Oyster reef might be key to saving Tangier Island

By Jeremy Cox
Posted 12/28/22

Tangier Island in the Chesapeake Bay has long been engaged with a battle against erosion and rising water. Has its salvation been skulking just offshore this whole time?

Two potential projects …

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Oyster reef might be key to saving Tangier Island

Posted

Tangier Island in the Chesapeake Bay has long been engaged with a battle against erosion and rising water. Has its salvation been skulking just offshore this whole time?

Two potential projects would deploy oysters, one of the cornerstones of the island’s seafood-based economy, as protection against land-devouring waves and storm surge. Both are in the early stages of development.

The efforts would construct oyster reefs close enough to the shoreline for the structures to be above the water’s surface during low tides and at least partially during most high tides. The result would be a kind of living wall that could deflect wave energy.

Tangier Island, Virginia’s only inhabited island not connected to the mainland by a bridge, has drawn media attention from around the world as an early battleground in the fight against sea level rise. One scientific forecast suggests that the island’s 400 residents will be forced to leave in about 30 years as the remaining dry land converts to saltmarsh.

Self-reliance may be at the core of Tangier’s culture, but for years its leaders have been clamoring for outside help to extend the life of their shrinking island.

Norwood Evans, a Tangier Town Council member, said the community can’t afford to wait much longer. “I’d like to see stuff move along,” he said.

He recalled watching helplessly recently as waves pummeled the shoreline, breaking off chunks “like flipping open a soda tab.” Evans said he believes that the two oyster restoration projects would go a long way toward sheltering the island from further losses.

Oysters already lurk in the surrounding waters, of course, but are nowhere near their historic densities, and their reefs no longer reach heights that break the water surface. The new efforts seek to change that.

The first project is an effort to shore up two vulnerable stretches of Tangier coastline. Both were identified by the council as top priorities for protection.

They lay along a low, marshy shard of land separated from the main island by a narrow boat channel. The “Uppards,” as it is known, was home to a settlement whose residents departed by the 1930s because of its isolation and increasing inundation.

The top-ranked site lies at the western opening of the boat channel. The construction would take place next to a stone jetty completed in 2020 by the U.S. Army Corps of Engineers. Plans call for constructing two spans of oyster reefs to knock down incoming waves. Behind that, a granite sill would provide the structural envelope for dredge material to create a sliver of new land consisting mainly of marsh and dunes.

The second-ranked site would build up an eroding peninsula on the easternmost point of the Uppards. Here, four rows of oyster reefs would stand guard over another new spit of land.

“We’re trying to preserve or re-establish that first line of defense, which is also their last line of defense because they don’t have that much land,” said Russ Burke, a marine scientist with Christopher Newport University in Virginia.

The university is part of a group of academic institutions that applied this fall for $11 million to fund the project through the National Oceanic and Atmospheric Administration’s Transformational Habitat Restoration and Coastal Resilience grant program, which received $85 million under the federal infrastructure law of 2021. The awards are expected to be announced by the end of this year.

Burke said that the proposed reef sites are located away from the populated portion of Tangier so that they won’t interfere with the navigation of fishing boats and tourist-carrying ferries. But their placement and orientation will still help protect the main island from erosion.

“Living shorelines,” which rely on natural techniques as opposed to rip-rap or bulkheads, have been created to stem erosion at many locations around the Chesapeake Bay. Supporters say that in addition to combating land loss, incorporating oyster reefs into such projects also takes advantage of their role as filter feeders that improve water clarity.

Both Maryland and Virginia have laws on the books that establish living shorelines as the preferred method of protecting coastal properties. But the science remains spotty over how much protection oyster reefs provide against erosion. Burke said that his team plans to use the Tangier sites as testing grounds for different techniques.

“What we learn from this will determine whether it’s worth expanding or tweaking on other parts of the island,” he said. “For an island that’s talked about a lot but doesn’t get that much help, this is a significant investment that could turn the tide for their ultimate fate.”

The second potential Tangier oyster project, being developed by the Army Corps, is not as far along. But Heather Lockwood, a project manager with the Corps’ Norfolk office, said she expects the design study to begin in the coming weeks.

One of the first tasks, she said, will be determining how water currents swirl around Tangier. That will show where oyster larvae would be expected to wind up — and indicate where reefs should be developed. Construction could begin as early as 2025.

The project is set to include both the restoration of underwater reefs as well as some constructed vertically near Tangier’s shoreline, which would provide erosion benefits, said David Schulte, an Army Corps marine ecologist who has conducted studies on the island’s erosion rates. He also is involved with Burke’s project.

The community won’t be saved by oysters alone, Schulte cautioned. Its land will also need to be raised out of the reach of sea level rise, probably with off-site dredge spoil. But if the oyster reefs can be built soon enough, they could help significantly extend the island’s lifespan, he said.

“It’s definitely not a cure-all, but it will reduce erosion in some of their key spots,” Schulte said. “I would consider this a part of a much larger effort to save the island.”

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