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ABSTRACT Lee, Y.B.; Kim, H.D., and Kwak, K., 2018. Verification of Beach Erosion in West Coast of Korea. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 256–260. Coconut Creek (Florida), ISSN 0749-0208. The factors that cause the coastal erosion are different depending on where the wave field dominates and where the tide effect is large; however, most coastal erosion studies have been conducted on areas where waves are dominant. The west coast of Korea has maximum tide difference of more than 9 m. This study aided to examine the relationship between coastal erosion and the area where the effect on tide is large. The selected study field, Kkotji Beach, is a representative coastal tourist location on the west coast of Korea. Due to serious coastal erosion, sandy beach has been graveled and the number of tourist has decreased which resulted in great economic loss. In this study, field observations and numerical simulations were used simultaneously. For the field observations, beach profile measurement, sediment observation, wave observation, and tide and current observations were conducted to investigate and analyze the causes of the coastal erosion. Numerical simulations were used to consider both wave and tide by reproducing the coastal erosion phenomenon and compare to the field observations. The effects of the tide on coastal erosion were presented through the simulations. As a result, the suspected causes of the erosion of the Kkotji Beach are the W direction induced wave during the winter, reduction of the erosion control forest due to coastal development, and large tide difference.