Role of Infragravity Energy in Bar Formation in a Strong‐Wind Bay: Observations from Seaford Beach, Port Phillip Bay, Australia

Abstract

Measurements of the surf zone wave field and morphology were obtained from a multi‐barred beach in a fetch‐limited, strong‐wind bay (Seaford, southeastern Australia) during both low‐ and high‐energy conditions. Analysis of the infragravity energy present during high‐energy events (onshore winds >7 ms−1) revealed that it was broad‐banded, consisting of a mixture of standing and progressive motions and displaying daily variations in standing wave length scales. Infragravity standing waves were therefore not considered significant to the formation and migration of bars at Seaford during this study, with bar behaviour during high energy events potentially attributable to either breaking wave‐bed return flow and/or self‐organisational mechanisms.

Sheltered sandy beaches of southwestern Australia

“…However, the dominant process interactions linked to the profile forms are anticipated to differ, with storm recurrence and inundation frequency playing a more significant role on the low-energy shores. In this respect, Goodfellow & Stephenson (2005, 2008 and Eliot et al (2006) have highlighted the importance of wind direction and speed in governing temporal changes in morphology and dynamics on sheltered beaches, with notable inheritance of morphology following the occurrence of high-energy events.…”

“…The 'highest energy' beaches in surgedominated environments, the convex-curvilinear profiles, are similar to the lowest energy forms described for open-ocean coasts and may grade into them in an alongshore direction. This was suggested by the work of Goodfellow & Stephenson (2008) at Seaford Beach in Port Phillip Bay, For each of the three environments under consideration profiles in the convex-curvilinear group are most exposed and those in the exponential group are least exposed. Site names are indicated in Table 2.…”

“…Research on sandy beaches in environments classified as 'low-energy' has increased dramatically in recent years (Davidson-Arnott & Fisher 1992;Nordstrom 1992;Nordstrom & Jackson 1992;Davidson-Arnott & Conliffe-Reid 1994;Jackson 1995;Hegge et al 1996;Makaske & Augustinus 1998;Jackson et al 2002;Goodfellow & Stephenson 2005, 2008. Such beaches may be sheltered, fetch limited or a combination of the two.…”

Beach Morphodynamics in Australia 1970s–2010

“…In Australia experiments continued in western Australia (Masselink and Pattiaratchi, 1997; 1998; 2001) and Victoria (Goodfellow and Stephenson, 2008); while elsewhere they were undertaken in New Zealand (Brander and Short, 2000); Canada (Canadian Coastal Sediment Study, Willis, 1987); and in the USA where the Field Research Facility at Duck, North Carolina has been the focus of ongoing multifaceted experiments since the 1980s (see Berkemeier, 1996; http://www.frf.usace.army.mil/). On the US west coast Seymour (1989) coordinated the ambitious Nearshore Sediment Transport experiments, while more recently MacMahan et al .…”