| Project/Area Number |
11660157
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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 |
林学
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| Research Institution | Toyama Prefectural University, College of Technology |
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Principal Investigator |
TAKAHASHI Goichiro Toyama Prefectural University, College of Technology, Section of Agricultural Engineering, Associate Professor, 農業技術学科, 助教授 (40163258)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 2000: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1999: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | riffle-pool structure / stream geomorphology / stream environment / nonparametric test / channel work / 魚道 |
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| Research Abstract |
This research aimed for 1) clarifying characteristics of riffle-pool structure and 2) evaluating near-nature channel works and finding improving points of the channel works.
For the research of the first point, Tahakashi's classification of channel unit was applied. At first, the classification system was made clear to be rational, and method for comparing riffle-pool structure among streams was developed by using standardized unit length and unit gradient. In the comparison of riffle-pool structure, nonparametric test was confirmed to be available. With these sets of analisys procedure, characteristics of riffle-pool structure were examined in several streams. Significance tests were carried out to all combinations between four natsural streams, with the result that the Ayumanai River was determined to be different from the other three streams. The result corresponded well to a comparison based on an impression of the landscape. Another analysis in a mountain stream which had a big source of much bed material load in the middle of the research site showed that lots of bed material load did not develope pool formation enough.
Near-nature channel works represented riffle pool sequence compared with the traditional channel works which made stream morpholoby thoroughly shallow. In this context, the nea-nature channel works would contribute to conservation of the stream environment. However, the near-nature channel works was different from natural streams as far as the function and structure of the stream environment was concerned. The channel works inevitably fixed the stream bed and bank more or less. Processes of riffles and pools in natural stream depends on erosion and sedimentation in channels. In order to incorporate conservation of the stream environment, development of a new type of channel works which al low dynamic change of stream bed including erosion and sedimentaion is needed.
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