Beyond the storm: science for managing our changing coast

There is a silver lining to every storm cloud, and to many coastal sites in the North Atlantic region, too.

Consider Blackwater National Wildlife Refuge on the eastern shore of the Chesapeake Bay in Maryland, established as a sanctuary for migratory birds because of the vast expanse of contiguous saltmarsh habitat encompassed within. A study conducted by Salisbury University revealed that between 1938 and 2006, the Refuge lost over 5,000 acres of that marsh to land subsidence, erosion, and sea-level rise. That’s equivalent to more than a third of Manhattan.

“It hasn’t gotten any better since then,” notes Matt Whitbeck, Supervisory Wildlife Biologist at Chesapeake Marshlands National Wildlife Complex, which includes Blackwater. For the communities of people and wildlife that rely on those tidal wetlands for food, shelter, and quality of life, the forecast probably looks pretty gloomy.

Supervisory Wildlife Biologist at the Chesapeake Marshlands National Wildlife Refuge Complex Matt Whitbeck explains that sustaining marsh habitat into the future means planning for change. Photo: Steve Droter

But hark, is that a bright spot on the horizon? “That study also shows that as sea levels rose, nearly 3,000 acres of upland at Blackwater converted to new tidal marsh,” explains Whitbeck.

That’s because Blackwater has both the physical space and functional processes, like inputs of sediment and freshwater, needed for marsh habitat to migrate inland. And it’s not the only bright spot. In a new study supported by Hurricane Sandy Resilience Funding, scientists from The Nature Conservancy (TNC) identified thousands of other coastal sites that have the potential to migrate, and in doing so, to offset more than 50 percent of the total predicted tidal habitat loss in the region.

TNC calls these places “coastal strongholds.” I call them silver linings.

The final product is called Identifying Resilient Coastal Sites for Conservation, and offers a resource for managers working at any scale to make strategic decisions toward helping coastal systems and communities adapt to changing conditions. The report and data are available to download from TNC’s Conservation Gateway, and will soon be rolled into the Nature’s Network conservation design to refine existing information on opportunities to maintain regional connections and connect tidal marshes to adjacent uplands.

A range of species, including saltmarsh sparrow and blue crab, depend on healthy saltmarsh habitat. People do too. Photos: FWS

“Because of the rate of change we are seeing in the Chesapeake Bay — where sea level rise is twice the global average — we need to think not only about where habitats are now, but where they are going in the future,” explains Whitbeck.

To his credit, he has been thinking about that for years. In 2011, Whitbeck partnered with The Conservation Fund, Audubon Maryland – DC, and the Chesapeake Conservancy to develop a strategy for salt marsh persistence at Blackwater.

But he says TNC’s tool represents a “huge step” forward. “It reinforces what we found in our study, but it also expands upon it, and can help us work across borders with new partners.”

A collaborative approach is critical for Refuges to meet their mandates for protecting fish and wildlife, and for ensuring that neighboring communities continue to benefit from functioning natural systems. Blackwater provides habitat for at-risk species like saltmarsh sparrow and Delmarva fox squirrel, and a nursery for species like blue crab that support the Chesapeake Bay’s economically and culturally important fishing industry.

The Refuge also provides a buffer against destructive storm surges that threaten infrastructure and public safety. TNC’s study is a call to action for protecting the marsh habitat we depend upon, but it also offers strategic guidance for how to do so effectively and efficiently.

“Although the study confirms that the Chesapeake Bay is seeing a great deal of marsh loss, it also shows that this system can be resilient moving forward if we plan right,” says Whitbeck.

And nowadays, planning “right” requires planning for change.

“When I was in school, pre-colonial conditions were the gold standard for land management. What was it like a few hundred years ago? That’s what we want to bring it back to,” remembers Whitbeck. “The lesson at Blackwater is that we have to let that go and think dynamically about maintaining a suite of habitats and ecosystem services across an entire landscape, and this tool can help us do that.”

The new gold standard might be to look for the silver lining.

Building a Stronger Delaware Bay

This guest post was written by “Captain Al” Modjeski, Habitat Restoration Program Director for the American Littoral Society, as part of our #StrongerCoast campaign. Here, Captain Al describes work to restore multiple beaches along the Delaware Bay.

A horseshoe crab on the sand at Reeds Beach. Photo credit: Steve Droter

In 2012, Hurricane Sandy’s powerful westerly winds caused a storm surge so strong it stripped the sand right off most of the beaches on the New Jersey side of Delaware Bay. The sand was washed into adjacent marshes, exposing large sections of peat and leaving the sand well above high-tide line.

