Effects of Riparian Forest on Disaster Prevention andPreservation of Natural Environments

河岸森林的防灾和自然环境保护作用

• 批准号: 10660152
• 负责人: MIZUHARA Kunio
• 金额: $ 2.05万
• 依托单位: Kyoto Prefectural University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10660152/
• 关键词: riparian forest; vegetated channel; flow resistance; bed-load transport; effective tractive force; roughness concentration; stream bank erosion; promoting deposition of debris; 河川環境; 防災; 減勢効果; 浸食速度; 抵抗測

We have investigated about 5 subjects, targeting the riparian forest where plays an important role to the environment fromation of mountainous region. A general outline of each study is explained in the following.(1) Flow resistance in woody vegetated channels with low forestCharacteristics of flow resistance in woody vegetated channels was studies by hydraulic model experiments. With the vegetated roughness concentration, the ratio of flow depth increased in an exponentially manner, wheras the ratio of glow velocity decreased in a similar manner. Flow velocity uniformity was established in cases of high roughness cocentration. Equations for calculating friction factor were proposed.(2) Bed-load sediment transport in woody vegetated channelsBed-load sediment transport rate in woody vegetated channels was studied by hydraulic model experiments. As the roughness concentration of trees in channels increased, the bed-load sediment transport rate decreased. Then, the necessity of taking add … More ount of effective tractive force was recongnized. Eqations for calculation effective tractive force were proposed.(3) Effect of density of trees on drag exerted on trees in river channelsDrag exerted on trees with defferent tree densty along straight channels was measured using by hydraulic experiments. Test results indicated that the drag varies greatly with the dencity of trees × flow depth and they were correlated with te drag coefficient of velocity. Equations were obtained for deriving the drag coefficient.(4) Characteristics of stream bank erosion in woody vegetated channelsCharacteristics of stream bank erosion in woody vegetated channels was studies by hydraulic model experiments. While erosion rate of stream bed decreased, erosion rate of stream bank did not always decrease in woody vegetated channels. Especially, at the edge of water, increasing of erosion rate was found according to circumstances.(5) Actual conditions of promoting deposition of debris caused by debris avalanches by forest zonesA number of debris avalanches occurred in southern Fukushima Prefecture in August 1998 was studiesd for the purpose of examining the functionality of forest zones for promoting deposition of debris caused by debris avalanches using aerial photo interpretation and topographic analysis. The functionality of forest zones for promoting debris deposition was confirmed. Less

针对对山地环境形成起重要作用的河岸林，进行了5个课题的调查。每项研究的概要说明如下。(1)低林下有木本植物的河道水流阻力通过水工模型试验，研究了有木本植物的河道水流阻力特性。随着植被粗糙度的增加，水流深度比呈指数增加，而辉光流速比呈指数下降。在高粗糙度浓度的情况下，建立流速均匀性。提出了摩擦系数的计算公式。(2)通过水工模型试验，研究了有木本植物的河道推移质输沙率。随着河道树木糙率的增加，推移质输沙率减小。那么，采取加法的必要性 ...更多信息 对有效牵引力的计算进行了认识。提出了有效牵引力的计算公式。(3)树木密度对河道内树木阻力的影响通过水力学试验，测量了不同树木密度的树木沿沿着河道的阻力。试验结果表明，阻力随树木密度×水深的变化规律很大，并与流速阻力系数有关。得到了计算阻力系数的公式。(4)通过水工模型试验，研究了木本植物河道的河岸侵蚀特性。当河床侵蚀速率降低时，河岸侵蚀速率并不总是降低。特别是在水边，侵蚀速率随环境的变化而增大。(5)1998年8月发生在福岛县南部的一系列泥石流被研究，目的是利用航空照片判读和地形分析来检查林区促进泥石流堆积的功能。森林地带促进碎片沉积的功能得到确认。少

项目成果

S. Hiramatu, Y. Ishikawa, N. Osanai and I. Miyoshi: "Report of Sediment-related Disaster on June 29, 1999 in Nishiyama Village Tokushima Prefecture, Japan (Prompt Report)"Journal of Japan Society of Erosion Control Enginering. Vol. 52 No. 3. 44-49 (1999)

S. Hiramatu、Y. Ishikawa、N. Osanai 和 I. Miyoshi：“1999 年 6 月 29 日日本德岛县西山村泥沙灾害报告（即时报告）”日本侵蚀控制工程学会杂志。

Yoshiharu Ishikawa, Toyokazu Sakamoto and Kunio Mizuhara: "Effect of Density of Riparian Trees on Effective Tractive Force"Journal of Forest Research (in contribution).

Yoshiharu Ishikawa、Toyokazu Sakamoto 和 Kunio Mizuhara：“河岸树木密度对有效牵引力的影响”森林研究杂志（投稿中）。

平松晋也、石川芳治、小山内信智、三好岩生: "1999年6月29日徳島県西祖谷山村で発生した土砂災害(速報)"砂防学会誌. 52(3). 44-49 (1999)

Shinya Hiramatsu、Yoshiharu Ishikawa、Nobutomo Koyamauchi、Iwao Miyoshi：“1999 年 6 月 29 日德岛县西谷山村滑坡灾害（突发新闻）”日本侵蚀控制学会杂志 52(3)。 1999）

Y.Ishikawa, K.Mizuhara, S.Ashida: "Effect of Density of Trees on Drag Exerted on Trees in River Channels"Journal of Forest Research. 5. 271-279 (2000)

Y.Ishikawa、K.Mizuhara、S.Ashida：“树木密度对河道树木阻力的影响”森林研究杂志。

Yoshiharu Ishikawa: "Damage to Forests by Sediment Movements and Control of Sediment Movements by Forests"INTERPRAEVENT 2000. Band 3. 191-199 (2000)

Yoshiharu Ishikawa：“沉积物运动对森林的损害以及森林对沉积物运动的控制”INTERPRAEVENT 2000. Band 3. 191-199 (2000)