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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)河床长期变化分析：以日本四国吉野河为例，建立了近40年的河床几何数据库。单项测量的横断面形状用固定的101个点表示。利用经验正交函数法对地貌过程进行了分析。2)植被和水文地貌河流调查与分析：对纳卡河和吉野河进行了广泛的泥沙坝植被调查。此外，参考航拍照片还观察到了河流植被的定殖成功。3)交替沙洲网状植被图的数字复制：通过实地调查，借助低空摄影技术，制作了吉野河下游形成的交替沙洲的详细网状植被图。应用偏好曲线模型和神经网络模型，根据自然生境属性判断网状区的优势植被类型。4)河床变化模拟模型的改进：从实验上阐明了植被区水流悬沙的机理，并建立了相应的模拟模型。此外，基于数值模拟，对混合沙的自生河流和交替沙洲的特性进行了研究。