At local forum, CSI’s Corbett says beach nourishment is expensive, but effective

By on October 1, 2022

During the Coastal Studies Institute’s first Science on the Sound lecture series since the COVID-19 pandemic, CSI Executive Director Dr. Reide Corbett told those gathered that while beach nourishment is both a short-term and expensive solution to significant and worsening erosion issues, it remains an effective response to the problem.

The Sept. 29 presentation, at East Carolina University’s Outer Banks Campus at CSI, discussed the nuts and bolts of beach nourishment on the Outer Banks as well as its potential impacts. Before 2022 ends, beach nourishment projects in Dare County will have included Duck, Southern Shores, Kitty Hawk, Kill Devil Hills, Nags Head, Avon and Buxton.

“Our [barrier islands] are truly made up of a pile of sand. It is a sandbar that is above sea level, and we are in an area that sticks out into the Atlantic fairly far,” Corbett said to about 50 audience members at East Carolina University’s Outer Banks Campus at CSI. That, along with a rapid change in sea level today compared to a century ago and the energy driven into the system by storms, all leads to some of the challenges associated with living in a coastal system.

Among Corbett’s messages was that beach nourishment is a short-term solution and doesn’t change the dynamics of the beach, but it is adding volume and buying time.

Increasing erosion rates coupled with growing coastal populations could lead to the need for more frequent and intense beach nourishment projects in the future, he said, which could be a challenge when it comes to cost. But these projects are effective and based on recent research, don’t appear to have a significant ecological impact in the long run provided the sand being pumped is compatible with that of the beach.

“There are certainly chronic erosion problems along the Outer Banks, it’s not unique to the Outer Banks and it’s not unique to North Carolina,” explained Corbett, who is also the Dean of ECU’s Integrated Coastal Programs. “That’s leading to some interesting challenges we face, as well as many coastal communities.”

Corbett said that of the 300 miles of Atlantic shoreline in North Carolina, 70 percent of it is eroding. “On average, that erosion rate sits at about three to five feet per year…but again, we have these hotspots that are upwards of ten to fifteen feet per year.” Coupled with a coastal population that has more than doubled, Corbett explained that a “coastal squeeze” is happening around the globe.

In North Carolina, where hardened structures along the Atlantic coast such as seawalls are prohibited and also environmentally unfriendly, one of the only solutions for adapting to the increased erosion rates is beach nourishment, Corbett said. “These projects are truly designed on the time scales of five to seven years – they aren’t permanent. They are not a solution to erosion [but] a temporary approach to dealing with the challenge associated with erosion.”

One of the challenges of beach nourishment, Corbett said, is the cost. This summer alone, the local beach nourishment projects funded by county and municipal revenues had a price tag of about $78 million. A collaboration between Dare County and its municipalities, along with municipalities planning projects simultaneously, have been successful so far and helped to reduce costs.

Corbett told the audience that there is a lot of science that goes into a beach nourishment project, and he noted that it is important to recognize that sand isn’t just being added to what he refers to as the “recreational beach,” but is also being added beneath sea level.

“One of the things you will see within the first several months of a nourishment project is that the beach begins to equilibrate between the bar offshore,” he said. `You might see what appears to be erosion, a loss of significant sand and say, ‘Why did we pay $10 million when it’s gone in the first three months?’ That sand has not gone, but has moved to that offshore bar,” Corbett said, adding, however, that certainly over time, sand is being lost.

Beach nourishment, he continued, is a fairly new process for the Outer Banks and really started with the Town of Nags Head in 2011. “At the time, that was the largest locally-funded nourishment project in the United States,” he said. “That’s pretty impressive for a couple reasons.”

One is that it cost roughly $25 million. But for many on the Outer Banks, that beach nourishment project offered a good lesson. “They saw not just the money it cost, not just the sand that was put on the beach, but the protection that it offered in the next several storms,” Corbett said. “And I think the town of Nags Head did a good job of showing that and demonstrating some of the protection that it did provide for infrastructure behind that primary dune.”

Corbett, who noted that the Outer Banks has significant sand resources off its coast, said that there are guidelines in North Carolina that are even more stringent than the Army Corps of Engineers regarding what sand is compatible for a beach in North Carolina.

Corbett also briefed the audience on a CSI research project conducted in Pea Island National Wildlife Refuge following the N.C. Department of Transportation beach nourishment project in 2013-2014. Noting that it’s the only study he is aware of that, from an ecological standpoint, looks at a nourishment project for longer than five years.

The study involved collecting samples from the nourished area of mole crabs, coquina clams and other animals that live in the sand, as well as tracking ghost crab burrows for about seven and a half years and comparing it to adjacent non-nourished beaches.

What CSI researchers found was that there was not a significant impact on these critters that live in the sand in the nourished area, and while there was a significant decline in ghost crabs, those numbers rebounded within a year.

Corbett credits that success to the fact that there was a good match when it came to sand compatibility.

