A Spatial Analysis of Coastal Erosion on Little Cumberland Island, Georgia to Guide Future Island Management

Author: Conlan Bertram

Faculty Supervisor: Robin McLachlan, Ph.D.

Abstract

Barrier islands along the United States southeastern coast are increasingly threatened by erosion due to sediment deprivation, sea-level rise, and storms. One such island is Little Cumberland Island (LCI) in Georgia, which is separated from Cumberland Island to the south by Christmas Creek and salt marsh. LCI is owned and maintained by the homeowners who strive to keep the island as natural as possible; there are currently only 43 homes on the island and all roads are made of sand. Much of the island’s shoreline is eroding, including large stretches to the south along Christmas Creek, to the east along the open ocean, and to the north along the inlet and back barrier. To quantify erosion, Google Earth Pro was used to measure changes in coastline position. A shore-parallel transect was used to anchor ten shore-perpendicular transects, which were positioned over key features including homes and a lighthouse. In Microsoft Excel, nonlinear regression analysis was used to predict future erosion rates and determine if any homes are at risk of falling into the water. Data were collected from 1988 to 2019. Erosional rates varied across the island; locations along Christmas Creek face higher rates than the rest of the more northern coastline. Some locations had minimal erosion or accretion. The rates ranged from -0.03 to 5.5 m/yr, with an average approximately 1.2 m/yr. Areas with a high concentration of homes tend to have higher erosion rates, and many homes are currently on the edge of the dune. Results of this study will be used to guide future development on the island, such as road construction and house relocation.

Crassostrea virginica recruitment dynamics in Southeast Georgia: A habitat suitability model evaluation

Author: Caitlyn R. Napier
 

Faculty Supervisor: Kimberly K. Takagi, Ph.D.

Abstract

The eastern oyster (Crassostrea virginica) is a vital organism in salt marsh ecosystems. Without them, critical ecosystem services such as water filtration and coastal erosion mitigation would significantly decline. Hence, understanding C. virginica habitat suitability along the Georgia coast is critical to ensuring the maintenance of healthy salt marsh ecosystems. Atkinson and Deemy (2019) previously established a C. virginica habitat suitability model in an effort to identify possible oyster reef restoration locations. The purpose of this study was to evaluate the accuracy of the Atkinson and Deemy (2019) model for a number of regions along the Georgia coast. Preliminary conclusions suggest that the Atkinson and Deemy (2019) model is appropriate in some regions, however the inclusion of additional parameters (such as nitrite and phosphate) would further refine its predictability.