRAEVENT in the Pacific Rim     page: 61 - 67   2014.11

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  49. Linkages among land use, macronutrient levels, and soil erosion in northern Vietnam: A plot-scale study Reviewed

    Pham Thi Quynh Anh, Takashi Gomi, Lee H. MacDonald, Shigeru Mizugaki, Phung Van Khoa, Takahisa Furuichi

    GEODERMA   Vol. 232   page: 352 - 362   2014.11

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    Objective: This study examined the interrelations among vegetative cover and biomass, soil macronutrient levels, and soil erosion in northern Vietnam.
    Methods: We selected ten dominant land-use types in a hilly area of western Hanoi including bare soil, agriculture (cassava or lemon grass), shrub land, five types of plantation forest, and indigenous forest. We measured the understory biomass, litter biomass, canopy openness, soil moisture content, soil pedestal height, soil hardness, soil bulk density,Cs-157 and Pb-210(ex) activities, and soil carbon and nitrogen on three 1 m(2) plots for each land-use type. Soil erosion was calculated from both pedestal heights and radionuclides. Multivariate statistical analysis was used to identify the key factors controlling soil erosion and nutrient accumulations.
    Results: Understoty biomass ranged from 2 to 375 g m(-2), and this tended to be higher in most of the forest types and shrubland than in cassava and lemon grass. In contrast, the amount of ground cover varied more by forest type than between the agricultural land uses and forest lands. The height of soil pedestals indicated that short-term soil erosion was negligible when understory biomass was greater than 130 to 150 g m(2). Cs-137 was only detected in the cassava plots, whereas Pb-210(ex). indicated widely different erosion rates across the land uses, with lower values in the agricultural lands and two types of forest plantations, although this may be due to soil management practices. Both the correlation and principal component analyses showed that soil organic carbon and nitrogen were positively correlated to understory biomass and strongly and inversely influenced by bulk density. Soil erosion as indicated by soil pedestal height was strongly and inversely controlled by ground cover, litter, and understory biomass. Soil erosion was also heavily influential to soil chemical richness and bulk density.
    Conclusions: Ground vegetation cover and the resultant soil erosion processes altered the production and accumulation of SOC, while forest cover did not always result in high soil fertility or low erosion. A simple characterization of forest or non-forest is not sufficient to calculate carbon and nutrient stocks, or assess erosion risk.
    Practice: Understory biomass of at least 130 g m(-2) and high ground cover are essential for reducing soil erosion and sustaining short- and long-term soil productivity. Implications: Rapidly developing areas in Southeast Asia, including hilly areas in North Vietnam, need to maintain understory biomass and ground cover for soil and nutrient conservation. (C) 2014 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.geoderma.2014.05.011

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  50. Vertical distribution of radiocesium in coniferous forest soil after the Fukushima nuclear power plant accident Reviewed

    Mengistu T. Teramage, Yuichi Onda, Jeremy Patin, Hiroaki Kato, Takashi Gomi, Sooyoun Nam

    JOURNAL OF ENVIRONMENTAL RADIOACTIVITY   Vol. 137   page: 37 - 45   2014.11

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    This study deals with the description of the vertical distribution of radiocaesium (Cs-137 and Cs-134) in a representative coniferous forest soil, investigated 10 months after the Fukushima radioactive fallout. During soil sampling, the forest floor components (understory plants, litter (Ol-) and fermented layers (Of)) were collected and treated separately. The results indicate that radiocesium is concentrated in the forest floor, and high radiocesium transfer factor observed in the undergrowth plants (3.3). This made the forest floor an active exchanging interphase for radiocesium. The raw organic layer (Ol + Of) holds 52% (5.3 kBq m(-2)) of the Fukushima-derived and 25% (0.7 kBq m(-2)) of the pre-Fukushima Cs-137 at the time of the soil sampling. Including the pre-Fukushima Cs-137, 99% of the total soil inventory was in the upper 10 cm, in which the organic matter (OM) content was greater than 10%, suggesting the subsequent distribution most likely depends on the OM turnover. However, the small fraction of the Fukushima-derived Cs-137 at a depth of 16 cm is most likely due to the infiltration of radiocesium-circumscribed rainwater during the fallout before that selective adsorption prevails and reduces the migration of soluble Cs-137. The values of the depth distribution parameters revealed that the distribution of the Fukushima-derived Cs-137 was somewhat rapid. (C) 2014 Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.jenvrad.2014.06.017

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  51. Estimating the Occurrence Ages of Deep Catastrophic Landslides using a Tephrochronological Approach. Reviewed

    Aoto K, Gomi T, Hiraoka M, Ishizuka T, Morita K, Isshiki H, Uchida T

    INTERPRAEVENT 2014- proceeding   Vol. 0 ( 0 ) page: 00 - 00   2014.10

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  52. The role of litterfall in transferring Fukushima-derived radiocesium to a coniferous forest floor Reviewed

    Teramage, M. T, Onda, Y, Kato, H, Gomi, T

    Science of The Total Environment   Vol. 490   page: 435 - 439   2014.5

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    DOI: 10.1016/j.scitotenv.2014.05.034.

  53. Human factors and tidal influences on water quality of an urban river in Can Tho, a major city of the Mekong Delta, Vietnam

    Hirokazu Ozaki, Thi Kinh Co, Anh Kha Le, Viet Nu Pham, Van Be Nguyen, Mitsunori Tarao, Huu Chiem Nguyen, Viet Dung Le, Hieu Trung Nguyen, Masaki Sagehashi, Sachi Ninomiya-Lim, Takashi Gomi, Masaaki Hosomi, Hideshige Takada

    ENVIRONMENTAL MONITORING AND ASSESSMENT   Vol. 186 ( 2 ) page: 845 - 858   2014.2

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    In this study, we focused on water quality in an urban canal and the Mekong River in the city of Can Tho, a central municipality of the Mekong Delta region, southern Vietnam. Water temperature, pH, electrical conductivity, BOD5, CODCr, Na+, Cl-, NH4 (+)-N, SO4 (2-)-S, NO3 (-)-N, and NO2 (-)-N for both canal and river, and tide level of the urban canal, were monitored once per month from May 2010 to April 2012. The urban canal is subject to severe anthropogenic contamination, owing to poor sewage treatment. In general, water quality in the canal exhibited strong tidal variation, poorer at lower tides and better at higher tides. Some anomalies were observed, with degraded water quality under some high-tide conditions. These were associated with flow from the upstream residential area. Therefore, it was concluded that water quality in the urban canal changed with a balance between dilution effects and extent of contaminant supply, both driven by tidal fluctuations in the Mekong River.

    DOI: 10.1007/s10661-013-3421-y

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  54. Merging perspectives in the catchment sciences: the US-Japan Joint Seminar on catchment hydrology and forest biogeochemistry Reviewed

    Kevin J. McGuire, Stephen D. Sebestyen, Nobuhito Ohte, Emily M. Elliott, Takashi Gomi, Mark B. Green, Brian L. McGlynn, Naoko Tokuchi

    HYDROLOGICAL PROCESSES   Vol. 28 ( 5 ) page: 2878 - 2880   2014.2

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    DOI: 10.1002/hyp.10129

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  55. Stream and bed temperature variability in a coastal headwater catchment: influences of surface-subsurface interactions and partial-retention forest harvesting

    S. M. Guenther, T. Gomi, R. D. Moore

    HYDROLOGICAL PROCESSES   Vol. 28 ( 3 ) page: 1238 - 1249   2014.1

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    Stream temperature was recorded between 2002 and 2005 at four sites in a coastal headwater catchment in British Columbia, Canada. Shallow groundwater temperatures, along with bed temperature profiles at depths of 1 to 30cm, were recorded at 10-min intervals in two hydrologically distinct reaches beginning in 2003 or 2004, depending on the site. The lower reach had smaller discharge contributions via lateral inflow from the hillslopes and fewer areas with upwelling (UW) and/or neutral flow across the stream bed compared to the middle reach. Bed temperatures were greater than those of shallow groundwater during summer, with higher temperatures in areas of downwelling (DW) flow compared to areas of neutral and UW flow. A paired-catchment analysis revealed that partial-retention forest harvesting in autumn 2004 resulted in higher daily maximum stream and bed temperatures but smaller changes in daily minima. Changes in daily maximum stream temperature, averaged over July and August of the post-harvest year, ranged from 1.6 to 3 degrees C at different locations within the cut block. Post-harvest changes in bed temperature in the lower reach were smaller than the changes in stream temperature, greater at sites with DW flow, and decreased with depth at both UW and DW sites, dropping to about 1 degrees C at a depth of 30cm. In the middle reach, changes in daily maximum bed temperature, averaged over July and August, were generally about 1 degrees C and did not vary significantly with depth. The pre-harvest regression models for shallow groundwater were not suitable for applying the paired-catchment analysis to estimate the effects of harvesting. However, shallow groundwater was warmer at the lower reach following harvesting, despite generally cooler weather compared to the pre-harvest year. Copyright (c) 2012 John Wiley & Sons, Ltd.

    DOI: 10.1002/hyp.9673

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  56. Effect of canopy interception on spatial variability and isotopic composition of throughfall in Japanese cypress plantations Reviewed

    Hiroaki Kato, Yuichi Onda, Kazuki Nanko, Takashi Gomi, Tsutomu Yamanaka, Shimpei Kawaguchi

    Journal of Hydrology   Vol. 504 ( 11 ) page: 1 - 11   2013.11

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    We conducted a field monitoring experiment examining throughfall in Japanese cypress plantations located in Tochigi Prefecture, eastern Japan. A set of 20 tipping-bucket rain gauges and throughfall collectors were placed in a lattice-like distribution throughout a 10× 10-m experimental plot to investigate the effect of the forest canopy on the spatial variability of throughfall. The isotopic composition of throughfall and open rainfall were analyzed and compared for each rainfall event. A clear relationship between throughfall rate and the radial distance to the nearest tree trunk was observed when the influence of wind was negligible
    however, such a systematic pattern of throughfall was not observed during rainfall events that occurred during windy conditions. The δ18O and δD values in throughfall varied considerably, reflecting different rainwater flow paths in the saturated canopy. The analysis of stable isotope ratios in the throughfall and its comparison with isotopic composition of rainwater hitting the canopy can help elucidate the interception processes in the forest canopy. © 2013 Elsevier B.V.

    DOI: 10.1016/j.jhydrol.2013.09.028

    Scopus

  57. Macroinvertebrates in headwater streamsn of Japanese cypress and Japanese ceder forests: A case study in Field Museum Karasawayama Reviewed

    渡邉祐介, 五味高志, 布川雅典, 境優

    Journal of Field Science   Vol. 11   page: 31 - 40   2013.3

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  58. Seasonal variation of sediment yields and potential source of sediment production in the Oobora monitoring watershed

    平岡, 真合乃, 五味高志, 小田智基, 熊倉歩, 宮田秀介, 内山佳美

    Bulletin of the Kanagawa Prefecture Natural Environment Conservation Center   Vol. 10   page: 71 - 79   2013.3

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  59. Distribution of amphipods (Gammarus nipponensis Ueno) among mountain headwater streams with different legacies of debris flow occurrence

    Kobayashi Sohei, Gomi Takashi, Sidle Roy C., Negishi Junjiro N.

    ECOHYDROLOGY   Vol. 6 ( 1 ) page: 117 - 124   2013.2

  60. Interception of the Fukushima reactor accident-derived Cs-137, Cs-134 and I-131 by coniferous forest canopies Reviewed

    Hiroaki Kato, Yuichi Onda, Takashi Gomi

    GEOPHYSICAL RESEARCH LETTERS   Vol. 39 ( 20 ) page: 00 - 00   2012.10

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    The Fukushima Daiichi nuclear power plant accident resulted in extensive radioactive contamination of the surrounding forests. In this study, we analyzed fallout Cs-137, Cs-134, and I-131 in rainwater, throughfall, and stemflow in coniferous forest plantations immediately after the accident. We show selective fractionation of the deposited radionuclides by the forest canopy and contrasting transfer of radiocesium and I-131 from the canopy to the forest floor in association with precipitation. More than 60% of the total deposited radiocesium remained in the canopy after 5 month of the initial fallout, while marked penetration of the initially deposited I-131 through the canopy was observed. The halflives of Cs-137 absorbed in the cypress and cedar canopies were calculated as 620 days and 890 days, respectively for the period of 0-160 days. The transfer of the deposited radiocesium from the canopy to the forest floor was slow compared with that of the spruce forest affected by fallout from the Chernobyl nuclear reactor accident. Citation: Kato, H., Y. Onda, and T. Gomi (2012), Interception of the Fukushima reactor accident-derived Cs-137, Cs-134 and I-131 by coniferous forest canopies, Geophys. Res. Lett., 39, L20403, doi:10.1029/2012GL052928.

