Historic Resources Survey Area 1S, Onslow Island, Savannah Harbor Expansion Project Chatham County, Georgia

This report presents the results of a Historic Resources Survey conducted on behalf of the U.S. Army Corps of Engineers, Savannah District in support of the Savannah Harbor Expansion Project (SHEP). As part of its commitments in the Final Environmental Impact Statement (FEIS) for SHEP, the Corps must provide mitigation for direct impacts to approximately 5.7 hectares (ha) of salt and brackish marsh that would be lost as a result of SHEP construction activities. Area IS (Onslow Island), within Savannah Harbor, was identified as having the greatest opportunity to support the long-term success of a restored salt and brackish marsh system.

The survey was conducted January 11 - 12, 2021 and consisted of a geomorphological assessment and Phase I archaeological survey of the archaeological Area of Potential Effects (APE) and a viewshed study of the architectural APE. The Historic Resources Survey was conducted under an Archaeological Resources Protection Act (ARPA) permit issued by the U.S. Fish and Wildlife Service (FWS), as well as a Special Use Permit issued by the Savannah National Wildlife Refuge.

The geomorphological assessment consisted of the excavation of 10 mechanically excavated soil test pits and two trenches in an attempt to determine the original ground surface within the APE. A buried A horizon, the top organic layer of soil, also known as topsoil, was identified in three soil test pits and one long trench. Disturbed buried surfaces were identified in three soil test pits. Ground water infiltrated the remaining excavations before the exposure of any buried surfaces.

A Phase I archaeological survey was conducted based on the geomorphological assessment. No additional excavations were conducted. The buried A horizons and disturbed buried surfaces were encountered at depths of greater than I meter, beyond the depth of manual excavations. One archaeological site was identified in the southern portion of the APE. The Onslow site (9CHI 542) was identified in Soil Test Pit 8 based on the recovery of six wood fragments at a depth of 200 centimeters at the interface of the dredged material and the disturbed original ground surface. The wood fragments are likely remnants of the rice culture once prevalent on Onslow Island; however, no features were observed within the trench. Based on the disturbed nature of the soils and the lack of integrity of the site, it is recommended as not eligible for the National Register of Historic Places and no further archaeological work is recommended for site 9CH1542 or within the archaeological APE.

A historic building and structure survey was also conducted as part of this project. Earthen berms found within the project area were constructed between ca. 1960 and the late 1990s and recommended as not eligible for the National Register of Historic Places. The APE also included a sugar refinery dating to the late 1910s, visible from the project area. This sugar refinery was recommended eligible for the National Register as a historic district. The line of sight between the project area and the sugar refinery, however, is mostly obscured by a screen of trees on the west edge of Onslow Island. In addition, the project involves turning this part of the island back to its original, pre- l 940s state, as marshlands. The project will, therefore, have no adverse effect upon any architectural resources within the APE.