2000 Fiscal Year Final Research Report Summary
Study on Water Quality Dynamics in Up-and Down-steam region of Estuary Barrage Concerned with Its Operation
| Project/Area Number |
10650514
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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 | Chubu University |
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Principal Investigator |
MATSUO Naoki Chubu University, college of Engineering, Professor, 工学部, 教授 (20093312)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEDA Makoto Chubu University, college of Engineering, Lecturer, 工学部, 講師 (50298486)
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| Project Period (FY) |
1998 – 2000
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| Keywords | Estuary Barrage / Characteristics of Water Quality / Monitoring / Chlorophyll-a / DO / Quantification Theory / Numerical Analysis |
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| Research Abstract |
The study to estimate water quality characteristics in up-stream area of Nagara River Estuary Barrage has been done based on statistical analysis of "Nagaragawa Estuary Barrage Monitoring Data". First, spectra of chlorophyll-a and DO data are evaluated by means of FFT(First Fourier Transform). Chlorophyll-a data have fluctuation component of about 10 day period affected by flood inflow in addition to fluctuation components of seasonal period and day period. Secondly, governing factors of chlorophyll-a and DO and their characteristics are investigated by means of Quantification Theory I. It is found that water temperature and growth of thermal stratification are the most important factors for the absolute value of chlorophyll-a and DO, though the governing factors seasonally change.
Flow characteristics in downstream area of the Nagara River Etuary Barrage are estimated by means of observed data obtained from ADCP(Acoustic Doppler Current Profilers) and observation plane for water qualit
… More
y. The flow in downstream area of the Nagara River Estuary Barrage in inflow of the tide is affected by the situation of density in mouth of river. In the case of existence of Low density water in mouth of river, the flow becomes two layer flow because of existence of high density water in bottom. In the case of existence of high density water in mouth of river, the flow get into deep area of river. In the case of the ebb tide, down stream flow pass upon high density water. This phenomena is concerned with decreasing of DO in downstream area of the estuary barrage. In the spring tide, inflow of the tide pass to the Ibi River because the water level in the area from the barrage to joint point with the Ibi River more rapid increase than the Ibi River.
Numerical Simulation of the flow and water quality in the upstream area of Nagara River Estuary Barrage has been done under real conditions in the summer seasons of 1995-1999. The results obtained from the simulations indicate that change of the river bed shape by dredge influence the flow characteristics, and that flow discharge, wind velocity and direction, gate operation at the barrage concern the temporal and spatial distribution of algae populations through the production and accumulation of them. In the numerical analysis of the flow and salt behavior in the down stream area of the barrage, the simulation results qualitatively represent their real behavior obtained from the observation. Less
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Research Products
(12 results)