    DOI: 10.1029/2012GL052928

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  61. Estimation of forest harvesting-induced stream temperature changes and bioenergetic consequences for cutthroat trout in a coastal stream in British Columbia, Canada

    J. A. Leach, R. D. Moore, S. G. Hinch, T. Gomi

    AQUATIC SCIENCES   Vol. 74 ( 3 ) page: 427 - 441   2012.7

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    Data from a paired-catchment study in south coastal British Columbia, Canada, were analyzed to assess the thermal effects of clearcut harvesting with no riparian buffer on a fish-bearing headwater stream. The approach used time series of daily mean water temperatures for East Creek (control) and A Creek (treatment), both before and after harvest. Statistical models were developed to predict (a) what the temperatures would have been in the post-harvest period had harvesting not occurred, and (b) what temperatures would have been in the pre-harvest period had harvesting already occurred. The Wisconsin Bioenergetics Model was used to simulate growth of coastal cutthroat trout (Oncorhynchus clarki clarki) for the first year following fry emergence using the predicted and observed stream temperatures to generate scenarios representing with-harvest and no-harvest thermal regimes. A Monte Carlo approach was used to quantify the effects of uncertainty associated with the regression models on predicted stream temperature and trout growth. Summer daily mean temperatures in the with-harvest scenario were up to higher than those for the no-harvest scenario. Harvesting-induced warming reduced growth rates during summer, but increased growth rates during autumn and spring. In the with-harvest scenario, trout were 0.2-2.0 g (absolute weight) smaller throughout the winter period than in the no-harvest scenario. However, the bioenergetic simulations suggest that trout growth may be more sensitive to potential changes in food supply following harvesting than to direct impacts of stream temperature changes.

    DOI: 10.1007/s00027-011-0238-z

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  62. Monitoring the dynamics of water and sediment in Oobora watersheds of Tanzawa mountains

    GOMI Takashi, ODA Tomoki, SUZUKI Masakazu, HIRAOKA Marino, MIYATA Shusuke, UCHIYAMA Yoshimi, YAMANE Masanobu

    Journal of the Japan Society of Erosion Control Engineering   Vol. 65 ( 1 ) page: 01 - 02   2012

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    DOI: 10.11475/sabo.65.1_01

    CiNii Research

  63. Downslope soil detachment-transport on steep slopes via rain splash

    Ghahramani Afshin, Ishikawa Yoshiharu, Gomi Takashi, Miyata Shusuke

    HYDROLOGICAL PROCESSES   Vol. 25 ( 15 ) page: 2471 - 2480   2011.7

  64. Slope length effect on sediment and organic litter transport on a steep forested hillslope: upscaling from plot to hillslope scale Reviewed

    Afshin Ghahramani, Yoshiharu Ishikawa, Takashi Gomi

    Hydrological Research Letters   Vol. 5   page: 16 - 20   2011.6

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    Upscaling and the effect of slope length on the sediment production are important issues in hillslope hydrology. This study investigated the effect of slope length at a steep forested site between 2006 and 2010 using erosion plots and neighboring sediment traps. The hillslope had high litter cover but sparse understory due to overgrazing by wild deer. Sediment transport increased for short distances (5 m to 10 m), then decreased over the hillslope (> 10 m). In plots this effect was due to organic litter accumulation. Organic litter production declined progressively along the hillslope continuum. When accumulated organic litter altered the microtopography, sediment production declined more with increase in slope length. Heavy precipitation events did not change the pattern of these scale effects. These results demonstrate that the slope length effect had inconsistent controls on sediment transport due to variations in soil surface conditions of the landscape. Such variations in the slope length effect cause uncertainty in sediment flux estimations in steep forested landscapes.<br>

    DOI: 10.3178/hrl.5.16

  65. Effect of forest thinning on overland flow generation on hillslopes covered by Japanese cypress

    Bui Xuan Dung, Shusuke Miyata, Takashi Gomi

    ECOHYDROLOGY   Vol. 4 ( 3 ) page: 367 - 378   2011.5

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    We examined the effect of forest thinning on overland flow generation on hillslopes covered by a Japanese cypress plantation in central Japan. We established hillslope plots in two small catchments for monitoring overland flow generation. Plot 1 was a treatment plot in which 58.3% of stems were removed, whereas plot 2 remained untreated as a control. Overland flow generation was examined using (1) time-trend analysis that compared overland flow to precipitation 2 years pre- and 2 years post-thinning in plot 1 and (2) a paired-plot approach that compared the treated hillslope plot to the control hillslope plot. The latter approach was more reliable for identifying treatment effects than time-trend analysis because it minimizes effects of climate variables such as precipitation. Unlike our initial hypothesis for decreasing overland flow after thinning, paired-plot analysis indicated that after thinning, mean overland flow increased 7.4% (corresponding to 2.1 mm) in response to individual storms and 4.8% (corresponding to 7.9 mm) based on monthly data. Although the increased overland flow is likely associated with reduced canopy interception, the reduction of canopy interception after the thinning was estimated to be greater than the increases in overland flow. Therefore, sonic of the increased throughfall was infiltrated into the soil matrix. Such changes in hillslope-scale runoff in response to thinning alter the distribution of water in the surface and subsurface layers of forested headwater basins. Copyright (C) 2010 John Wiley & Sons, Ltd.

    DOI: 10.1002/eco.135

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  66. Effect of ground cover on splash and sheetwash erosion over a steep forested hillslope: A plot-scale study Reviewed

    Afshin Ghahramani, Yoshiharu Ishikawa, Takashi Gomi, Katsushige Shiraki, Shusuke Miyata

    CATENA   Vol. 85 ( 1 ) page: 34 - 47   2011.4

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    The contributions and relationships of erosion by splash and overland flow over a steep slope in a Japanese beech forest in plots with different percentages of ground cover were examined. Three erosion plots (2 m wide x 5 m long) with average understory coverage of 1%, 45%, and 94% were installed. Sediment transported by rain splash and by overland flow was sampled separately. For the plots with sparse, moderate, and high understory coverage, the average proportions of splash soil to total soil erosion during the monitoring period were 16%, 32%, and 18%, respectively. A significant correlation between the amount of splash soil and precipitation was found in the plots with 1% and 45% understory coverage, whereas no statistical relationship was identified for the plot with high understory coverage. At the sparse ground cover plot showing the largest sediment movement, the contribution of splash transport decreased with increasing precipitation. The amount of sheetwash erosion was significantly correlated with the amount of splash soil under the condition of sparse ground cover. This relationship was more pronounced during high precipitation events and the rainy season. Splash contribution to the sediment transport was in the range of 0.8%-76.7%. 2.8%-81% and 2.1%-60.8% for plot with high, moderate and low ground cover, respectively. The sparse ground cover showed the largest variation of splash and sheetwash contribution in soil erosion. This variability was due to variation in ground cover and soil surface wetness condition which led to a variation of detachment and non-linear relationship of sheetwash splash. (C) 2010 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.catena.2010.11.005

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  67. Analysis of stream water temperature changes during rainfall events in forested watersheds

    Luki Subehi, Takehiko Fukushima, Yuichi Onda, Shigeru Mizugaki, Takashi Gomi, Ken'ichirou Kosugi, Shinya Hiramatsu, Hikaru Kitahara, Koichiro Kuraji, Tomomi Terajima

    LIMNOLOGY   Vol. 11 ( 2 ) page: 115 - 124   2010.8

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    Despite continued interest in stream water temperature (Tw) analysis, there are few studies of Tw response to rainfall events at forested watersheds. We examined 61 sets of data on Tw for 21 rainfall events at 16 watersheds with various slope gradients (from 0.08 to 0.56) in four regions of Japan from June 2004 to December 2005. The investigation focused on the changes of specific discharge (Delta Qs) and Delta Tw at medium-sized watersheds (0.5-100 ha). The results clearly demonstrated different flow patterns expressed by Qs vs. Tw hysteretic loops. Those were clockwise in Period I (April-September) and counterclockwise in Period II (October-March), except for lower slope gradient at Aichi, where counterclockwise loops were observed in both periods. These differences in hysteretic loops could be explained by the differences in Tw and in response times to rainfall between surface/subsurface and groundwater flows. The response times were probably determined by the slope gradient and the vertical level of groundwater. We also found that the changes in air temperature (Delta Ta) influenced Delta Tw to a lesser degree than Qs. The average rainfall intensities in Period I and Period II (9.3 +/- A 1.7 and 5.4 +/- A 0.2 mm/h, respectively) affected the average values of Delta Qs and Delta Tw (6.62 +/- A 4.08 mm/h and 1.7 +/- A 0.4A degrees C; 0.85 +/- A 0.68 mm/h and 0.9 +/- A 0.3A degrees C, respectively). This indicates that slope gradient and Qs influenced Delta Tw by changing the relative proportions of flow paths. In addition, the water table changes influenced the percentage of groundwater flow to the stream.

    DOI: 10.1007/s10201-009-0296-2

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    Scopus

  68. Short-term responses of macroinvertebrate drift following experimental sediment flushing in a Japanese headwater channel Reviewed

    Takashi Gomi, Sohei Kobayashi, Junjiro N. Negishi, Fumitoshi Imaizumi

    LANDSCAPE AND ECOLOGICAL ENGINEERING   Vol. 6 ( 2 ) page: 257 - 270   2010.7

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    We examined short-term responses of macroinvertebrate drift associated with experimental sediment flushing in a headwater. Increases in the drifting abundances of Ephemeroptera and Plecoptera coincided with increases in bed load yield rather than peaks in discharge or suspended sediment concentrations. The approach and arrival of a sediment wave may provide a physical cue that initiates the escape of benthic macroinvertebrates. Because fine bed load sediments, with diameters &lt; 4 mm, tended to accumulate on and in the substrate matrix, such sedimentation affected the benthic macroinvertebrates residing on and in the substrate, increasing the number of macroinvertebrates in the drift. Therefore, the decreases observed in the densities of most macroinvertebrate taxa following sediment flushing were probably associated with sediment deposition and the resulting escape of macroinvertebrates from benthic habitats. The magnitudes of the decreases in macroinvertebrate density were lower at sites located 200 m downstream from the sediment sources than at sites located 20 m downstream. The results from this experimental flushing study suggest that bed load movement and resulting sediment accumulation alter macroinvertebrate drift patterns and cause decreases in the abundances of benthic macroinvertebrates in headwater streams.

    DOI: 10.1007/s11355-010-0107-2

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  69. An overview of the field and modelling studies on the effects of forest devastation on flooding and environmental issues

    Yuichi Onda, Takashi Gomi, Shigeru Mizugaki, Toshiro Nonoda, Roy C. Sidle

    HYDROLOGICAL PROCESSES   Vol. 24 ( 5 ) page: 527 - 534   2010.2

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    Intensive field observations as well as monitoring of discharge, water quality, and soil erosion have been conducted in forest plantations in order to identify the effects of forest cover and management practices on runoff generation, sediment transport, and downstream environmental issues. Five experimental catchments, each with rather uniform lithology, were established in both managed and unmanaged plantations of Japanese cypress and cedar, as well as broadleaf forests. Field monitoring was conducted from sub-plots (e. g. splash cups) to small hillslope plots (0.5 x 2 m) to large hillslope-scale plots to first order streams (0.1-4 ha) and finally to larger catchments (&gt;4 ha) in a nested structure. Remote sensing techniques were employed to identify broad scale forest stand and soil surface conditions. As part of this integrated study, these field-based monitoring and remote sensing techniques provide information for modelling runoff generation and developing adaptive management schemes with respect to catchment-scale water resources. Copyright (C) 2010 John Wiley & Sons, Ltd.

