Author(s): Harshinie Karunarathna; Dominic E. Reeve; Hajime Mase; Yoshiaki Kuriyama; Roshanka Ranasinghe
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Keywords: Beach profiles; Hydrodynamics; Sediment transport
Abstract: This paper compares and contrasts the behaviour of four beaches which have significant differences in wave climate and sediment characteristics. The selected beaches are Narrabeen Beach, Australia; Milford-on-Sea Beach, UK; Hasaki Coast, Japan; and Joetsu-Ogata Coast, Japan. Empirical Orthogonal Function analysis is used to analyse and investigate spatial and temporal variability of cross shore profilesof the four selected beaches. Some remarkable similarities and considerable differences were found inthe characteristics of profile variability. All beaches show evidence of multiscale morphodynamicchange but Milford-on-Sea, Joetsu-Ogata and Hasaki profiles show some significant inter-annual scale variability, which may be due to climate variability of the incident waves. The nature of sediment exchange across the profile, which contributes to profile shape variability, shows a distinct relationship to sediment type. Inmixed sediment Milford-on-Sea beach, sediment exchange is prominent between the upper beach and intertidal zone while in Narrabeen and Joetsu-Ogata beaches where beach sediment is predominantly medium to fine sand, sediment exchange occurs mainly in intertidal and subtidal zones. However, in Hasaki Coast, sediment exchange primarily takes place between inter-tidal zone and beach face, even though it is a fine sand beach.
Year: 2016