Hydraulic model tests on hastening and control of sediment runoff for various open-type sabo dams

Takahiro ITOH, Takahiko NAGAYAMA and Takahisa MIZUYAMA

There are two kinds of sabo dam such as open]type and close]type, and especially several kinds of dams for open|type dam have been proposed taking into account continuity of water flow and sediment runoff. Sedimentation by sabo dam such as sediment control function is usually examined using hydraulic model tests, because hydrostatic pressure distribution is always not satisfied near open parts in a storage area of the dam in case of open]type sabo dam. However, the sediment control function and the effect of sediment runoff on bed variation is not fully discussed for open]type sabo dam. In present study, hydraulic model tests are conducted for several kinds of open]type dam, and, for some examples, we will introduce the sediment control function and the temporal change of bed variation along the river channel. Additionally, hydraulic characteristics near open parts of sabo dam are shown such as vertical distributions of pressure and velocity, longitudinal of free surface and flow patterns.