    DOI: 10.1002/hyp.7548

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  70. Disturbances structuring macroinvertebrate communites in steep headwater streams: relative importance of forest clearcutting and debirs flow occurrance

    Kobayashi S, Gomi T, Sidle R.C, Takemon Y

    Canadian Journal of Fishries and Aquatic Sciences   Vol. 67   page: 1 - 18   2010.1

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    DOI: 10.1139/F09-186

  71. Erosion processes in a Japanese cypress plantation catchment estimated from measurement of Cs-137 and Pb-210ex activities in suspended sediment Reviewed

    Fukuyama T, Onda Y, Gomi T, Yamamoto K, Kondo N, Miyata S, Kosugi K, Mizugaki S, Tsubonuma N

    Hydrological Processes   Vol. 24 ( 0 ) page: 535 - 545   2010.1

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  72. Evaluation of storm runoff pathway in steep nested catchments draining a Japanese cypress forest in central Japan : A hydrometric, geochemical, and isotopic approaches Reviewed

    五味 高志

    Hydrological Processes 24     page: 550 - 566   2010

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  73. Overland flow generation and the contribution on storm runoff in headwater catchments draining Japanese cypress forest

    GOMI Takashi, MIYATA Shusuke, ONDA Yuichi

    Water Science   Vol. 53 ( 6 ) page: 77 - 94   2010

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    Language:Japanese   Publisher:Japan Forest Conservation Association  

    DOI: 10.20820/suirikagaku.53.6_77

    CiNii Research

  74. Impact of road-generated storm runoff on a small catchment response

    Woldie Daniel W., Sidle Roy C., Gomi Takashi

    HYDROLOGICAL PROCESSES   Vol. 23 ( 25 ) page: 3631 - 3638   2009.12

  75. Effects of forest floor coverage on overland flow and soil erosion on hillslopes in Japanese cypress plantation forests

    Miyata Shusuke, Kosugi Ken'ichirou, Gomi Takashi, Mizuyama Takahisa

    WATER RESOURCES RESEARCH   Vol. 45   2009.6

  76. Changes in bedload transport rate associated with episodic sediment supply in a Japanese headwater channel Reviewed

    Fumitoshi Imaizumi, Takashi Gomi, Sohei Kobayashi, Junjiro N. Negishi

    CATENA   Vol. 77 ( 3 ) page: 207 - 215   2009.6

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    We conducted field monitoring of bedload transport rate associated with experimental sediment release in a natural channel to clarify behavior of the supplied sediment on mixed size bed. Observation of bedload rate at two sites along the 30 m channel reach revealed that downstream migration of finer particles delay compared with coarser particles. Ratio of the bedload sediment that deposited during the migration was higher for finer sediments. These behaviors of the mixed size particles were clear during passage of the sediment wave without changes in water discharge. Flashing peak of discharge that caused artificially by opening of the dam gate did not destroy channel bed structure including steps and pools formed by coarser sediments, and only small amount of bedload was mobilized. Both reach scale channel features including steps, pools, and riffles as well as fine scale features (i.e., armour coat) likely increased critical shear stress of particles and decreased bedload rate during our experiment. Extreme sediment supply induced two types of sediment deposition; (1) filling the pools in reach sales and (2) the intrusion of fine particles into the coarser sediment that formed an armour layer. The all grain size fractions can deposit as type (1) when shear stress of stream water is not enough to entrain bedload particles, while deposition type (2) occurs when finer sediment pass over channel bed on which armour coat is well-developed. Deposition of finer sediment into coarser sediment that forms armour coat is affected by grain size distribution of bed surface sediment. Thus, impact of the sediment supply on downstream channel depends on both bedforms and grain size distribution of bed surface sediment over which the supplied sediment pass. (C) 2008 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.catena.2008.12.015

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  77. Influences of forested watershed conditions on fluctuations in stream water temperature with special reference to watershed area and forest type

    Luki Subehi, Takehiko Fukushima, Yuichi Onda, Shigeru Mizugaki, Takashi Gomi, Tomomi Terajima, Ken&apos;ichirou Kosugi, Shinya Hiramatsu, Hikaru Kitahara, Koichiro Kuraji, Noriatsu Ozaki

    LIMNOLOGY   Vol. 10 ( 1 ) page: 33 - 45   2009.4

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    In order to gain insight into the effect of watershed conditions on fluctuations in stream water temperature, we statistically analyzed water temperature data for 1 year, using root mean square (Rms) and harmonic (A Amplitude, phi delay time) methods. The average values of delay time (days) between air and water temperatures (T (a) and T (w)) of small (&lt; 0.5 ha), medium (0.5-100 ha) and large (&gt; 100 ha) watersheds were 4.53 +/- A 0.82 days, 11.83 +/- A 3.88 days and 4.45 +/- A 1.52 days, respectively. Fluctuations in stream water temperature expressed by Rms (Rms T (w)/Rms T (a)) and harmonic methods (A -T (w)/A -T (a)) in the medium-sized watersheds with moderate slope gradients were 0.37 +/- A 0.09 and 0.56 +/- A 0.14, respectively. These values increased in the larger watersheds with low slope gradients, including five large rivers covered by various landscapes, with their averages of 0.53 +/- A 0.09 and 0.78 +/- A 0.09, respectively, indicating the influences of solar radiation and heat transfer processes. In the smaller watersheds with high slope gradients, these values were 0.73 +/- A 0.02 and 0.87 +/- A 0.03, respectively, suggesting that shorter passage time affected water temperatures. With respect to forest type, these values at badly managed hinoki forest watersheds (0.45 +/- A 0.04 and 0.73 +/- A 0.07) were larger than those at broadleaf forest (0.34 +/- A 0.04 and 0.51 +/- A 0.12) and well-managed hinoki forest (0.33 +/- A 0.04 and 0.51 +/- A 0.07) watersheds, indicating different proportions of flow paths.

    DOI: 10.1007/s10201-008-0258-0

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  78. Roles of soil water repellency on hydrological processes in a small catchment covered by a Japanese cypress plantation

    MIYATA Shusuke, KOSUGI Ken’ichirou, GOMI Takashi

    Journal of the Japanese Society of Soil Physics   Vol. 111 ( 0 ) page: 9 - 16   2009

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    We examined effects of soil water repellency on hydrological processes in various scales from small plot to catchment in a Japanese cypress plantation. We measured soil water repellency and infiltration rate along a hillslope transect, and monitored overland flow at small plots (1 × 2 m) with sparse and dense fern cover and a large plot (8 × 25 m) and stream discharge at the outlet of a small catchment (0.43 ha). Strong water repellency in surface soil horizon was partially associated with Hortonian over-land flow, which volume potentially depended on sever-ity of water repellency. Relationships between matric po-tential and soil water content indicate that changes in the soil water repellency and consequently runoff coefficient of overland flow could occur during a single storm event. Greater amounts of overland flow at small plots compared to ones at large plot suggests that overland flow generated in hillslope was discontinuously transferred. Higher infil-tration rate at the bottom of hillslope likely caused little contribution of overland flow on catchment runoff. Despite the substantial overland flow generated in hillslope due to soil water repellency, water repellency was not a dominant factor accelerating runoff directly at the small catchment scale.

    DOI: 10.34467/jssoilphysics.111.0_9

    CiNii Research

  79. A new method to measure substrate coherent strength of Stenopsyche marmorata

    Nunokawa Masanori, Gomi Takashi, Negishi Junjiro N., Nakahara Osamu

    LANDSCAPE AND ECOLOGICAL ENGINEERING   Vol. 4 ( 2 ) page: 125 - 131   2008.11

  80. Characteristics of overland flow generation on steep forested hillslopes of central Japan Reviewed

    Takashi Gomi, Roy C. Sidle, Masayasu Ueno, Shusuke Miyata, Ken&apos;ichirou Kosugi

    JOURNAL OF HYDROLOGY   Vol. 361 ( 3-4 ) page: 275 - 290   2008.11

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    Overland flow generation was monitored. in large plots (8 x 25 m) on four hillslopes in a 4.9-ha catchment in Mie Prefecture, Japan. Three Japanese cypress (hinoki, Chamaecyparis obtusa) treatments (including three different understory conditions) and one deciduous forest treatment were studied. For all plots, including deciduous hillslopes, we observed overland flow even for small storm events (&lt;10 mm in total precipitation). The mean runoff coefficients in dense Japanese cypress plots with sparse understory were highest (13.0%) followed by dense Japanese cypress with fern ground cover (6.7%), and coefficients in managed cypress and deciduous forest were 3.6% and 1.2%, respectively. The runoff coefficients tended to be higher during storms that were preceded by dry conditions. High soil water repellency initially occurred in Japanese cypress forests between the titter and mineral. soil horizon and might have been partly responsible for overland flow generation. During storms with total precipitation &gt;180 mm, runoff from Japanese cypress plots with dense fern understory exhibited a delayed and higher peak associated with return flow. The dominance of hillslope-scale flow contribution to catchment runoff was also affected by changes in the dominance of overland flow and return flow. Understory vegetation cover and the availability of a titter layer altered the amount of overland flow, which was mediated by soil water repellency and soil moisture. Observations at the hillslope scale are essential for conceptualization of runoff mechanisms and pathways in forested headwaters. (C) 2008 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.jhydrol.2008.07.045

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  81. Baseflow concentrations of nitrogen and phosphorus in forested headwaters in Japan Reviewed

    Zhao Zhang, Takehiko Fukushima, Peijun Shi, Fulu Tao, Yuichi Onda, Takashi Gomi, Shigeru Mizuyaki, Yuko Asano, Ken'ichirou Kosugi, Shinya Hiramatsu, Hikaru Kitahara, Koichiro Kuraji, Tomomi Terajima, Kazuo Matsushige

    SCIENCE OF THE TOTAL ENVIRONMENT   Vol. 402 ( 1 ) page: 113 - 122   2008.8

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    A comprehensive investigation on all dissolved nitrogen and phosphorus components at both local and regional scales in the headwaters from forested watersheds is valuable to improve our understanding of the factors controlling water quality. Here, we investigated the baseflow concentrations of dissolved nitrogen and phosphorus components, N:P ratio, and their associations with region and vegetation type in forested headwaters in fives regions of Japan. We found that inorganic nitrogen and phosphorus were the dominant components in the 26 temperate forested streams, rather than organic forms. There were significant positive correlations between the concentrations of N and P components. Furthermore, the regional patterns of the concentrations of nitrate, dissolved inorganic P (DIP), and dissolved total N (DTN) and P (DTP) were similar. Our results suggest that the regional patterns of the concentrations of N and P components should be related to the regional atmospheric deposition of both N and P nutrients. We also found that the nitrate and DTN concentrations were higher in man-made evergreen conifer (EC) than those in the natural deciduous broadleaf (DB). in contrast, the DIP and DTP concentrations in EC were lower than those in DB. The uniformly higher NT ratio in EC-than in DB-forested streams for each region suggest that EC-forested streams could be more affected by P-limited than DB-forested streams when N inputs from atmospheric sources increased. (c) 2008 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.scitotenv.2008.04.045

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  82. Dynamic runoff connectivity of overland flow on steep forested hillslopes: Scale effects and runoff transfer Reviewed

    Takashi Gomi, Roy C. Sidle, Shusuke Miyata, Ken&apos;ichirou Kosugi, Yuichi Onda

    WATER RESOURCES RESEARCH   Vol. 44 ( 8 ) page: W08411   2008.8

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    Both scaling effect and connectivity of overland flow were examined in steep hillslopes covered by (1) Japanese cypress (hinoki, Chamecyparis obtusa) plantations with sparse understory vegetation, (2) hinoki plantations with fern understory vegetation, and (3) deciduous forests. Two sizes of plots were installed for monitoring overland flow: small (0.5 x 2 m) and large hillslope scale (8 x 24-27 m). For all hillslopes, measurable amounts of overland flow occurred during storms. Runoff coefficients of large plots (0.1-3%) were consistently smaller than those of small plots (20-40%). Estimated runoff flow lengths at the hillslope scale were based on runoff coefficients from small plots and were used to calculate runoff volume from large plots. Then we compared the differences between observed and estimated runoff volumes of large plots. Estimated runoff from large plots was smaller than observed runoff in hinoki slopes with sparse understory vegetation. Greater amounts of observed compared to estimated overland flow suggest that more runoff occurred from hillslopes with sparse understory. In contrast, estimated overland flow was larger than observed runoff from the deciduous forest, implying greater opportunities for infiltration compared to hinoki hillslopes. Comparison of estimated versus observed overland flow for successive 5 min intervals during storms indicates that runoff networks expand upslope during short and intense precipitation periods. Our examination and comparison of storm runoff from small and large plots facilitate better understanding of runoff mechanisms, scaling effects in hillslopes, and connectivity of the overland flow network.

