Choi, K. H. and Kim, J. S. and Lee, J.C., 2016. Migration of coastal erosional hotspots due to coastal protection structures. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 1062 - 1066. Coconut Creek (Florida), ISSN 0749-0208.
Measures to protect coasts with artificial structures have recently become popular for beach management, notably in the east coast of South Korea. In many cases, however, some structures induced unwanted effects on adjacent beaches. Yet local governments continue to build these kinds of structures to solve erosion problems. In this study, coastline changes due to such construction were investigated by comparing historical aerial photographs, taking two beaches (Gusan-Wolsong coast and Osan-Yeongsin coast) as examples. In these two beaches, submerged artificial breakwaters and groins were constructed to reduce erosion which had been accelerated since the extension of the existing harbors in the north. These defence measures seemed to work successfully initially, but they soon caused new erosional problems on the neighboring beaches. Historical changes of the two shorelines for the last 30–40 years showed that the standard deviations of beach widths estimated from the sections comprising the entire coastline have been continuously increased since the construction of the artificial structures, with minimal changes of mean beach width or total areas. The beach width of protected areas was largely increased but that of neighboring coast was severely affected. These findings indicate that the artificial structures in the east coast of the peninsula may cause erosion on the adjacent beaches, simply moving the erosional hotspot to the south.