Living Shoreline Demonstration Project, Louisiana Photo cutesy of CPRA’s St. Bernard Parish Living Shoreline Demonstration Project, funded by the Coastal Impact Assistance Program
The Tetra Tech team used analytical and numeric modeling to evaluate reef breakwater product alternatives in Louisiana
Photo Courtesy of CPRA’s St. Bernard Parish Living Shoreline Demonstration Project, funded by the Coastal Impact Assistance Program
The Louisiana coastline loses an average of more than 16 square miles of wetlands per year according to the U.S. Geological Survey. The Coastal Protection and Restoration Authority of Louisiana (CPRA) is the single state entity with authority to develop, articulate, implement, and enforce a comprehensive coastal restoration and protection master plan to reduce hurricane storm surge flood impact, restore Louisiana’s bountiful natural resources, build land to protect critical energy infrastructure, and secure Louisiana’s coast now and for future generations. CPRA selected the Tetra Tech team to design a bio-engineered oyster reef demonstration project to show the potential of using reef breakwater product to combat coastal erosion in St. Bernard Parish. This project was funded through the Coastal Impact Assistance Program (CIAP) and is part of Louisiana’s Comprehensive Master Plan for a Sustainable Coast.
The project is located in St. Bernard Parish’s coastal fringe marsh, which is susceptible to high rates of shoreline erosion due to wind-wave action. The project aimed to establish a living shoreline along 21-miles of coastal fringe marsh to dissipate wave energy before it reaches the shoreline thereby protecting vulnerable shoreline and the valuable marsh behind.
The Tetra Tech team evaluated reef breakwater products to serve as a first line of defense for coastal marshes in the project area, helping to sustain the lower Biloxi Marsh. The project’s secondary goals were to allow sediment accretion between the shore and reef to create new land; stimulate oyster growth and increase the biodiversity in the immediate area; and provide CPRA with valuable data on the performance of various configurations of the selected products that can be used to design more effective projects in the future.
Our team evaluated numerous living shoreline products to determine their potential to meet project goals. Products evaluated included A-jax, gabion mattresses, Reefballs, Reefblk, Hesco basket, and OysterBreak.
The Tetra Tech team performed an environmental analysis of each product, including determining its ability to promote oyster growth, thereby increasing the biodiversity in the immediate area. Our team used analytical and numeric modeling to evaluate the shoreline response and performance of the alternatives using parameters including wave attenuation and sediment transport.
The Tetra Tech team’s services for the living shoreline demonstration included:
Recent and historical data collection (topographic, bathymetric, and geotechnical)
Coastal engineering and modeling analysis
Preliminary engineering and design
Construction administration support, primarily ensuring all environmental requirements in the permits and specifications were followed
The engineering and design of the project met all three project goals, and our team obtained all necessary permits on schedule to complete project construction during the grant funding period.
Using living shoreline products to protect coastlines in Louisiana provides ecosystem services not available through traditional shoreline protection techniques. The products evaluated as part of this project will provide habitat for fish and other aquatic species, in addition to providing erosion control and shoreline stabilization. Project construction was completed in November 2016, and CPRA is conducting monitoring to evaluate the results of the living shoreline products’ performance.
You might want to talk to Professor Jennifer Mattei who’s project has shown great success. Or just listen to this video
Read the article from Sacred Harts University at
Living Shorelines are more than just a breakwater. You want it to meet the needs of the people as well as a wide variety of organisms. Think back to why we feel we need to do something. The answer is simple in the developing world man has had a major impact. No, many of the systems are over stressed and we need to find better ways to enjoy the water we love and have a viable healthy food source. There is some great research going on in the North East. I hope you will take this information and build on it in your region. We at Reef Innovations are happy to share successes and ideas for your project. Horseshoe crabs and sea turtles also need access to the shoreline. J.McFarlane
Late 2016 more Reef Balls hit the coast of CT at the site of a pilot project designed for the accretion of soil and protection of marsh grasses. The pilot project was successful and now, the protected area has increased. This is a great example of how other estuaries in the NE could protect area’s from erosion,
The Reef Balls were constructed at Reef Innovations site in Sarasota, FL and trucked to CT. There was some discussion of building in CT but the aggregate would be garnite instead of the Florida limerock used in the pilot project. Observation in Jim McFarlane’s surveys of sites from CT to LA showed few encrusting species on granite. McFarlane’s belief was that Reef Balls more resembled a natural oyster reef structure when made with materials from Sarasota. The practice of constructing Reef Balls with local materials in one used around the world, so it would be easy for someone to do a study in about every ecosystem you can imagine. I look forward to someone doing some surveys of the Stratford Point site during high tides, as an evaluation of plagic species visiting the area.
