Tsunamis generate a large amount of bed load and suspended load in shallow water region because of large tractive force and turbulence. The sediment transport causes serious damages in coastal region. Many various basic formulae have been proposed for sediment transport. In this study, a sand grain size is assumed to be dominant parameter for the difference among the formulae and a hydraulic experiment is conducted. The experiment uses a closed rectangular channel with a wavemaker. In the channel, there is movable bed section and sand of 0.166, 0.267 or 0.394 mm in median diameter is spread there. At the downstream end, two types of trap for sand are installed and sediment transport rate is measured. Finally, formulae for bed load and rising load are proposed. Both coefficients of the formulae vary with sand grain size.
