6/15/20: CONSIDERING THE ‘NEED’ FOR BEACH NOURISHMENT IN SOUTHERN SHORES AND TOMORROW’S TOWN COUNCIL WORKSHOP AGENDA.

seaturtle
 A sea turtle comes ashore to lay her eggs on the wide Southern Shores beach at 174 Ocean Blvd. last July. The beaches oscillate in width from season-to-season and year-to-year and are at their widest in late July and early August.

The main event scheduled at tomorrow’s 9 a.m. Town Council workshop session is the public hearing on the proposed town-wide beach nourishment project for 2022. The Beacon makes one last pitch, below, for delaying approval of a project, for which there is no present need.

Before the hearing, however, the Council will be taking up other important business, including the three no-left-turn weekends that it approved for this summer.

The morning workshop, which will be held in the Pitts Center, is open to the public, but seating will be limited because of social-distancing requirements. You also may view the workshop on Zoom or listen to it by telephone.

For information about Zoom participation, as well as the telephone means for hearing the meeting, see https://www.southernshores-nc.gov/wp-content/uploads/2020/06/Electronic-Participation-June-16-2020.pdf.

After preliminaries, tomorrow’s workshop agenda will progress as follows:

  • General public comment

If you would like to submit written comments that would be read into the record at the meeting, please email them to Town Clerk Sheila Kane at skane@southernshores-nc.gov. Be sure to write in the email subject line: “Public comment for Town Council’s June 16 meeting.”

You also may address the Town Council in person or via Zoom videoconferencing. If you choose to speak via Zoom, you must click on the “Chat” button once you have joined the meeting and type a message to Ms. Kane, requesting time to speak. She will acknowledge your request and then inform you when your microphone is open.

You are not restricted in the topics that you may bring up in public comments. There is a time limit, however, of three minutes.

  • Planning Board appointments

The term of current regular Planning Board member Ed Lawler, who was appointed in January 2019 to complete the late Glenn Wyder’s unexpired three-year term, is ending June 30. Mr. Lawler has expressed an interest in being appointed to a new three-year term. No other people have applied for the vacancy.

  • Continued discussion of town engineer contract

This discussion will pick up with a motion made by Town Councilman Jim Conners at the Town Council’s June 1 meeting to approve hiring the engineering “team” of Joe Anlauf and Andy Deel, although only Mr. Anlauf submitted a Statement of Qualifications in response to the Town’s April 27 Request for Qualifications for a new town engineer. By his own representation, Mr. Anlauf has been the engineer for Southern Shores for the past 20 years. Three other engineering firms have applied for the contract. The Beacon supports one of the other applicants. See The Beacon, 6/9/20, for more details.

  • Discussion of no-left-turn weekends

The Town Council approved, by a 4-1 vote, with only Mayor Tom Bennett objecting, the scheduling of three no-left-turn weekends this summer. The weekends discussed at the June 1 Council meeting were July 4-5, July 25-26, and Aug. 1-2. We imagine that the crush of traffic during this past weekend, particularly on Saturday, will come up in the Council’s discussion, and we are hopeful that Police Chief David Kole will provide some traffic counts for the weekend.

  • Public hearing on beach nourishment project for 2022

You may speak during this hearing in the same manner as outlined above: 1) by submitting written comments, with the subject line, “For the June 16 public hearing on beach nourishment”; 2) by presenting comments in person; or 3) by remotely commenting via Zoom.

Comments during a public hearing are not time-limited.

The Beacon has written extensively about the results of Southern Shores shoreline surveys and the possibility of a beach nourishment project. We refer you, in particular, to posts on 2/28/19, 3/31/19, 4/3/19, 9/17/19, 9/20/19, 12/14/19, and 2/1/20.

We do not support beach nourishment in 2022. We support annual beach profiling, but not nourishment.

ABOUT SOUTHERN SHORES’ ‘NEED’ FOR BEACH NOURISHMENT

In 2017, the Wilmington, N.C.-based coastal engineering firm of APTIM Coastal Planning & Engineering of North Carolina conducted a baseline assessment of Southern Shores’ beaches. Emphasis on baseline.

At a March 6, 2018 Town Council meeting, Ken Willson, project manager of APTIM, presented his firm’s survey of the Town’s 3.7-mile coastline, which was based on 22 beach “profiles” or shoreline locations that are spaced 1,000 feet apart from each other.

APTIM determined that 1) the Southern Shores shoreline is “stable,” having lost only 0.4 feet (that’s five inches) between 2006 and 2017; and 2) the volume of sand in the system had actually increased during the same time period.

Mr. Willson told the Council at the March 2018 meeting that “the shoreline is looking fairly stable” and there is “no big rush” to “jump” on beach nourishment.

Nonetheless, he still wanted to do a “vulnerability assessment of the oceanfront structures [i.e., houses]” in Southern Shores and determine the “minimum cross-section of [sand] volume” that should be maintained to protect the shoreline from storm damage.