Corbett’s presentation was followed by a discussion period in which a number of ideas were discussed, including taking a multi-structured approach to erosion. Also part of the discussion was for the possibility of developing, from a financial standpoint, a 30-50-year plan to address these challenges.


(The next Science on the Sound talk will be Dr. Chris Oakley on Oct. 27 and Dr. Mike Muglia on Nov. 17. The lectures are free of charge and open to the public.)

 

 

 




Comments

  • surf123

    Nothing quite like subsidizing those on the oceanfront. I realize they have a higher assessment for the sand, but it does not represent but a pittance of their rent revenue. If we are going to add sand do it they way nature does…add to the sound. Man created this “problem” by building dunes and then drawing an arbitrary line in the sand for oceanfront homes. Adding sand is more meddling with Mother Nature.

    Saturday, Oct 1 @ 12:56 pm
  • BB Wylie Walden

    I can’t help but wonder what Dr. Stanley Riggs (Distinguished Research Professor and Harriot College Distinguished Professor of geology at East Carolina University) would have to say if he’d been present for this discussion?

    There is a really interesting article that can be accessed by the CoastalReview.org here: https://stories.pulitzercenter.org/tide-and-time/ titled Time And Tide by Justin Cook. This story is all about the Outer Banks, its old families, local politics, as well as climate change – and one doesn’t need to be a scientist to understand it, learn from it and be very moved by it. I urge people to read this article, and have to wonder if Dr. Corbett has himself.

    Sunday, Oct 2 @ 8:09 am
  • Steven

    Always the voice of reality from surf123, thank you.
    I wish more people would realize the destructiveness of dune lines, they multiply erosion rates by tenfold, also prevent sound side from being replenished.

    Overwash is vital and necessary for the survival of barrier islands.
    Look at overwash areas, they gain elevation. Storms can bring a gain of five feet of elevation to the area.

    Sunday, Oct 2 @ 8:20 am
  • Bill

    These Barrier Islands are also migrating to the west. What good is a bridge if it is no longer attached to land?

    Sunday, Oct 2 @ 9:59 am
  • surf123

    The next sand related issue is Oregon Inlet jetties. I don’t recall which congressman is pretending to care in order to buy votes, but if he were to get this moving forward it will be very bad for HI, more specifically RWS, as these will strip the beaches as natural sand flow is interrupted. Environmentalists will do everything possible to stop this so we have that going for us.

    Sunday, Oct 2 @ 1:23 pm
  • Ghost Crab

    Well that explains it! I thought someone was watching me for quite a while now

    Sunday, Oct 2 @ 3:36 pm
  • Browny Douglas

    Having had a boat in the water (sport and commercial) since 1960 I respectfully disagree that there is sea level rise. Due to time and pressure encroachment has become the thinly veiled culprit purported to be sea level rise.

    Not to learn and capitalize from others around the coastal world about the benefits of sand recycling and sand transfer systems is a mistake IMO.

    I know there is an environmental claim that the beach nourishment sand becomes incompatible for re use once it has traversed the inlet. I do believe Capt Omie Tillett would say ” I find that hard to hoist on board”.

    Monday, Oct 3 @ 11:06 pm
  • Jon

    Mr. Douglas, respectfully, the Duck pier tide gauge shows a 10″ increase since 1981. That’s not only sea level rise but also from land subsidence, which if we’re talking about putting sand on the beach is the same problem.

    Tuesday, Oct 4 @ 10:52 am
  • Reality Check

    Let’s get a few things straight. The majority of the dunes along the Outer Banks were built during the work era. Water seeks its own level, which means if there is the massive sea level rise that people are saying there is then the sound side should be disappearing at a similar rate and it’s not. What we have is an erosion problem. I’m not saying there isn’t sea level rise, nor am I saying there isn’t climate change but our problem is erosion! The next thing you know sea level rise is going to be blamed for the lakes drying up in the western states.

    Tuesday, Oct 4 @ 6:31 pm
  • Browny Douglas

    Jon,
    Your input, and thanks, raises this question. Do you know if ,since water seeks it’s own level, the tide guage on the Cashie R bridge in Windsor indicate a 10 inch sea level rise? It should, should it not?

    Tuesday, Oct 4 @ 7:07 pm
  • olin hardy

    The OBX needs this service !

    Wednesday, Oct 5 @ 3:58 pm
  • Lemonshirt

    I frequent Bay Drive in KDH. And over 20+ years I’ve seen “erosion” on the sound side too.
    When you head out on West 64 you can see a wide swath of dead trees. Dead from salt water intrusion. ….which comes from….yep…Sea level rise.

    Monday, Oct 10 @ 7:41 pm
  • ray ferta

    get rid of all the holes, troughs and small sandbars and make the surf area one big shallow sand bar and watch all beach fishing die, this is what kill devil hills and kitty hawk is now. No enviromental impact? SURE. GET YOUR HEAD OUTOF YOUR BOOK AND INTO THE SAND. KILL THE FISHING TOUREST INDUSTRY.

    Friday, Oct 14 @ 8:04 pm