Journal of the Korean Geographical Society ISSN:1225-6633(Print) 대한지리학회지

To improve the understanding of the relationship between the morphological changes of the ridge and runnel in macro-tidal beach and the seasonal circulation, we investigated the long-term cross-section change of the Baeksajang Beach in Anmyeon-do, Chungcheongnam-do, Korea. Three transects were selected and a total of 14 topographic surveys were conducted for seven years. The most influential factors in the change of the beach morphology were the ridges and runnels as the secondary morphology. Their formation, migration, and extinction were closely related to changes in the beach topography. As a result of visualizing the movement of ridge and runnel, we confirmed that the ridges and runnels were moving toward the land direction. Over time, the ridges and runnels that were located nearer to the land were annihilated together with the upper beach, and new ridges and runnels were formed on the far side of the land (more than 100m apart) and moved to the landward direction. EOF analysis showed also that the migration of ridges and runnels was an important topographic change mechanism. The low contribution rate of the first component was shown, whereas the second component related to the ridges and runnels was clear. Also, the third component of weakening the relief of ridge and runnel was shown. The migration of ridge and runnel seems to be a factor that can explain that the beach classification of the Baeksajang Beach was not clear in the previous studies.