Submerged Cultural Resource Remote Sensing Survey of Proposed Borrow Area off Tybee Island and Diver Identification of Five Anomalies, Chatham County, Georgia

The U.S. Army Corps of Engineers, Savannah District (USACE-SAS) proposes to perform periodic renourishment to the Tybee Island Beach Erosion Control Project, Chatham County, Georgia. In order to determine the proposed project's effects on potentially significant submerged cultural resources USACESAS contracted with LG2 Environmental Solutions, Inc. (LG2ES) of Jacksonville, Florida, and their subcontractor Tidewater Atlantic Research, Inc. (TAR) of Washington, North Carolina, to conduct a comprehensive submerged cultural resources investigation of the proposed Borrow Area to consist of a Remote Sensing Survey followed by a Diver Identification Survey. Field research for the project was conducted between 9 March and 10 May 2019. The Remote Sensing Survey detected 64 magnetic anomalies, five acoustic side-scan sonar targets, and zero sub-bottom features. TAR's analysis of the remote sensing data indicated that six sets of two or more anomalies were identified by geographical proximity association and/or signature characteristics as potentially associated with historical vessel remains or other potentially significant submerged cultural resources. As the survey area has a high potential for historically significant shipwrecks, those six target sites were recommended for avoidance or additional investigation. The remaining targets are small single source signatures that appear to have been generated by modern debris such as fish and crab traps, pipes, small diameter rods, cable, wire rope, chain, small boat anchors. No additional investigation of those sites was recommended in conjunction with dredging in the proposed Borrow Area. USACE/SAS, in coordination with the LG2ES/TAR team, identified five anomaly/target sites considered to be of the highest priority in order to clear the largest area. These five sites were investigated by archaeological divers through visual search and hydroprobing. The source of the primary anomaly/target at each site proved to be modern debris. No additional investigation of those sites is recommended in conjunction with the proposed dredging plan for the Borrow Area.