Field observations on bottom profile and vertical distributions of sediment for the modelling of sediment transpotation process

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Both quantitative and qualitative aspects of sediment distribution would be recognized to play an important role for proper management in a coastal zone.In this research, some field observations below have been conducted in Joetsu-Ogata coast, Japan since 2009 in order to investigate sediment distribution in the cross-shore direction and the cross-section.1. bottom profile measurement by GPS sounder, 2. sediment sampling(on the bottom surface), 3. sampling of boring coresMain results are as follows1. only fine sand deposits offshore of the bar2. layered structure observes in some sample and the depth of the structure is around less than 1m3. coarse and very coarse sand exist in the core sample close to the shore line4. very coarse sand and clay layer in the trough. The layered structure would be the consequence of mixing process by the most recent high-wave conditions. The vertical distributions of sediment show both the qualitative information of existing sediment and the mixing history by the external forces.