Erosion threatens Coastal Georgia archaeological sites

Along the Savannah River in Chatham County are the remains of a large, complex, former rice plantation. Archaeologists may be able to learn much about the life of Georgia’s early inhabitants by studying this site, but only if they hurry. Site 9CH685, as it is known, is threatened by shoreline and tidal creek erosion – the result of the nearby river moving closer to the site every day.

Site 9CH685 is just one of 42 archaeological sites on Georgia’s back barrier islands recently studied by a team from the Skidaway Institute of Oceanography and the Georgia Department of Natural Resources (DNR) Historic Preservation Division. The sites include a range of types, from Native American shell middens to colonial cemeteries and Civil War artillery batteries. The team spent two years studying the erosion and accretion patterns near each site to assist DNR in prioritizing the sites that require the most immediate attention. Funding for the project came from the Georgia Coastal Zone Management Program.

“The Georgia coast is constantly evolving,” said Clark Alexander, the Skidaway Institute scientist who directed the project. “During the past 150 years, the shoreline has moved more than a hundred meters along many parts of the Georgia coast.  The natural forces of wind and water have formed and changed the shape of our coastline over the centuries and continue to do so.”

Typically it is not feasible to preserve sites against these forces, so it is critical to document the sites before they are lost if there is any hope to record the history contained within them.

“Once an archaeological site has been eroded away, it cannot be replaced and the information it contained is lost forever, said Chris McCabe,  deputy state archaeologist for the Georgia Department of Natural Resources (DNR). “The loss of archaeological information to natural processes in our dynamic coastal setting is an ongoing issue for us.”

The team used a combination of current shoreline measurements near the known sites, combined with historical shoreline information from aerial photographs, charts and maps, some dating back to the mid-19th century.

Skidaway Institute's Claudia Venhern uses a highly accurate GPS instrument to record the shoreline of a Georgia coastal island.

It was Skidaway Institute researcher Claudia Venherm’s job to survey the current shoreline. Using an extremely precise GPS receiver, she walked the shorelines measuring the exact location of the high water mark within a few inches. Later, she mapped the shoreline and compared it with the historic data for the same location to determine how fast the shoreline is changing.

“We can use Geographic Information System (GIS) technology to overlay the location of the current shoreline with the shorelines from older photos and maps and obtain a very good picture of what is happening to any piece of coast,” Venherm said.

All the sites were examined to determine which were in the most danger of loss to erosion. The projected life of each site was calculated as the number of years until erosion would destroy the entire site.

Six sites had already been lost to erosion by the time the team visited the coordinates for these sites. Four more sites were still present, but are completely or almost completely submerged at all stages of the tide. The team determined 21 of the sites were eroding, and three of those have a projected life of less than 50 years.

“This study will be a big help to us,” said McCabe. “We can’t stop the erosion, but we can prioritize our work, and maximize the amount of cultural information we obtain before a site is lost.”

That rice plantation site has already yielded clues about the early Georgia economy. The tidal creek threatening the main site has produced several surface artifacts from the late 19th and early 20th centuries. A section of whiteware dinner plate etched with the name “Greenwood China Company”, which designed dinnerware specifically for use aboard coastal steamboats, was found in the creek bed.

“This artifact suggests that materials from maritime vessels had found their way to a group of individuals living at the plantation,” said McCabe. “In addition, an aqua colored bottle embossed with the name ‘Packard & James New York’ was found.”

This merchant firm distributed spices and coffee at the end of the 19th century, and its discovery at a Savannah River site hints at important turn-of-the-century maritime sail and steam trading networks.

These glimpses into the past are fleeting however, as time and tide erase these ephemeral fragments of history.  This study provides the data that the DNR needs to save as much of Georgia’s rich coastal history as possible.

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