2002 Fiscal Year Final Research Report Summary
Influence of the construction of Nagaragawa Barrage on habitats and ecosystems in the estuary
| Project/Area Number |
13305035
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Civil and environmental engineering
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| Research Institution | Kanazawa University (2002)
The University of Tokyo (2001) |
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Principal Investigator |
TAMAI Nobuyuki Kanazawa University, Dept, of Civil Eng., Prof., 工学部, 教授 (90010818)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEMON Yasuhiro Kyoto Univ., Water Resources Center, Disaster Prevention Research Institute, Assoc. Prof., 防災研究所水資源研究センター, 助教授 (50222104)
FUJITA Yuichiro Gifu Univ., River Basin Science Center, Prof., 流域圏科学研究センタ, 教授 (90027285)
ARITA Masamitsu Tokyo Denki Univ., Faculty of Science and Engineering, Prof., 理工学部, 教授 (90130294)
YAMAUCHI Katsusuke Gifu Univ., Faculty of Education, Prof., 教育学部, 教授 (30021322)
MURAKAMI Tetuo Nagoya Women's Univ., Faculty of Domestic Science, Assoc, Prof., 家政学部, 助教授 (50329695)
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| Project Period (FY) |
2001 – 2002
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| Keywords | Nagaragawa Barrage / stratification / post construction monitoring / chrolophil concentration / fine organic material / brook type fishway / planktonic algae |
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| Research Abstract |
Major results obtained by this research group are summarized as follows.
1) Exhaustive study both on five-year monitoring data and other existing field data clarified a present situation that the upstream of the Barrage is fresh water zone and the downstream of the Barrage is sea water zone with no blackish zone. Salinity distribution downstream of the Barrage changed from mixed type to fully mixed type almost all days through a year.
2) Recorded total number of fish species is 94 within which 16 species disappeared and 19 species appeared newly during 1994 through 1999. Altered ratio of fish species amounted to 37% and especially blackish species were affected greatly to disappear.
3) A major component that governs the dissolved oxygen concentration in an estuary is a tidal cycle with disturbance of floods. Large floods recover DO concentration but bring about low DO conditions after floods by the intrusion of anoxic water body from Ise Bay.
4) Complete mixing including the bottom water did not occur every day, maintaing temporary thermal stratification for a few days in summer. Judging from the rapid oxygen consumption rate by the water column, such temporary thermal stratifications could cause frequent oxygen deficits in the impoundment of the Barrage in summer.
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