In the world of climate change studies, there are extensive global and regional models but fewer site-specific models. Lindsey Cochran, a postdoctoral research associate with the University of Georgia Laboratory of Archaeology, is working with digital data from the Georgia coast to recreate models that simulate site-specific changes from now until 2100.
“Archaeologists care a lot more about the context in which an artifact was found than the artifact itself. The combination of data--artifacts, soil types and stratigraphic layers, and features allow us to best interpret the ‘big picture’ of our collective past,” said Cochran. “Because of various site formation processes, the context, or different kinds of soil, around an artifact are extremely delicate, meaning that if a site gets flooded or inundated, it will very likely be destroyed. Without knowing the context of a site archaeologists cannot interpret who was at that site or what occurred at that place.”
Natural and anthropogenic climate changes, specifically from sea-level rise, are drastically reshaping coastal waterways and shorelines. Cochran will combine georeferenced maps from 1868-2015 with LiDAR data, which stands for Light Detection and Ranging, a remote sensing method that uses light in the form of a pulsed laser to measure ranges to the Earth. These light pulses generate precise, three-dimensional information about the shape of the Earth and its surface characteristics. This geospatial analysis will test if climate changes are occurring at an increasingly rapid rate and calculate the rate of change on the Georgia coast.
Using the models created from the digital data, Cochran will turn to the Archaeological State Site Files (GASF) for information to measure the number and type of our cultural resources that will be irrevocably damaged or destroyed by ongoing climate changes. The GASF, located in UGA’s archaeology lab, is the official repository for Georgia’s archaeological site information. The Historic Preservation Act established the GASF in 1976 to centralize information about historic properties and archaeological sites.
“These data are input into open sourced software, Sea Levels Affecting Marshes Model, or SLAMM, that processes LiDAR elevation data, wetlands inventory data, and sea level rise scenarios from the Intergovernmental Panel on Climate Change to produce estimates of site-specific climate changes,” said Cochran. “Using the SLAMM model, I can estimate when certain archaeological sites will be impacted by sea level rise, shoreline changes, and inundation.”
Identifying at-risk sites will allow researchers to catalogue the history of Georgia before it is lost, but it will help more than just archaeologists.
“The coastal sea level rise simulations should hold utility for disciplines outside of archaeology,” said Cochran. “The results from my research will be available to cultural resource specialists, site managers, and other resource officials so that we can work together to create a triage system to best document and preserve our state's resources before they are gone.”
Image: Lindsey Cochran taking water samples on Sapelo Island, Georgia.