In the storm’s aftermath, conservation groups rallied together with community and state leaders, local biologists, and local contractors to deal with the environmental damage.

“It was a crisis response; we were racing against a firm deadline of the horseshoe crabs arriving on the beach,” said Tim Dillingham, executive director of the American Littoral Society. “But we were also intent on rebuilding habitats along Delaware Bay in order to strengthen the ecology, communities, and economy of that area. We set out to build partnerships and relationships that would invest everyone in working for a healthy and resilient Delaware Bay.”

The immediate concern was that nearly 70 percent of horseshoe crab beach habitat was destroyed and its loss imperiled not only the horseshoe crabs that spawn there, but also shorebirds like the Federally listed red knot, which stop on those beaches each spring to feed on crab eggs before flying to their nesting grounds in the Canadian Arctic. The birds and crabs help fuel a multi-million-dollar annual ecotourism industry in New Jersey’s Bayshore region.

“The horseshoe crabs can’t lay eggs on these beaches because the exposed sediment is anoxic [devoid of oxygen]. If the crabs were to lay eggs here, they would just die,” said local biologist Larry Niles. “In just one day, these very important beaches went from highly suitable to unusable.”

Horseshoe crabs spawning on Thompsons Beach as restoration finishes just in the nick of time. Photo credit: Shane Godshall, American Littoral Society

Within days after the storm had passed, just over a mile of damaged horseshoe crab beach habitat was restored. With further funding from the Service and National Fish and Wildlife Foundation, the team was able to continue efforts and by 2017 had restored eight Delaware Bay beaches to their pre-Sandy footprints by bringing in more than 200,000 cubic yards of coarse-grained sand and removing 2,000 tons of rubble. The team also designed and constructed five inter-tidal oyster reefs to keep the sand on the beach, while beginning work to restore portions of the marsh behind those beaches.

“No one seemed to care about [Reeds] beach before,” said local resident Harry Bailey. “Storms came and destroyed the beaches, and no one came to fix it. These organizations came in; now the beach is built up, the horseshoe crabs are back, and birders from all over the world come here to see the birds.”

Harry Bailey, resident of Reeds Beach. Photo credit: Steve Droter

“The economy of Cape May County is so heavily tourism dependent, and more and more people come to the bay because of the scenic beauty and the wildlife,” said Cape May-Lewes Ferry Marketing Manager Michal Porch. “It’s in our best interest to maintain the economy and peoples’ jobs by protecting and preserving the environment.”

For the construction companies involved, millions of dollars of the grant funding went directly to them and further stimulated local businesses indirectly.

“It’s what drives our economy down here,” said JR Heun of H4 Enterprises. “Without the tourism, the infrastructure wouldn’t be there for us to have our workload.”

However, this restoration may mean more to the bay communities, the residents, the businesses, and the economy of the bay than simply protecting streams of revenue.

“Our restoration did not just restore the ecologic resource value for birds and crabs, but it also restored Bay-wide faith and hope. In the face of despair, the Bay community saw it had not been forgotten and people’s lives could be restored and even improved,” said Capt. Al Modjeski, Habitat Restoration Program director for the American Littoral Society.

As part of the restoration, the Society began a paid U.S. Military Veteran Intern Program, where local veterans were hired to help with the restoration work and monitoring.

That program “has given me something to do and I’m learning as I’m doing it, so I’m enjoying it tremendously,” said U.S. Army Veteran William Anderson, regarding his internship.

Tim Dillingham, American Littoral Society executive director, tosses shell bags to Beth Freiday of the Service during the 3rd Annual “Shell-A-Bration” at Thompsons Beach. Photo Credit: David Hawkins, American Littoral Society

The Society also held Local Leader Focus Groups to engage surrounding municipalities and community events like annual “Shell-a-Brations,” where hundreds of volunteers were involved in constructing the oyster reefs at restored beaches. Tying together all of those other efforts were yearly “Veteran’s Day on the Bay” gatherings, where the reefs were named to honor U.S. military veterans and the resolve of the Bay community to persevere against all odds.

“I think it’s very important that with this project, these organizations are helping both veterans and youth as well as educating people about the environment and how important it is to take care of it,” said former mayor of Middle Township Tim Donohue. “It’s good to get kids and families involved in the project to understand the significance of the Bay.”

Though it has been only five years since the storm, the Society and its partners hope to continue to holistically restore the Bay, and thereby help create even more sustainable and resilient natural and human-built communities that are informed by events of the past in order to be better prepared for the future.

