Modeling sandbar effects on nearshore waves and morphological change using SWAN

Numerical model simulations (Delft3D SWAN) are used to examine the impact of small alongshore variations in the bathymetry of an outer sandbar (in about 5-m water depth) on the nearshore wave field as the shallow (< 3 m) bathymetry changes from near alongshore uniform to strongly spatially variable to understand wave driven morphologic evolution. Waves were observed at Duck, NC with an array of 14 pressure gages between 1- and 3-m water depth spread over 250 meters alongshore. Bathymetry was measured between the dune toe and about 8-m water depth on September 26 and October 2, 2013. The bathymetry evolved from roughly alongshore uniform on September 26 to strongly alongshore variable on October 2. Between these dates incident significant wave heights ranged from 0.5 meters to 2.3 meters, with incident angles from 20 degrees north to 5 degrees south of shore normal. Simulations were run with observed bathymetry for both the outer bar and inner shallow bathymetry, with smoothed outer bar and observed shallow bathymetry, and with digital elevation model bathymetry to determine the effects of outer bar and shallow bathymetry on wave evolution.

Grantor dc:publisher

Massachusetts Institute of Technology and Woods Hole Oceanographic Institution

Year dc:date.issued

2024

Author dc:creator

• Murman, Charles E.

Advisor dc:contributor.advisor

• Raubenheimer, Britt

• SWAN
• Nearshore waves
• Sandbar

Statement dc:rights

• ©2024 Charles E. Murman. The author hereby grants to MIT and WHOI a nonexclusive, worldwide, irrevocable, royalty-free license to exercise any and all rights under copyright, including to reproduce, preserve, distribute and publicly display copies of the thesis, or release the thesis under an open-access license.

Language dc:language.iso

en_US

DOI

10.1575/1912/70548

OAI identifier oai:identifier

oai:darchive.mblwhoilibrary.org:1912/70548