Remote Sensing and Diver Investigations Atlantic Intracoastal Waterway Chatham, Bryan, Liberty, McIntosh, Glynn, and Camden Counties, Georgia, and Portions of Beaufort County, South Carolina

The U.S. Army Corps of Engineers, Savannah District is responsible for the maintenance of the federally authorized 12-foot-deep and 150-foot-wide inland navigation channel known as the Atlantic Intracoastal Waterway Project located within their boundaries. Covering a 161-mile length that extends between Port Royal Sound/Hilton Head Island (AIWW Mile 52) in South Carolina south to the Cumberland Sound/Florida state line (AIWW Mile 713), the U.S. Army Corps of Engineers, Savannah District is in the process of developing a dredged material management plan for the District's portion of the Atlantic Intracoastal Waterway that will address management for the next 20 years. The plan requires development of Confined Disposal Facilities and obtaining the necessary environmental approvals to develop them. As an agency of the Federal Government, the U.S. Army Corps of Engineers must consider the effects that their project activities will have on cultural resources. Therefore, the U.S. Army Corps of Engineers, Savannah District is responsible for determining if any cultural resources are located within the current project area, and if so, prior to the implementation of any project activities determining if any resources are eligible for listing on the National Register of Historic Places. Subsequently, and in compliance with the U.S. Army Corps of Engineers' responsibilities towards cultural resources, Panamerican Consultants, Inc. of Memphis, Tennessee was subcontracted by DCA/GEC A Joint Venture, LLC, of Jacksonville, Florida, to conduct a comprehensive submerged cultural resources investigation of 12 reaches within the Atlantic Intracoastal Waterway. In response to the U.S. Army Corps of Engineers, Savannah District's Scope of Work entitled, Remote Sensing Survey and Diver Investigations, Atlantic Intracoastal Waterway, Chatham, Bryan, Liberty, Mcintosh, Glynn and Camden Counties, Georgia and Portions of Beaufort County, South Carolina, Panamerican Consultants, Inc. conducted the survey between May and June, 2012 for the U.S. Army Corps of Engineers, Savannah District, under Contract No. W912HN-12-D-0016, Delivery Order No. 0001. Consisting of archival research, a remote sensing survey of the 12 reaches, and diver investigation of ten potentially significant targets within those reaches, the remote sensing survey identified total of 473 magnetic anomalies, 538 sidescan sonar contacts, and 156 subbottom features within the survey reaches. Of these, five anomaly clusters were considered to potentially represent significant historic cultural resources, and four sonar contacts and two subbottom features were considered to potentially represent significant prehistoric cultural resources. Recommended for testing, archaeological diving operations indicated that all potentially historic resource targets were negative for cultural resources sites. Relative to potential prehistoric targets, the area containing sidescan sonar Contact C282 in the Wilmington River Reach does however represent a large paleolandform that dates to 7,300 years before present and therefore has the potential for the presence of prehistoric sites, and if present, which would predate those on adjacent dry land areas. The depth of the landform at between 20 feet and 28 feet indicates the landform can be avoided by potential project impacts. However, in the event that avoidance is not possible by project activities, the area should be mapped with georeferenced imagery of high resolution by multibeam and/or ROV in search of any evidence of human behavior and pattern of any "post" array. The materials at the preserved contact area and its overlying sediments should be sampled. The species of wood and other organic debris should be determined and additional radiocarbon dating to determine precisely when the surface was transgressed should be undertaken. In addition to sidescan sonar Contact C282, the two mounded features in the Rockedundy River study area, SB Features 7/20 and 49, remain as unknowns with respect to significance. SB Features 20/7 and 49 are essentially the same kind of seismic reflector, but Feature 49 is somewhat deeper and therefore possibly older. The formation process is unknown but includes alternating beds of clay, shell, clay, and shell. At 5-foot and 14-foot depths below water surface respectively, both are on the edge of the channel ROW. A result of dredging, natural deposition, or due to prehistoric peoples, these features continue to be enigmatic and in need or more study to truly understand their presence. If they cannot be avoided by project activities, it is suggested that additional sampling and dating be conducted to help answer the question of origination.