Disturbance and recovery of riparian and fresh water ecosystem caused by sediment transport associated with flood events

洪水事件引起的泥沙输送对河岸和淡水生态系统的干扰和恢复

• 批准号: 09460071
• 负责人: MARUTANI Tomomi
• 金额: $ 6.27万
• 依托单位: KYUSHU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09460071/
• 关键词: Flooding; Magnitude of disturbance; Recurrence interval; Relaxation time; Bank erosion; Rock size distribution; Sediment production; Sediment storage; 河岸浸食; 河床堆積土砂; バンクエローション; 支流流域; セデイメントバジェット; 河床変動; 生産土砂量; 河畔生態系; 水中生態系; 河岸崩壊; Bank Eros

Based on three years observation for morphological riverbed changes and sediment transport, the factors disturbing riparian and freshwater ecosystems were analyzed. Rainfall, runoff, sediment storage volume, sediment production volume, bank erosion rate, suspended sediment volume and rock size distribution along the drainage net were measured at the Oyabu creek of a headwater of the Hitotsuse River located in the middle mountain range of Kyushu island, Japan. The following results were gained.(1) Sediment accumulated after a flood event trended to restore sediment storage volume to the minimum value (4000mィイD13ィエD1/km) with time elapse. (2) Sediment slug associated with riverbed degradations was occurred with 2.65m/day in velocity and that with riverbed aggradations was occurred with 4.6m/day in velocity respectively. (3) The volume of sediment supply from tributary channels decreased exponentially against time elapse. (4) Rock size distribution along a channel related with macroscopically the distance from sediment production source, and slope and catchment area of significant tributaries (slope<0.15, area>10ha) joined with main channel. (5) Bank erosion rate of the upper channel (8m in averaged channel width) of the Oyabu creek was 10cm/year.These results imply that the recovery of riparian and freshwater ecosystems is likely to be controlled by magnitude of riverbed aggradation, frequency of flooring as the recurrence interval and the time lapse after flood event. Furthermore rock size distribution along drainage net can influence on the relaxation time of ecological property of fresh water.

根据3年的河床形态变化和泥沙输移观测资料，分析了影响河岸带和淡水生态系统的主要因素。在日本九州岛中山区一津濑川上游的大薮溪，测定了降雨量、径流量、输沙量、产沙量、河岸侵蚀率、悬沙量和沿着排水网的岩石粒径分布。获得了以下结果。(1)随着时间的推移，洪水后的泥沙淤积量有恢复到最小值（4000 m × 13 × 104 D1/km）的趋势。(2)与河床冲淤有关的泥沙段塞流速为2.65m/d，与河床冲淤有关的泥沙段塞流速为4.6m/d。(3)支流输沙量随时间呈指数下降。(4)沿河道的岩石粒度分布沿着与宏观上距产沙源的距离、与主河道相连的重要支流（坡度<0.15，面积> 10 ha）的坡度和集水面积有关。(5)结果表明，大薮河上游河道（平均宽度为8 m）的河岸侵蚀速率为10 cm/a，河岸生态系统和淡水生态系统的恢复可能受河床淤积量、河床底质发生频率和洪水发生后的时间间隔的控制。此外，岩石粒径分布沿着排水网对淡水生态特性的弛豫时间也有影响。

项目成果

中村純也: "一ッ瀬川源流大藪川における1997年洪水直後の堆積砂礫経の特徴"九大農学芸誌. 53(1,4). 65-70 (1999)

Junya Nakamura：“1997 年一之濑河源头 Oyabu 河发生洪水后的砾石沉积特征”九州大学农业科学杂志 53(1,4) (1999)。

丸谷知己: "崩壊地を含む小面積流域における流出土砂量"砂防学会誌. 52(6). 24-31 (2000)

Tomomi Marutani：“包括塌陷区域的小盆地中的沉积物径流”，日本侵蚀控制学会杂志 52（6）（2000 年）。

Mio Kasai: "Estimation of temporally averaged sediment delivery ratio using aggradational terraces in headwater catchments of the Waipaoa River, North Island, New Zealand"Earth Surf. Processes and Landforms. (in press). (2000)

Mio Kasai：“利用新西兰北岛 Waipaoa 河源头集水区的沉积阶地估算时间平均沉积物输送率”Earth Surf。

Tomomi Marutani: "Sediment generation from numerous shallow landslides relatedslides with clear cutting at Granite Mountain,Mt,Ichifusa,Japan"(in press). (2000)

Tomomi Marutani：“日本一房山花岗岩山与皆伐相关的大量浅层滑坡产生的沉积物”（正在出版）。

Tomomi Marutani: "Sediment generation from numerous shallow landslides related with clear cutting at Granite Mountain, Mt. Ichifusa, Japan"Proc. Interpraevent. (in press). (2000)

Tomomi Marutani：“日本一房山花岗岩山与皆伐相关的大量浅层滑坡产生的沉积物”Proc。