Wetlands are a stalwart feature of coastal Virginia’s landscape, serving as home to wildlife, cleaning the water and helping protect shorelines.
But in the coming decades, the region is sure to lose a large amount of these marshes – and it could even be a majority of them.
A recent analysis by NASA and Norfolk-based nonprofit Wetlands Watch estimated a 78% decline in Virginia’s tidal wetlands by the end of the century, largely due to rising sea levels.
Even if humans take action, the region would still lose about half of that by 2100, the analysis says.
“Unfortunately, that is the huge crux: even with intervention, we will still lose a significant amount of our wetland ecosystems,” said Gabi Kinney, community engagement project manager for Wetlands Watch. “That's why this kind of research is critical now, so that we can see what those high priority areas are and where the possible intervention lies.”
The nonprofit teamed up with NASA earlier this year to get high-resolution data on wetlands, including detailed information about different scenarios of land use decisions.
“We wanted to understand what wetlands are currently doing and what their future could look like,” Kinney said.
The team focused on Hampton Roads, extending to the Middle Peninsula and Eastern Shore.
The projected wetlands loss of nearly 80% by 2100 echo findings from the state’s Coastal Resilience Master Plan back in 2021, which predicted a loss of 89%.
Wetlands are low-lying areas of vegetation that are covered in water. So why can’t they handle more?
Kinney said wetland plants can grow by only about five millimeters per year. The rate of relative sea level rise — due to a combination of rising ocean water and sinking land — is outpacing that vertical growth, causing the plants to “drown in place.”
Some marsh grasses are also less able to filter saltwater, causing further die-offs as ocean water intrudes, Kinney said. This leads to a phenomenon called “ghost forests,” where coastal trees are slowly poisoned by saltwater.
The wetlands’ only option is to retreat inward toward land. That’s already happening naturally in some areas, like along the Back River in Poquoson.
In a notoriously flooded spot along Llewellyn Avenue in Norfolk, marsh grass has hopped across the street.
Allowing wetlands to migrate can help them survive, Kinney said. But that’s difficult in highly developed areas of Hampton Roads, where the plants have no room to retreat.
Wetlands Watch’s project with NASA looked at how much urban land would need to be converted to wetlands in order to preserve their numbers – for example, removing paved surfaces or seawalls to allow marsh to grow.
The analysis identified areas where that could be feasible, along with agricultural land where intrusion of saltwater is making it harder to grow crops.
Kinney said the team estimates that if all of those areas are created as “wetland corridors,” they could save about half of the projected losses.
“Even large-scale efforts to maximize re-naturalization cannot fully offset the inevitable loss of wetlands area due to sea level rise,” their analysis says.
A time-lapse graphic from NASA's DEVELOP Program shows projected decline in intertidal wetlands in Poquoson.
But that will be a heavy lift – and needs to happen quickly.
Molly Mitchell, a research assistant professor at William & Mary’s Virginia Institute of Marine Science, said most of the anticipated loss will happen in the next 30 years.
“As sea level is rising, it’s accelerating. It’s coming up faster and faster each year,” Mitchell said. “So we’re getting closer and closer to a threshold of what the marsh can do to keep up.”
Losing those wetlands, which help suck up carbon and filter out pollutants, will make it increasingly harder for local and state officials to meet water quality requirements, Mitchell said.
At the same time, changes at the federal level threaten wetland preservation efforts. A 2023 Supreme Court decision, Sackett v. EPA, narrowed the definition of wetlands protected by the Clean Water Act.
A recent analysis by the Environmental Defense Fund, published in the journal Science last week, found that 938,000 acres of wetland habitat in Virginia have lost federal protections in the wake of the Sackett decision.
Kinney said Wetlands Watch hopes to use its new data to inform policymakers.
The nonprofit Elizabeth River Project’s new headquarters on Colley Avenue in Norfolk is one example of an approach to saving wetlands.
The backyard of the property, which the nonprofit calls a “resilience lab,” is designed to allow wetlands to migrate inward over time.
