Beach cusp and beach volume change relationship: A South Korean case study

Keywords: Beach cusps, coastal geomorphology, coastal erosion, beach volume, sUAS
Abstract Type: Paper Abstract

Abstract

Beach cusps are rhythmic crescentic coastal morphologies found on the shoreface of beaches worldwide. Despite their ubiquitous distribution, scientific consensus on their formation processes has yet to be reached. Small unmanned aerial systems (sUAS) in coastal research have enabled the examination of morphological changes with higher spatiotemporal resolution. Although recent studies have demonstrated the usefulness of sUAS in beach cusps research, it has not been applied to studying beach cusp distribution and beach volume change relationships on a single beach for more than one year. This will compare beach volume change and beach cusp distribution along Wonpyeong Beach, South Korea, for 16 months. Digital elevation models (DEM) are generated from sUAS survey data to calculate beach volume changes. Beach cusp dimensions (spacing, elevation, depth, and amplitude) and spatial distributions are measured using DEM-derived slope, hill shade, aspect, and contour data. Results show that beach cusps evolve either on the lower foreshore or the upper foreshore, each group having distinct elevations (above MSL) and different sizes. The upper foreshore beach cusps typically have wider spacings. The lower foreshore cusps have narrower spacing and are distributed mainly in accretion-dominant zones, which indicates a favorable environment for beach cusp evolution. We expect these findings to provide an alternative measure of tracking erosion/deposition patterns along a beach and an increased understanding of beach cusp environment.