    DOI: 10.1029/2007WR005894

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  83. Hyporheic flow as a potential geomorphic agent in the evolution of channel morphology in a gravel-bed river Reviewed

    Goichiro Takahashi, Takashi Gomi, Kaichiro Sasa

    CATENA   Vol. 73 ( 3 ) page: 239 - 248   2008.5

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    Morphologic and hydrologic properties of head-cut gullies formed in meandering bends of a gravel-bed river in northern Japan were examined to investigate their topographic development. head-cut gullies had incised to 2 in below the floodplain surface and had perennial seepage outflows. Because no surface runoff was observed across the meandering necks, we hypothesized that hyporheic flow erosion cutting into the down-river edge of the meandering necks is one factor for the development of head-cut gullies. Several topographic features caused by sapping and piping erosion were observed within the head-cut gullies. A tracer experiment and examination of the water table, water chemistry, and water table responses in wells on the floodplain and within the head-cut gully revealed that significant preferential hyporheic flow occurred between coarse cobble and fine sediment layers of the floodplain materials. During a storm event, water tables around the head-cut gully quickly responded to changes in the water table of the stream channel; this result also suggests that hyporheic flow occurred across the meandering bends. Hyporheic flow around the head-cut gullies had higher hydraulic conductivities and preferential flow paths that may relate to buried beds of paleochannels. An erosion model suggests that it is unlikely that hyporheic flow alone had enough energy to account for all the soil erosion. Thus, a combination of hyporheic flow (sapping erosion) and channel erosion (bank erosion) appeared to contribute to the formation of the head-cut gullies. Hyporheic flow is an important component in the geomorphic evolution of channels and the floodplain in a gravel-bed river. (C) 2007 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.catena.2007.10.004

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  84. Development, evaluation and interpretation of sediment rating curves for a Japanese small mountainous reforested watershed Reviewed

    S. H. R. Sadeghi, T. Mizuyama, S. Miyata, T. Gomi, K. Kosugi, T. Fukushima, S. Mizugaki, Y. Onda

    GEODERMA   Vol. 144 ( 1-2 ) page: 198 - 211   2008.3

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    Extensive reforestation using Cypress, Pinus and Cedar has widely taken place in Japan since early 1960s in attempt to fulfill national wood demands and control soil erosion. In 2004 one small headwater mountainous reforested watershed encompasses 4.8 ha was established in Mie Prefecture in Japan to monitor the hydrological response. Frequently and automatically collected values of discharge and suspended sediment concentration were examined for the main outlet and five other stations, spanning from June 2004 to July 2006. In the present study, the different functional linear and non-linear sediment rating curves analytical methods were employed in the investigation of ordinary and some transformed flow discharge-suspended sediment concentration relationships for the study watershed using from 48 to 162 simultaneous discharge-sediment records (2004-2006).
    According to the results of statistical analyses using different criteria and out of many types of regression functions and data transformation, power rating curve by least square regression on fourth root transformed flow discharge and suspended sediment concentration data performed well. Contrary to what is oft-reported, the best fitted rating curves to the entire data collected for each individual station excessively overestimated the suspended sediment concentration in the study area by 113-430%. The temporal and magnitude stratification of flow discharge and sediment data, flow components separation as well as employing bias correction factor did not improve the relationship, while better estimates were obtained when power regression was applied to the fourth root transformed data separated based on their locations on rising and falling limbs of hydrographs. Results also showed a complex suspended sediment concentration and flow discharge relationship in different subwatersheds of the study reforested watershed reflecting the effect of different physical local characteristics, sediment availability, contribution of various hydrologic cycle components, and subtle variation of soil hydrophobicity on runoff generation and consequently sediment supply. (c) 2007 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.geoderma.2007.11.008

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  85. Characterisation of diffuse pollutions from forested watersheds in Japan during storm events - Its association with rainfall and watershed features Reviewed

    Zhao Zhang, Takehiko Fukushima, Yuichi Onda, Shigeru Mizugaki, Takashi Gomi, Ken'ichirou Kosugi, Shinya Hiramatsu, Hikaru Kitahara, Koichiro Kuraji, Tomomi Terajima, Kazuo Matsushige, Fulu Tao

    SCIENCE OF THE TOTAL ENVIRONMENT   Vol. 390 ( 1 ) page: 215 - 226   2008.2

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    Forest areas have been identified as important sources of nonpoint pollution in Japan. The managers must estimate stormwater quality and quantities from forested watersheds to develop effective management strategies. Therefore, stormwater runoff loads and concentrations of 10 constituents (total suspended solids, dissolved organic carbon, PO4-P, dissolved total phosphorus, total phosphorus, NH4-N, NO2-N, NO3-N, dissolved total nitrogen, and total nitrogen) for 72 events across five regions (Aichi, Kochi, Mie, Nagano, and Tokyo) were characterised. Most loads were significantly and positively correlated with stormwater variables (total event rainfall, event duration, and rainfall intensity), but most discharge-weighted event concentrations (DWECs) showed negative correlations with rainfall intensity. Mean water quality concentration during baseflow was correlated significantly with storm concentrations (r = 0.41-0.77). Although all pollutant load equations showed high coefficients of determination (R-2= 0.55-0.80), no models predicted well pollutant concentrations, except those for the three N constituents (R-2=0.59-0.67). Linear regressions to estimate stormwater concentrations and loads were greatly improved by regional grouping. The lower prediction capability of the concentration models for Mie, compared with the other four regions, indicated that other watershed or storm characteristics should be included in the prediction models. Significant differences among regions were found more frequently in concentrations than in loads for all constituents. Since baseflow conditions implied available pollutant sources for stormwater, the similar spatial characteristics of pollutant concentrations between baseflow and stormflow conditions were an important control for stormwater quality. (c) 2007 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.scitotenv.2007.09.045

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  86. 国際シンポジウム「山岳地域の水資源管理と洪水軽減のための持続可能な森林管理」開催報告

    恩田,裕一, 蔵治,光一郎, 五味,高志, 水垣,滋

    水文・水資源学会誌   Vol. 1   page: 69 - 71   2008

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  87. Hortonian overland flow from Japanese forest ptantations - an aberration, the real thing, or something in between? Reviewed

    Roy C. Sidle, Tomonori Hirano, Takashi Gomi, Tomomi Terajima

    HYDROLOGICAL PROCESSES   Vol. 21 ( 23 ) page: 3237 - 3247   2007.11

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    There is a growing opinion that poorly managed plantation forests in Japan are contributing to increased storm runoff and erosion. Here we present evidence to the contrary from runoff plots at two scales (hillslope and 0.5 x 2 m plots) for several forest conditions in the Mie and Nariki catchments. Runoff coefficients from small plots in untended hinoki forests were variable but typically higher than from better managed or deciduous forests during small storms at Nariki; at Mie, runoff during small events was highly variable from all small plots but runoff coefficients were similar for hinoki plots with and without understory vegetation, while the deciduous plot had lower runoff coefficients. Storm runoff was less at the hillslope scale than the plot scale in Mie; these results were more evident at sites with better ground cover. During the largest storms at both sites, differences in runoff due to forest condition were not evident regardless of scale. Dynamic soil moisture tension measurements at Nariki indicated that during a large storm, flow in the upper organic-rich and root-permeated soil horizons was 3.2 times higher than measured overland runoff from a small hinoki plot with poor ground cover and 8.3 times higher than runoff from a deciduous forest plot. On the basis of field observations during storms, at least a portion of the monitored 'Hortonian overland flow' was actually occurring in this near-surface 'biomat'. Therefore our field measurements in both small and large plots potentially included biomat flow in addition to short-lived Hortonian runoff. Because overland flow decreased with increasing scale, rill erosion did not occur on hillslopes. Additionally, runoff coefficients were not significantly different among cover conditions during large storms; thus, the 'degraded' forest conditions appear not to greatly enhance peak flows or erosion potential at larger scales, especially when biomat flow is significant. Copyright (C) 2007 John Wiley & Sons, Ltd.

    DOI: 10.1002/hyp.6876

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  88. Is MUSLE apt to small steeply reforested watershed?

    Sadeghi S. H. R., Mizuyama T., Miyata S., Gomi T., Kosugi K., Mizugaki S., Onda Y.

    JOURNAL OF FOREST RESEARCH   Vol. 12 ( 4 ) page: 270 - 277   2007.8

  89. Surface runoff as affected by soil water repellency in a Japanese cypress forest Reviewed

    Shusuke Miyata, Ken'ichirou Kosugi, Takashi Gomi, Yuichi Onda, Takahisa Mizuyama

    HYDROLOGICAL PROCESSES   Vol. 21 ( 17 ) page: 2365 - 2376   2007.8

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    Recent studies have suggested that soil water repellency can be one of the important factors affecting hydrological processes on headwater catchments. In Japan, water repellency is known to occur under Japanese cypress (Chamaecyparis obtusa) forests, a typical plantation type in Japan, however, previous studies have not evaluated the severity of water repellency and its effects on surface runoff generation. To quantify water repellency and its effects, this study combined the critical surface tension (CST) test with a new spraying experiment in which the infiltration rates of water and ethanol solutions sprayed over 0.09-m(2) plots were compared. Long-term intensive hydrological observations of surface runoff from 2-m(2) plots, soil water potential, and soil water content were conducted concurrently.
    The spraying experiment revealed that strong water repellency in surface soils, as quantified by the CST test, caused Hortonian overland flow despite the high conductivity measured under saturated hydrophilic conditions. Generally, the surface runoff coefficient for a storm event was negatively correlated with initial soil moisture conditions. However, during a period of successive storm events separated by short intervals, the coefficient decreased gradually even when the initial moisture conditions were similar. indicating a weakening of water repellency by repeated wetting. On the other hand, a drying period r with long inter-rainfall intervals and increasing air temperature was associated with increases in the surface runoff coefficient. These results suggest that the water repellency and the resultant surface runoff depended on the history of rainfall at the site. Relationships between soil water potential and soil water content indicate that changes in the soil water repellency and consequently surface runoff coefficient could occur during a single storm event. Copyright (c) 2007 John Wiley & Sons, Ltd.

    DOI: 10.1002/hyp.6749

    Web of Science

  90. Structures linking physical and biological processes in headwater streams of the maybeso watershed, southeast Alaska

    Mason D. Bryant, Takashi Gomi, Jack J. Piccolo

    FOREST SCIENCE   Vol. 53 ( 2 ) page: 371 - 383   2007.4

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    We focus on headwater streams originating in the mountainous terrain of northern temperate rain forests. These streams rapidly descend from gradients greater than 20% to less than 5% in U-shaped glacial valleys. We use a set of studies on headwater streams in southeast Alaska to define headwater stream catchments, link physical and biological processes, and describe their significance within watersheds. We separate headwater stream systems into four units that have distinct hydrologic and geomorphic processes that link terrestrial processes to aquatic systems. Headwater streams collect, process, and transport material downstream. Physical and biological processes in headwater streams are complex and closely tied to terrestrial processes. Steps and step pools formed by large wood are keystone structures that link physical processes to biological processes and increase channel complexity. Large and coarse wood debris dams form in-channel step structures and act as valves that regulate the downstream flow of material. A large amount of inorganic and organic sediment is stored in step structures, which may be biological hotspots in headwater streams. Step pools formed by large woody debris are critical habitat for Dolly Varden (Salvelinus malma), juvenile coho salmon (Oncorhynchus kisutch), steelhead (O. mykiss), and cutthroat trout (O. clarkii) in reaches with gradients from less than 4% to those greater than 10%. Landslides and debris flows are the dominant channel-altering processes in headwater streams and remove the step profile. Management activities that increase the number and frequency of channel disturbance events in headwater streams can have important and long-term consequences throughout a watershed.

    Web of Science

  91. 河川上流と下流のつながり:上流管理の重要性 Reviewed

    五味高志

    河川   Vol. 729   page: 75 - 77   2007.2

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  92. JST/CRESTプロジェクト"森林荒廃が洪水・河川環境に及ぼす影響の解明とモデル化"研究サイト

    恩田,裕一, 五味,高志, 水垣,滋

    砂防学会誌   Vol. 5   page: 70 - 73   2007

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  93. Headwater stream temperature response to clear-cut harvesting with different riparian treatments, coastal British Columbia, Canada Reviewed

    Takashi Gomi, R. Dan Moore, Amod S. Dhakal

    WATER RESOURCES RESEARCH   Vol. 42 ( 8 ) page: 1 - 11   2006.8

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    [ 1] A 6-year study documented the effects of clear-cut harvesting with and without riparian buffers ( 10 m and 30 m wide) on headwater stream temperature in coastal British Columbia. The experiment involved a replicated paired catchment design. Pretreatment calibration relations between the treatment and control streams were fitted using time series of daily minimum, mean, and maximum temperatures. Generalized least squares (GLS) regression was used to account for autocorrelation in the residuals. While water temperature in streams with 10 and 30 m buffers did not exhibit marked warming, daily maximum temperature in summer increased by up to 2 degrees - 8 degrees C in the streams with no buffer. The effectiveness of the buffers may have been maximized by the north-south orientation of the streams, which meant that the streams would be well shaded from late morning to early afternoon by the overhead canopy, even under the 10 m buffer. The variation in response for the no-buffer treatments is consistent with the differences in channel morphology that influence their exposure to solar radiation and their depth. Relations between treatment effect and daily maximum air temperature suggested that recovery toward preharvest temperature conditions was occurring, with rates appearing to vary with stream and by season.

