Evaluation of Effect of Beach Nourishment Using Imageries Produced from Photographs Taken from Fixed Point by Geometric Transformation

Abstract

On the Chigasaki coast, beach nourishment using coarse material has been carried out since 2004 to recover the sandy beach. To investigate the daily changes of the nourished beach, photographs have been taken from a fixed point. The 51 photographs taken at 1 s intervals were selected under the conditions that the tide level is within M.S.L.±0.1 m, the significant wave height is less than 0.5 m, and the photograph was taken between 8 and 12 am. The weighted average of these photographs was obtained to clearly determine the shoreline position. The imageries were produced from these photographs by the geometric transformation method. The change in shoreline position after the beach nourishment was monitored using the imageries