sea level, they can do quite well and keep up with rising water levels by building dense root structures and trapping storm-transported mud and sand. “If sea level rises too fast, marshes can begin to drown and shift to open-water areas or mudflats. Flooding during the nesting season can destroy bird nests or chicks of American oystercatchers and laughing gulls and many other bird species that depend on the marsh to nest and raise young.” As part of the lab’s work, dredged sand and mud from the nearby 117-mile New Jersey Intracoastal Waterway have been used to restore drowning marshes and create new habitats that are vanishing, using a variety of techniques. This work provides habitat for long-legged wad - ing birds, beach nesting birds, migratory shorebirds, and other species that use the marsh, and can also increase marsh elevations to protect the marsh itself. “Sediment is the currency of these ecosystems, and we know these marshes are sediment-starved, so we must work to find innovative ways to utilize the clean sediments that clog navigation channels to enhance marshes and offset sea-level rise,” said Tedesco. Thus far, USACE and its partners have completed multiple dredging and marsh restoration projects throughout the back bays of Seven Mile Island. The goal is to use dredged sand and muddy sediment to fill in low-lying and drowning areas of the islands and increase marsh elevations. This elevated marsh can provide nesting habitat for long-legged wading birds, such as egrets, herons, and ibis, as well as colonial and marsh nesting birds, such as the salt marsh sparrow, which builds a teacup- sized nest on or close to the ground. Two of the islands enhanced with dredged materials support nesting for 25 percent of the long-legged wading bird colonies in New Jersey in - cluding the glossy ibis, little blue heron, snowy egret, tricolored heron, great egret, and black-crowned night heron, according to The Wetlands Institute. Almost all of these birds are considered priority species of greatest conservation or are state endangered species or species of concern in New Jersey. In the last few years, birds have flocked to the project sites including beach nesting birds and migratory shorebirds including black skim- mers, common and least terns, American oystercatchers, sandpipers, plovers, and whimbrel. In addition, diamondback terrapins and horse- shoe crabs are also using these habitats, and the team’s restoration work is also enhancing some fish habitats. Innovation lab team members are monitoring these marshes and place- ment sites and seeking innovative ways to improve dredging and place- ment techniques. These projects are always evolving, and the team is using lessons learned to improve them through adaptive management. The team members find the work rewarding and enjoy working togeth - er. “It’s been wonderful. There is a true sense of respect and admiration
for each other and a sense of the importance of the work we are all doing,” said Tedesco. Philadelphia District’s use of dredged material has proven successful restoring bird habitats endangered by mother nature. USACE Norfolk District, on the other hand, is finding ways to beneficially use dredged sand and mud to create solutions for bird habitats endangered by progress. Hampton Roads Beneficial Use of Dredged Material Project, Norfolk, Virginia USACE Norfolk District During the summer in Norfolk Harbor, Virginia, people used to see an island filled with birds— thousands of them. For this reason, the locals called it “Bird Island.” Its official name is South Island, and for the last 30 years until 2020, it was home to the largest and most productive bird colony in Virginia. Approximately 25,000 seabirds, wading birds and other migratory bird species used the island for shelter, forging and nesting — away from disturbances and predators. Bird species on this island included the royal tern, sandwich tern, com- mon tern, gull-billed tern, black skimmer, laughing gull, herring gull, and the great black-backed gull. In Virginia, many of these species are identified as “species of great - est conservation need.” The gull-billed tern is designated as a state threatened species. With the exception of herring gulls and great black- backed gulls, many of these birds are in peril or need to be protected. On the federal level, the gull-billed tern and the black skimmer are U.S. Fish and Wildlife Service “species of conservation” and are listed as decreasing on The International Union for Conservation of Nature’s “Red List of Threatened Species.” South Island is part of the Hampton Roads Bridge-Tunnel complex, a se - ries of bridges, anchoring islands, and tunnels, which is presently undergo- ing a massive expansion that includes widening lanes and adding tunnels. This has required substantial construction activity on South Island, making the island unsafe and unsuitable for the birds to use as a nesting location. Understanding the importance of providing a safe alternative habitat, several agencies teamed together to investigate the feasibility of us- ing dredged sand and mud. These agencies include USACE Norfolk District, the Virginia Department of Conservation and Recreation, Virginia Tech Shorebird Team, Virginia Department of Transportation, and Virginia Department of Wildlife Resources. In Virginia, protecting bird habitats like “Bird Island” is especially important. According to Michelle Hamor, Norfolk District’s chief of the planning and policy branch, in Virginia, seabirds often nest in large groups. Because of this behavior, and because they like open, sandy areas, they typically breed in very few locations, so if a breeding area is lost, it can have profound consequences.
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October 2022
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