    DOI: 10.1029/2005WR004162

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  94. 土壌侵食と森林-森林斜面から流域の視点へ- Reviewed

    五味高志

    森林科学   Vol. 47   page: 10 - 14   2006.6

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    Language:Japanese   Publisher:THE JAPANESE FORESTRY SOCIETY  

    DOI: 10.11519/jjsk.47.0_10

    CiNii Books

  95. Factors affecting distribution of wood, detritus, and sediment in headwater streams draining managed young-growth red alder - conifer forests in southeast Alaska Reviewed

    Takashi Gomi, Adelaide C. Johnson, Robert L. Deal, Paul E. Hennon, Ewa H. Orlikowska, Mark S. Wipfli

    CANADIAN JOURNAL OF FOREST RESEARCH-REVUE CANADIENNE DE RECHERCHE FORESTIERE   Vol. 36 ( 3 ) page: 725 - 737   2006.3

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    Factors (riparian stand condition, management regimes, and channel properties) affecting distributions of wood, detritus (leaves and branches), and sediment were examined in headwater streams draining young-growth red alder (Alnus rubra Bong.) - conifer riparian forests (&lt; 40 years old) in southeast Alaska. More riparian red alder were found along streams affected by both timber harvesting and mass movement than in streams affected by timber harvesting alone. Young-growth stands produced little large wood material (diameter &gt;= 10 cm) and had little effect on altering the size distribution of functional large wood in channels, although more alder wood pieces were found in streams with greater numbers of riparian alder trees. Legacy wood pieces (&gt; 40 years old) remained in channels and provided sites for sediment and organic matter storage. Despite various alder-conifer mixtures and past harvesting effects, the abundance of large wood, fine wood, and detritus accumulations significantly decreased with increasing channel bank-full width ( 0.5-3.5 m) along relatively short channel distances (up to 700 m). Changes in wood, detritus, and sediment accumulations together with changes in riparian stand characteristics create spatial and temporal variability of in-channel conditions in headwater systems. A component of alder within young-growth riparian forests may benefit both wood production and biological recovery in disturbed headwater stream channels.

    DOI: 10.1139/X05-272

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  96. Sediment and wood accumulations in humid tropical headwater streams: Effects of logging and riparian buffers Reviewed

    T Gomi, RC Sidle, S Noguchi, JN Negishi, AR Nik, S Sasaki

    FOREST ECOLOGY AND MANAGEMENT   Vol. 224 ( 1-2 ) page: 166 - 175   2006.3

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    The amount of sediment, wood, and detritus (leaves and small branches) accumulations were examined in four headwater tributaries subjected to different treatments (unlogged, logged with riparian buffer, and logged with no buffer) 16 and 40 months after timber harvesting in the Bukit Tarek Experimental Watershed, Peninsular Malaysia. Sediment transport from hillslope logging roads and skid trails resulted in large sediment storage in the stream channels. Riparian reserves appear to mitigate logging impacts to streams; however, more sediment was found in a tributary channel with a 20-m buffer than an unlogged channel because some of the nearby roads and skid trails were connected to the stream. Sediment storage in channels declined within 40 months after logging in catchments with and without riparian buffers. Vegetation recovery on skid trails and logging roads reduced both sediment supply and delivery. The volume of large wood was 1.5 to 2-times greater in the stream without riparian reserves than the stream of an unlogged catchment or in a stream with a riparian buffer. No consistent change in detritus accumulations was found among streams in 2001 and 2003, although more detritus was present in 2003 in all streams. The effects of logging and the effectiveness of riparian buffers appear to depend on the hydrologic connections between hillslopes and headwater streams. (c) 2005 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.foreco.2005.12.016

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  97. Suspended sediment dynamics in small forest streams of the Pacific Northwest

    Gomi T, Moore RD, Hassan MA

    JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION   Vol. 41 ( 4 ) page: 877 - 898   2005.8

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  98. Thermal regime of a headwater stream within a clear-cut, coastal British Columbia, Canada Reviewed

    RD Moore, P Sutherland, T Gomi, A Dhakal

    HYDROLOGICAL PROCESSES   Vol. 19 ( 13 ) page: 2591 - 2608   2005.8

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    This study examined the thermal regime of a headwater stream within a clear-cut. The stream had a complex morphology dominated by step-pool features, many formed by sediment accumulation upstream of woody debris. Maximum daily temperatures increased up to 5 degrees C after logging, and were positively associated with maximum daily air temperature and negatively with discharge. Maximum daily temperatures generally increased with downstream distance through the cut block, but decreased with distance in two segments over distances of tens of metres, where the topography indicated relatively concentrated lateral inflow. Localized cool areas within a step-pool unit were associated with zones of concentrated upwelling. Bed temperatures tended to be higher and have greater ranges in areas of downwelling flow into the bed. Heat budget estimates were made using meteorological measurements over the water surface and a model of net radiation using canopy characteristics derived from fisheye photography. Heat exchange driven by hyporheic flow through the channel step was a cooling effect during daytime, with a magnitude up to approximately 25% that of net radiation during the period of maximum daytime warming. Heat budget calculations in these headwater streams are complicated by the heterogeneity of incident solar radiation and channel geometry, as well as uncertainty in estimating heat and water exchanges between the stream and the subsurface via hyporheic exchange and heat conduction. Copyright (c) 2005 John Wiley & Sons, Ltd.

    DOI: 10.1002/hyp.5733

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  99. Hydrogeomorphic linkages of sediment transport in headwater streams, Maybeso Experimental Forest, southeast Alaska Reviewed

    T Gomi, RC Sidle, DN Swanston

    HYDROLOGICAL PROCESSES   Vol. 18 ( 4 ) page: 667 - 683   2004.3

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:WILEY-BLACKWELL  

    Hydrogemorphic linkages related to sediment transport in headwater streams following basin wide clear-cut logging on Prince of Wales Island, southeast Alaska, were investigated. Landslides and debris flows transported sediment and woody debris in headwater tributaries in 1961, 1979, and 1993. Widespread landsliding in 1961 and 1993 was triggered by rainstonns with recurrence intervals (24 h precipitation) of 7.0 years and 4.2 years respectively. Occurrence. distribution, and downstream effects of these mass movements were controlled by landform characteristics such as channel gradient and valley configuration. Landslides and channelized debris flows created exposed bedrock reaches, log jams, fans, and abandoned channels. The terminus of the deposits did not enter main channels because debris flows spread and thinned on the unconfined bottom of the U-shaped glaciated valley. Chronic sediment input to channels included surface erosion of exposed till (rain splash, sheet erosion, and freeze-thaw action) and bank failures. Bedload sediment transport in a channel impacted by 1993 landslides and debris flows was two to ten times greater and relatively finer compared with bedload transport in a young alder riparian channel that had last experienced a landslide and debris flow in 1961. Sediment transport and storage were influenced by regeneration of riparian vegetation, storage behind recruited woody debris, development of a streambed armour layer, and the decoupling of hillslopes and channels. Both spatial and temporal variations of sediment movement and riparian condition are important factors in understanding material transport within headwaters and through channel networks. Copyright (C) 2004 John Wiley Sons, Ltd.

    DOI: 10.1002/hyp.1366

    Web of Science

  100. Bed load transport in managed steep-gradient headwater streams of southeastern Alaska

    Gomi T, Sidle RC

    WATER RESOURCES RESEARCH   Vol. 39 ( 12 )   2003.12

  101. Characteristics of channel steps and reach morphology in headwater streams, southeast Alaska

    Gomi T, Sidle RC, Woodsmith RD, Bryant MD

    GEOMORPHOLOGY   Vol. 51 ( 1-3 ) page: 225 - 242   2003.3

  102. Understanding processes and downstream linkages of headwater systems

    Gomi T, Sidle RC, Richardson JS

    BIOSCIENCE   Vol. 52 ( 10 ) page: 905 - 916   2002.10

  103. The characteristics of woody debris and sediment accumulation in headwater streams, southeastern Alaska Reviewed

    Gomi T, Sidle, R.C, Bryant, M.D, Woodsmith, R.D

    Canadian Journal of Forest Research   Vol. 31   page: 1386 - 1399   2002.8

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1139/cjfr-31-8-1386

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Books 14

  1. 水資源対策としての森林管理 大規模モニタリングデータからの提言

    ( Role: Joint editor)

    東京大学出版会  2022.12  ( ISBN: 978-4-13-071107-4

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    Total pages:260   Language:Japanese

  2. 森林林業実務必携第二版補訂版

    五味高志( Role: Joint author ,  山地防災と流域保全)

    朝倉書店  2024.3 

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    Total pages:485   Responsible for pages:24   Language:Japanese Book type:Textbook, survey, introduction

  3. Wetzel's Limnology (Fourth Edition) Lake and River Ecosystems Reviewed International journal

    Roy Sidle, Takashi Gomi( Role: Contributor ,  Hydrological Systems)

    Academic Press  2024.1 

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    Total pages:1088   Responsible for pages:16   Language:English Book type:Scholarly book

    DOI: https://doi.org/10.1016/B978-0-12-822701-5.00005-7

  4. ほんとうのエコシステムってなに? 漁業・林業を知ると世界がわかる

    五味高志( Role: Contributor ,  災害と森林との関係)

    農山村文化協会  2023.3  ( ISBN:9784540221156

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    Total pages:162   Responsible for pages:110-113  

  5. 森林水文学入門

    五味高志( Role: Contributor ,  流出解析)

    朝倉書店  2022.9 

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    Total pages:245   Responsible for pages:145-162   Language:Japanese Book type:Textbook, survey, introduction

  6. Sika Deer: Life History Plasticity and Management

    Takashi Gomi, Mitsuru Oohira, Marino Hiraoka, Shusuke Miyata, Yoshimi Uchiyama( Role: Joint author)

    2022.6  ( ISBN:978-981-16-9553-7

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    Total pages:634   Responsible for pages:399-413   Language:English Book type:Scholarly book

    DOI: https://doi.org/10.1007/978-981-16-9554-4

  7. Impact s of Fukushima Nuclear Accident on freshwater environments International journal

    Fujino T, Jayasanka Senavirathna MDH, Sakai M, Gomi T( Role: Contributor ,  Characteristics of 137Cs Concentration and Radioactivity Transfer in Large Aquatic Insect Species)

    2021.11  ( ISBN:978-981-16-3670-7

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    Total pages:197   Responsible for pages:169-184   Language:English Book type:Scholarly book

    DOI: https://doi.org/10.1007/978-981-16-3671-4

  8. 森林林業実務必携

    五味高志( Role: Contributor ,  山地防災と流域保全)

    岩波書店  2021.4  ( ISBN:978-4-254-47057-4

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    Total pages:504   Responsible for pages:133–158   Language:Japanese Book type:Scholarly book

  9. 森林学の百科事典

    五味高志( Role: Contributor ,  森林における災害の歴史とその背景)

    丸善出版  2021.1  ( ISBN:978-4-621-305843

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    Total pages:694   Language:Japanese Book type:Dictionary, encyclopedia

  10. 保持林業−木を伐りながら生き物を守る

    五味高志( Role: Contributor ,  カナダ・BC州の事例: 保持林業が渓流生態系に及ぼす影響)

    築地書館  2018.11  ( ISBN:978-4-8067-1570-2

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    Total pages:372   Responsible for pages:95–120   Language:Japanese Book type:Scholarly book

  11. 森林と災害

    五味高志, 戸田浩人, 境 優( Role: Contributor ,  原子力災害がもたらす森林−渓流生態系の放射性セシウム汚染)

    共立出版  2018.3  ( ISBN:9784320058194

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    Total pages:248  

  12. Sustainable forest management: from concept to practice

    Moore RD, Sidle RC, Eaton B, Gomi T, Wilford D( Role: Joint author)

    Routledge  2017.9 

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    Responsible for pages:161-247   Language:English Book type:Scholarly book

  13. ヒノキ林流域と広葉樹林流域の降雨流出の違い(人工林荒廃と水・土砂流出の実態・恩田裕一編)

    恩田裕一, 水垣滋, 平松晋也, 寺嶋智巳, 五味高志( Role: Joint author)

