Jamestown Island Up Against The Wall As Rising Waters Imperil Artifacts

Annapolis MD

16 December, 2021

8:46 PM

Description

By Jeremy Cox, the Chesapeake Bay Journal Jamestown's story is overflowing with twists and turns. So, why not one more? When experts talk about how climate change is undermining the site of America's first permanent English settlement, the top of their list of threats is usually sea level rise. Water has risen in the lower Chesapeake Bay region by 1.5 feet over the past 100 years and is projected to rise another 3 feet by the end of this century. Dave Harp Virtually all of Jamestown Island's 1,500-acres lie less than 3 feet above the current water line. But the story behind the weakening of the property's seawall, 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 an engineering study of the seawall last spring and summer as part of an effort to save it. In October, the results arrived — but not the ones the organization was expecting. The analysis confirmed that, yes, rising water is damaging the 120-year-old revetment from the outside in. But it also showed that another consequence of climate change — heavier rainfall — is undoing it from the inside out. "We were thinking about climate change from rising water and sinking land, and that is absolutely the case," said David Givens, director of archaeology for Preservation Virginia. "But what we are seeing lately is extensive rain." Over the past two decades, a grass lawn known as Smith's Field — so named because it is the site where Capt. John Smith drilled his troops — has been devolving into a mud hole. Givens said the long-held belief among Jamestown's caretakers was that the swampy area was full of saltwater, pushed up from beneath the ground by a rising James River. A simple test proved otherwise. "We started testing the salinity of the water," Givens said, "and the encroaching swamp in the middle of our property has less salinity than tap water. And it's from the heavy rainfall. I never would have guessed that." Photographs dating from around 1900 show that Smith's Field was then dry enough to be used for raising corn, Givens said. As recently 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 rainfall, sometimes surpassing 4 inches a day, are increasingly causing water to pool on the field. The inundation kills off the grass. Left unprotected, the bare soil is prone to blow away once the ground dries out, lowering the elevation and making the area more apt to flood again, Givens said. About seven of the 22 acres owned by Preservation Virginia have turned into wetlands, the archaeologist said. He blames much of that loss on precipitation. Like much of the Chesapeake Bay region, Jamestown in southeastern Virginia is experiencing more rainfall. In James City County, which includes the settlement site, average annual precipitation amounts have been increasing by roughly 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 northern bank of the James River about 35 miles upstream from the Chesapeake. Preservation Virginia's holdings include the original fort site and a church tower from the 1600s. The National Park Service owns the balance of the acreage, which includes the ruins of the town that later spilled outside the fort's triangular footprint. The town was abandoned after the Colony of Virginia's seat of government moved to Williamsburg in 1699. The National Park Service released a climate change vulnerability report in 2019 that covered Jamestown Island. Of 59 historic structures or archaeological sites catalogued on the island in 1995, two had already been lost to erosion and rising seas, it stated. Another 24 had been damaged by the same forces. By 2065, the report estimated, only two archaeological sites will be entirely above water. By 2100, projections show, much of the 1,500-acre island will be underwater. "We are the poster child for history and climate change," Givens said. The 121-year-old seawall, a concrete slope built by the U.S. Army Corps of Engineers, continues to provide critical protection from erosion and storm surge, experts say. But that punishment has damaged the structure itself. Frequent repairs will likely be necessary for years to come, they say. The new assessment used ground-penetrating radar to reveal that the groundwater beneath Smith's Field is putting pressure on the seawall from its land side, Givens said. For that, he added, there is no immediate answer. Whatever the strategy, it will likely involve what he called "interesting mitigation." The final engineering report, due soon to Preservation Virginia, is expected to include recommendations. Most of the archaeological excavations in recent years have taken place in the vicinity of the old fort. But records of digs conducted in the 1930s and 1950s suggest that Smith's Field likely contains important artifacts as well, Givens said. Among them: human remains, buried building foundations and the remnants of a brick furnace dating from the 1600s, which probably supplied material for the church tower and the original statehouse. Much of that history is already inaccessible to archaeologists because of the rising groundwater, Givens said. Marcy Rockman served as the National Park Service's climate change adaption coordinator for cultural resources from 2011 to 2018, helping parks nationwide grapple with climate realities. When asked if the new findings about rainfall at Jamestown surprised her, she said, "At this point, there isn't a whole lot that surprises me about climate change … I'm expecting it to be surprising." Rockman and Givens described the current Jamestown archaeological efforts as a race against time and a changing climate. "There are going to be parts of that island that are going to be unreachable, and we will lose access to those archaeological sites," said Rockman, now a climate consultant. "They will still be there, but our ability to study them will be effectively impossible." The Chesapeake Bay Journal is a nonprofit news organization covering environmental issues in the Bay region. Sign up for a free subscription at BayJournal.com.