TRACKING NOURISHED SAND GRAINS ON THE ERODING TIDE-DOMINANT LOW ENERGY BEACH

摘要

Ultimate goal of this study is to understand how the nourished sediment behaves on eroding beach. Field nourishment experiment was carried out at the Murozumi coast in Yamaguchi prefecture, Japan. Besides beach nourishment, two different color sands, blue and green, were also placed as tracers. To enhance the temporal and spatial resolutions of the tracking survey of these color sands, this study aims to develop an image-based technique for estimation of the rate of color sand grains from the on-site images of the beach sand surface, directly captured and recorded by a GPS digital camera. Validity of the newly developed image-based technique was examined through comparisons with the data obtained from sampled sand. Obtained movement of color sand was then compared to the morphology change of nourished beach observed by a field camera.