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.
|Title||Field observations of alongshore runup variability under dissipative conditions in presence of a shoreline sandwave|
|Authors||Nadia Senechal, Giovanni Coco, Nathaniel G. Plant, Karin R. Bryan, Jennifer Brown, Jamie MacMahan|
|Publication Subtype||Journal Article|
|Series Title||Journal of Geophysical Research C: Oceans|
|Record Source||USGS Publications Warehouse|
|USGS Organization||St. Petersburg Coastal and Marine Science Center|