Sediment Monitoring in Sakiyama and Amitori Bays

This chapter focuses on a technique for directly measuring suspended sediment or directly collecting coastal sediment for analysis. Simple and low-cost techniques employing sediment traps using a polyvinyl chloride pipe to capture suspended sediment and a handheld analyzer for X-ray fluorescent analysis and a digital scanner for image analysis were employed for sediment measurement and analysis. In laboratory experiments, the sediment catch performance of a cylindrical sediment trap was evaluated according to differences in the intake and outlet sizes. The characteristics of the measurement principle of the X-ray fluorescence analysis were described. Furthermore, a technique for digital image analysis that can estimate sediment diameter was constructed. In addition, color measurements using the CIE L* a* b* color space system ascertained sediment color characteristics. Next, these measurement and analysis techniques were applied to sediment monitoring in the Sakiyama and Amitori bays. Fine sediment was captured in the sediment traps. The element content of the coastal sediment from multiple points within the bays and their spatial distributions obtained through X-ray fluorescence analysis were ascertained. The color, diameter, and chemical composition of the sediments were classified using clustering analysis, and the distribution of the cluster within the bays matched the topographical features.