In other words, he wanted to calculate how much sand would need to be added to the beaches to restore them to their pre-storm condition in the event of a severe hurricane the likes of which may never occur in Southern Shores—and, in fact, has not occurred in Southern Shores since 1962.

To calculate the minimum cross-section of sand–called “volume density”–APTIM ran computer simulations of an “Isabel-like” hurricane, using storm characteristics such as wave heights, wave period, and storm duration, and three different sea-level scenarios.

Those of you who were here for Hurricane Isabel in 2003 may recall that it did not reach Southern Shores. It fizzled out.

You also may know that Southern Shores has not had a major storm since the Ash Wednesday storm of 1962.

The beach-nourishment plan options that APTIM eventually proposed along with its “vulnerability assessment” are based on calculations of sand volume density that would be required to correct theoretical “potential damage” to the Southern Shores beaches caused by a storm that is highly unlikely ever to happen.

This is not beach nourishment based on environmental science or oceanography or any other coastal science. And it’s not beach nourishment based on damage done. This is beach nourishment cooked up by computer storm simulations and engineering to fix “potential damage” that is as unlikely to occur as the hurricane that theoretically caused it.

ABOUT SOUTHERN SHORES’ COASTLINE HISTORY

We quote below an excerpt from an article that we posted 2/1/20, which was titled, “Shoreline History of Southern Shores is One of Low Long-Term Average Erosion Rates, Some Accretion.” Accretion is the accumulation or addition of sand, not the loss of it. We have edited the article for length:

According to coastal engineer and geologist Spencer Rogers, who works with the research/education/outreach program, N.C. Sea Grant, in its Wilmington office, historical erosion rates provide a model for the future.

They are the “best indicator,” Mr. Rogers said in a telephone interview with The Beacon yesterday, of what will happen to a shoreline.

And yet, these rates have not been part of the conversation that Southern Shores has had during the past two years with APTIM. APTIM’s emphasis has been on erosion in the event of a severe storm, whose parameters (e.g., winds, wave action) it modeled after Isabel, the 2003 hurricane that, as Mr. Rogers noted, “pretty much petered out by the time it got to Kitty Hawk.”

As the highly regarded coastal specialist aptly pointed out, Southern Shores has not been directly hit by a severe storm since the Ash Wednesday storm of 1962, an Extreme Nor’easter that took out the old Sea Ranch Hotel at the current site of Pelican Watch, next to the Kitty Hawk Pier.

Since this March 1962 event, no buildings in Southern Shores have been destroyed or threatened by erosion.

When Duck and Kitty Hawk did beach nourishment in 2017, houses in both towns were teetering at the ocean’s edge. Some in Kitty Hawk had already been lost. This has never been the case in Southern Shores.

While APTIM is advising the Town Council how to achieve “storm damage reduction protection” in the event of a monster hurricane, the reality is, as Mr. Rogers observed, that “storm patterns are pretty scattered” in the northern Outer Banks, in contrast to Hatteras Island and the southern Outer Banks.

Another reality—in addition to the town’s known 60-year history since the Ash Wednesday nor’easter—is that no hurricane of the magnitude of Katrina or Michael has ever hit Southern Shores.

Looking at Types of Beach Erosion

As Mr. Rogers explains in his book, “The Dune Book,” there are four types of erosion: 1) seasonal erosion; 2) erosion caused by a severe storm; 3) long-term erosion; and 4) inlet erosion. Beach nourishment projects are designed to address #2, an “extreme storm event” and/or #3, “chronic day-to-day losses,” he said.

Fortunately, we do not have to contend with inlet erosion. Shorelines adjacent to inlets—such as Topsail Beach—experience hazards that shorelines along oceanfront do not.

One such shoreline is along Ocean Isle Beach, which is between Holden and Sunset beaches near the North Carolina-South Carolina line. Beach nourishment done there 20 years ago by the U.S. Army Corps of Engineers “disappeared in a couple of months,” Mr. Rogers said. The town and Corps had to go back to the drawing board.

To compare the Southern Shores’ shoreline with a shoreline where an inlet is the major driver of erosion, as some local property owners have done, is to make the proverbial apples-to-oranges comparison. There are no inlets off of our coast.

(Mr. Rogers also noted that Dare County’s nourishment of unincorporated Buxton and Rodanthe, which had high long-term erosion rates, “disappeared very quickly,” too.)

Seasonal erosion occurs because of a variation in wind and wave energy.

As Mr. Rogers explained: “The beach oscillates in width from season-to-season and from year-to-year.” During the summer, he noted, sand moves north, so Southern Shores should benefit from Kitty Hawk’s 2017 nourishment project.

The beach is at its widest in late July and early August, according to retired longtime USACE Field Research Facility coastal engineer and former Southern Shores homeowner Bill Birkemeir, who also spoke with me by telephone last week. (To calculate beach widths recently, APTIM used measurements from May, not from the summer. See The Beacon’s articles on 9/17/19 and 9/20/19 for background.)

