2003 Fiscal Year Final Research Report Summary
FLOW STRUCTURES DETERMINING RIVER LEVEL IN AN ESTUARY
| Project/Area Number |
13450199
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | Hokkaido University |
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Principal Investigator |
YOSHIDA Shizuo Hokkaido Univ., Grad. School of Eng., Asso. Prof., 大学院・工学研究科, 助教授 (30001324)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIDA Shuzo Osaka Univ., Grad. School of Eng., Asso. Prof., 大学院・工学研究科, 助教授 (40172663)
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| Project Period (FY) |
2001 – 2003
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| Keywords | ESUTURY / WATER LEVEL / WIND STRESS / TIDE / RIVER DISCHARGE / ATMOSPHERIC PRESSURE / SALT WEDDGE / H-Q CURVE |
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| Research Abstract |
It is essential to find the correct relationship between flow rate and river level in order to have information about the flow rate during flood and about uses of the river water like agriculture and hydroelectric generation. Normally, the river flow rate is assumed to be given by the level through the empirical H-Q equation, where H is the water level (height) and Q is the flowrate, but during drought, it becomes extremely more difficult to apply this expression to the estuary than to locations upstream. This is because the river level can take a large range of values under the influence of the four key factors of tide, atmospheric pressure, wind direction and wind speed. In this study, it was attempted to derive a method for quantitative estimation of the effects of tide, atmospheric pressure, wind direction and wind speed on flowrate in the estuary of the Ishikari River, where these four factors dramatically lower the correlation between water level (H) and river flowrate (Q). It was found that the effect of tide and atmospheric pressure on sea level is almost exactly reflected in the fluctuations of river level. Data from observations of river level under windless conditions and steady river flowrate allowed application of empirical rules for river rise due purely to flowrate, providing a quantitative estimate of the relation between wind and river behavior. Next, the flowrate was estimated at a certain location using the obtained quantitative relation between the four factors and river level, and this was found to be nearly identical to the observed flowrate. This confirmed the practical validity of this study.
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Research Products
(10 results)
