Mechanisms of maintaining cobble-bar vegetation - focused on the intensity of disturbances and the refugia of the vegetation during large floods -

维持鹅卵石植被的机制 - 重点关注大洪水期间干扰的强度和植被的避难所 -

• 批准号: 23510298
• 负责人: ASAMI Kayo
• 金额: $ 2.25万
• 依托单位: University of Hyogo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2011
• 资助国家: 日本
• 起止时间: 2011 至 2013
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-23510298/
• 关键词: 礫原植生; カワラハハコ; 乱流シミュレーション法; 画像解析; 撹乱; 洪水; レフュージア; 掃流力; 生物多様性保全; 植生動態; LES; 礫原; 攪乱; LESシミュレーション

A vegetation monitoring study and a field survey using an image velocimetry of river flows as well as a fluid-dynamic numerical simulation have been conducted to find the effects of disturbances caused by floods of different intensities and return periods on a cobble-bar vegetation that is sustained by these disturbances. It has been found that there is an area near the downstream edge of a cobble bar where the bed shear force stays below the critical level required to move bed material and vegetation during very large flood events. This area coincided with the location where some vegetation actually survived large floods and served as a 'refugia'. Furthermore, it has been suggested that this special condition needed to maintain the cobble-bar vegetation is created by the morphologic characteristics of a sharp bend, a shortcut secondary channel and a bar with a steep-sloped downstream edge.

通过河流图像测速和流体动力学数值模拟进行了植被监测研究和实地调查，以找出不同强度和重现期的洪水对卵石坝植被造成的干扰的影响。受到这些干扰的持续。已经发现，在卵石坝下游边缘附近有一个区域，其中河床剪切力保持低于在特大洪水事件期间移动河床物质和植被所需的临界水平。该地区恰好是一些植被在大洪水中幸存下来并充当“避难所”的地方。此外，有人认为，维持卵石坝植被所需的特殊条件是由急弯、快捷的次河道和下游边缘陡峭的坝的形态特征造成的。

项目成果

Simulation of shallow water surface patterns with hemisphere roughness elements by large eddy simulation

大涡模拟半球粗糙度单元模拟浅水面形态

• 发表时间: 2012
• 作者: Fujita; I.; Okanishi; T.;Furutani; Y.
• 通讯作者: Y.

時空間ビデオ画像解析による揖保川洪水流シミュレーションの定量的評価

利用时空视频图像分析对伊博河洪水模拟进行定量评估

• 发表时间: 2014
• 作者: 熊野元気・藤田一郎・浅見佳世・中山昭彦・川谷健

揖保川中流カワラハハコ群落成立地の植生学的および水理学的考察

伊博河中游 Kawarahahako 社区建立的植被和水力考虑

• 发表时间: 2013
• 作者: 浅見佳世;中山昭彦;川谷健;藤田一郎
• 通讯作者: 藤田一郎

建設工学研究所HP 論文報告集第54号 平成24年11月29日発行

建设工程研究院 HP 论文报告集第 54 期 2012 年 11 月 29 日发布

Conditions of flood disturbances and refugia for conservation of cobble-bar vegetation

洪水扰动条件和卵石植被保护保护区

• 发表时间: 2014
• 作者: Asami; K.; Nakayama; A.; Kawatani; T.;Fujita; I.
• 通讯作者: I.