Huge wetland restoration touted for Blackwater
Standing near the water’s edge at Blackwater National Wildlife Refuge, John Gill pointed to a small island far offshore, in the middle of what appeared to be a large lake. A lake, he says shouldn’t be there, and which he wants to make go away.
Gill has a grand vision that is increasingly shared by others: He would like to see the water between the shore and the distant island filled with millions of cubic yards of muck dredged from the Chesapeake Bay’s shipping channels, then topped with millions of wetland plants.
The result would make Dorchester County on Maryland’s Eastern Shore the site of the most massive habitat restoration effort undertaken in the Bay: the creation of 11,000 acres—more than 17 square miles—of tidal wetlands.
“To me, this could be the Everglades of the Chesapeake as far as a restoration project,” said Gill, a biologist with the U.S. Fish and Wildlife Service’s Maryland Fisheries Resources Office. “What we are trying to do is not manipulate it so much as return it to what it should be.”
What Blackwater should be, he and others contend, is one of the largest marshes fringing the Chesapeake Bay. But a combination of factors—a canal that altered the area’s salinity, sea level rise, to a massive invasion of plant-chomping nutria—have devastated the wetlands.
The wetland loss has cost habitat for fish, blue crabs and waterfowl. It is also believed to have contributed to the loss of underwater grass beds in nearby areas of the Bay. As marshes erode away, plumes of sediment flow downstream, blocking sunlight critical for grasses.
Bringing them back, Gill said, would help to meet Bay Program goals to restore water quality, increase wetland acreage and protect habitat. “They are going to dredge,” he said, “and they have to put the material somewhere, so why not put it someplace where it fulfills Bay Program objectives?”
It’s a question that is getting a close look.
Restoration of the marshes at Blackwater is one of three new options offered in a draft 20-year plan developed by the U.S. Army Corps of Engineers in cooperation with the Maryland Port Administration for dealing with tens of millions of cubic yards of clean sediment that will be dredged from shipping channels in coming decades.
The other two options are expanding the existing Poplar Island restoration site and recreating two mid-Bay islands—James and Barren. Of the three, the Blackwater restoration is considered both the most costly, and the most environmentally beneficial.
As a result, the Corps included it in a draft environmental impact statement for its 20-year-plan even though it has not had a full feasibility study. “We felt it was too much environmental benefit to ignore,” said Scott Johnson, project manager for the corps.
The USF&WS and other agencies are urging the Corps to keep the Blackwater option alive when it issues its final environmental impact statement this summer.
The idea is attracting support, even among agencies that are often at odds over how dredged sediment is handled. The USF&WS, which is often associated with terrestrial habitat projects, and the National Oceanic and Atmospheric Administration, which seeks to protect aquatic habitat, often have opposing views on what to do with dredged material. But on Blackwater, they see nearly eye-to-eye.
NOAA is urging that the Blackwater alternative be included for further study because the restored marsh should improve fish habitat and protect downstream underwater grass beds by stabilizing sediment, said Peyton Robertson, deputy director of NOAA’s Chesapeake Bay Office.
“It looks like one that is worth talking about even if it expensive,” he said. “It has potential benefits that are worth examining and costing.”
The EPA was also expected to endorse further study of the option.
In the next 20 years, the Corps and the port administration estimate that 122 million cubic yards of sediment must be dredged to maintain shipping channels leading to Baltimore and to the Chesapeake and Delaware Canal.
Right now, there is no place to put nearly half of that amount—about 57 million cubic yards—as several existing sites will reach capacity in the next few years, and Maryland will end the controversial practice of “open water” disposal in the Bay.
The three new options would meet most needs for the 20-year planning period, and beyond. Blackwater restoration, Gill said, could potentially use between 12 million and 50 million cubic yards of sediment.
In fact, sediment from the Bay channels may be the only source that could supply the huge amount of material needed: Dorchester County is one of the lowest areas around the Bay.
“If we don’t do it, who will?” Johnson asked. “Where are you going to get that kind of material? Dorchester County doesn’t have millions of yards of spare material lying around.”
The biggest hurdle for the project could be cost. The federal government only pays for what is considered to be the least-cost, environmentally acceptable alternative. In the Bay, the least-cost option is dumping the dredged material in deep water, which costs only $5-6 per cubic yard.
The Corps estimates that the cost of restoring wetlands at Blackwater and nearby areas could hit $38 per cubic yard—one of the most expensive alternatives examined. Restoration of other mid-Bay islands is estimated to cost about $20 per cubic yard.
The fact that open water disposal is illegal in Maryland does not change the equation. It just means the state has to pay the difference between the least-cost option, and the option which is ultimately agreed upon. That’s a potentially huge bill. The tab for any of the restoration projects could be hundreds of millions of dollars over coming decades.
But if the dredged material is for an environmental restoration project, the federal government can foot 75 percent of the additional costs, as long as Congress agrees.
That option allowed the Corps to use dredged sediment to rebuild Poplar Island off Maryland’s Talbot County. The island once measured more than 1,000 acres, but rising sea levels washed almost all of the land away: By the early 1990s, only a few acres remained.
Under a plan developed by the Corps, the port administration and several state and federal agencies, the island is being rebuilt, using about 33 million cubic yards of dredged material to create 1,140 acres of wetland and upland habitats, all surrounded by a dike to prevent future erosion. Poplar Island remains the largest project in the nation for the beneficial use of dredged materials.
