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A Method for Restoring the River Environment by Restoring Meanders

一种通过河曲恢复来恢复河流环境的方法

基本信息

批准号：
15360271
负责人：
WATANABE Yasuharu
金额：
$ 7.87万
依托单位：
Civil Engineering Research Institute of Hokkaido (CERI)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15360271/
关键词：
River environment Meandering Restoration Shibetsu River River channel variation Bent channel 2 Way channel Model of river channel variation Restoration 2way河道

项目摘要

Research was performed from 2003 to 2005 toward developing a method of reconnecting a cut-off meander on the Shibetsu River. Previous surveys at the test site showed that two-channel restoration in which the meander channel is reconnected while the straightened channel is maintained has promise with respect to flood control and environmental restoration. The findings are summarized here.1)In movable-bed hydraulic model tests to reproduce bank erosion at river channels where mid-scale sand waves occur, the most suitable bed materials were those low in specific gravity and viscosity.2)From field surveys, a method for studying the optimum channel centerline at the divergence and confluence of the two channels was developed based on the shapes of the restored channel and the straightened channel. When channel bifurcation is conducted, riverbed degradation at the confluence cannot be ignored.3)At riverbank locations of sharply redirected flow, cherry salmon were observed in higher population densities and more diverse age breakdowns when fallen trees were placed than when no fallen trees were placed. Such placing is expected to be effective in fostering a favorable habitat for fishes.4)By surveying the pollutant budget of the oxbow lake (the cut-off meander) and by constructing a model for estimating the water quality, the applicability of the model was confirmed. By developing a model for estimating the ground water level in wetlands, the effect of changes in river water level on changes in ground water level near the rivers were clarified.

从2003年到2005年进行了一项研究，旨在开发一种重新连接石别津河断流曲流的方法。以往对试验场的调查表明，在恢复曲流河道的同时保持直流河道的双通道修复在防洪和环境修复方面具有良好的前景。研究结果总结如下。(1)在重现中尺度沙波发生的河道侵蚀的动床水力模型试验中，最适合的河床材料是低比重和低粘度的材料。2)在野外调查的基础上，提出了以修复河道和理直河道形态为基础，研究两河道汇合处最佳河道中心线的方法。河道分岔时，汇合处的河床退化不容忽视。(3)在水流急转的河岸位置，有倒树的樱桃鲑鱼种群密度比没有倒树的樱桃鲑鱼种群密度高，年龄分布也更多样化。这样的放置预计将有效地为鱼类培育一个有利的栖息地。4)通过对牛轭湖（断流曲流）污染物收支的调查，建立了水质估算模型，验证了模型的适用性。通过建立湿地地下水位估算模型，阐明了河流水位变化对河流附近地下水位变化的影响。