Estimation of Longshore Sediment Transport Using Video Monitoring Shoreline Data

Jung-Eun Oh,Weon Mu Jeong,Kyong Ho Ryu,Yeon S Chang,Ki Hyun Kim

doi:10.3390/jmse8080572

Abstract

Video monitoring systems (VMS) have been used for beach status observation but are not effective for examining detailed beach processes as they only measure changes to the shoreline and backshore. Here, we extracted longshore sediment transport (LST) from VMS in order to investigate long- and short-term littoral processes on a pocket beach. LST estimated by applying one-line theory, wave power, and the oblique angle of incident waves were used to understand shoreline changes caused by severe winter storms. The estimated LST showed good agreement with the shoreline changes because the sediments were trapped at one end of the pocket beach and the alongshore direction of transported sediments was corresponded to the direction of LST. The results also showed that the beach that was severely eroded during storms was also rapidly recovered following the evolution of LST, which indicates that the LST may play a role in the recovery process while the erosion was mainly caused by the cross-shore transport due to storm waves. After the beach was nourished, beach changes became more active, even under lower wave energy conditions, owing to the equilibrium process. The analysis presented in this study could be applied to study inhomogeneous beach processes at other sites.

Highlights

Video monitoring systems (VMS) installed on beach faces have been successfully employed as tools for the remote sensing of coastal processes such as shoreline change [1,2]
The pattern of long-term shoreline variation was analyzed using data measured by a VMS at Bongpo Beach, a pocket beach located on the eastern coast of Korea, along with wave data measured at Gonghyeonjin station located 12 km off the beach at a water depth of 32 m
The beach response was investigated using beach width data from a VMS located in the middle of the beach with four cameras that could monitor changes along the 1-km-long beachline

Summary

Introduction

Video monitoring systems (VMS) installed on beach faces have been successfully employed as tools for the remote sensing of coastal processes such as shoreline change [1,2]. Remote sensing data measured by satellites and airborne light detecting and ranging (LiDAR) systems have been applied to mapping coastal zones more efficiently because they can cover wide regions in a short time period. These images, collected by satellites or aircraft, are especially useful in studying nearshore morphology as they provide information both outside and inside of the water, detecting shallow water bathymetry [9,10,11,12]. Regardless of the advantages, snapshot images from the air remain of limited use in monitoring active coastal processes because they are only available at specific times; continuously changing shoreline evolution cannot yet be recorded. Techniques using VMS remain useful for measuring quantities that are difficult to detect using satellite or LiDAR images, and for providing data continuously over long periods as it is limited to the data measured by drones

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Methods

Conclusion