This article was retrieved from the CT Post Dec 2017 http://www.ctpost.com/local/article/Creating-a-living-shoreline-with-Reef-Balls-10778523.php#item-38492 Photo comments were added by J.McFarlane
STRATFORD — Jennifer Mattei crouched along the low-tide mark at Stratford Point to scoop up a mound of inky gray sediment in the palm of her hand.
It is proof, the Sacred Heart University biology professor said, that her Reef Balls are working to restore the beach.
Her meandering rows of thousand-pound, dome-shaped cement balls create an artificial reef. Each ball is punctuated with holes that allow the tide and small sea creatures through. Over the past couple, years the reef, planted just off shore, has begun to not only stop erosion but reverse it — enough for Mattei to win another grant to expand her work.
A swath of sediment estimated at four feet deep and 100 feet wide has disappeared along the of shoreline over the past three decades. The property is now owned by the DuPont Corp. and managed by the Audubon Society.
So far, surveyors periodically measuring the terrain estimate sediment about 12 inches thick has re-accumulated over the past two years behind the barrier.
The just-announced $115,198 grant from the National Fish and Wildlife Foundation’s Long Island Sound Futures Fundwill be used this summer, with the aid of a team of Sacred Heart students, to plant thousands of marsh grass plugs along the shoreline in front of the barrier.
The pilot study began with 64 Reef Balls. This November, another 327 were added with the help of DuPont and the Army Corps of Engineers. Mattei checks on them periodically, searching for signs of algae, barnacles and any oysters that now call them home.
At one time, reefs made of clinging oysters protected the shoreline. They disappeared centuries ago.
It was the oysters, the horseshoe crabs, the piping plover and all other species, Mattei said, that got her into this kind of research. Those creatures depend on the shoreline and their access has been compromised by decades of beach erosion and climate change.
“The ocean level is rising,” Mattei said. “Storm frequency is increasing. Global climate change is real.”
Seawalls don’t help. They hurt. When waves crash against them, sediment is pulled away from the shore and sea creatures lose access to the shore.
Mattei hit upon the idea of Reef Balls, which got their start in Florida to protect coral. The are made with a special cement formula that resists erosion and heavy enough to withstand hurricanes. The holes are positioned so that when a wave hits, the water shoots through more gently.
Although used worldwide, they are rare in Connecticut. Scientists like Juliana Barrett, with the University of Connecticut Center for Land Use Education and Research hopes that will soon change.
Barrett said state law now severely restricts the construction of traditional seawalls. Mattei’s project is a great example of an alternative.
“What she is doing is really, really important,” Barrett, said. “She is creating a living shoreline I hope will be replicated. She has the most extensive project going on.”
In addition to rebuilding dunes and salt marsh grass, Mattei said she also has her eye on sediment she expects to be dredged next fall from the nearby boat channel at the mouth of the Housatonic River, on the opposite end of Stratford’s beach front.
Although some is earmarked for Hammonasett Beach in Madison, Mattei said, some directed her way would speed up her stabilization project.
“I hope this can become a demonstration site for what to do,” Mattei said.
“One of our projects, Morris Landing, seemed untouched by the hurricane; the sill structure looked as it did before and that’s the point of them,” Skrabal said, a coastal scientist with the federation.
The comparative studies or living shoreline treatments by The North Carolina Coastal Federation, shows the value of homeowners taking steps other than bulkheads to protect their shoreline from erosion during high energy events.
Prior to the hurricane I surveyed the site that consists of rows of Reef Balls that have oysters growing on the. The site also compares Shell Baggs, A freestanding bulkhead, granite riprap, and loose oyster shell.
It was great hearing they didn’t have any loss of shoreline at this site during the storm. A 360degree video of the Morris landing site is at https://reefinnovations.com/archives/4383
Article Retrieved from: http://www.coastalreview.org/2016/12/living-shorelines-withstand-matthews-force/
Living Shorelines Withstand Matthew’s Force
Third in a multi-part series
HOLLY RIDGE – When Hurricane Matthew approached North Carolina in October, many in the state – from scientists to casual observers – watched to see the effects on shorelines. Storm surge and increased wave action can visibly wear away the coast. How would properties with bulkheads fare? Or, for those with wetlands conservation in mind, would living shorelines deliver what they promised?
Living shorelines are designed to protect vulnerable marsh habitats. In the case of hurricanes, though, living shorelines are also meant to be filters of stormwater runoff and to mitigate the erosion caused by the water that inevitably comes with the storms.
