Sedimentation Patterns and Hydrodynamics of a Wave-Dominated Tidal Inlet: Blind Pass, Florida

Blind Pass, a heavily structured wave-dominated tidal inlet on the west central coast of Florida, has undergone substantial morphologic changes in the past 150 years. Initially Blind Pass was a mixed-energy inlet. In 1848 a hurricane opened a new inlet to the north called Johns Pass, which captured...

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Main Author: Tidwell, David K
Format: Others
Published: Scholar Commons 2005
Subjects:
Online Access:https://scholarcommons.usf.edu/etd/885
https://scholarcommons.usf.edu/cgi/viewcontent.cgi?article=1884&context=etd
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spelling ndltd-USF-oai-scholarcommons.usf.edu-etd-18842019-10-04T05:22:17Z Sedimentation Patterns and Hydrodynamics of a Wave-Dominated Tidal Inlet: Blind Pass, Florida Tidwell, David K Blind Pass, a heavily structured wave-dominated tidal inlet on the west central coast of Florida, has undergone substantial morphologic changes in the past 150 years. Initially Blind Pass was a mixed-energy inlet. In 1848 a hurricane opened a new inlet to the north called Johns Pass, which captured a large portion of the tidal prism of Blind Pass. Since then Blind Pass migrated southward until it was structurally stabilized in 1937. The decreasing tidal prism resulted in significant inlet channel filling. The channel has been dredged 12 times since 1937. The present inlet is stabilized by two jetties and a series of seawalls. Detailed time-series field measurements of bathymetry and tidal flows were conducted between 2001 and 2004, after the last channel dredging in the summer of 2000. The measured depositional rate in the inlet channel approximately equals the net southward longshore transport rate. This suggests that the inlet has served as a trap for the southward longshore transport allowing negligible bypassing to the eroding downdrift beach. Most of the active sedimentation occurs on the northern side of the inlet. The sediment in the thalweg is largely coarse shell lag, indicating adequate sediment flushing by the ebbing tide. The cross-channel flow measurements revealed that ebb flow was approximately twice as high in the channel thalweg as compared with the rest of the channel. The flood flow was largely uniform across the entire inlet and dominated over the northern portion of the inlet due to the weak ebb flow there. This cross-channel flow pattern is crucial to the understanding of the sedimentation patterns in the Blind Pass channel. Two years after the last dredging the mouth has become shallow enough to induce wave breaking across the shoal area. Distinctive seasonal patterns of sedimentation were measured thereafter in the inlet channel, influenced by seasonal wave climate. The sedimentation is event driven from passage of cold fronts bringing elevated wave energy that accelerates the southward longshore transport. During normal conditions the sediment deposited in the mouth area is redistributed further into the inlet by the flood current combined with wave-driven current. 2005-04-12T07:00:00Z text application/pdf https://scholarcommons.usf.edu/etd/885 https://scholarcommons.usf.edu/cgi/viewcontent.cgi?article=1884&context=etd default Graduate Theses and Dissertations Scholar Commons Hydrodynamics Progradation Microtidal Morphodynamics Tidal inlets American Studies Arts and Humanities
collection NDLTD
format Others
sources NDLTD
topic Hydrodynamics
Progradation
Microtidal
Morphodynamics
Tidal inlets
American Studies
Arts and Humanities
spellingShingle Hydrodynamics
Progradation
Microtidal
Morphodynamics
Tidal inlets
American Studies
Arts and Humanities
Tidwell, David K
Sedimentation Patterns and Hydrodynamics of a Wave-Dominated Tidal Inlet: Blind Pass, Florida
description Blind Pass, a heavily structured wave-dominated tidal inlet on the west central coast of Florida, has undergone substantial morphologic changes in the past 150 years. Initially Blind Pass was a mixed-energy inlet. In 1848 a hurricane opened a new inlet to the north called Johns Pass, which captured a large portion of the tidal prism of Blind Pass. Since then Blind Pass migrated southward until it was structurally stabilized in 1937. The decreasing tidal prism resulted in significant inlet channel filling. The channel has been dredged 12 times since 1937. The present inlet is stabilized by two jetties and a series of seawalls. Detailed time-series field measurements of bathymetry and tidal flows were conducted between 2001 and 2004, after the last channel dredging in the summer of 2000. The measured depositional rate in the inlet channel approximately equals the net southward longshore transport rate. This suggests that the inlet has served as a trap for the southward longshore transport allowing negligible bypassing to the eroding downdrift beach. Most of the active sedimentation occurs on the northern side of the inlet. The sediment in the thalweg is largely coarse shell lag, indicating adequate sediment flushing by the ebbing tide. The cross-channel flow measurements revealed that ebb flow was approximately twice as high in the channel thalweg as compared with the rest of the channel. The flood flow was largely uniform across the entire inlet and dominated over the northern portion of the inlet due to the weak ebb flow there. This cross-channel flow pattern is crucial to the understanding of the sedimentation patterns in the Blind Pass channel. Two years after the last dredging the mouth has become shallow enough to induce wave breaking across the shoal area. Distinctive seasonal patterns of sedimentation were measured thereafter in the inlet channel, influenced by seasonal wave climate. The sedimentation is event driven from passage of cold fronts bringing elevated wave energy that accelerates the southward longshore transport. During normal conditions the sediment deposited in the mouth area is redistributed further into the inlet by the flood current combined with wave-driven current.
author Tidwell, David K
author_facet Tidwell, David K
author_sort Tidwell, David K
title Sedimentation Patterns and Hydrodynamics of a Wave-Dominated Tidal Inlet: Blind Pass, Florida
title_short Sedimentation Patterns and Hydrodynamics of a Wave-Dominated Tidal Inlet: Blind Pass, Florida
title_full Sedimentation Patterns and Hydrodynamics of a Wave-Dominated Tidal Inlet: Blind Pass, Florida
title_fullStr Sedimentation Patterns and Hydrodynamics of a Wave-Dominated Tidal Inlet: Blind Pass, Florida
title_full_unstemmed Sedimentation Patterns and Hydrodynamics of a Wave-Dominated Tidal Inlet: Blind Pass, Florida
title_sort sedimentation patterns and hydrodynamics of a wave-dominated tidal inlet: blind pass, florida
publisher Scholar Commons
publishDate 2005
url https://scholarcommons.usf.edu/etd/885
https://scholarcommons.usf.edu/cgi/viewcontent.cgi?article=1884&context=etd
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