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Field observations of alongshore runup variability under dissipative conditions in presence of a shoreline sandwave

Nadia Senechal·Giovanni Coco·Nathaniel G. Plant·Karin R. Bryan·Jennifer Brown·Jamie MacMahan
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Abstract

Video measurements of runup were collected at low tide along several profiles covering an alongshore distance of 500 m. The morphology displayed a complex shape with a shoreline sandwave in the lower beach face of about 250 m long mirrored in the inner sandbar. Wave conditions were stationary and moderate (offshore height of 2 m and peak period of nearly 13 s) but yet dissipative. Runup energy was dominated by infragravity frequencies. Alongshore variations in runup (by a factor up to 3) observed both in the incident and infragravity bands were much higher than reported previously (e.g., Guedes et al., 2012, https://doi.org/10.1016/j.csr.2012.08.022 ; Ruggiero et al., 2004, https://doi.org/10.1029/2003JC002160 ) while the alongshore variations in other environmental parameters (e.g., foreshore beach slope) appear to be much lower. Our data suggest that the beach morphology in the inner surf zone plays a crucial role by inducing rapid and significant modification in the incident wave pattern and the alongshore coherence length scales were consistent with the typical alongshore length scale of the morphology.

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Journal of Geophysical Research C: OceansArticle

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Nadia Senechal, Giovanni Coco, Nathaniel G. Plant, Karin R. Bryan, Jennifer Brown, Jamie MacMahan. 2018-09-22. Field observations of alongshore runup variability under dissipative conditions in presence of a shoreline sandwave. https://doi.org/10.1029/2018jc014109

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