Climate Change

Living Shorelines: The Space Where Engineering Meets Science

October 6, 2015

Aerial view of John H. Chafee National Wildlife Refuge. Photo © Greg Thompson/USFWS on Flickr

To create a shoreline that reduces erosion while providing habitat for everything from shorebirds to horseshoe crabs, sometimes nature could use a helping hand. Enter engineers and conservationists.

Scientists and engineers assess the degrading shoreline of the Narrow River.
Scientists and engineers assess the degrading shoreline of the Narrow River.

During a raging spring downpour, scientists from the Conservancy, ecologists and engineers from CH2M, and wildlife refuge managers from the U.S. Fish and Wildlife Service (USFWS) assessed the Narrow River’s degrading shoreline.

Shorebirds, marsh wrens, and horseshoe crabs carried on as though it were any other day, unaware that the boatload of humans working their way through the estuary—despite the weather—were on a serious mission: to figure out a way to give nature a chance. By installing natural infrastructure, they hoped to limit accelerated marsh erosion caused by boat wakes, sea level rise, and other factors.

In summer 2014, scientists and conservation leaders installed Rhode Island’s first living shoreline on the Narrow River, experimenting with large coconut fiber “coir logs” and oyster shell bags to protect 500 feet of eroding marsh edge. While they’ve seen some success, these biodegradable materials have not withstood higher wave energy in some areas.

IMG_9767In comes the Conservancy’s Jeff DeQuattro, Director of Restoration for the Gulf of Mexico Program, who manages multiple shoreline and oyster restoration projects in Alabama, including the $3 million Recovery Act project to restore 1.5 mile of oyster reef at Mobile Bay. After working with CH2M engineers and scientists on an 8-mile living shoreline project in Pensacola Bay, Florida, DeQuattro encouraged Scott Comings, Associate State Director for the Conservancy’s Rhode Island chapter, along with his Narrow River team, to engage engineering ingenuity. CH2M also recently helped the Conservancy protect the Gulf of Mexico coastline by designing and installing precast oyster castle reef units in Arlington Cove. Using hybrid green infrastructure solutions that are built to last while reducing wave energy, the project encourages marsh regrowth and beach stability, while providing sea life habitat. In addition to helping design the reef, CH2M engineers and scientists helped coordinate the five volunteer teams who built the structure.

IMG_9823-(800x600)Fortunately, the collaborative agreement between the Conservancy and CH2M made it easy to tap into an engineering brain trust. It all started with a few phone calls. Then, understanding the project’s budget limitations, CH2M and vendor personnel visited the area on a Sunday, off work hours. Next, the scientists, engineers, and agency stakeholders met onsite on June 1, 2015 to consider new possibilities. After the site visit, the CH2M team facilitated a workshop to identify what success means for this site and for the Conservancy, USFWS, and the regulatory community. This is what all of the team members have learned in the process:

  • IMG_9716Collaboration between engineers and scientists delivers better conservation outcomes. In simple terms, engineers like to build things they know will work, while scientists are more comfortable with experimentation. Scientists who know how to “speak engineering” can bridge and translate between these distinct disciplines. Mark Jaworski and Hans Ehlert, CH2M senior ecologists, facilitated the workshop. As Ehlert said, “this kind of project definitely challenges us, as we like to design things that won’t fail, meaning a more permanent solution. Instead, we are looking at features that could experience disturbance but have a resiliency pattern…a solution that is easy to get on its feet again when the largest storms or events happen.”
  • IMG_9781-(800x600)Applying engineering principles delivers more bang for the buck. The first effort at restoring the shoreline in Narrow River (using coconut fiber coir logs and oyster shell bags) offered many lessons learned. As Conservancy scientists in the Gulf discovered, engineers can help enhance efficient use of limited funds by developing strong, long-lasting solutions. By bringing trusted vendors to the workshop, participants could be more creative in dreaming up ways to respond to different environmental conditions. One coir log vendor at the workshop, who owns Pinelands Nursery in New Jersey, recently donated 2,000 Spartina alterniflora plants, 2 large buckets of seed, and over 14 hours of volunteer labor and training to make the project’s coir logs more stable and resilient. Everyone pulled together for this project.
  • Hybrid solutions can be the best fit where all-natural or hard structures won’t work: New hard shoreline structures aren’t an option in Rhode Island, and all-natural materials (coir logs and shells) cannot withstand the high wave energy and boat wakes in some areas. One option that emerged from the workshop is to use cultured stone, with flora and fauna already established, which will integrate with the shoreline. “As we looked at the site, nobody could deny that a tiny rock feature in one portion of the shoreline was working,” said Jaworski, CH2M’s project manager. “Combining that with other technologies and biodegradable materials, looking at a whole-systems perspective, the cultured stone could be a shoreline stabilization solution that can withstand the higher wave energy environment while still using natural materials.”
  • Getting the right people in the room sets the stage for success. The Narrow River team was able to get going immediately because of the Conservancy’s collaborative agreement with CH2M. As Comings said, “The project got kicked off with a phone call, and the entire process has been effective and efficient. Jeff DeQuattro convinced us that we need to take a fresh look at coming up with the best design for the location, even though it meant stepping back a bit. For this project, time is of the essence. Fortunately, the collaborative agreement set the stage for us to get started quickly with a great team of engineers and scientists.”

NarrowRivFieldTrip-029-(2)During the workshop with agency partners, permitting agencies, vendors, and interested parties, everyone had an opportunity to weigh in on what success looks like. After looking at examples of green, grey, and hybrid projects, the group rolled up their sleeves and worked through a list of a dozen criteria, from durability and habitat creation to ongoing maintenance.

For example, if project success is defined by durability in the face of hurricanes, the approach would involve robust, hard-engineered solutions that require heavy equipment for installation. However, if the success is defined in terms of resiliency, or the ability to easily recover after a disturbance, the door opens to a more natural hybrid solution using human-scale labor. Similar to Arlington Cove, a project can be designed with volunteers in mind. In the case of Narrow River, if the project is designed to be enhanced and maintained over time by people who care deeply about the estuary, then the project could be implemented incrementally as funding allows. It could create a platform for engaging and educating the community on the health and protection of their living shoreline.

“That workshop was so important because it pulled all the rats out of the woodpile,” said Comings. “We set the parameters for what can and can’t be done. Although there were not a lot of huge surprises, we got it all on the table.”

While the stakeholders discussed their values and outcomes through the lens of the criteria for success, they had some “aha moments” about what is a sustainable solution. For example, one vendor suggested a plastic mesh cage that could contain the oyster shells and last two decades, but most preferred natural shell bags that last only a few years. This led to a fruitful discussion of what is sustainable. Is it durability, or biodegradability? As Jaworski said, “Given the constraints, goals, and opportunities, our goal isn’t to find the one ‘right’ solution, but rather to rethink things in a way to emphasize resiliency yet incorporate flexibility.”

This collaboration between scientists and engineers is helping the team develop the best whole systems solution for Narrow River’s ecosystem. As the team develops a list of possible solutions at different locations in the estuary that could deliver the outcomes needed, they are inspired by the synergy that results from combining these two different cultures and approaches. Jaworski commented, “Since we’ve been up there, everyone, including USFWS, has been pulling together with all the right ingredients—excellent knowledge, great science and engineering, and most of all, people who care.”

Scott Comings agreed, “Both of our site visits took place in pouring rain. That sticks in my mind because they were among the few days of rain we’ve had. But the bad weather did not matter. It speaks to how strongly we believe in this work. All three of us—the Conservancy, USFWS, and CH2M—will deliver together no matter what the conditions are.”

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