30 Undergraduate Research: In Honor of Mike Higgins (Posters)

Friday, 1 April 2016
8:00 AM - 5:30 PM
Exhibit Hall

ANALYSIS OF COMPLEX SAND WAVES IN RACCOON STRAIT, SAN FRANCISCO BAY

Paper number: 30-35
Program: Theme Sessions
Time: 8:00 AM – 5:30 PM

Authors

Abstract

College of Charleston BEAMS (BEnthic Acoustic Mapping and Survey) students sailed aboard the eTrac, Inc. vessel S/V Pulse in December 2014 as part of a multibeam survey of Raccoon Strait, the channel separating Point Tiburon and Angel Island in San Francisco Bay. Multibeam data were processed using CARIS HIPS 9.0 software, revealing complex and dynamic bathymetry of Raccoon Strait, consisting of sand waves varying significantly in length, height, and orientation. Water depths within the strait range from 8 to 65 m, and sand waves range in length from less than 5 m to more than 500 m, with several having heights exceeding 30 m. These sand waves were classified by their geomorphology. Wave symmetry, dimensions, and orientation were used to compare the relative ebb and flood tidal energy flowing through the channel. Raccoon Strait is known to have some of the strongest tidal currents in the San Francisco Bay, due to both the narrow 1 km channel width and its proximity to the bay’s mouth. The Strait’s southern margin sand waves are oriented eastward towards the inside of the bay and northern margin sand waves are oriented westward towards the bay mouth indicating forceful tidal currents in both ebb and flood directions. The distinctly different flow paths may be the result of Coriolis influence within this large estuarine bay. This study shows how high resolution bathymetry and backscatter can be used to study dynamic inshore sites. Repeated surveys of this area could be used to document migration of these large sand bodies.

Geological Society of America Abstracts with Programs. Vol. 48, No. 3

doi: 10.1130/abs/2016SE-273249

© Copyright 2016 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.