On the hydraulic and environmental functions of flood defense woods.

防洪林的水力与环境功能研究.

基本信息

批准号：
07455197
负责人：
FUKUOKA Shoji
金额：
$ 5.12万
依托单位：
HIROSHIMA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07455197/
关键词：
flood defense woods meandering phase sift groin cut flood control flood channel main channel 蛇行流路洪水流水面変動河床変動

项目摘要

The flood defense woods were planted and has been preserved because the house and the field along the riverside are defended from the flood damage. Recently, because the tree clusters in the river channel cause the resistance of flows, The flood defense woods was deforested for the flood control. To maintain an excellent river environment, the effect on the leaving method and the flood control of the woods was examined. The effect of the trees changes depending on the arrangement of the tree clusters to the shape of the river channel, depth on the flood channel, and the velocity of the flow in the main channel. The bed topography of river changes due to the flow which is influenced by flood defense woods. A plane structure of the flow between a flood channel and the main channel was clarified in this research. The exchange of the current is caused between the flood channel and the main channel in a compound meandering channel. In addition, flood flow are controlled by the flood control woods along river bank. A numerical model by which such flow fields were able to be explained enough was developed. It was shown to be able to analyze the flow of the compound meandering channel seen in the actual river by using this model. If the flood defense woods are deforested, high velocity is caused in that part. As a result, it has been understood that the flood control woods around damaged part may be lost due to flow if the part where were damaged is covered by a bank protection made of blocks. On the other hand, when a part of the flood defense woods was deforested, the flow velocity of the rive bank neighborhood is decreased and the secondary current in the outer bank are weaken. It is shown that there is a necessity for evaluating the value of the flood defense woods overall including such an effect of the flood control in the future.

种植并保留了防洪林，是为了保护河边的房屋和田地免受洪水的破坏。近期，由于河道内树木丛生，造成水流阻力，防洪林被砍伐以防洪。为了保持良好的河流环境，检查了对森林的离开方法和防洪的影响。树木的影响取决于树丛的排列对河道形状、洪水河道的深度以及主河道中的水流速度的影响。河流的河床地形因水流受防洪林的影响而发生变化。本研究阐明了洪水河道和主河道之间水流的平面结构。复合曲流河道中，洪水河道与主河道之间发生水流交换。此外，河岸防洪林也控制了洪水流量。开发了一个能够充分解释这种流场的数值模型。事实证明，利用该模型能够分析实际河流中看到的复合曲流河道的流量。如果防洪林被砍伐，该部分就会产生高流速。因此，据了解，如果受损部分用块状护岸覆盖，受损部分周围的防洪树林可能会因水流而消失。另一方面，当部分防洪林被砍伐时，河岸附近的流速降低，外岸二次流减弱。表明有必要对防洪林的整体价值进行评价，包括未来的防洪效果。