Larry Jansen chose his home in Holly Ridge’s Preserve at Morris Landing in part because of water and coastal access. As a volunteer with the North Carolina Coastal Federation, he’s been watching the 310-foot living shoreline completed there in July as the fifth phase of an ongoing restoration project, and he returned to the site soon after the hurricane passed through.
“I couldn’t really see any impact at all,” Jansen said.
Living shoreline proponents say that’s no surprise.
“For the most part, these shorelines are behaving exactly the way we expect them to,” said Tracy Skrabal, a coastal scientist with the federation.
Living shorelines are generally made with a permeable sill, such as bagged oyster shells or rock, that follows the natural slope of the land, with marsh grasses and other wetland plants behind.
“When the water rushes up, there’s nothing impeding the flow,” Skrabal said. So, they are designed for the water to come in and go back out.
Although these observations are a good sign, there is more meticulous work being done in the aftermath of the hurricane. Carter Smith is a doctoral student at the University of North Carolina – Chapel Hill Institute of Marine Sciences in Morehead City.
“It started about a year and a half ago, with the goal of comparing how bulkheads, living shorelines and natural shorelines perform in major storm events,” Smith said of the research.
In the weeks since the hurricane, Smith has visited the project’s 30 study sites from Southport to Manteo.
At each, there are comparable shoreline structures that will face similar storm surge and wave energy. For the purposes of the study, living shorelines are those that have had some type of restoration work, such as the addition of marsh sills and aquatic plantings, and natural shorelines are unmodified. Both are compared to the hardened bulkhead type structures that are common along the coast. In the coming months, Smith will work on assessing the post-storm effects. Right now, though, she has made some preliminary findings.
“For the living shorelines, I would say there are no detectable instances of damage,” Smith said. For natural shorelines, there was measurable marsh erosion. “In some cases, a loss of over five meters (about 16.4 feet) from last year.”
Some bulkheads remained intact, but there are some stretches where bulkheads were damaged. Hardened structures such as bulkheads can fail in a number of ways during storms and the damage is often obvious.
“What we see is that the vertical surface of bulkheads is more susceptible to high-energy events,” Skrabal said. “And storm waves can scour away what’s in front of them.”
The same can happen behind the bulkhead, when saltwater overlaps the structure and weakens it, causing structural damage or collapse.
Smith’s project also includes conducting boat surveys along 100 kilometers, or about 62 miles, of North Carolina shorelines, taking photos and noting the location coordinates of damaged structures.
“I would say that at least 50 percent of the bulkheads we surveyed were damaged, from minor damage to full-on collapse,” Smith said.
A post-storm assessment is also expected to be released by the Division of Coastal Management, analyzing how sills, marshes and bulkheads fared during the storm.
For years, coastal conservationists have been championing living shorelines for protection of marsh habitat.
“When you look at bulkheads, they ecologically bisect the habitat,” Skrabal said. “Marsh needs sediment, and they (bulkheads) tend to starve them of that with erosion and wave energy.”
Conservationists also have been encouraging property owners to consider living shorelines for better, more sustainable protection of their property. But bulkheads are by far the most popular choice for property owners. A previous study from the Institute of Marine Sciences estimates that as much as 9 to 16 percent of the coast is protected with bulkheads, and permits for bulkheads are easier to obtain. Whereas, it can be more difficult, months-long process to get permits needed to install a living shoreline. Bulkheads are more expensive, though, and can cost thousands of dollars, depending on the length of the shoreline.
“And the cost of repairing bulkheads after storms is considerable, too,” Skrabal said. It is her hope that the example of how well living shorelines did during the storm will convince more homeowners to consider them rather than repairing or replacing bulkheads.
“One of our projects, Morris Landing, seemed untouched by the hurricane; the sill structure looked as it did before and that’s the point of them,” Skrabal said.
This resiliency is something Erin Fleckenstein, a coastal scientist with the federation’s northeast office, has noticed, too. She cited a homeowner at Silver Lake Harbor on Ocracoke Island who had a living shoreline built there this past summer.
“Before, they were facing considerable erosion, mostly due to ferry traffic,” Fleckenstein said. But the owner reached out to Fleckenstein after the hurricane and made a point of saying how pleased they were with the erosion control and how well the shoreline did.
Get out your virtual reality goggles, adjust up to 4K and take a look around.
This month Jim surveyed the Audubon project designed as a living breakwater at Bird Island located in Tampa Bay off the Alafia River.
During this study I collected some 360 degree video above and below the water. I continue to attempt to establish a protocol for scientific surveys using 360 degree
Adding an offshore break provides a great launching point for kiteboarding. So, the artificial structure serves as recreation as well as fisheries, and shoreline resilience.