Document Type
Thesis
Abstract
Virginia’s Eastern Shore is bordered on its Atlantic Coast by a chain of largely uninhabited barrier islands, which exist in a mostly natural state, with little direct anthropogenic influence on their movement through time. These islands are migrating landwards across the backbarrier lagoon, which results in loss of salt marsh, a globally significant carbon sink, due to burial as the island overruns the marsh. These migration rates were calculated to range from approximately 2 to 7 m yr-1. It has been theorized that the speed at which the islands transgress is controlled by the tidal prism, which strongly affects sediment distribution, at each island. This research investigated that hypothesis by looking at modern imagery and historical maps of the Eastern Shore, but failed to find evidence to support the hypothesis that tidal prism controls barrier retreat rate. This research also quantified marsh loss in the backbarrier environment of the Eastern Shore, largely driven by the migration of the barrier islands. Since 1870, the area of the marshes was found to have decreased by a net 54.6 km2, or 17.7% of the 1870 extent, a rate of 0.39 km2 yr-1. Of that marsh loss, 30.9 km2, or 56.6%, was found to be directly caused by the barrier islands migrating over the marsh, while the remainder of the marsh loss was largely due to wave erosion around open-water bays.
Date Awarded
2015
Department
Geology
Advisor 1
Christopher Hein
Advisor 2
Matt Kirwan
Recommended Citation
Deaton, Charlie, "Barrier Island Migration, Changes in Tidal Prism, and Marsh Loss on Virginia's Eastern Shore" (2015). Geology Senior Theses. William & Mary. Paper 335.
https://scholarworks.wm.edu/geologyseniors/335
