As sea levels rise along U.S. coasts, it may soon get easier for people and local governments to obtain federal permits to build what are known as “living shorelines,” natural or nature-based structures designed to protect communities and infrastructure from extreme storms and flooding even as they protect habitat.
The Army Corps of Engineers is considering a new category to its nationwide permits that would allow speedier approval of living shorelines, which include wetlands with sea and marsh grasses, sand dunes, mangroves, and coral reefs.
Currently, it’s much faster for property owners in many parts of the country to get a permit for sea walls, bulkheads and other so-called gray infrastructure than it is to get a permit for construction of nature-based systems. If the corps moves forward with the new category, though, permits to build living shorelines could be issued in as few as 45 days, instead of 215, a spokesman for the agency said.
“The living shoreline piece is a part of what we’re pushing as a nonstructural, nature-based method that is a lot less costly,” said Lt. Gen. Thomas Bostick, who ushered in the proposed permit during his time as chief of the Army Corps of Engineers, before his retirement last week. “It helps us with our environmental focus; it helps us with the endangered species, perhaps. All of that is a natural way that we can reclaim some of our land and take the focus off of expensive infrastructure.”
The move toward more natural coastline protection comes as federal agencies, state governments, and local and business leaders focus increasingly on the concept of resilience as they plan for how communities will adapt to climate change.
The spotlight on dynamic systems is a major shift for agencies like the Army Corps, which in the past paid more attention to engineered solutions, Bostick said last week during an event at the National Academy of Sciences that focused on the state of resilience in the country. Unlike with engineered solutions, there’s greater uncertainty with living shorelines. Researchers and engineers have less information about how they will respond to sea-level rise, storm surge and other extreme events. They’re learning to be more nimble, Bostick said.
“How do you know the unknowns? Forget about it. You’re never going to know,” Bostick said. “I’m going to accept uncertainty. I’m going to accept a little give in this system.”
Natural shorelines protect species, but what about homes?
Other federal agencies, including the National Oceanic and Atmospheric Administration, support living shorelines in places where they’re warranted. They work best in more sheltered systems with moderate wave energy, like the Chesapeake Bay, river systems, Puget Sound and even the Great Lakes.
A study by the Pew Charitable Trusts found that about 14 percent of the U.S. coastline is what researchers described as “armored.” A 2015 report from NOAA on living shorelines noted that if coastal populations continue to increase, and if so-called “shoreline hardening” continues at the current rate, nearly one-third of the contiguous U.S. coastline could have sea walls or other gray infrastructure by 2100.
The agency found evidence that shorelines with intact natural coastal habitats not only see less damage but bounce back more quickly from severe storms.
Studies have shown that living shorelines host greater populations of fish and other organisms crucial for shorebirds and for recreation and commercial fisheries, said Rachel Gittman, a postdoctoral research associate at Northeastern University’s Marine Science Center. Gittman, who spends much of her time in North Carolina, was asked by the Pew Charitable Trusts to analyze the effectiveness of natural shorelines compared to hard infrastructure. The work is part of the foundation’s climate adaptation efforts to improve flood readiness in U.S. communities.
Bulkheads, sea walls and vertical structures with marginal structural complexity don’t provide the same habitat for marine organisms as natural shorelines, Gittman said.
“It’s not the same type of habitat. It’s a difference in the slope of the shoreline. A vertical wall is very different than the slope of the shoreline. We think it has to do with the wave dynamic, so how sediment is transported changes when you put in a wall,” she said. “And we also just think it’s a simplification of that shoreline. So you go from a shoreline that might have lots of pools and crevices and rocks ... to a wall. Organisms are not finding refuge along that shoreline.”
The biggest drawback to living shorelines so far has been the uncertainty about how well they’ll work, and whether they’re truly less expensive than hard infrastructure.
Finding hidden economic savings
Some organizations are trying to quantify whether living shorelines cost less to build and can provide the same protection. The Nature Conservancy found a perfect opportunity in Miami-Dade County in South Florida, said Kathy McLeod, director of global risk reduction and resilience at the environmental organization.
There, the county’s aging wastewater plant was under orders to stop dumping waste into the ocean. The Nature Conservancy is studying whether marshes surrounding the low-lying plant can help protect it from storm surge and flooding.