    岩波書店  2008.10  ( ISBN:9784000054638

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    Responsible for pages:73-85   Language:Japanese Book type:Scholarly book

  14. Compatible management of red alder-conifer ecosystems in Southeastern Alaska. Chapter 4 In Wood compatible initiative for future forest management

    Wipfli M.S, Hennon P.E, Deal R.L, Johnson, A.C, De Santo T.L, Gomi T, Edwards R.T, Bryant M.D, Schultz M.E, Orilowaska E.H, Lesage C. Kimbirauskus R, D’Amore D.V( Role: Joint author)

    Kluwer Academic Publishers  2003.10 

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    Responsible for pages:55-84   Language:English Book type:Scholarly book

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MISC 5

  1. Seasonal variation in food web-based transfer factors of radiocesium in white-spotted char (Salvelinus leucomaenis) from headwater streams

    M. E. Haque, T. Gomi, M. Sakai, J. N. Negishi

    Landscape and Ecological Engineering   Vol. 14 ( 1 ) page: 45 - 53   2018.1

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    Language:English   Publisher:Springer Tokyo  

    The seasonal variability of food web-based transfer factors (TFweb) of radiocesium (137Cs) in white-spotted char (Salvelinus leucomaenis) was examined in the 2nd and 3rd year after the Fukushima Daiichi Nuclear Power Plant accident. Two headwater streams with similar landscape characteristics, but different amounts of fallout, were selected in Fukushima and Gunma Prefectures, Japan. The TFweb of predator–prey systems was based on the dietary contributions of prey items estimated from stable isotopes compared to their respective 137Cs activity concentrations. Char consumed more terrestrial food sources with higher contamination levels in summer than in winter based on their dietary-based 137Cs contributions. The TFweb values in Fukushima and Gunma in all seasons indicated 137Cs bioaccumulation from prey to predator. The TFweb in Gunma exhibited significant seasonal variation
    the greatest values were observed in winter, while the lowest values were observed in summer. In contrast, the seasonal TFweb in Fukushima did not vary seasonally. Despite similar consumption patterns and the specific metabolic rates of char, the different seasonal patterns of TFweb at the two sites can be explained by the relative excretion rate with respect to the concentration of 137Cs consumed. 137Cs levels can remain relatively constant in the char body throughout the year in areas with high contamination, such as Fukushima, possibly because 137Cs intake overwhelms the excretion rate. Examining seasonal patterns in the transfer processes of 137Cs in white-spotted char are essential for understanding mechanisms of 137Cs accumulation in aquatic biota.

    DOI: 10.1007/s11355-016-0324-4

    Scopus

  2. Characteristics of landslides in unwelded pyroclastic flow deposits, southern Kyushu, Japan

    M. Yamao, R. C. Sidle, T. Gomi, F. Imaizumi

    NATURAL HAZARDS AND EARTH SYSTEM SCIENCES   Vol. 16 ( 2 ) page: 617 - 627   2016

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    Language:English   Publisher:COPERNICUS GESELLSCHAFT MBH  

    We investigated 184 landslides that occurred in unwelded pyroclastic flow deposits (Shirasu) on southern Kyushu Island, Japan, that included detailed data on the rainfall characteristics and the timing of slope failure. Localized rainfall intensity, antecedent precipitation index (API), and topography affected the hydrologic processes that triggered landslides. API (adjusted for evapotranspiration losses) for large (&gt;200 mm) storms that triggered landslides was much lower than for smaller (&lt;= 200 mm) storms. Mean storm intensity and 7-day API (API7) thresholds of &gt;5mm h(-1) and &lt;= 30mm (or API(30) &lt;= 60 mm), respectively, were useful to identify landslides triggered by rapid pore water pressure response, especially for shorter (&lt;20 h) duration events. During smaller storms with lower intensity, landslides are likely affected by a combined increase in soil weight and loss of suction when API(30) &gt;= 150 mm; simulations indicated that these weight and suction changes due to rainfall accumulation decreased the factor of safety in steep Shirasu slopes, but did not necessarily trigger the landslides. Most of the landslides that were plotted below a general rainfall intensity-duration threshold for landslide initiation occurred during smaller storms with API(30) values &gt; 200 mm, indicating that they were highly influenced by the combined effects of the accumulated weight of rainfall and loss of suction. Our findings show that both event rainfall characteristics and API affect the hydrogeomorphic processes that trigger different types of landslides in Shirasu. This knowledge and the thresholds we have identified are useful for predicting the occurrence of different types of landslides in unwelded Shirasu deposits and improving sediment disaster prevention practices, including real-time warning systems.

    DOI: 10.5194/nhess-16-617-2016

    Web of Science

    Scopus

  3. The effect of strip thinning on tree transpiration in a Japanese cypress (Chamaecyparis obtusa Endl.) plantation

    Xinchao Sun, Yuichi Onda, Kyoichi Otsuki, Hiroaki Kato, Akiko Hirata, Takashi Gomi

    AGRICULTURAL AND FOREST METEOROLOGY   Vol. 197   page: 123 - 135   2014.10

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    Language:English   Publisher:ELSEVIER SCIENCE BV  

    This study analyzes the effect of strip thinning on tree transpiration (E-t) in a dense and mature Japanese cypress (Chamaecyparis obtusa Endl.) plantation in central Japan. Strip thinning, which removed 50% of stems, was conducted in a headwater basin in October 2011. Xylem sap flow densities (F-d) were measured using thermal dissipation (Granier-type) sensors in a 156-m(2) plot before and after thinning. The canopy conductance (G(c)) was calculated on the basis of E-t values. The results revealed that the F-d at the outer xylem (0-20 mm) increased remarkably, whereas the F-d at the inner xylem (20-40 mm) had no significant change after thinning. Mean stand sap flow density (Is) values were higher in the post-thinning period than in the pre-thinning period, and the differences significantly increased with increasing vapor pressure deficit (VPD) values. Furthermore, the daily single tree E-t increased, particularly in the small tree class. Unlike the daily tree E-t, the daily stand E-t decreased from 1.29 +/- 0.60 to 1.00 +/- 0.40 mm d(-1) during the growing season or decreased from 1.23 +/- 0.48 to 0.74 +/- 0.42 mm d(-1) on the annual scale. The total stand E-t decreased by 23.0%, from 214.9 to 165.5 mm, during the growing season or decreased by 38.3%, from 441.0 to 272.1 mm, on the annual scale. G, decreased after thinning, which implies lower stand E-t and photosynthesis. G, was primarily related to the VPD and would be an effective model to predict E-t from these Japanese cypress plantations. This study provides useful information for understanding the E-t responses at individual tree and stand levels to strip thinning and contributes to obtaining a thorough understanding of the change in tree water use under different management strategies. (C) 2014 Elsevier B.V. All rights reserved.

    DOI: 10.1016/j.agrformet.2014.06.011

    Web of Science

    Scopus

  4. Linkages of hydrologic, geomorphic, and biological processes in forested headwater systems

    GOMI Takahi, NUNOKAWA Masanori, SIDLE Roy C.

      Vol. 58 ( 1 ) page: 72 - 73   2005.5

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    Language:Japanese  

    CiNii Books

  5. Managing young upland forests in southeast Alaska for wood products, wildlife, aquatic resources, and fishes: Problem analysis and study plan

    Mark S. Wipfli, Robert L. Deal, Paul E. Hennon, Adelaide C. Johnson, Toni L. De Santo, Thomas A. Hanley, Mark E. Schultz, Mason D. Bryant, Richard T. Edwards, Ewa H. Orlikowska, Takashi Gomi

    USDA Forest Service - General Technical Report PNW     page: 1 - 46   2002.9

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    Red alder (Alnus rubra Bong.) appears to influence the productivity of young-growth conifer forests and affect the major resources (timber, wildlife, and fisheries) of forested ecosystems in southeast Alaska. We propose an integrated approach to understanding how alder influences trophic links and processes in young-growth ecosystems. The presence of red alder is expected to increase understory biomass, and aquatic, riparian, and terrestrial invertebrate abundance, providing more food for herbivores, fish, and birds. We predict that most red alder trees will die standing, and woody debris will be small and mobile in streams. Nitrogen fixation by red alder in mixed stands may result in larger, more commercially valuable conifers. Inclusion of red alder in the regenerating stand may therefore mitigate some negative impacts of clearcutting, and may increase total wood production from the landscape.

    Scopus

Presentations 43

  1. 地下水モデルへの接続を目的とした広域森林情報の活用と森林水循環評価 Invited

    五味高志・恩田裕一・猪越翔大・邱湞瑋・橋本朝陽・Yupan Zhang

    第135回日本森林学会  2024.3.8  日本森林学会

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    Event date: 2024.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:東京   Country:Japan  

  2. UAV-LiDAR データを活用した林内日射量と林床面蒸発の推定 Invited International coauthorship

    高村詩央里・恩田裕一・加藤弘亮・Zhang Yupan・橋本 朝陽・Chiu, Chen Wei・五味高志

    第135回日本森林学会  2024.3.8  日本森林学会

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    Event date: 2024.3

    Language:Japanese   Presentation type:Poster presentation  

    Venue:東京   Country:Japan  

  3. ヒノキ人工林における列状間伐後蒸散量の長期変動およびその要因

    邱湞瑋・五味高志・恩田裕一・橋本朝陽・孫新超

    第135回日本森林学会  2024.3.8  日本森林学会

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    Event date: 2024.3

    Language:Japanese   Presentation type:Poster presentation  

    Venue:東京   Country:Japan  

  4. 北方冷温帯林において植生が出水時のリン流出 に及ぼす影響について

    井手淳一郎・内藤陸斗・荒田洋平・廣川令真・遠藤いず貴・ 五味高志

    第135回日本森林学会  2024.3.8  日本森林学会

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    Event date: 2024.3

    Venue:東京   Country:Japan  

  5. 下層植生が林床面蒸発散量に与える影響と推定 モデルの開発

    橋本朝陽・ChiuChen-Wei・恩田裕一・五味高志・小野里尚哉

    第135回日本森林学会  2024.3.8  日本森林学会

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    Event date: 2024.3

    Language:Japanese   Presentation type:Poster presentation  

    Venue:東京   Country:Japan  

  6. 日本のダム上流域を対象とした森林・地形状態 と土砂・流木流出特性の関係

    中島啓太・五味高志・田中隆文・小谷亜由美

    第135回日本森林学会  2024.3.8  日本森林学会

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    Event date: 2024.3

    Language:Japanese   Presentation type:Poster presentation  

    Venue:東京   Country:Japan  

  7. 北海道胆振東部地震による崩壊斜面でのリル ネットワークの形成と土砂動態

    八十川伊織・荒田洋平・大平充・五味高志・猪越翔大・ 遠藤いず貴・井手淳一郎

    第135回日本森林学会  2024.3.8  日本森林学会

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    Event date: 2024.3

    Language:Japanese   Presentation type:Poster presentation  

    Venue:東京   Country:Japan  

  8. 山地上流域を対象とした流量の時空間変動特性 とその支配的な地形条件 Invited

    鯉江知樹・五味高志・田中隆文・小谷亜由美・猪越翔大・ 中瀬孝・津田その子・根津涼

    第135回日本森林学会  2024.3.8  日本森林学会

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    Event date: 2024.3

    Language:Japanese   Presentation type:Poster presentation  

    Venue:東京   Country:Japan  

  9. 山地上流域における水貯留機能評価手法の構築と貯留量の流域間比較 Invited

    猪越翔大・五味高志・田中隆文・小谷亜由美・中瀬孝・ 津田その子・恩田裕一・邱 湞瑋・小田智基・勝山正則

    第135回日本森林学会  2024.3.7  日本森林学会

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    Event date: 2024.3

    Language:Japanese   Presentation type:Poster presentation  

    Venue:東京   Country:Japan  

  10. Evaluating the Factors of Watershed Water Storage: A Comparative Study in Temperate Forested Headwater Watersheds in the United States and Japan International coauthorship International conference

