The State of North Carolina has authorized Phase II of the shoreline stabilization work at Brunswick Town / Fort Anderson (BTFA) – installing 240’ of the Atlantic ReefMaker structure to arrest shoreline erosion. The BTFA historic site continues to experience rapid shoreline erosion from constant tide forces and dynamic wave action. The NCDCR seeks to halt the shoreline erosion in order to prevent additional buried colonial-era wharf destruction, the undermining of Civil War-era batteries and three other colonial-era wharf sites.
Phase I of the shoreline stabilization work was completed in September 2017. This work included 220’ of ARM structure installation to protect against erosion of Battery ‘A’.
Phase I was implemented because past stabilization efforts, using a marine mattress along the edge of the existing marsh, failed or were not providing the needed protection of these sensitive and historically significant resources from the high energy wave environment that it abutted. Since the installation of the structure, there is accretion along the shoreline.
ARM and a rock sill were considered as potential shoreline stabilization methods. ARM was chosen over the rock sill because ARM:
- Dissipates destructive wave energy
- Serves as ideal habitat for marine life
- Sits off of the substrate, thereby
- Minimizing scour along the structure
- Minimizing sand redistribution
- Provides flushing along the entire shoreline whereas the rock sill would be limited to ‘breaks’ in the rock sill structure every 100 feet
- Works in high energy environments
- Minimizes ‘footprint’ substrate impacts
- 25 square feet/ unit
- a ReefMaker structure that is 500’ long would impact 2,500 ft2
- a Rock Sill wavebreaker structure that is 500’ long with 2:1 slopes would impact 10,000 ft2
- Involves for modular construction which allows for post-installation modification (i.e., accommodating subsidence)
Specifically, for Phase III involving Roger Moore Wharf (a colonial site), the ARM structure accommodates installation with no impacts to the existing marsh and minimal substrate. If a rock sill wavebreaker were to be implemented to protect the shoreline at this site, there would be an impact to the historic wharf and to the existing marsh which the structure would be intending to protect.
Phase II is scheduled to begin construction in late spring 2018.
Living shoreline protecting Brunswick Town/Fort Anderson
WINNABOW, N.C. — Brunswick Town and Fort Anderson have been working on a way to save their shoreline after recent years have seen the washing away of countless historical artifacts.
Recently, officials have been working to combat erosion with a living shoreline.
Last year, officials put in a wave attenuator, a device that reduces wave strength.
Director Jim McKee says they have noticed a huge difference already. Sand is accumulating behind the attenuator and wildlife are being attracted to the living shoreline.
The device was even a major help during Hurricane Irma.
“Where, in other parts of the site, we lost more waterfront and had more damage on the bluff. Here, not one problem,” says McKee.
Engineers hope to begin phase two of the project in May. Eventually, they would like to protect the entire mile of shoreline.