Sand dunes are an integral component of a barrier island system. Barrier islands are highly dynamic systems that are easily affected by wind, tides, currents, storms, and humans. The main function of a barrier island is to protect the mainland behind them. Sand dunes are our first line of defense against coastal storms and beach erosion. They absorb the impact of storm surge and high waves, preventing and delaying flooding and damage to structures. They are also sand storage areas that supply sand to eroded beaches during storms and buffer windblown sand and salt spray.
Over time wind blown sand is trapped by vegetation forming dunes. Since the dunes are very susceptible to wind erosion, they depend upon vegetation, such as beach grass, for their growth and survival. Beach grass traps windblown sand causing it to accumulate around the plants and keep accumulated sand from blowing away. The network of underground roots extends the plants laterally, while the plants continue to grow upwards through accumulating layers of sand. Although the typical dune vegetation is hardy and amazingly tolerant to high salinity conditions, direct sun, extreme heat, lack of fertile soil and a fluctuating water supply, it cannot survive being trampled by humans or vehicles.
As part of its resistance to salinity and drying conditions this type of vegetation has developed a thick brittle stalk, which unfortunately snaps easily when trampled or driven upon. The passage of only one vehicle or a few people over the dune at the same point will kill a strip of grass. Without the anchoring protection provided by the grass, the wind quickly erodes a cut into the dune that enlarges with time. If not repaired, this cut becomes susceptible to breaching by waves during a coastal storm.
In addition, our beaches and dunes experience seasonal fluctuations. In the winter storm season, beaches become narrow as larger waves impinge against the coast, carrying sand offshore and depositing it offshore bars. This process of moving sand offshore helps to dissipate much of the wave energy by causing waves to break further offshore. During storms, large waves washing against the base of the dune erode sand causing the seaward face of the dune to collapse, at times completely destroying the dune. If the supply of sand remains constant this natural process will repeat itself and the dunes will eventually rebuild in width and height.
So, as a property owner or visitor what can you do?
1. Plant dune vegetation
Sea oats, seashore elder, saltmeadow cordgrass, and bitter panicum are warm season grasses that can be planted from April – September. American beach grass is a cool season grass that can be planted from November – March.
2. Erect sand fence in accordance with CAMA regulations
Sand fencing helps trap wind blown sand and deters people from crossing the dunes in undesignated locations. Click here for information on how to install sand fencing that is compliant with CAMA regulations.
3. Utilize designated public beach crossovers
In order to protect the dunes and maintain the effectiveness of these barriers as storm buffers, pedestrian crossovers have been constructed. Damage to the dunes from pedestrian traffic can be avoided by using these designated crossovers:
Kitty Hawk Bath House
Lillian Street (3 walkovers)
4. Utilize roll out wooden walkways or construct an elevated walkway according to CAMA regulations
Property owners can utilize roll out wooden walkways to gain access to the beach across the dunes in front of their homes. These types of walkways have been installed by the Town and can be seen at any of the Town Beach Accesses other than Eckner Street, Byrd Street, and the Bath House. These “temporary” walkways are allowed without a permit from CAMA. They can be purchased online at www.mrboardwalk.com, www.sportsmansguide.com, or www.plowhearth.com.
Property owners could also construct elevated wooden walkways with a permit from CAMA. Contact Ben Alexander, CAMA officer, at 261-3552 or [email protected] for more information.
5. Tell others about the importance of sand dunes
A useful resource for property owners and visitors is “The Dune Book”, by Spencer Rogers and David Nash. It can be viewed by clicking here.
For more information on where to purchase dune grasses, sand fencing, or other related questions, contact Rob Testerman, Director of Planning and Inspections at [email protected] or 252-261-3552.