2004 Fiscal Year Final Research Report Summary
Study on the morphological equilibrium condition on river mouths and tidal inlets
| Project/Area Number |
14550506
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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 | Tohoku University |
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Principal Investigator |
MANO Akira Tohoku University, Graduate school of engineering, Professor, 大学院・工学研究科, 教授 (50111258)
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| Project Period (FY) |
2002 – 2004
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| Keywords | river mouths / morphological equilibrium / tidal inlets / littoral drift / tidal current / river flow |
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| Research Abstract |
River mouths and tidal inlets in sandy beaches develop sand spits by trapping littoral drift. Since narrowing of the channels often causes obstruction of flood passage or navigation, appropriate control of the channels is one of the important subjects in coastal management. The aim of this study is to find the universal condition of the morphology equilibrium for the channels in order to serve the management.
Morphological development is quantified by the sediment budget with the sediment supply from littoral drift and sediment removal by river and tidal flows. The equilibrium condition is theoretically derived as the balance of the supply and removal and is equivalent with the stationary condition of the morphology. The dimensionless channel width in equilibrium is expressed as a function of two dimensionless parameters, Φ_R and Φ_T which proportional to the relative importance of the sediment removals by the fiver flows and tidal flows to the sediment supply respectively.
This equilibrium condition on the river mouths is verified by the field data. The Indonesian rivers, Opac, Serayu, Wawar, Tipar, and Bogowanot, which all face the Indian Ocean in the south coast of Jawa Island and prone to close in the dry season for the high wave, were examined. Six major rivers in Japan were also examined.
The condition was also examined for the tidal inlets in the Pacific, Atlantic and Gulf coasts in USA. The equilibrium condition derived here is shown to be universal and to unify the river mouths and tidal inlets.
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Research Products
(8 results)
