Hydrodynamic Measurements of Propagating Waves at Different Nearshore Depths in Hujeong Beach, Korea

Jong Dae Do,Yeon S Chang,Jae-Youll Jin,Ho Kyung Ha,Weon Mu Jeong,Byunggil Lee

doi:10.3390/jmse8090690

Abstract

This paper reports the results of hydrodynamic measurements at two different water depths to observe wave properties in the course of wave propagation, especially during storm periods, in Hujeong Beach, Korea. In addition to hydrodynamic measurements, video monitoring data and satellite images from Sentinel-II were employed to compare the temporal changes in shoreline positions and shallow water bathymetry during the storms. Through combination of a variety of observational data sets, the accuracy of analysis could be enhanced by preventing possible misinterpretation. Two significant storms were observed from two experiments conducted at different times and locations of the beach. The hydrodynamic conditions were similar in both of the periods in terms of wave and current conditions as well as wave nonlinearity such as skewness. However, the response of shoreline during the two storms was the opposite because it was eroded during the first storm but advanced during the second storm. This suggests that other controlling factors such as storm duration need to be investigated to support the analysis of cross-shore sediment transport and consequent shoreline evolution for future studies.

Highlights

Coastal erosion is a critical issue as it may cause impacts on human life when the sand in recreational beaches or sediments used to protect coastal facilities are lost permanently
The results showed that there were two storm periods (23–30 December 2016 and 15–19 January 2017) in which the maximum wave heights were higher than 2 m
The two cases had similar hydrodynamic conditions as strong onshore currents were observed at only shallower observational location during the storm periods

Summary

Introduction

Coastal erosion is a critical issue as it may cause impacts on human life when the sand in recreational beaches or sediments used to protect coastal facilities are lost permanently. When the waves are obliquely incident, the momentum of breaking waves generates shore-parallel radiation stresses that produce longshore current and the consequent longshore sediment transport. The direction of cross-shore transport is not predictable as it depends on a variety of wave and current conditions that are difficult to be precisely measured. Sediments move offshore under energetic wave conditions causing sediment erosions from the shore, which occurs in short time period during such as storm events [1,2]. The net cross-shore sediment transport is the result of a balance between these onshoreand offshore-directed components, and an accurate description of them is important in predicting the dynamic evolution of beach profiles [4]

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