A Bottom-up Boost for Coastal Habitat

Today we hear from Elizabeth Rogers, with the National Park Service at Fire Island National Seashore in New York State. Elizabeth spent some time this spring and summer working as a Public Affairs Specialist with the Fish and Wildlife Service, sharing the stories and science of resilient coastal communities and systems. On her days off, she can be found exploring the outdoors or dabbling in the kitchen.

The smell of the salt marsh can be overwhelming. Deep layers of mud dampened by the tides are rich in nutrients but low in oxygen. Bacteria within these layers feed on sulfate from seawater and produce the characteristic rotten-egg smell of the salt marsh. It is here, in the sometimes-smelly subsurface of the salt marsh, that Dr. Bart Wilson focuses his attention.

Salt marshes are considered “green” infrastructure. These natural habitats can help protect neighboring coastal communities by buffering against wind and waves and absorbing, then slowly releasing, floodwaters.

Salt marshes also provide habitat for fish, birds, and invertebrates and purify water by taking up nutrients that can be harmful in excess. According to Wilson, the U.S. Fish and Wildlife Service’s Northeast region coastal resiliency coordinator, marshes and the many benefits they provide are threatened by accelerated sea-level rise.

Salt marshes, like this one at Prime Hook National Wildlife Refuge in Delaware, offer habitat for fish and wildlife, while purifying water, absorbing floodwaters, and buffering wind and waves. Credit: USFWS

“Marsh elevation builds naturally from the bottom up,” says Wilson. “Organic material, like the roots of saltmarsh grasses, gives the surface a lift.”

To the plants and animals in tidal marshes, elevation is everything. Higher ground is home to plants and animals adapted to survive occasional flooding, and species that can withstand daily flooding by high tide live at lower elevations within the marsh. Smooth cordgrass (Spartina alterniflora) is salt-tolerant and typically grows where high marsh and low marsh meet, near the mean-high-water mark.

In addition to the bottom-up boost from below-ground plant roots, marsh elevation can slowly increase as sediments accumulate at the surface. Sediment may come from a nearby creek or river, or from the adjacent marine environment. Salt marshes tend to thrive in locations where these elevation gains are in a natural balance with elevation losses due to sea-level rise, erosion, and subsidence (the natural, gradual sinking of a land mass).

In many salt marshes, elevation loss has been outpacing elevation gain, threatening the survival of these systems. In response to this trend, nearly three decades ago, scientists began looking for a way to give salt marshes a lift.

According to Wilson, dredging sediment from nearby rivers or other waterways and spreading it onto high marsh free of vegetation builds “elevation capital.” The technique, called thin-layer deposition or TLD, helps salt marshes better withstand sea-level rise and subsidence. In some cases — where ditches or channels have been dug and have altered the way water naturally moves through the marsh, where upstream dams starve a salt marsh of sediment, or where infrastructure impedes the natural shoreward migration of marshes — restoration methods like TLD may be a way to maintain these ecosystems and preserve their many benefits.

The saltmarsh sparrow, whose numbers are declining, is one of many species that depend upon salt marsh habitat for survival. Credit: K. Papanastassiou

The Service first tested TLD in the Northeast in 2003 at Blackwater National Wildlife Refuge in Maryland. This small demonstration project succeeded but left managers and scientists with more questions, including how to decrease costs while maximizing results.

In 2013, dredge material was used for the first time by the State of Delaware to restore a marsh at Pepper Creek. Not only did this effort help land managers better understand the amount of material needed to build maximum resiliency, it also demonstrated the practicality of reusing sediment from nearby dredge sites.

Following Hurricane Sandy in 2012, federal funding for recovery and resiliency offered the opportunity to begin to answer those questions. Sandy funds are supporting five TLD projects at four national wildlife refuges in the Northeast.

For Wilson, these restoration projects go beyond just testing the technique. TLD projects, he says, are about, “conserving bird, fish, invertebrate and mammal habitat; enhancing flood attenuation, carbon sequestration, and nutrient uptake; and, protecting roads, houses, and waterways.”

By restoring elevation, TLD is helping restore natural marsh function, and the multiple benefits of this gorgeous green infrastructure lining our coasts.

A small-scale study with big impact at Blackwater Refuge

For thousands of years, tidal marshes have “kept their heads above water by building up roots below the surface,” says Blackwater National Wildlife Refuge Supervisory Biologist Matt Whitbeck. Only recently has the natural ability of these systems to grow vertically not been enough. As a result, says Whitbeck, “the marsh is essentially sinking.”

The Blackwater Marsh is unique in that the causes of its decline have been well-studied. Until the Chesapeake Bay Nutria Eradication Project began in 2002, nutria, root-loving rodents introduced to the United States in the nineteenth century, hindered natural marsh build-up. Since then, erosion from storm waves and subsidence have been the primary causes of marsh loss.

