Community, Culture, Conservation, Coast

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Archeological sites in the Coastal Zone and a 1' increase in sea levels.

Archeological sites in the Coastal Zone and a 1′ increase in sea levels.

The Mississippi River Delta has hundreds of archeological sites that cover thousands of years of human occupation. Archeological sites are rapidly disappearing due to the effects of climate change such as sea level rise, as well as storm surge, and modern development.

Levees and floodgates provide flood control and aid in navigation. These forms of water management channel the Mississippi River into the Gulf of Mexico, thereby robbing coastal areas of fresh water and sediment it needs to survive. Additionally, canals and pipelines allow salt water to spread to inland coastal wetlands killing vegetation and making a path for storm surge waters.

MRDAM researchers arriving at an archeological site in the marsh.

MRDAM researchers arriving at an archeological site in the marsh.

The loss of these coastal lands and archeological sites happens faster in Louisiana than anywhere else in the United States. The amount of land loss has been estimated at 16.57 square miles per year from 1985 to 2010, which is about one football field per hour. The Mississippi River Delta Archeological Mitigation Project collects information on archeological sites to document Louisiana’s historical places before they disappear. Despite efforts to reduce rates of land loss, hundreds of archeological sites are currently being damaged, with a high risk of complete destruction over the next 50 years.

Methods

A geographic information system database was used to rank sites for excavation or preservation. This database takes information from archaeology, geology, and environmental sciences to make a cultural resource management plan. By using the most recent data on coastal erosion, sea level rise, and archaeological sites, we can estimate and plan for the possible impacts from climate change and human impacts These results will shape our knowledge of history, environmental science, and geology of southeast Louisiana.

Researchers piloting a drone during survey.

Researchers piloting a drone during survey.

Fieldwork was conducted in 2019 by a team of two archeologists, a geomorphologist, and three students. The team visited 21 archeological sites, six of which were underwater. At many of the sites that were not yet underwater, the team found shells, ceramics, and stone tools. Erosion and sea level rise was noted at all sites. The geomorphologists used a drone to collect aerial photos, which were used to make 3D images of the archeological sites and their landscapes. Additionally, historic photos were compared to contemporary photos to see how the landscapes and archeological sites had changed over time. These historical and recent photos were also used to measure how much land has been lost at each archeological site. This study will be used to make predictions about climate change and human activities and their effects to archeological sites.

Benefits

The Magnolia Mounds archeological site is seen rising out of the marsh from Magnolia Lagoon.

The Magnolia Mounds archeological site is seen rising out of the marsh from Magnolia Lagoon.

This project will help us understand how human settlements adapted to the natural processes of erosion, and sea level rise. Today, environmental changes are forcing people in Louisiana to move further inland as the coastline shrinks. This is a small-scale version of what is and will continue to happen along coasts and other deltas around the world. Environmental changes and unsustainable development practices have the potential to displace millions of people around the world. Future generations may not know or be able to appreciate what places and heritage was lost to sea level rise and coastal erosion. Many of these archaeological sites have never been studied and much of the knowledge connected with these places will be lost. Our archeological sites and cultural histories have the potential to tell a story of strength and adjustment to these extreme changes over a long period of time.

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National Center for Preservation Technology and Training
645 University Parkway
Natchitoches, LA 71457

Email: ncptt[at]nps.gov
Phone: (318) 356-7444
Fax: (318) 356-9119