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Interrelation between hydrogeomorphic and vegetative processes in rivers.

河流水文地貌和植物过程之间的相互关系。

基本信息

批准号：
11650531
负责人：
OKABE Takeshi
金额：
$ 2.18万
依托单位：
The University of Tokushima
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11650531/
关键词：
river morphology alternate bar tidal flat river bed variation plant community colonization success sediment transport data base 河床変動計算浮遊砂濃度 GISデータベース河床変動計算法乱流モデル植生分布・動態モデル流砂量

项目摘要

1) Analysis of long-term riverbed variation : Regard to the Yoshino River, Shikoku, Japan, a data base of riverbed geometry was composed, with respect to the past 40 years. The cross-sectional shapes of individual measuring were represented by fixed 101 points. The geomorphic process was analised with the aid of empirical orthogonal function method. As a result, remarkable bed aggradation was observed and its major modes were identified.2) Vegetative and hydro-geomorphic river survey and analysis : Regarding to the Naka and Yoshino River, vegetation survey on sediment bars was were widely carried out. In addition, colonization success of riverine vegetation was observed referring to aerial photographs. Colonization traits were quantitatively related to historical hydro-geomorphic conditions of the reivers.3) Numerical reproduction of meshed vegetation maps of alternate bars : Detailed meshed vegetation maps of alternate bars formed in a downstream reach of the Yoshino River were produced by field surveys with the aid of an low aerial photography technique. A preference curve model and a neural network model were applied to judge dominant vegetation types of mesh areas from physical habitat attributes. The both models showed similar accuracy of slightly higher and lower than 70 %, however, significant difference was found in the resultant maps.4) Improvement of simulation model for riverbed variation : Mechanism of sediment suspension in flows passing vegetated areas was experimentally clarified, and its simulation model was developed. In addition, characteristics of self-formed streams and alternate bars of mixed sediment were investigated based on numerical simulation.

1)长期河床变化分析：以日本四国吉野川为例，建立了近40年来的河床形态数据库。个体测量的横截面形状由固定的101个点表示。本文用经验正交函数法对地貌过程进行了分析。2）植被和水文地貌调查与分析：针对纳卡河和吉野河，广泛开展了沉积物沙洲的植被调查。此外，参照航空照片，观察到河边植被的殖民化成功。定殖特征与河流的历史水文地貌条件定量相关。3）交错沙洲网格植被图的数值复制：通过野外调查，借助低空航空摄影技术，制作了吉野川下游形成的交错沙洲详细的网格植被图。应用偏好曲线模型和神经网络模型，从生境物理属性判断网格区域的优势植被类型。结果表明，两种模型的计算精度均略高于70%和低于70%，但计算结果存在显著差异。4）河床演变模拟模型的改进：通过试验研究，阐明了水流在植被覆盖区的悬沙机理，建立了河床演变模拟模型。此外，还通过数值模拟研究了混合沙的自生流和交错沙坝特征。