    Shodai Inokoshi, Takashi Gomi, Adam S Wymore, William H McDowell

    American Geophysical Union Fall meeting  2023.12.15  American Geophysical Union

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    Event date: 2023.12

    Language:English   Presentation type:Poster presentation  

    Venue:San Fransisco   Country:United States  

  11. グリーンインフラとしての森と水 Invited

    五味高志

    世界で進むグリーンインフラ  2023.12.7  名古屋大学フューチャー・アース研究センター

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    Event date: 2023.12

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:名古屋   Country:Japan  

  12. 源流部湧水湿地における炭素蓄積 量と温室効果ガスの収支量評価: 湿地とその集水域の水文プロセス の関係

    青木翔太・五味高志・小谷亜由美・水内佑輔

    第13回中部森林学会大会  2023.10.14  中部森林学会

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    Event date: 2023.10

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:富山   Country:Japan  

  13. 表層崩壊発生に至る地形変異と崩壊発生時の土壌水分特性:模型実 験による検討

    大久保太貴・五味 高志・田中隆文・小谷亜由美・岩佐直人

    第13回中部森林学会大会  2023.10.14  中部森林学会

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    Event date: 2023.10

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:富山   Country:Japan  

  14. 北海道胆振東部地震 4 年後までの 崩壊斜面の植生および土砂動態の 季節変動特性

    八十川伊織・荒田洋平・大平充・ 五味高志・猪越翔大・ 遠藤いず貴・井手 淳一郎

    第13回中部森林学会大会  2023.10.14  中部森林学会

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    Event date: 2023.10

    Language:Japanese   Presentation type:Oral presentation (invited, special)  

    Venue:富山   Country:Japan  

  15. 異なる気象条件における流域貯留 量の季節変動性の評価

    猪越翔大・五味高志・田中隆文・小谷亜由美・中瀬孝・ 津田その子・邱䈭 瑋

    第13回中部森林学会大会  2023.10.14  中部森林学会

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    Event date: 2023.10

    Venue:富山   Country:Japan  

  16. 森林小流域における水流出の空間 的時間的変動特性の把握

    鯉江知樹・五味高志・小谷亜由美・田中隆文・猪越翔大・中瀬孝・ 津田その子

    第13回中部森林学会大会  2023.10.14  中部森林学会

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    Event date: 2023.10

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:富山   Country:Japan  

  17. 日本全国の山地流域を対象とした 土砂・流木流出特性

    中島啓太・五味高志・田中隆文・小谷亜由美

    第13回中部森林学会大会  2023.10.14  中部森林学会

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    Event date: 2023.10

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:富山   Country:Japan  

  18. 安価な深度画像センサーを用いたLAIデータの5バンド画像解析

    GEI LEBAGAN、田中隆文、小谷亜由美 、五味高志

    水文・水資源学会2023年度研究発表会  2023.9.3  水文・水資源学会

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    Event date: 2023.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:長崎   Country:Japan  

  19. ヒノキ林における日射量シミュレーションと蒸散量評価のための冠層構造モデルの開発

    王 昕瑋、五味 高志

    水文・水資源学会2023年度研究発表会  2023.9.3  水文・水資源学会

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    Event date: 2023.9

    Language:English   Presentation type:Oral presentation (general)  

    Venue:長崎   Country:Japan  

  20. 森林斜⾯における⽴⽊密度と根系効果の評価 -斜⾯模型実験によるアプローチ- International coauthorship

    五味⾼志・Rozaqqa NOVIANDI・岩佐直⼈・蓮沼佑晃・⼤⾼範寛

    公社砂防学会研究発表会  2023.5.15  砂防学会

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    Event date: 2023.5

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:札幌   Country:Japan  

  21. 胆振東部地震により崩壊を有する火山性土壌の小流域における降雨流出応答

    荒田洋平, 五味高志, 井手淳一郎, 遠藤いず貴

    公社砂防学会研究発表会  2023.5.15  砂防学会

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    Event date: 2023.5

    Language:Japanese   Presentation type:Poster presentation  

    Venue:札幌   Country:Japan  

  22. 北海道胆振東部地震による崩壊斜面での土砂・地形動態と植生回復過程

    八十川伊織, 五味高志, 荒田洋平, 大平充, 遠藤いず貴, 井手淳一郎

    公社砂防学会研究発表会  2023.5.15  砂防学会

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    Event date: 2023.5

    Language:Japanese   Presentation type:Poster presentation  

    Venue:札幌   Country:Japan  

  23. 模型斜面実験による森林根系強度を考慮した斜面安定解析

    蓮沼佑晃, Rozaqqa NOVIANDI, 大高範寛, 岩佐直人, 五味高志

    公社砂防学会研究発表会  2023.5.15  砂防学会

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    Event date: 2023.5

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:札幌   Country:Japan  

  24. Estimation of Solar Radiation in Forests Using Drone LiDAR Data in Japanese Artificial Forests Invited International conference

    Shiori Takamura, Yuichi Onda, Yupan Zhang, Asahi Hashimoto, Hiroaki Kato, Takashi Gomi, Chenwei Chiu

    European Geosciences Union  2023.5.1  European Geosciences Union

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    Event date: 2023.5

    Language:English   Presentation type:Poster presentation  

    Country:Austria  

  25. Estimation of rainfall interception from merged drone and terrestrial LiDAR data by modeling 3D canopy structure in plantation forest Invited International conference

    Yupan Zhang, Yuichi Onda, Yiliu Tan, Hangkai You, Thuy Linh Pham, Asahi Hashimoto, Chenwei Chiu, Takashi Gomi, Shiori Takamura

    European Geosciences Union  2023.5.1  European Geosciences Union

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    Event date: 2023.5

    Language:English   Presentation type:Poster presentation  

    Country:Austria  

  26. 森と水のつながり:流域の中の森林を考える Invited

    五味高志

    令和4年度 小金井市成人大学講座  2022.9.3  小金井市

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    Event date: 2022.9

    Language:Japanese   Presentation type:Oral presentation (invited, special)  

    Venue:東京都小金井市   Country:Japan  

  27. 平岡真合乃・五味高志・小田智基・宮田秀介・内山佳美

    丹沢山地大洞沢試験流域における土砂生産と流出, 斜面プロットと沈砂池の観測結果

    平成25年度砂防学会研究発表会  2013.5.30  公益社団法人砂防学会

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    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:静岡市  

  28. 山地森林流域におけるイワナへの放射性セシウム蓄積量評価:摂食- 代謝解析

    五味高志, 境優, 岡田健吾, 岩本愛夢, 根岸淳二郎, 布川雅典

    応用生態工学会東京大会  2014.9.20  応用生態工学会

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    Language:Japanese   Presentation type:Poster presentation  

  29. 山地上流域における放射性同位体核種を用いた細粒土砂起源の推定と流出プロセス Invited

    熊倉歩, 五味高志, 水垣滋, 石川芳治, 古市剛久, 宮田秀介, 内山佳美

    平成23年度砂防学会研究発表会  2011.5.18  (社)砂防学会

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    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:横浜  

  30. 入れ子状観測流域における列状間伐後の流量と水温応答:FM唐沢山の事例

    五味高志, 平岡真合乃, 大平充, 恩田裕一

    第127回日本森林学会  2016.3.27  日本森林学会

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    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:神奈川県藤沢市  

  31. 入れ子状流域観測による地下水涵養と間伐による流量変化の評価

    五味高志, Bui Xuan Dung, 恩田裕一

    森林水文ワークショップ「持続的な水供給に向けた森林管理よる資源涵養の上と地下利用技術開発」  2014.3.27  森林水文ワークショップ

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    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:大宮  

  32. 世界各地の大規模崩壊の発生分布・崩壊特性・規模

    五味高志, 平岡真合乃, 青戸一峰, 菊池京子

    平成26年度砂防学会研究発表会  2014.5.20  砂防学会

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    Language:Japanese   Presentation type:Oral presentation (general)  

  33. シカ食害の顕著な東丹沢小流域における林床植生空間分布と表土侵食 Invited

    五味高志, 坂上賢, 熊倉歩, 古市剛久, 内山佳美, 石川芳治

    平成23年度砂防学会研究発表会  2011.5.18  (社)砂防学会

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    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:横浜  

  34. Storm runoff pathways in steep nested catchments draining a Japanese cypress forest in central Japan Invited

    Gomi T, Asano Y, Uchida T, Onda Y, Miyata S, Sidle R C, Kosugi K, Shigeru M, Fukuyama T, Fukushima T

    The Western Pacific Geophysics Meeting  2010.6.22  American Geophysical Union (AGU)

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    Language:English   Presentation type:Oral presentation (general)  

    Venue:Taiwan  

  35. Hydrological response to strip thinning and catchment scales in Japanese headwater basin

    Dung BX, Gomi T, Onda Y, Kato H, Hiraoka M

    International symposium on sediment disasters under the influence of climate change and tectonic activity (3rd)  2013.9.26  砂防学会

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    Language:English   Presentation type:Poster presentation  

  36. How Much Understory Vegetation Matters for Evaluating Changes in Annual Runoff Due to Timber Harvesting?

    Takashi Gomi, Dung X.Bui, Yuichi Onda, Marino Hiraoka

    3rd International Conference on Forests and Water in a Changing Environment  2012.9.18  Japan

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    Language:English   Presentation type:Oral presentation (general)  

    Venue:Kyushu, Fukuoka  

  37. How dose confounding effects of thinning and floods affect benthic invertebrate communities in headwater streams of Japan? Invited

    Gomi T, Watanabe Y, Dung BX, Onda Y

    XXIV IUFRO World Congress 2014  2014.10.10  IUFRO

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    Language:English   Presentation type:Oral presentation (general)  

    Venue:Salt Lake City, UT, United States  

  38. How did runoff and stream temperature responses after 50% thinning differ among nested observations of headwaters?

    Gomi T, Onda Y, Dung BW

    4th International Conference Forest & Water in a changing envrionment  2015.7.7  IUFRO

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    Language:English   Presentation type:Oral presentation (general)  

    Venue:BC, Canada  

  39. Field and modeling studies on the effects of forest devastation on flooding and environmental issues Invited

    Onda Y, Gomi T, Mizugaki S, Nanko K, Fukushima T

    The Western Pacific Geophysics Meeting  2010.6.22  American Geophysical Union (AGU)

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    Venue:Taiwan  

  40. Examining the Regional Legacy of Deep Catastrophic Landslides Invited

    Gomi T, Aoto K, Marino H, Ishizuka T, Uchida T

    Asia Oceania Geosciences Society (AOGS) 11th annual meeting  2014.7.30  Asia Oceania Geosciences Society (AOGS)

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    Language:English   Presentation type:Oral presentation (general)  

    Venue:Sapporo, Hokkaido, Japan  

  41. Examining the occurrence ages of deep catastrophic landslides using tephrochronological approches

    Aoto I, Gomi T, Hiraoka M, Ishizuka T, Morita k, Isshiki H, Uchida T

    International symposium on sediment disasters under the influence of climate change and tectonic activity (3rd)  2013.9.26  砂防学会

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    Language:English   Presentation type:Poster presentation  

    Venue:Kyoto  

  42. Estimating annual loss and annual evapotranspiration in forested headwater catchments: Analysis of the short-term water balance in pre- and post-thinning

    Sano K, Gomi T, Sato T, Hiraoka M, Onda Y

    4th International Conference on Forest and Water in a Changing Environment  2015.7.8  IUFRO

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    Language:English   Presentation type:Poster presentation  

    Venue:BC, Canada  

  43. 深層崩壊の発生頻度の推定方法検討:鰐塚山の事例 Invited

    五味高志, 平岡真合乃, 山越隆雄, 横山修, 石塚忠範, 内田太郎, 南光一樹

    平成24年度砂防学会研究発表会  2012.5.24  日本

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    Venue:高知  

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KAKENHI (Grants-in-Aid for Scientific Research) 15

  1. Disentangling the relationship among forest structures, riverine environmental regimes, and biodiversity under climate change

    Grant number:22H03796  2022.4 - 2026.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

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    Authorship:Coinvestigator(s) 

  2. Will radioactive materials continue to leak from the forests of Fukushima?

    Grant number:22H00556  2022.4 - 2025.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

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    Authorship:Coinvestigator(s) 

  3. Changes of objective nature as potential and social agreement in the floodplain of the Tama River

    Grant number:17H03960  2017.4 - 2020.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    Kuramoto Noboru

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    Conservation biology, sabo science, river engineering, and limnology have clarified the effects of the potential environment of the riverbed of the Tama River and the ecological network on the riverbed of the Tama River. Since a large-scale flood occurred in 2019, some of its dynamic aspects were elucidated. Although the gravel riverbed temporarily expanded due to the flooding, the gravel riverbed endemic species remained sharply reduced due to the flooding and did not recover. Based on the results of the natural sciences, we conducted experiments to form social consensus through pamphlets and workshops, and the citizens were enthusiastic about being taught by researchers. It turns out that the percentage of citizens who can reach consensus is small. It is necessary to develop a method for further social consensus building.

