Southeastern Section - 66th Annual Meeting - 2017

Paper No. 9-1
Presentation Time: 1:20 PM


ALEXANDER, Clark, Skidaway Institute of Oceanography, University of Georgia, 10 Ocean Science Circle, Savannah, GA 31411,

Hurricane Matthew caused billions of dollars in damages to coastal communities along the southeast coast of the United States. Coastal communities have begun to develop strategies to increase their resilience to, and speed their recovery from, another such an event. A detailed understanding of the distribution and character of nearshore and inner continental shelf sand resources is a critical component in developing these strategies. These sand resource data are critically needed in Georgia, as the sand resources on the continental shelf off of Georgia are the most poorly known of all the states along the East Coast. Three developed barrier islands along the Georgia coast (Sea, St. Simons and Jekyll Islands) are without identified renourishment resources and are the focus of these studies. This presentation will describe the current status of these projects, present new and existing samples and datasets compiled for these studies, and outline goals for the future. Results to date include a synthesis of existing textural and subbottom data, and show that sediments range widely in size within and across the Georgia shelf: estuarine and sound sediments exhibit a mean size of 2.5 +/- 2.2 phi and span from -1.1 to 8.5 phi; sediments in State waters (0-3 nm of the coast) exhibit a mean size of 2.4 +/- 1.2 phi and span from -0.5 to 6.4 phi; sediments in the nearshore OCS zone (3-8 nm offshore) exhibit a mean size of 2.4 +/- 0.9 phi and span from 0.3 to 5.7 phi; and sediments in the offshore OCS (8-400 nm) exhibit a mean size of 1.5 +/- 0.8 and span from -2.2 to 6.2 phi. These findings validate the concept of a zone of modern sediment influence in state waters and the nearshore OCS zone. The general location of the boundary between the Recent and relict sediments does not appear to have changed, within the limits of our analyses, since previous studies in the 1970s first observed this pattern. However, the boundary’s sinuous location is now much better constrained.