Jamestown Island Against Wall As Rising Waters Endanger Artifacts | Climate change
Jamestown’s history is full of twists and turns. So why not one more?
When experts talk about how climate change is undermining the site of the first permanent English colony in the United States, the first on their list of threats is usually sea level rise. The water has risen by 1 , 5 feet in the lower Chesapeake Bay area over the past 100 years and is expected to increase 3 feet by the end of this century.
Virtually all of the 1,500 acres of Jamestown Island are within 3 feet of the current waterline.
But the story behind the weakening of the property’s sea wall, built in 1900 and itself a historic structure, was more complicated than that. Preservation Virginia, the nonprofit that has owned the Jamestown site since 1893, commissioned a technical survey of the seawall this spring and last summer as part of an effort to save it. In October, the results arrived, but not what the organization expected.
The analysis confirmed that, yes, the rising waters are damaging the 120-year-old coating from the outside to the inside. But it also showed that another consequence of climate change – more rainfall – is defeating it from within.
âWe were thinking about climate change from rising sea levels and sinking land, and it absolutely is,â said David Givens, director of archeology for Preservation Virginia. “But what we’re seeing lately is heavy rains.”
Over the past two decades, a lawn known as Smith’s Field – so named because it’s the site where Captain John Smith trained his troops – has turned into a mud hole. Givens said the long-held belief among Jamestown wardens was that the swampy area was full of salt water, pushed out of the basement by a swollen James River.
A simple test proved the opposite. âWe started testing the salinity of the water,â Givens said, âand the overgrown swamp in the middle of our property has less salinity than tap water. And that’s because of the heavy rains. would never have guessed that.
Photographs from around 1900 show Smith’s Field was then dry enough to be used for growing corn, Givens said. As late as the early 1990s, it was grassy and regularly mowed. Givens recalled playing touch football there with his colleagues during their lunch breaks.
But heavier precipitation, sometimes exceeding 4 inches per day, increasingly causes water to accumulate on the ground. The flood is killing the grass. Left unprotected, bare ground is likely to blow away once the ground dries up, lowering the elevation and making the area more susceptible to flooding again, Givens said.
About seven of the 22 acres owned by Preservation Virginia have become wetlands, the archaeologist said. He attributes much of this loss to precipitation.
Like much of the Chesapeake Bay area, Jamestown in southeast Virginia experiences more precipitation. In James City County, which includes the settlement site, average annual precipitation has increased by about half an inch per decade since 1895, according to the National Oceanic and Atmospheric Administration.
Jamestown was founded in 1607 on a pine forested island along the north shore of the James River about 35 miles upstream from Chesapeake. Preservation The Virginia possessions include the site of the original fort and a church steeple dating from the 1600s. The National Park Service owns the remainder of the area, which includes the city ruins which then flowed into the exterior of the fort’s triangular footprint.
The city was abandoned after the seat of government from the Colony of Virginia moved to Williamsburg in 1699.
The National Park Service released a 2019 Climate Change Vulnerability Report that covered Jamestown Island. Of 59 historic structures or archaeological sites listed on the island in 1995, two had already been lost due to erosion and rising waters, he said. 24 others were damaged by the same forces.
By 2065, according to the report, only two archaeological sites will be entirely above water. By 2100, according to projections, much of the 1,500-acre island will be underwater.
âWe are the poster child of history and climate change,â Givens said.
The 121-year-old sea wall, a concrete slope built by the US Army Corps of Engineers, continues to provide essential protection against erosion and storm surges, experts say. But this punishment damaged the structure itself. Frequent repairs will likely be needed for years to come, they say.
The new assessment used ground-penetrating radar to reveal groundwater beneath Smith’s Field is pushing the dike from its land side, Givens said. To this, he added, there is no immediate answer. Whatever strategy is, it will likely involve what he called âinteresting mitigationâ. The final engineering report, due soon to be submitted to Preservation Virginia, is expected to include recommendations.
Most of the archaeological digs in recent years have taken place near the old fort. But records from excavations conducted in the 1930s and 1950s suggest Smith’s Field likely contains significant artifacts as well, Givens said. Among them: human remains, buried building foundations, and the remains of a brick kiln dating from the 1600s, which likely provided material for the original church steeple and state house.
Much of this story is already inaccessible to archaeologists due to rising groundwater, Givens said.
Marcy Rockman was the National Park Service’s Climate Change Adaptation Coordinator for Cultural Resources from 2011 to 2018, helping parks across the country cope with climate realities. When asked if the new findings on precipitation in Jamestown surprised her, she replied, âAt this point, there isn’t much that surprises me about climate changeâ¦ expect it to be surprising.
Rockman and Givens have described Jamestown’s current archaeological efforts as a race against time and a changing climate.
“There are going to be parts of this island that are going to be inaccessible, and we will lose access to these archaeological sites,” said Rockman, now a climatology consultant. âThey will always be there, but our ability to study them will indeed be impossible. “