Baltimore City Is Investing in Wetlands Restoration For Climate Resiliency and Adaptation. Scientists Warn About Unintended Consequences

Brad Rogers and Brett Berkley stepped carefully on the gravel sill along the Middle Branch of the Patapsco River in South Baltimore, which when covered with sandy fill will serve as the bed for 11 acres of newly constructed wetlands.

Rogers, executive director of the nonprofit South Baltimore Gateway Partnership, has a big role in overseeing the $200 million redevelopment of 19 neighborhoods along one of the Chesapeake Bay’s most neglected shorelines. He aims to double that investment in the next five years.

He’s a bricks-and-mortar guy by trade, but wetlands, he said, are “the first line of defense” to protect those redeveloped neighborhoods against storm surge, and climate change. 

Berkley, his environmental consultant, peered out as if he could see the future. “A successful restoration will depend on the construction of the sill, planting of native vegetation, and creating a gradual elevation change to support a diverse salt marsh ecosystem,” he said on a late summer afternoon. 

Six miles north up the Patapsco, in Baltimore’s Inner Harbor, Jack Cover walked through the floating wetlands exhibition recently opened at the National Aquarium.

A curator at the aquarium, Cover felt that wetlands were like nature’s connective tissue, where many species converged to weave the web of life. He sat down on a bench, recalling childhood memories of visiting the Chesapeake Bay and discovering a world of natural wonders. 

Back down on the Patapsco’s Middle Branch, Dr. Eric Schott, a marine researcher at the University of Maryland Center for Environmental Science, felt the same reverie from his boyhood on the Chesapeake as he stepped, long boots on, into the inky waters to measure temperature, salinity, dissolved oxygen, pH and turbidity, not far from the shoreline Rogers and Berkley had walked. 

Schott had momentarily traded places, assisting the graduate student he’s advising, Ronita Sequeira, who is studying the impact of wetland restoration on fish populations in the Chesapeake Bay. 

Her research completed the circle: She’d selected the floating wetlands at the National Aquarium as a study site for her dissertation, while Schott had, for years, co-chaired the scientific advisory committee for Roger’s wetlands restoration work, which he considered a unique research opportunity to understand wetland restoration in an urban setting. 

Under the Biden administration’s Investing in America agenda, federal and state agencies have received billions of dollars to incorporate nature-based solutions in their planning and infrastructure development works. Last September, the federal government rolled out the first-ever National Climate Resilience Framework, which embeds nature-based approaches in climate policies and actions undertaken by federal agencies. 

Wetlands can counteract climate change and extreme weather events and bring a host of ecological benefits, filtering water, reducing pollutants and flooding and providing a sanctuary for animals.

Rogers, whose organization is restoring a total of 50 acres of wetlands, felt it was a story of lost and found. The pursuit of economic growth and industrialization in South Baltimore had led to the loss of ecosystems, and now the push to restore these natural assets offered immense value. 

He found himself tied to the effort to restore the lost wetlands, which Cover thought were nature’s connecting tissue, and Schott was working to fully understand, 

“We’ve changed so much of the earth,” Schott says, “that we really need to understand how nature works in our presence.” 

Reclaiming Lost Wetlands One Acre at a Time 

Rogers and Berkley had pulled into a narrow 700-foot-long driveway next to Hanover Street, freshly layered with gravel. It used to be a tangle of invasive vegetation, large perennial reed grasses called phragmites, debris and litter, all of which a construction crew had cleared recently so trucks could bring in rock and sand for the sill that would be the base to hold planted marshes along the river. 

The smell of freshly cut plants and marshy water hung in the air. A giant excavator stood still in the distance. A construction worker was waist-deep in the Patapsco.

“He’s putting in the turbidity curtain in the river that will prevent debris from getting kicked up and carried into the main stem of the Middle Branch,” Berkley said, as he and Rogers walked along the sill. 

With $11.5 million in funding, the Hanover Street project will restore 11 acres of wetlands near the Brooklyn neighborhood and is expected to be complete by the end of 2025. It’s the first in the series of projects that would restore 50 acres of wetlands altogether along the 11-mile Middle Branch shoreline. 

South Baltimore communities suffer from historic disinvestment, which make them vulnerable to extreme weather such as heatwaves, heavy rain and flooding. The wetlands will help make South Baltimore’s disinvested neighborhoods climate resilient and protect the critical infrastructure nearby—MedStar Harbor Hospital and an oil and gas facility owned by the utility company BGE. 

But the task was not an easy one. Decades of urban development in and around the Chesapeake Bay watershed had fundamentally changed its historic outlook and that of its tributaries, including the Patapsco River. The onset of climate change and weather extremes put extra demand on mitigation strategies, including green infrastructure such as wetlands. 

“During the 20th century, there was a focus on engineering solutions like concrete and stone to address issues like flooding. However, these solutions had limitations,” Rogers said, adding that New Orleans was a good example of a city now employing green solutions to address environmental challenges. 