The marshes aren’t just protection for the plant’s $3 billion in upgrades—they’re a part of the massive federal Everglades restoration project.
The Nature Conservancy hopes that what it learns about the project will make it easier for other communities weighing similar projects to move forward with natural systems, McLeod said last week, speaking on a panel about climate adaptation and resilience at the same event as Bostick.
She argued that wetlands like the ones in Miami-Dade County also have benefits that can’t be captured in traditional cost-benefit analysis. For example, mangroves might be used on either side of a road that frequently gets washed out during high tides. That allows people to get to work and protects infrastructure, she noted. Those are more challenging metrics to capture, she said, but they’re crucial for keeping an economy operational after a storm, and for minimizing expensive damage to roads due to sea-level rise.
“We want nature to play its maximum, most cost-effective role,” McLeod said.
Jennifer Molloy, green infrastructure coordinator for U.S. EPA, said last week at the event that the agency often is criticized for not giving enough weight to the complexities of operating and maintaining living shorelines. But hard structures also have operational and maintenance issues. Both need flexibility with climate change, she said.
“They’re not that different,” she said of green systems. “We ought to not see them as so different. We’re going to end up with combinations of both, and they function together.”
As the corps considers public comment on the new permit, Pew is spotlighting living shorelines across the country, said Laura Lightbody, program director for the foundation’s efforts aimed at reducing the impact of weather-related catastrophes, such as floods and hurricanes, on the U.S. economy, communities and environment.
They’re seeing what Lightbody described as “a real openness to new solutions.” People are curious about what works, she said.
“The research—and failing infrastructure—has opened the eyes of a lot of these practitioners on the ground to new alternatives,” she said. “Sometimes I talk about this like it’s a new technology. There’s a need for education and understanding. People are looking for new solutions; they are looking for alternatives. It takes seeing one and understanding it to realize the benefit and the value.”
Wide support in N.C.
The corps’ proposal, which is open to comment through Aug. 1, has drawn wide support from environmental groups, particularly in North Carolina.
“The traditional use of seawalls and bulkheads has slowly been hardening our coastline and destroying our marsh and wetland environments, which in turn damages the wildlife dependent upon them,” Rep. Gale Adcock, a Democratic member of the North Carolina House of Representatives, wrote to the agency. “A sensible and environmentally friendly alternative, the living shoreline, has been burdened by unnecessarily cumbersome scrutiny. The health of our shores is integral to our fishing industry, our tourism appeal, and the Carolina way of life.”
Business owners like Darrin Siefken, owner of Crawdaddy Outdoors in Waverly, Iowa, say they, too, support the new permit category.
“As a seller of outdoor sporting goods, kayak rentals, and guided tours, my business and employees are dependent on a strong and healthy natural environment, particularly vibrant coastal settings,” he wrote, urging the corps to approve the streamlined permit. “We know that the more shoreline we wall off with concrete bulkheads, the harder it is for fish and other native wildlife to survive. And the impact of these bulkheads [isn’t] limited to just their surrounding area. Because these bulkheads block the small flow of health sediment, one section of bulkhead can impact fragile ecosystems for miles downstream.”
Despite the massive push for living shorelines, such natural systems may not be appropriate everywhere, Gittman said. But they do give communities options that might supplement hard infrastructure, Gittman said.
“I think it would be naive to say you shouldn’t modify your shorelines, because obviously we’ve built along our shores. We have a lot of infrastructure and communities that we need to protect,” she said. “If you’re talking about a really urban area, you’re probably going to still need other structures for flood protection. Maybe there are places where a sea wall is the only option, maybe it’s a major port, so you really have to have a deep channel.”
She’s working on a chapter of a book, along with engineers and landscape architects, ecologists, and other experts, that will help guide the private sector in designing the living shorelines of the future. Its message is that people can design shorelines that are more dynamic than static, she said.
“What it means is that we need to be more creative in how we stabilize shoreline, and I think we also need to learn a bit more from nature,” she said. “We should be thinking about how to incorporate natural shore protection components. Anywhere where naturally stabilizing features can be incorporated—I think that’s what we need to be thinking about.”
Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500