MORPHOLOGICAL RESPONSE OF THE NEARSHORE SEABED DUE TO OFFSHORE PRECONDITIONING FEATURES

Abstract

Nearshore submerged structures for coastal protection are being applied in increasing numbers worldwide, with Multi-Purpose Reefs (MPR’s) also becoming a favoured approach. MPR’s look to combine coastal protection through the dissipation of wave energy offshore and a consequent increased beach width, marine habitat/ecological enhancement, and public amenity (e.g., diving, snorkelling, surfing, etc.). However, while there have been improvements in performance with respect to the addition of surfing amenity by using traditional construction methods (e.g., large rock such as used to construct the MPRs in Borth, Wales and Palm Beach, Australia), there are still issues of high design tolerances and challenging construction conditions close to the beach on exposed coasts. This work continues research regarding offshore preconditioning features; the companion manuscript to this work takes an iterative design approach to establish the relationships between preconditioning features and surf zone response using the parameters of peel angle as a proxy for surfing wave quality (Atkin et al., 2019). This work adds to the literature base of our theoretical understanding of the integration of coastal protection and surfing amenity.