The ability to accurately quantify shoreline variability along sandy beaches is essential in order to establish aggressive mitigation strategies, based on recent global climate change projections. This investigation employed a suite of coastal data -- topographic maps, aerial photography, high-resolution satellite imagery, and Lidar survey data-- to establish decadal trends of shoreline movement along sandy barrier islands on the northwest and southeast coasts of Florida. An extensive collection of data was assembled for the project, comprising nearly two dozen historic shoreline positions dating from the mid-19th century to the present. The techniques used to detect morphologic change with time were the Digital Shoreline Analysis System (DSAS) and a modernized analytical approach, Analyzing Moving Boundaries Using R (AMBUR). The latter approach was modified with a storm function to provide a forecast of the shoreline under predictions of more intense storminess. Results reveal that severe storms produce dramatic morphological alterations of the coast and in some cases, can result in shoreline retreat in excess of 50 meters during a single event. Special emphasis was placed on rates of change during the past decade and a half period (1995-2013) of active storm conditions. Of the three study areas analyzed, Little St. George Island returned the highest average rate of change of -4.33 m/yr in response to increased storminess. The average rate of change along Perdido Key in response to storms was -0.57 m/yr. Northern Merritt Island however, demonstrated the most stable shoreline of the three study sites and returned an overall mean rate of change of 0.41 m/yr. The results reveal that shoreline orientation, along with engineering projects, act over a variety of spatial and temporal scales to influence shoreline evolution. The trends of shoreline movement also indicate that nearshore bathymetry wields some influence on the behavior of local segments of a barrier island's shoreline. Tidal inlet dynamics were found to cause increased shoreline fluctuations and more notably, accelerated rates of erosion, especially immediately downdrift from the inlets. This project also enumerated volumetric and morphologic change in coastal dunes along a low-profile barrier island. The investigation established that natural dune recovery is directly related to the duration and frequency of storms. Further, the intensity of individual storms was found to be strongly correlated to trends in dune stability and shoreline evolution. Results show that the maintenance of viable dune fields is dependent on several ancillary factors. Such factors include: sediment supply via longshore drift or artificial nourishment, island width, dune field width, continuity of the dune complex, inner-shelf bathymetry and dune re-vegetation. In many cases, dune re-vegetation after storm passage delayed volumetric loss, favoring dune growth and reducing erosion. The analyses indicated that beach and dune recovery was initiated approximately six years following a major storm event. The results demonstrate that the most stable dunes were located along undeveloped and un-nourished segments of the island. In areas where nourishment had taken place however, foredune volumetric loss was significantly less pronounced. The results of this project provide a better and more detailed understanding of the vulnerability of coastal environments to the effects of climate change. / A Dissertation submitted to the Department of Earth, Ocean, and Atmospheric Science in partial fulfillment of the Degree Awarded:. / Spring Semester, 2015. / March 30, 2015. / barrier islands, sea-level rise, shoreline change, storms / Includes bibliographical references. / Stephen A. Kish, Professor Co-Directing Dissertation; Joseph F. Donoghue, Professor Co-Directing Dissertation; James B. Elsner, University Representative; William Parker, Committee Member; Yang Wang, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_253032 |
| Contributors | Sankar, Ravi Darwin (authoraut), Kish, Stephen A. (professor co-directing dissertation), Donoghue, Joseph F. (Joseph Francis) (professor co-directing dissertation), Elsner, James B. (university representative), Parker, William C., 1952- (committee member), Wang, Yang (committee member), Florida State University (degree granting institution), College of Arts and Sciences (degree granting college), Department of Earth, Ocean, and Atmospheric Science (degree granting department) |
| Publisher | Florida State University, Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text |
| Format | 1 online resource (215 pages), computer, application/pdf |
| Rights | This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). The copyright in theses and dissertations completed at Florida State University is held by the students who author them. |
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