  4. Evaluation method of ecosystem resilience function in low deer density process after culling

    Grant number:16H02555  2016.4 - 2020.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

    Kaji Koichi

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    In areas where vegetation has declined due to overbrowsing, high deer density is maintained depending on fallen leaves. Chronic overbrowsing reduces the number of species in the seed bank faster than ground vegetation and negatively affects the function of nutrient cycling and seed dispersal through changes in the food habits of dung beetles during larvae. On the other hand, the low deer density resulted in the increase in deer body mass and fertility, the negative direct effect of deer feeding on sapling renewal and the positive indirect effect through reduction of sasa coverage, and the increase in the forest floor vegetation coverage and a decrease in soil erosion. In addition, it was clarified that the position at the watershed scale of the deer fence installation site affected vegetation cover and invasion, and the light conditions affected on persistence of seed banks.

  5. Developing unified forest management system by integrated water and carbon cycle analysis in forested watersheds

    Grant number:16H02556  2016.4 - 2020.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

    Gomi Takashi

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    Grant amount:\39780000 ( Direct Cost: \30600000 、 Indirect Cost:\9180000 )

    From hillslope and large watershed scales, we examined hydrological processes and carbon flux due to changes in volume and forest environment after timber harvesting. At the slope and sub-watershed scales, we assessed interception and evapotranspiration by thinning as well as evapotranspiration by forest floor vegetation. We also assessed changes in the amount of interception due to the growth of forest floor vegetation. Based on continuous monitoring of catchment runoff, we also identified seasonal patterns of evapotranspiration and changes in water loss by timber harvesting. Because landslides and related carbon foot print is important, we also examined sediment-related wood runoff in mountainous watersheds. Using spatial extensive information from forest inventory, we developed method to estimate large scale water balance using forest density and tree height in regional scales.

  6. 森林小流域における放射性セシウムの移動・蓄積・流出を予測する林床有機物動態の解析

    Grant number:15H04511  2015.4 - 2018.3

    科学研究費助成事業  基盤研究(B)

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  7. The use of stable isotope ratios of nitrate in the forest ecosystems for the better understanding of nitrogen status

    Grant number:26252020  2014.4 - 2017.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

    Koba Keisuke, INAGAKI Yoshiyuki, TATENO Ryunosuke, WATANABE Mirai

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    It is crucial to explore the nitrogen status of the forest ecosystems due to the management of the healthy forested ecosystems. However, due to the high spatiotemporal variations in nitrogen dynamics even in a small watershed, it is difficult to grasp its nitrogen status. We applied the isotope technique to estimate the gross nitrification rate and the denitrification with the help of the isotopic fractionation factors for different nitrogen processes occurring in the watershed. We found the high gross nitrification rates and denitrification rates in the watershed with more N deposition. However, the efficiency of the nitrogen removal by the denitrification was relatively low in high N deposition sites, indicating that the removal of nitrogen cannot work effectively in nitrogen-polluted sites.

  8. Impact of overabundance of sika deer on vegetation and feedback effects on their life history

    Grant number:25292085  2013.4 - 2017.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    Koichi Kaji, IGOTA HIROMASA, TAKAHASHI HIROSI, MATSUURA YUKIKO, UENO MAYUMI, IKEDA TAKASHI, TAKESHITA KAZUTAKA, MASUDA YASUSHI, AZUMAYA MUNMITSU, UEHARA HIROYO

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    Authorship:Coinvestigator(s) 

    Chronic overgrazing by sika deer has caused smaller body size due to density dependent resource limitation and various impacts on ecosystems. These involved feedback mechanism that available nitrogen for canopy tree increased and supplied litter with low C/N subject to degradation into soil. In addition, we found the complex changes in species diversity and phylogenetic diversity of vegetation, possibility of decrease in bumblebee population due to extinction of bloom phenology. For insects, the responses to high density of deer were different among taxon and functional group, and overgrazing by deer might cause negative feedback effects on insects which depend on understory vegetation through depression of food resources and habitat.

  9. 森林‐農地移行帯における放射性核種の移動・滞留と生態系濃縮の評価

    Grant number:24248058  2012.5 - 2015.3

    科学研究費助成事業   基盤研究(A)

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    Authorship:Principal investigator  Grant type:Competitive

  10. Development of an assessment system for fate and transport of rice pesticide based on a basin scale water and material cycle simulation model

    Grant number:24580352  2012.4 - 2015.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    WATANABE Hirozumi, KATO Tasuku, GOMI Takashi, SAITOU Hirotaka, INAO Keiya

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    Authorship:Coinvestigator(s) 

    The main objective of this study is to develop and validate the basin scale simulation model to simulate and evaluate the behavior of rice pesticides in the watershed containing paddy rice field in order to be used in the environmental impact assessment and registration/regulations of pesticides. In studies performed in 2012 fiscal year and the 2013 fiscal year , the construction of the model system for simulating pesticide behavior in rice paddy for the basin scale (PCPF-1 @ SWAT) was first carried out. A basin scale material circulation model (SWAT model) developed by the United States, Department of Agriculture, Agricultural Research Service were used as a base model to plug in the pesticide fate and transport model (PCPF-1), previously developed by the principal investigator. The new model (PCPF-1@SWAT) was first verified using a monitoring survey data in Ibaraki Prefecture, Sakuragawa basin and then with the data set obtained in the Sacramento River basin in California.

  11. 森林生態系における放射性核種と有機物・土壌養分の物質循環的解析

    Grant number:24380076  2012.4 - 2015.3

    科学研究費助成事業  基盤研究(B)

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    Authorship:Coinvestigator(s) 

  12. Spatial and temporal distribution of hydraulics at mountain channels

    Grant number:23380081  2011.4 - 2014.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    ASANO Yuko, UCHIDA Taro, GOMI Takashi

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    Authorship:Coinvestigator(s) 

    Predictions have shown that climate change may increase the occurrence of large storms and consequently increase the frequency and magnitude of floods in the Japanese archipelago. We have to be able to predict the vast increase in water and sediment discharge during large storms at mountain area which consist more than 60% of Japanese land. The objective of our study was A) to obtain discharge, water depth and velocity during storms at mountain channel and B) to clarify the relationships between hydraulics and channel morphology during flood at mountain channels. We showed that at mountain channel, water level rise was quick and large but flow velocity does not increase as much. Hydraulic characteristics were different between step and pool during low flow. During large storm, however, hydraulics became depending on morphology of whole channel including step and pool. New survey methods for submerged channel bed using green wavelength terrestrial laser scanner was developed.

  13. Impact of environmental pollution and ecological expansion of large-scale irrigation in the arid land of Central Asia

    Grant number:20405004  2008 - 2011

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    KAWABATA Yoshiko, KATAYAMA Yukio, NAGAI Masahiro, YAMAMOTO Masayoshi, YAMADA Masaaki, GOMI Takashi

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    Authorship:Collaborating Investigator(s) (not designated on Grant-in-Aid) 

    We were investigated following the effects of environmental pollution caused by agriculture and ecosystems to large-scale irrigation at Amu-Darya river basin in Uzbekistan, 1) Central Asia. It was researched of drinking water. 2) We collected Irrigation water and drainage water, and river water. There were investigated the effects of them by irrigated agriculture. 3) In the Nukus region, we were interviewed about the impact of the human body. 4) We collected water samples from river and groundwater one time of every month.
    As a result, all ions concentrations of groundwater were higher than river water. In addition, in winter time, especially, nitrate concentration in groundwater is high than other seasons. Toxic substances which were dissolved the enamel of teeth in children were observed in rural areas of Nukus district. Toxic substances may be, included in the well water. However, the changes of ion concentrations were different on every year. There is a need to examine in more detail was revealed.

  14. Evaluation and modeling the effects of road runoff on catchment storm runoff.

    Grant number:20580151  2008 - 2010

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    GOMI Takashi, SIDLE Roy C.

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    Authorship:Principal investigator 

    Grant amount:\4810000 ( Direct Cost: \3700000 、 Indirect Cost:\1110000 )

    The infiltration capacity was measured by using an oscillating nozzle rain simulator to estimate infiltration capacity of forest road surface and analyze the associated factors. The experimental results showed that the mean infiltration capacity of forest road surface was 33.3 mm/h. Bulk density and porosity were significantly correlated to infiltration capacity. Findings from both field experiments and monitoring can be applied for prediction rainfall-runoff from forest road surface which is important to be examining road runoff contribution at a watershed scale.

  15. Development of management methods for natural parks used by Ecological Limits of Acceptable Change

    Grant number:20310142  2008 - 2010

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    ISHIKAWA Yoshiharu, KAJI Koichi, TSUCHIYA Toshiyuki, FUKUSHIMA Tsukasa, HOSHINO Yoshinobu, YOSHIKAWA Masato, SAKAI Kenshi, TODA Hiroto, IWAOKA Masahiro, CHE Donsu, WATANABE Naoaki, SHIRAKI Katsushige, GOMI Takashi, KOGANEZAWA Masaaki

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    Authorship:Coinvestigator(s) 

    Levels (high, medium, low, and slight) for evaluating the influence by feeding of deer on ecosystem and limits of acceptable were set concerning several indices ; understory (change of species, density, percentage of flowering, height of bamboo grass, density of bamboo grass), organism and chemical property (soil small animal, soil respiration, amount of soil organic matter), physical property and erosion (forest floor cover percentage, amount of soil erosion ) and forest damage (damage by peeling) etc.. The developed "Ecological Limits of Acceptable Change (ELAC)" will be used for appropriate management of deer density in natural parks.

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Teaching Experience (On-campus) 2

  1. 生物圏環境学

    2022

  2. 森林環境学特論

    2022

Teaching Experience (Off-campus) 17

  1. リモートセンシング論

    2008.4 - 2022.9 Tokyo University of Agriculture and Technology)

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    Level:Undergraduate (specialized)  Country:Japan

  2. Forest Ecology and Management

    2015.10 - 2022.3 Tokyo Gakugei University)

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    Level:Undergraduate (specialized)  Country:Japan

  3. 山地保全学

    2008.4 Tokyo University of Agriculture and Technology)

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    Level:Undergraduate (specialized)  Country:Japan

  4. 地域環境計画学

    2008.4 - 2018.9 Tokyo University of Agriculture and Technology)

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    Level:Postgraduate  Country:Japan

  5. 国際イノベーション農学概論Ⅰ

    2019.4 - 2022.9 Tokyo University of Agriculture and Technology)

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    Level:Postgraduate  Country:Japan

  6. 論文レビュー特別演習Ⅰ〜Ⅱ

    2019.4 - 2022.9 Tokyo University of Agriculture and Technology)

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    Level:Postgraduate  Country:Japan

  7. 農学特別演習Ⅰ〜Ⅱ

    2019.4 - 2022.9 Tokyo University of Agriculture and Technology)

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    Level:Postgraduate  Country:Japan

  8. 農学展開研究Ⅰ〜Ⅱ

    2019.4 - 2022.9 Tokyo University of Agriculture and Technology)

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    Level:Postgraduate  Country:Japan

  9. 農学特別演習Ⅰ

    2019.4 - 2022.9 Tokyo University of Agriculture and Technology)

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    Level:Postgraduate  Country:Japan

  10. 農学特別研究Ⅰ

    2019.4 - 2022.9 Tokyo University of Agriculture and Technology)

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    Level:Postgraduate  Country:Japan

  11. 21世紀農学特論

    2019.4 - 2022.9 Tokyo University of Agriculture and Technology)

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    Country:Japan

  12. 地域生態システム学Ⅰ

    2015.4 - 2022.9 Tokyo University of Agriculture and Technology)

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    Level:Undergraduate (specialized)  Country:Japan

  13. 河川生態論

    2009.10 - 2015.3 Tokyo University of Agriculture and Technology)

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    Level:Undergraduate (specialized)  Country:Japan

  14. 山地保全砂防実習

    2009.4 - 2022.9 Tokyo University of Agriculture and Technology)

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    Level:Undergraduate (specialized)  Country:Japan

  15. フィールド/ラボ安全管理と研究倫理

    2009.4 - 2022.9 Tokyo University of Agriculture and Technology)

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    Level:Postgraduate  Country:Japan

  16. 国際環境農学概論

    2008.10 - 2021.3 Tokyo University of Agriculture and Technology)

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    Level:Undergraduate (specialized)  Country:Japan

  17. 国際環境農学課題別演習

    2008.4 - 2018.9 Tokyo University of Agriculture and Technology)

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    Level:Postgraduate  Country:Japan

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Social Contribution 1

  1. 令和5年度環境影響評価研修

    Role(s):Lecturer

    環境省  2024.2