SPATIAL DISTRIBUTION OF SAND RIPPLES ON A TIDAL FLAT

Abstract

 The existence of sand ripples on tidal flats is closely related to sediment movement and topographic changes. In this study, a UAV photograph of a tidal flat called Higashi-hazu tidal flat in Nishio City, Aichi Prefecture in Mikawa Bay was conducted to investigate the sand ripple characteristics by using image analysis based on luminance information of the obtained images. Based on the results, the sand ripple formation area was revealed and the relationship between the sand ripple direction and topography was analyzed. As a result, it was confirmed that the ripple direction can be detected with high accuracy by using the luminance information. Furthermore, by visualizing the ripple directions in the entire tidal flat, it was clarified that the normal direction of the contour line of the tidal flat and the sand ripple direction coincided to some extent. It was reconfirmed that investigation and analysis focused on sand ripples led to the estimation of topographic changes on tidal flat.