The Function of Flood Control by Vegetation in Stream

1995 Fiscal Year Final Research Report Summary

• Project/Area Number: 06680421
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: Natural disaster science
• Research Institution: University of Tsukuba
• Principal Investigator: AMADA Takaaki University of Tsukuba, Institute of Agricultual and Forest Engineering, Professor, 農林工学系, 教授 (80114031)
• Co-Investigator(Kenkyū-buntansha): ITOGA Lei Shinshu University, Faculty of Agricalture, Professor, 農学部, 教授 (40114037) ; ITO Taiichi University of Tsukuba, Institute of Agricultual and Forest Engineering, Lecturer, 農林工学系, 講師 (40175203)
• Project Period (FY): 1994 – 1995
• Keywords: non-uniform flow / flood flow / vegetation in stream / dead water zone / land utilization / function of flood control

Research Abstract

People's demands for nature seem to be on the increase in recent years. It is expected that the vegetation in stream have a function of sedimentation as they can be hydraulically regarded as a group of roughness, thus performing to reduce the velocity of flow.
However, the function of the flow resistance and sedimentation by vegetation has not been estimated yet.
The points of this study are as below.
1. Transition of the river bed utilization
2. Influence of the vegetation to fluctuation of river bed
3. Influence of the vegetation to flood control
It became clear that shear stress in the stream flow with vegetation can be estimated accurately.
As a result when the percentage of area occupied by vegetation is large, the coefficient of roughness increase and the fluctuatin of river bed is reduced.
Therefore it is understood that the vegetation has a function to fix river bed.