Temporal-Spatial Variation of Sediment and Vegetation on Sand and Gravel Beach Located Between Inner Bay and Open Sea

In this study, to clarify the temporal-spatial variation of the median grain size on the surface of the sand and gravel beach and its topography change, field observation, spatial analysis and laboratory experiment were carried out. Study site is the east coast beach in the Narugashima Island located between inner bay - Osaka bay - and open sea - Kii channel -. The result of field observation makes it clear that the temporal-spatial variation of the median grain size on the beach is decided by wave, tide and seasonal wind. The result of the spatial analysis shows that the continuity of bed material on the beach in the direction of longshore is more apparent than that of on-offshore. Moreover, the effect of decreasing the blown sand by vegetation on the beach was confirmed in both field observation and laboratory experiment.