This historic perspective, and information collected by scientists over the years, helped Whitbeck strategically select 40 of Blackwater Refuge’s 28,000 acres of salt marsh for a Sandy-funded TLD project managed by the Conservation Fund.

Sediment is dredged from one place in a salt marsh at Blackwater National Wildlife Refuge in Maryland, to be sprayed in another. Credit: Dave Harp, Chesapeake Photos

Sediment is sprayed onto a marsh at Blackwater National Wildlife Refuge to compensate for its natural tendency to sink and the effects of sea-level rise. Credit: Dave Harp, Chesapeake Photos

To the casual observer, the project site looks as lush and green as any other on the marsh. But Whitbeck, who has spent more than nine years monitoring the marsh, says this project was a much-needed boost for marsh threatened by rising seas and more frequent powerful storms.

“Because we knew this area was losing elevation faster than elsewhere on the marsh, we could work to protect it.” And safeguarding this relatively small site helps protect a swath of salt marsh that supports one of the densest populations of bald eagles on the East Coast.

Partnering for the future at Forsythe Refuge

Restoring marsh elevation requires resources. Securing funds, permits, and a sediment source can be a major challenge for land managers. At Edwin B. Forsythe National Wildlife Refuge in New Jersey, the Service is solving this problem by partnering with federal, state, and local agencies on three TLD projects.

Though the first project is still in the design phase, Edwin B. Forsythe National Wildlife Refuge stands to benefit from a New Jersey Department of Transportation channel-dredging project that will supply sediment for nearly 70 acres of degraded salt marsh. An environmental assessment of the project was completed in the fall of 2016 and will guide implementation, ensuring channel sediment is placed on the marsh when it is least likely to affect fish and wildlife.

This salt marsh at Edwin B. Forsythe National Wildlife Refuge in New Jersey will be restored using thin-layer deposition. Credit: USFWS

The goal of the project is to “re-establish an optimum elevation for salt marsh plant growth,” says Amy Drohan, a Service biologist and lead on the project. As a bonus, Drohan says pulling the permits and plans together for this project will help speed the process in the future.

Recycling sediment to protect marshes at Rhode Island Refuges

The Service’s Hurricane Sandy resiliency coordinator, Dr. Jen White, has managed two TLD projects in Rhode Island since the storm hit in 2012. A focus of these projects has been to work with partners like The Nature Conservancy and Save the Bay to make use of available sediment to restore marsh habitat and function.

TLD, or “elevation enhancement,” as White prefers to call it, is considered a “beneficial reuse” of dredge or construction sediment. Material that would otherwise be disposed of at upland or offshore sites can instead be used to build up degraded salt marsh sites.

Elevation enhancement treatments were carried out at two Rhode Island refuges, where sediment placement helped restore saltmarsh sparrow habitat. “This is really new to Rhode Island,” said White, who is hopeful that understanding how these restoration projects perform will help the Service protect salt marshes for years to come.

Seeing how the marsh responds to restoration treatments will take time White says, but community interest was immediately apparent. Neighbors have been interested in the work and its benefits to coastal communities. Some have even offered to pitch in by planting vegetation at newly restored sites.

Though project sites can sometimes look like a sandy beach, many lie within marshes and require nimble footwork to avoid ditches and pools.

“Getting volunteers out to some of the elevation enhancement project sites can be an adventure,” says Wenley Ferguson, director of habitat restoration at Save the Bay. “But by the end of the day, they look forward to returning to see how their work helps protect this habitat.”

Volunteers from Schneider Electric, led by Save the Bay, plant native vegetation on recently created high salt marsh at Sachuest Point National Wildlife Refuge in Rhode Island. Credit: USFWS

Recently planted Spartina patens on newly created high salt marsh at Sachuest Point National Wildlife Refuge. Credit: USFWS

Nature has shaped salt marshes for thousands of years, building resilient natural systems that serve as an important stopover site for migratory shorebirds, critical nesting habitat for vulnerable species like the saltmarsh sparrow, and nursery grounds for valuable fish and shellfish. This productive habitat naturally provides additional benefits for people, like water purification, nutrient cycling, and flood protection.

Restoration techniques like TLD are giving salt marshes a fighting chance against sea-level rise and subsidence. And Hurricane Sandy Relief Aid gave the Service an opportunity to apply and study this technique.

With an improved understanding of TLD and help from partners, the Service can continue to work to ensure that salt marshes are healthy, sustaining species and making coastal communities more resilient to future storms.