Sediment Transport in the Field Swash Zone for a Tide Cycle

Field data observed continuously with sampling frequency of 5Hz over two years by many wave (and bottom) gages in the swash zone are analyzed. The bottom heights measured by the gages at low tides are used to evaluate the sediment transport rate in the swash zone between the tides. Relationship among the direction of the transport, the bottom profile (the slope in the swash zone) and the waves is studied. When employing offshore wave information given by NOWPHAS, Sunamura's C parameter does not show any tendency but larger wave height is likely to correspond to offshore sand transport. Local waves measured in the inner surf zone do not give any indication for the direction of transport either. Finally, waves measured in the swash zone show that offshore transport is observed for the waves of low wave steepness.