Planar Installation Characteristics of Crown Depth-Variable Artificial Coral Reef on Improving Coastal Resilience: A 3D Large-Scale Experiment

Abstract

Coastal resilience has received significant attention for managing beach erosion issues. We introduced flexible artificial coral reef (ACR) structures to diminish coastal erosion, but planar installation effects should be considered to evaluate the feasibility of coastline maintenance. In this study, we conducted a three-dimensional large-scale experiment to investigate the characteristics of planar installation of ACR, focusing on the wave mitigation performance, wave profile deformation with delay, nearshore current movement, deposition and erosion trends, and beach profile variation. We found that the ACR diminished the wave height by ~50% and the current intensity by ~60% compared with that of a conventional submerged breakwater made of dolos units. Using the dispersion velocity of the dye in a tracer experiment, the dispersion time of the ACR was approximately 1.67-times longer than that of the dolos and the current velocity was reduced, revealing that ACR significantly reduced structural erosion. With dolos, severe erosion of >10 cm occurred behind the structure, whereas there was only slight erosion with the ACR. Moreover, in a vertical beach-profile analysis, the ACR exhibited greater shoreline accretion than that of dolos. These results indicate the potential of ACR in improving coastal resilience.

Remote sensing capabilities to support EWN® projects : an R&D approach to improve project efficiencies and quantify performance

“…In shallow, clear, and/or non-turbid waters, data collected from airborne and autonomous surface vehicles (ASVs) can be used to assess key reef characteristics, such as width and height, proximity to shore, roughness, porosity, and coral color (useful in detecting coral bleaching events) (Asner et al 2020;Hong et al 2021). Remote sensing can also assist in the monitoring of coral formation, sediment trapping, shoreline change (i.e., erosion and accretion), richness and diversity, and wave attenuation (Brodie et al 2010;Zhang 2019;Sierra-Escrigas et al 2020).…”