By the end of this century, the shoreline along the Port Norfolk Beach Reflection Walk in Portsmouth will likely look quite different.
Researchers at Old Dominion University have mapped the gradual march of marshes as rising sea levels drive them inward.
But it’s hard to imagine those impacts from looking at a computer screen. That’s what drove ODU’s recent “Green Line” project at the Port Norfolk park.
The team put up flags and signs and drew chalk outlines to illustrate the marshes’ projected future boundaries.
“The purpose of this was to get people thinking not just about when things flood, but how our landscape changes when these changes happen,” said Nick Carpenter, a doctoral student in ocean earth science. “And it is easier for all of us to visualize things in a 3D space on the ground.”
The initiative builds off of ODU’s previous “Blue Line” project a few years ago, said Professor Tom Allen, chair of the department of political science and geography.
The community engagement project marked “blue lines” around Norfolk to denote the potential range of tidal flooding under different sea level rise scenarios.
Allen said they then shifted focus to studying coastal squeeze, which is the loss of wetlands when rising sea levels push them against human infrastructure, such as bulkheads, seawalls and roads. That “squeezes” the natural habitat.
Coastal Virginia could lose up to 80% of its tidal wetlands by 2100, according to analysis by NASA and local nonprofit Wetlands Watch. The combination of rising waters and sinking land is outpacing marsh grasses’ ability to grow and is drowning them.
But they can be preserved if given space to retreat.
ODU chose Port Norfolk because it’s a prime example of an area quickly transformed by industrialization, said Austin Wood, a student in urban planning and emergency and hazards management.
The neighborhood grew in the late 19th century to house employees of the nearby shipyard. Hundreds of homes went up on land crisscrossed by wetlands and creeks.
“It's like you have marshes one day, and then the next day they're pouring stuff in to fill the marshes,” Wood said. “Nobody might have known the impact that that would have in the future. But we know now.”
The Green Line team created a digital tool overlaying an 1894 historical map with current aerial imagery.
Comparing the two reveals how land use has changed. A section of Route 164 and land at the Portsmouth Marine Terminal, for example, were previously home to a small branch of the Elizabeth River.
Houses on the outskirts of the neighborhood also sit on former inlets.
As waters rise, the sinking land wants to return to those watery days, threatening current residents.
The shoreline of the Beach Reflection park, which faces the West Norfolk Bridge along the Elizabeth River, includes a mixture of sand, rocks and vegetation.
The ODU team’s recent markers outlined projected retreat in 2040, 2060, 2080 and 2100. The closest years show slow progression inward through the park, with the latter years edging onto or across Bayview Boulevard.
On a map, the lines “look kind of small,” Carpenter said. “But when you go down to actually mark the lines, you're like, ‘Oh, this was a lot farther than I thought,’ definitely a lot bigger.”
These projections, however, will depend on whether humans allow the marshes to migrate.
“I can see things expanding if we let them expand,” Carpenter said. “But I can also see things just slowly withering away.”
Wood said they hope people will be motivated to advocate for preserving wetlands, but also use the information to make decisions on where and how to live in the area.
The goal is to highlight what we’d be losing, Allen said.
“What would we have without wetlands? We would have poorer water quality, less seafood, less pristine areas to recreate and have sports and aesthetic quality of life. So we need wetlands.”
