Analysis of Virginia Barrier Island Shoreline Movement and Correlations to Sea Level, Wave Height Changes, and Teleconnection Patterns

• Main Author: Haluska, James Daniel
• Format: Text
• Language: unknown
• Published: ODU Digital Commons 2017
• Subjects: Barrier islands; Shoreline change; Time series analysis; Virginia coast; Oceanography; Barrier Island; Barrier Islands; North Atlantic
• Online Access: https://digitalcommons.odu.edu/oeas_etds/8; https://digitalcommons.odu.edu/cgi/viewcontent.cgi?article=1008&context=oeas_etds

The Virginia barrier islands stretch from Assateague Island in the north to Fisherman’s Island in the south. This string of islands is subject to frequent North Atlantic extra-tropical storm and hurricane influence. In addition, sea level rise has the potential to cause continued shoreline loss and inlet widening for this island group. This dissertation describes the effect of sea level rise, changes in wave height, and teleconnection pattern (AO, NAO, and MEI) correlations to shoreline location changes to the islands and inlet location and width changes. Locations of island shorelines were determined from satellite and aircraft images using ArcGIS software and the USGS Digital Shoreline Analysis System (DSAS). Geographically registered images were digitized, and multiple transect locations on each island were measured from a common offshore baseline using DSAS. The resulting distances along with the remote sensing image dates were used to construct time series of shoreline location for each island. Data frequency was controlled by image availability, and ranged from weekly to semi-monthly. Approximately 250 shorelines per island from 1990 to 2014 were digitized. The results were then interpolated to give a monthly shoreline location for each transect. The combined observations were analyzed by empirical orthogonal function (EOF) and wavelet analysis. The analysis shows that the barrier islands are moving to the south as well as becoming narrower. As a group, the shoreline movement is primarily correlated with sea level change (r2 = 0.41). The islands also respond to storms and other episodic events. The response can be resilient or catastrophic depending on the extent of shoreline loss which precedes the event. If the island shoreline has narrowed to a width that cannot withstand wave and high water level induced loss, the island and associated shoreline is permanently lost. The rate of shoreline loss returns to the pre-storm rate within several weeks after the events unless island shore is permanently lost ...