Officials weigh how to address the effects of climate change at Jamestown

jojacobs@vagazette.com

Underground monitoring wells and drone-mapping are the first steps in determining how to save a colonial outpost from the effects of climate change.

The threat posed to Historic Jamestowne, the first permanent English settlement in the New World, by climate change has been on the minds of preservationists and scientists for years. Now, the agencies tasked with preserving the island’s history have taken the first steps in new efforts to address threats created by climate change.

“The outlook is they’re talking about as much as a meter of sea level rise,” Jamestown Rediscovery senior staff archaeologist David Givens said, adding the United States Geological Survey study he uses as a reference suggest that increase could happen in as little as 50 years.

A meter is about 3 feet. Such an increase would put much of Jamestown Island under water. The western portion of the swampy island, where Historic Jamestowne’s museum facilities and fort dig sites are located, would be less affected than the eastern part of the island, according to a National Oceanic and Atmospheric Administration map.

But a threat to the island anywhere spells a threat to historic preservation. Researchers have identified 58 sites with historic significance — scattered artifacts left behind by English settlers and Powhatan Indians — across the island. Some sites could be underwater in the future, said Dorothy Geyer, Colonial National Historical Park natural resource specialist.

“We’re worried about the whole island,” Geyer said, adding that subsidence — or the gradual sinking of land — compounds the effects of sea level rise.

Some outlying areas of the island have lost up to 200 feet of land since 1874 through a combination of subsidence and sea level rise, though that decrease has been uneven. Researchers are still trying to develop methods to measure shoreline change on the island, Geyer said.

There’s also a threat from below: river water has started to infiltrate into the soil underneath the island, pushing up the freshwater aquifer. Saltwater mixed with decaying swamp materials can create a potent cocktail that destroys artifacts, Givens said.

“That groundwater rising is definitely a problem. We’re digging down and some of the stuff is 16 feet deep,” Givens said, referring to buried artifacts.

Some artifacts have already been lost through centuries of change at the island, Geyer said.

And there are also the storms.

A more than century-old Army Corps of Engineer seawall protects the fort area from the James River. In the future, it likely will need to be repaired and a new breakwater will need to be built in front of it to help hold back waves, Givens said.

The seawall is going to need all the help it can get as some studies suggest future hurricanes will be more destructive.

A study conducted by National Center for Atmospheric Research scientists earlier this year found future hurricanes may have higher winds, move more slowly and dump more rain than current storms due to changes caused by climate change.

Storms have been a challenge since Preservation Virginia and the National Park Service first began their mission to preserve Jamestown Island, starting in 1893 and 1934, respectively. The organizations jointly administer the roughly 1,500-acre island.

Heavy rains make the ground unstable and high winds knock trees down, Givens said.

Hurricane Isabel hurled 9-foot waves at the site in 2003, and while the fort area escaped harm, offices and support buildings were damaged, Givens said.

Finding solutions

Faced with these threats, officials need a sense of what areas of the island are most susceptible.

“We’re still trying to figure out what’s going on,” Geyer said.

Five monitoring wells were placed at sites to track the rise and fall of salt and fresh water on the island in 2016. Researchers have identified 58 sites of value on the island, and an effort is underway to begin soil sampling at the other sites, said Gary Speiran, a research hydrologist of the U.S. Geological Survey.

The soil sampling could begin as early as October, pending the approval of a federal grant to fund the project. The proposal is to do a two-year study with a $150,000 budget split evenly between the years, Speiran said.

The study will determine how sites are affected by changes to the water table. Decisions will have to be made about which sites are higher priorities to excavate, Geyer said.

There’s also a drone-based mapping project underway, which will give officials a literal lay of the land. The project, which started in January, is an important first step toward establishing which areas of the island are at risk, Givens said.

“It starts with mapping. What do we have to lose and how are we going to fix that?” Givens said.

So far, the drone has only mapped Smith’s Field, a low-lying patch of grass just outside the Historic Jamestowne fort. Visiting graduate students and archeologists once played soccer on the field, but recently the area remains muddy, a reminder of the changes taking place beneath the feet of visitors, Givens said.

What comes after researchers take full stock of the danger hasn’t been determined. Generally, the information is seen as an argument to leverage funding for future projects, whatever they may be.

“We’re building a case,” Givens said, adding that the efforts will allow for planning and continued monitoring of the issue. “Longterm, it’s looking bad.”

There are a number of state and federal resources to consider when determining how to fund future preservation projects. Geyer didn’t rule out a request to Historic Triangle localities for project funding.

The solution to saving American history might be to dig artifacts up sooner rather than later, Givens said.

Faced with a variety of threats that will span decades, both today and tomorrow’s preservationists have a challenging road ahead.

“It’ll be ongoing for the rest of my career,” Givens said. “We are and will be training our replacements to address this.”

Jacobs can be reached by phone at 757-298-6007.

Copyright © 2018, The Virginia Gazette
28°