Rip current observations on a low-sloping dissipative beach

Shari L. Gallop, Karin R. Bryan, Sebastian Pitman, Roshanka Ranasinghe, Dean Sandwell

Research output: Chapter in Book/Report/Conference proceedingConference proceeding contribution

3 Citations (Scopus)

Abstract

Rip currents are the main cause of beach rescues and fatalities. Key drivers of rip current hazard are: (1) fast current speeds; and (2) the exit rate of floating material from inside to outside of the surf zone. Exit rates may vary temporally, such as due to Very Low Frequency (VLF) motions, which have a period on the order of 10 minutes. However, there is little field data to determine the driver(s) of exit rate. Therefore, the aim of this research was to determine rip current circulation patterns, and specifically, determine their relationship to surf zone exits, on a high-energy dissipative beach. Three days of field measurements were undertaken at Ngarunui Beach, New Zealand. Three daily surf zone flow patterns were found: (1) alongshore; (2) surf zone eddy with high exit rate; and (3) surf zone eddy with no exits. There were strong infragravity peaks in energy within the surf zone, at 30-45s, although none at VLF (∼10 minute) frequencies. Further research is underway to determine what drove the high surf zone exit rate observed at Ngarunui Beach.

Original languageEnglish
Title of host publicationAustralian Coasts and Ports 2015 Conference
Place of PublicationBarton, ACT
PublisherAustralian Coasts and Ports
Pages304-307
Number of pages4
Publication statusPublished - 2015
EventAustralian Coasts and Ports 2015 Conference - Auckland, New Zealand
Duration: 15 Sep 201518 Sep 2015

Other

OtherAustralian Coasts and Ports 2015 Conference
CountryNew Zealand
CityAuckland
Period15/09/1518/09/15

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