“In the 20th century, New Orleans was building gray infrastructure like dikes, flood walls and pumps to protect against flooding. Now, it’s restoring the damaged wetlands that protect the shoreline,” he said. 

To protect South Baltimore’s neighborhoods from climate-amplified weather extremes, the sandy sill had to be prepared with rock and sand and then three months of waiting would begin. “When everything is settled, the sill is in place, and the base of the marsh is in place, it gets planted. And when it’s all done, it will look pretty incredible,” Rogers said. 

Afterward, the wetlands will be reinforced with new vegetative berms to form a natural barrier against sea level rise, increasingly frequent storm surges and flooding, Berkley said. 

They recalled the time and effort it took to get to this point—regulatory approvals, community support, millions in funding and a team of technical specialists. By state law, Rogers’ nonprofit receives $7 million to $9 million a year in funding from the nearby Horseshoe Casino Baltimore. 

Once the current 11-acre restoration along Hanover Street is done by the end of 2025, Rogers hopes the restoration work will then extend along the shoreline, starting at the south fork of the Patapsco River and continuing around the Harbor Hospital area.

For a moment, he seemed immersed in the vast stretch of the Middle Branch, its gentle tides glittering under the afternoon sun, and the waves breaking against the shoreline with a splash. 

He looked at his watch. It was time to go back to his office and organize his thoughts from this reconnaissance mission along the shoreline before members of his board of directors would get on a boat in a couple of hours and come see the wetlands restoration for themselves. 

The National Aquarium’s Floating Wetlands

Jack Cover had been out in the sun for over an hour, talking to visitors and answering their questions about the National Aquarium’s newly inaugurated floating wetland exhibit. 

Dressed in a blue t-shirt and khakis, Cover sat down on one of the benches for a quick break, his eyes still fixed on the lush green marshes between the wooden walkways floating on the brackish tidal water of the Inner Harbor. 

“It wasn’t our intention to build a pollinator garden. But we have one now. And there’s hundreds of honeybees coming to that. I don’t think anyone would miss us if we disappeared,” he said of human beings. “But if we lost the honeybees, it’s game over for us. We depend on coexistence.” 

He considered it a marvel of technology and ambition that made it possible to create a durable, adjustable and buoyant structure to keep the marshes afloat but still partly submerged through tides of varying intensity. 

He got up, leaned against the railing and pointed out the intricate pressure valves and small tubes that were keeping the marshes afloat and able to withstand the tidal currents that can damage vegetation that has not yet grown natural roots.

“The wetlands have a unique adjustable buoyancy system, with pontoons underneath that can be filled with air or water to control the wetland’s elevation and prevent it from sinking as the weight of the vegetation increases,” Cover explained. 

The structure is made of fiber-reinforced plastic and high-density polyethylene, which are durable and flexible materials that can withstand storms and wave action. It is powered by a compressed air system, which forces water out of the pontoons to raise the structure and mimics the tidal changes in a natural wetland environment. A complex network of pipes, hoses, and valves controlled the flow of air and water to the different components of the wetland. 

A system of pilings driven precisely 50 feet into the substrate below allowed the wetlands to rise and fall with the tides as they would in natural settings. 

“I really feel we’re bringing the best of the Chesapeake Bay to Baltimore.”

— Jack Cover, Baltimore National Aquarium curator

The aquarium’s experience with maintaining natural environments for marine animals was applied to the wetland project, Cover said, benefiting both fish and bird species that are able to utilize the new habitat and food sources it provides.

“The wetland provides a nursery habitat for small fish like menhaden, which are a critical food source for larger predatory fish and birds like ospreys and herons. The shallow, flooded areas of the wetland offer protection for juvenile fish,” he said, adding that they also improve water by removing excess nutrients, which fuel algal blooms that deplete oxygen and harm fish populations. 

“When we were building these wetlands, I found two diamondback terrapins during my walk. It was just like what I remember as a child,” Cover said in a deep, measured tone, his gaze fixed on the expanse of marshes. “And it’s right here in the city. I really feel we’re bringing the best of the Chesapeake Bay to Baltimore.” The diamondbacks, a hatchling and a 4-year old, have since made the wetlands their permanent refuge. 

Urban Estuaries Are Making a Comeback

Eric Schott and Ronita Sequeira, his graduate student, had finished setting up lift nets and minnow traps around the fishing pier at Middle Branch Park, not far from the wetlands restoration along Hanover Street that Rogers and Berkley visited. 

Dressed for wet field conditions with rain threatening, Schott, an associate research professor at the University of Maryland’s Center for Environmental Science, and Sequeira were carefully navigating the shoreline littered with debris and lined with trees and bushy plants that inhibited movement. 

A researcher from India with a master’s in oceanography, Sequeira came to the United States to pursue a master’s degree in marine environmental and estuarine sciences at the University of Maryland, Baltimore County. Her degree program, a collaboration between various schools within the University of Maryland system, allowed Schott to be her mentor. 