“We broke ground by getting this agreement to do this on such a large scale, and also to get agreement to not do the least-cost method of disposal,” said Charlie Stek, an aide to Sen. Paul Sarbanes, D-MD, who helped secure support for the project.
Because such projects are costly and take years to complete, they need to be authorized by Congress, and the administration needs to include the project in its budget for years into the future. That could be difficult in tight budget times, Stek said, and competition for Corps projects is stiff.
But, he added, “Blackwater is a great idea. The habitat restoration benefits that you are going to get out of it are really terrific.”
Most officials agree that any action at Blackwater could be a decade or more in the future. The other alternatives are further along in the process, and likely to proceed before Blackwater can be studied and started.
Even if the Corps keeps the project in its environmental impact statement, it would require a feasibility study, which would take three to five years and cost $5 million to $6 million to complete.
And there could be significant hurdles.
Don Boesch, president of the University of Maryland Center for Environmental Science, called the inclusion of Blackwater as a recommended option a “major win” for the environment.
But, he added, many practical issues remain before the project could take place. “There are lots of questions that have yet to be addressed,” he said. “There are potential show-stoppers.”
For instance, the water is too shallow to barge material into Blackwater, so the dredged material, mixed in water to create a slurry, would have to be piped to the refuge and nearby sites.
In addition, the dredged material and associated water would have higher salinities than what is in the marsh, with potential negative effects on soil chemistry. The dredged material could also contain potentially large amounts of nutrients that had been buried in the sediment. Those nutrients could help spur the revegetation of wetland plants on the site, but if adequate measures were not taken, they could leach from the site and cause downstream water problems.
But Boesch added that those issues could likely be addressed, and lessons could be gleaned from the large-scale marsh restoration using dredged materials in coastal Louisiana, which has had the greatest marsh loss in the nation.
But on such a unique project as Blackwater, Boesch said, engineers will have to be able to adapt to conditions as the project develops. “At some point,” he said, “you have to start doing it, and you’ve got to learn from what you are doing about how to do it more effectively.”
“The other thing you have to think about,” Boesch added, “is what are the alternatives—is it just to let the marshes go?”
Tidal marshes are critical habitats between open water and upland areas that provide habitat for myriad species. They also filter contaminants, trap sediment and stabilize shorelines.
Tidal marshes are also one of the habitats most in jeopardy around the Bay, largely because of pressure from rising sea levels.
Project proponents say the stakes at Blackwater are huge.
Its wetlands are considered internationally significant. They were one of only 19 sites identified as globally significant by an international team of scientists in 1971. They are one of only six priority wetlands identified by the North American Waterfowl Management Plan. And, The Nature Conservancy considers the refuge to be one of the “Last Great Places.”
Since the 1930s, when Blackwater National Wildlife Refuge was created, it has lost roughly 8,000 acres of tidal wetlands. That’s almost as much area as the 8,200 acres that was set aside in 1933. “We’ve lost a lot of the original reasons for which this place was established,” said Glen Carowan, the refuge manager.
Another 3,000 acres have been lost in surrounding marshes, which are part of the Chesapeake Marshlands National Wildlife Refuge Complex.
A canal, dug in the 1800s, connected the previously freshwater headwaters of the Blackwater to the salt waters of the Little Choptank River. The increased salinity and eliminated fish spawning habitat in the Blackwater. It also wiped out the freshwater wetland plants over hundreds of acres of marsh, causing some of it to erode, and the rest to be converted to a mud flat.
Things got worse in the 1930s when an exotic rodent from South America, the nutria, was released into the wild after a failed attempt at fur farming on the Eastern Shore. The rodents took up residence in the marshes, where they burrowed into the mud and chewed off the roots of marsh grasses.
With the loss of these anchoring roots, huge amounts of soil washed into the river, and ultimately into the Bay. Today, the river bottom is a mass of muck that Gill described as “brown mayonnaise.”
Sea level rise and land subsidence have also played a role. Water levels are about a foot higher today than they were in the 1930s, sending tidal waters into the weakened marsh communities and eroding them away.
But some things are looking up.
An effort to eradicate nutria, launched in 2002, turned the refuge into a nutria-free zone by last fall. A project scheduled for this spring will construct a barricade separating the Blackwater and Little Choptank rivers for the first time in more than a century.
In 2003, muck was dredged from the bottom of the lake, placed near the eroding shore, and topped with 70,000 plants by volunteers gathered by the National Aquarium in Baltimore.
The result was 15 acres of wetlands. But more impressive, they are wetlands that have persisted—and look fine—after two years. “I don’t think anyone can not be impressed with the results we have seen on the small scale,” Carowan said.
Once restored, the marshes may need periodic infusions of sediment to keep pace with rising water levels, Gill said. But he said such infusions may not be needed frequently. He noted that a 12-acre wetland restoration project undertaken 20 years ago was still in good shape.
While the task is daunting, Gill believes it can happen. “When we started cheerleading Poplar, we always thought that it was too expensive, and it would never happen,” Gill said. Then the state banned using the Bay’s deep trough as a sediment disposal site, forcing the need for new sites. Besides, he said, “the no-action alternative is that we lose it all.
Comments are now closed for this article. Comments are accepted for 60 after publication.