Journal of the Japan Society of Erosion Control Engineering, Vol.62,No.2,2009

Hydraulic model tests for evaluating sediment control function with grid]type high dam

Shigeo HORIUCHI, Jun]ichi AKANUMA, Kazuhiko OGAWA, Senro KURAOKA,@@
Minoru SUGIYAMA, Takenori MORITA, Takahiro ITOH and Takahisa MIZUYAMA


Abstract

Much of the experimental and numerical research on sediment control by open]type check dams tries to take into account the continuity of sediment routing from upstream to downstream reaches of the river basin. For example, the minimum grid size of the grid]type check dam, which is a type of open]type check dam, can be experimentally set to dXT of sediment, which is based on the size distribution of bed material and flume data as determined for a straight, open channel.
In the case of a high check dam constructed in a curved ravine, the effects of curved flow and bar formation on sediment deposition in the storage area are supposed to be significant. A plan for constructing grid]type check dam with heights around 20 m can be newly proposed in a basin. In the main river with a reservoir in a basin at the downstream reach, previous heavy rainfall events may result in a huge amount of sediment deposited in the upstream reach through numerous torrents. Sediment transportation should be controlled to prevent huge amounts of sediment from moving to downstream reaches. Additionally, the main flow has many curved reaches. Therefore, sediment load passing through check dams in flash floods should be reduced as much as possible and, however, higher amounts of sediment should be transported in small sized floods.
Present study discusses preliminarily the effects of bed configuration on sediment control function in a check dam using experimental data obtained by hydraulic model tests such as sediment runoff rate from check dam, bars induced channel shifting, longitudinal and cross sectional bed profiles, temporal changes of mean diameter and sediment concentration passing through the check dam.

Key wordsFgrid]type high dam, debris flow, hydraulic model test, channel shifting


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