Preparing For Climate Change In The Nation's Oldest City

Aug 19, 2016

Climate change in Florida is already taking its toll, in the form of rising temperatures, extreme weather events and shifting tides. The changes are sending archaeologists scrambling to protect the state’s historical resources. WFSU traveled to the country’s oldest city to tell this story.

A view of the Castillo de San Marcos and the Matanzas River.
Credit Kate Payne/ WFSU

On a sweaty summer morning in St Augustine, a group of archaeologists gathered at one of the state’s oldest and most iconic landmarks. The Castillo de San Marcos is a more than 330 year old limestone fort perched on the edge of the water, in a city first established by the Spanish in 1565. The Castillo offers commanding views of the Matanzas River, and beyond that, the Atlantic Ocean.

James Crutchfield, a National Park Service guide, gave the group a tour of the fort.            

“By the way the area you’re in right now is what’s called the ravellin. It is the defense for the one entry point into Castillo. So this was our first line of defense for the main entry point into the Castillo. We’re going to head down the Castillo,” Crutchfield said.

James Crutchfield is the last in a line of historic masons, and one of the only people left in the city who knows how to cut the hunks of coquina stone that make up the fort’s walls.

“The coquina is a very great material for protecting the fort in an attack, for cannonballs or muskets. Coquina is not a great material when it comes to fighting the everyday elements such as rain,” Crutchfield said.

The Castillo de San Marcos is built out of blocks of coquina, a kind of limestone made of seashells and coral. The coquina is vulnerable to rain and run off.
Credit Kate Payne/ WFSU

Crutchfield, like the fort itself, is struggling to keep up with the changing tides. St Augustine and coastal and low-lying areas across the state are already plagued by so-called nuisance flooding. Florida’s notorious summer showers, combined with high tides, are enough to flood the streets in some cities. And in a town where it’s difficult to dig a hole without hitting some 17th century artifact, there’s a lot at stake. A hundred archaeologists, architects and urban planners gathered in St Augustine to make a plan.

Archaeologist Rachael Kangas she monitors Native American mounds on Pine Island in Southwest Florida.

“So when we look at a one foot rise, we already are seeing pretty significant effects to our coastal regions. And once we get to a six foot sea level rise, you can see that most of our coastal cities are at least partially flooded, if not completely flooded,” Kangas said.

She’s uncovered, among other things, a thousand year old fishing net made out of palm fibers. But why bother with archaic tools and ancient trash piles? Shouldn’t basic infrastructure – roads and wastewater plants - take precedence? Archaeologist and out-going University of West Florida president Judy Bense made this argument.

“No one else can tell the human story except us. And we know that. And it is something that is deeply important to who we are as not just humans, but as American citizens. And certainly as anthropologists and archaeologists. We’re very special people. It doesn’t mean we’re better or we’re worse than anybody else. But we have a very special view that we look back into the past and deduce what must have happened,” Bense said.

A view of the Castillo de San Marcos from across the Matanzas River, circa the early 1900s.
Credit Florida Memory / https://www.floridamemory.com/

Bense and her colleagues believe it’s vital to understand past civilizations and their impact on the present. There’s even evidence of previous residents of St Augustine fortifying their city against the changing tides, hundreds of years ago.

“There could be multiple tidal events shown in the archaeological record and you could see multiple floor levels that show that they were rebuilt right on site. So the materials that were used for construction such as say, coquina buildings, when properly maintained, they could withstand tidal events and they would just repair and move forward,” Wolfe said.

Statewide, the Florida Public Archaeology Network is monitoring more than 29,000 buildings and nearly 4,000 sites endangered by sea level rise. Some members, like Rachael Kangas, are already seeing sites disappear.

“So when we talk about sea level rise at Pineland, right now it’s fairly stable. And even with a two foot rise, we’re pretty stable as long as there’s no storm activity. But once we get to a six foot rise, the entire site is inundated with water, again with the exception of those two nice tall mounds,” Kangas said.

Many coastal communities are establishing living shorelines: beds of oysters and seagrasses that act as a natural buffer. Some private homeowners in St Augustine have taken to simply raising their houses, some by 10 feet or more. But back at the Castillo, that just isn’t an option. And the city isn’t keen on building a large, obtrusive sea wall either. Their current wall can withstand a Category 1 hurricane, and they think that will do for now. In the meantime, Crutchfield and his team are documenting everything, preserving what they can, and enjoying the view of the water.