Yoon, J.-J., 2017. Numerical study of rip current generation at Daecheon Beach, west coast of Korea. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 259–263. Coconut Creek (Florida), ISSN 0749-0208.
Daecheon Beach in Boryeong, Korea, is one of the most popular places on the west coast of Korea. The world famous “Mud Festival” attracts visitors in summer and this beach has many tourists throughout the year. However, the irregular occurrence of rip currents threatens swimmers during every summer season. Two people were swept away by fast moving rip currents in August 2010, and could not be rescued. To investigate the dominant mechanism of rip currents in this region, a numerical simulation was carried out using the non-hydrostatic model Surface WAves till SHore (SWASH), with observed wave and topographical data. In this paper, the applicability of SWASH for modeling wave transformation and rip current circulation near the shallow foreshore is investigated. Assuming that rip current dynamics are controlled by a combination of variations in wave dissipation, tidal currents, and morphological flow constriction, this study tested the effects of wave parameters (such as height, period, and direction) on rip current generation. Rip currents were simulated when longshore currents flowed out through a channel with very small wave energy in the seaward direction. The occurrence of rip currents increased under conditions of higher waves and longer wave periods. In the case of wave direction, cases were tested from northwest to southwest, and the spatial characteristics of the simulation results are presented. Rip currents have often appeared in SW types of wave direction conditions. The change of the wave direction changed the locations of rip current generation. However, the influence of topographic features has not been shown significantly at Daecheon Beach because the bathymetry of the area is shallow and the bottom slope is mild.