Sediment Resuspension by Vessel-Generated Waves along the Savannah River, Georgia
Publication: Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 137, Issue 5
Abstract
Vessel-generated waves have the potential to erode the shoreline where there is regular commercial and recreational boat traffic in otherwise low-energy estuarine and fetch-limited environments. Whereas it is well established that vessel-generated waves are capable of resuspending significant quantities of bottom and bank sediment, there are limited field data showing how and when sediment is resuspended by the wake and the direction of net transport. This paper presents the results of an instrumented field study to measure sediment resuspension and transport in response to wakes generated by supercritical pilot boats and subcritical container ships at the mouth of the Savannah River in Georgia. Suspended sediment concentrations increase with the turbulent kinetic energy of the supercritical pilot-boat wake. The amount of sediment resuspended dependent on the available supply of sediment on the upper-foreshore. Whereas sediment is transported landward by the individual waves of the group, net transport is offshore in response to a low-frequency oscillation similar to a second-order group-forced current. In some cases, the direction of net transport is reinforced or reversed depending on the timing of the pilot-boat wake with the seiche forced by a passing container ship. In contrast to the pilot boats, sediment transport by subcritical container ships tends to be landward, but can also be weakly offshore depending on the timing of the wave group with the low-frequency drawdown and surge.
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Acknowledgments
This study was supported by a grant from the National Park Service. Field assistance was provided by Brent Rothschild, Mike Hosti, and Linda York from the National Park Service; Tim Brunk and Eugene Farrell from Texas A&M; and Mike Robinson and Clark Alexander from Skidaway Institute of Oceanography. Charlie Fenwick, Superintendent for Fort Pulaski National Monument provided important background information to the site and was helpful in providing access to the site.
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Information & Authors
Information
Published In
Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 137 • Issue 5 • September 2011
Pages: 246 - 257
Copyright
© 2011 American Society of Civil Engineers.
History
Received: Aug 27, 2010
Accepted: Jan 25, 2011
Published online: Jan 28, 2011
Published in print: Sep 1, 2011
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