| Project/Area Number |
11650531
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
水工水理学
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| Research Institution | The University of Tokushima |
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Principal Investigator |
OKABE Takeshi The University of Tokushima, Fac. of Engineering, Prof., 工学部, 教授 (10035652)
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| Co-Investigator(Kenkyū-buntansha) |
KITANO Toshikazu Nagoya Industrial Univ., Fac. of Engineering, Lecturer, 工学部, 講師 (00284307)
KAMADA Mahito The University of Tokushima, Fac. of Engineering, Associate Prof., 工学部, 助教授 (40304547)
NAKANO Susumu The University of Tokushima, Fac. of Engineering, Associate Prof., 工学部, 助教授 (50198157)
TAKEBAYASHI Hiroshi The University of Tokushima, Fac. of Engineering, Assistant Prof., 工学部, 助手 (70325249)
YUUKI Toyokatsu Anan Technical College, Associate Prof., 助教授 (50158333)
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| Project Period (FY) |
1999 – 2001
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| Keywords | river morphology / alternate bar / tidal flat / river bed variation / plant community / colonization success / sediment transport / data base |
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| Research Abstract |
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.
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