In the “seasonal cycle,” Mr. Birkemeier said, the beach is “narrow and steep in winter” and “comes back in the summer.” Passing hurricanes and other storms push the sand off-shore, but it returns. “It’s really simple,” he noted, and very important to understand.

When Mr. Willson attempted to update in September 2019 what he called erosional and accretional “trends” in Southern Shores on the basis of data obtained between December 2017 and May 2019, oceanographers from the Field Research Facility [also known as the Duck Research Pier] challenged his conclusions.

As The Beacon reported 9/20/19, Dr. Katherine L. Brodie and Dr. Nicholas Cohn, both of whom live in Southern Shores, told the Town Council at its Sept. 19 planning session that APTIM’s conclusions were “based on limited data” and “on short-term trends that are not particularly helpful.”

“It is very challenging to understand what’s really happening to our coastline,” said Dr. Brodie, who characterized the Southern Shores dune system and shoreline as being “stable” over time. (“It is very difficult to eyeball the shoreline,” said Mr. Rogers. There are “radical changes” going on that the eye cannot detect.)

Dr. Brodie also told the Town Council that “there is lots of seasonal variability” in erosion (loss) and accretion (gain) of beaches. The time to measure beach erosion is not in the winter, as APTIM had done.

Because Southern Shores has not been annually profiling its shoreline, we do not have what Mr. Birkemeier called “built-up knowledge” to evaluate short-term data. Some of us thought that APTIM’s 2017 profile would be the first in a series of annual surveys to keep track of the shoreline. But it did not take long for Mr. Willson to shift into recommendations for beach nourishment, with encouragement from the Town.

Southern Shores Has History of Low Long-Term Average Erosion Rates

According to its website, the N.C. Division of Coastal Management (“DCM”) evaluates long-term average erosion rates for North Carolina’s 300-mile ocean coastline every five years. It updates these rates by obtaining new aerial photographs of the shoreline to add to its database and running the data through computer programs that yield “thousands of numbers.” It started this effort in 1979, using photographs that date back to 1940.

In a January 2019 report about the methods it used to update long-term average erosion rates in 2016, the DCM reported that 88 percent of the Southern Shores shoreline had measured erosion, while the remaining 11 percent had measured accretion. The DCM calculated the average long-term erosion rate for our beaches to be 0.5 feet per year.

This does not mean that every year part of the Southern Shores shoreline is losing six inches of width while another part is gaining sand.

The DCM explains the calculation by comparing a 1992 shoreline with a 1942 shoreline. To derive the long-term average erosion (or accretion) rate, you would divide the distance that the shoreline has moved by 50, which represents the 50-year time period. If it has eroded 100 feet, you have a long-term average erosion rate of 2 feet per year, 100 divided by 50.

[It is possible to determine long-term average erosion rates for the Southern Shores beaches through an interactive mapping service offered online by the N.C. Division of Coastal Management. For my article, I researched these rates for different locations along our shoreline, and this is what I discovered:]

[The] DCM has calculated a long-term average accretion rate of 0.2 feet/year over a 76-year period from 1941 to 2017 at the Seventh Avenue oceanfront, which two homeowners have complained is so narrow as to be unusable. (Because of their complaints, the Town Council approved extending any beach nourishment plan that the Town undertakes to the Duck line, even though APTIM did not originally recommend the inclusion of northern Southern Shores beaches.)

A number of spots along the Southern Shores shoreline between Chicahauk Trail and Skyline Road have long-term average accretion rates of 0.1 to 0.2 feet/year. There is long-term accretion on the oceanfront at Third Avenue and Hickory Trail, too.

In my interactive mapping explorations, I discovered that the only areas of the Southern Shores shoreline that have long-term average erosion rates above the state median rate of 1.0 ft./yr. are a section around Trout Run, south to Yellowfin, and the southern part of the beach, from Ocean View Loop to the Kitty Hawk line. These erosion rates are generally 1.0 ft./yr. to 1.1 ft./yr. The 2017 nourishment at Pelican Watch should have made a difference at the southern end.

“You don’t have to put sand everywhere,” Mr. Rogers said, in addressing the perceived “need” for beach nourishment, “or put the same amount everywhere.”

You can distinguish among different sections of the beach, but first, The Beacon believes, you should know your beach.

Both Mr. Rogers and Mr. Birkemeier recommend annual surveys. We do not know where the sand on our beaches is and where it goes. We need to start keeping track.

“It helps a lot to understand what your beach is doing,” Mr. Rogers said, “and to design a project [to suit your beach] when you do” decide that nourishment is warranted.

Ann G. Sjoerdsma, 6/15/20

2 thoughts on “6/15/20: CONSIDERING THE ‘NEED’ FOR BEACH NOURISHMENT IN SOUTHERN SHORES AND TOMORROW’S TOWN COUNCIL WORKSHOP AGENDA.

  1. What was the result of the Town’s recent request for comment re beach nourishment- how many in favor and how many against?

    Like

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