Mechanism of rapid change from natural to artificial coast in japan-the example of node coast in kujyukuri coastal plain-

In the analysis of shoreline changes on a coast, where continuous longshore sand transport is interrupted by structures such as breakwaters or groins, causing downcoast erosion, comparison of shoreline changes based on aerial photographs is often carried out and useful results have been obtained for many coasts. However, the analysis of shoreline change does not necessarily lead to sufficient understanding of the events occurring on the coasts, thus a direct comparison of aerial photographs is necessary. The disappearance of the natural coastal sand dune and sandy beach in Japan has been caused not only by the recession of the shoreline due to erosion, but also by the excessive expansion of the coastal forest due to the land use change behind the coastline. This study aims at investigating this issue by using the method of direct comparison of aerial photographs taking the Node coast as the example. Finally it is concluded that in order to prevent further degradation of the coastal environment, overall comprehensive management of the wide coastal zone including the coastal forest is required.