As her academic advisor, Schott was guiding Sequeira through her research, which involved comparing two different wetland settings—a restored wetland and an adjacent non-restored vegetated site—to understand how the habitats affect water quality and fish behavior, including changes in fish breeding and feeding habits. She had selected the floating wetlands at the National Aquarium as a site she would also study. 

They had carefully set up nets and minnow traps baited with fish heads to capture small fish and other aquatic organisms. Another net was attached to a long bamboo pole that could be used to capture and lift fish out of the water. They were experimenting with different ways to deploy and retrieve the lift nets to effectively catch the fish.

“My overall goal is to better understand how wetland restoration projects in urban estuaries like the Chesapeake Bay impact the local fish ecology and community,” she said. 

As they waited until enough fish found their way into the traps to satisfy their sampling requirement, Schott, with the long boots on, took measurements of water quality. 

For years, Schott had known about Baltimore’s plan to redevelop the Middle Branch of the Patapsco River and restore a portion of lost wetlands. “When I heard about this project, it sparked my interest,” he said. “I’ve always been interested in the Middle Branch because it looked like a great ecological spot.”

Schott thought serving as co-chair of Rogers’ scientific advisory committee provided an opportunity for the research and scientific community to get involved in a way that could help the redevelopment project achieve a longer lasting benefit. 

“I grew up in Colorado, but I remember visiting the Chesapeake Bay as a child because my grandparents and cousins lived in this area. So, I have an affinity for the Bay and its ecology,” Schott said. 

As a scientist, he chose to focus on estuaries, particularly in urban environments, and Baltimore, with its nearly severed connection with the Chesapeake watershed because of rampant industrialization, provided a perfect backdrop for his research interests. 

Beyond protecting against climate change, could restoring wetlands help bring nature back to the Patapsco? “Wetlands can provide the necessary structure and habitat to support diverse fish communities,” Schott said, “and we want to quantify if the restored wetlands are actually increasing the abundance, diversity and condition of the fish populations.” 

He agreed with Cover’s assessment that wetlands served as nature’s connecting tissue, and he thought restored wetlands could provide a natural pitstop for migratory species along the urban estuary.

“This could be this little gem of natural space where the fish and birds that migrate in and out of the bay can come and have a healthy stopping point,” he said. 

He also felt initiatives like Rogers’ shoreline rehabilitation and wetlands restoration could provide an attractive and uplifting natural space for the surrounding communities, including working class and communities of color that have historically been underserved.

But the success of the project in delivering these benefits, Schott cautioned, will depend on the city and its partners’ long-term commitment to supporting the communities, and maintaining the wetlands. 

A Science in Its Infancy

Earlier, in an interview, another University of Maryland scientist, Bill Dennison, vice president for science applications at University of Maryland Center for Environmental Science, said he, too, was reassured by the investments coming to South Baltimore. But he emphasized the need to carefully assess wetland restoration. 

“Restoration science is still in its infancy, and there are challenges in how to restore wetlands well and make them resilient to climate change, especially with the rapid rates of sea level rise,” Dennison said. 

Citing research by Stephanie Yarwood, associate professor at University of Maryland College of Agriculture and Natural Resources, Dennison said that in some restored wetlands, like in the Delmarva bays, methane emissions are very high and not the same as in natural wetlands, even decades after restoration. 

“When you look at the biogeochemical processes, which include the microbial community, the soil microbes responsible for all the chemical cycling, even 40 years later, they’re still not achieving the same efficiency structure as natural wetlands,” he said. “It’s not easy once you’ve disrupted nature so significantly,” he said. “It’s a challenge to put it back together in a way that operates as we would like it to operate.”

But wetlands and marshes, he said, were much better at withstanding and mitigating impacts from storm surges than engineering solutions such as levees and seawalls. 

“In 2003, Hurricane Isabel brought a huge storm surge in Chesapeake Bay. The hard infrastructure was significantly damaged but the marshes were fine. They absorbed that storm surge, and when the water retreated, they recovered quite nicely,” he said. “So, we’ve got plenty of examples of how natural shorelines fare better than brick-and-mortar solutions.” 

Rogers wanted members of his board and other guests to get a sense of this first hand, out on the river. They started arriving at the South Baltimore Gateway Partnership’s offices as the late afternoon sun cast a magnificent radiance over the skyline of downtown Baltimore in the distance. 

They walked to the nearby pier where a mid-sized ferry, fitted with benches, was ready to take the visitors on a cruise around the Middle Branch. The ferry stopped close to the site where wetlands reconstruction had begun. 

Rogers, microphone in hand, explained that the project would be completed by the end of 2025—heavily planted wetlands, filled with migratory birds and teeming with fish and other aquatic life, mimicking the aquarium’s floating marshes.

 In that moment, with the sun setting, Rogers felt everyone on board could envision what he was talking about, connected to nature all around them.