Kitty Hawk and Coastal Studies Institute Have Plans in Permitting Process
The Outer Banks is a fragile environment. Strips of sand that are, if strictly defined, essentially sandbars that have risen above sea level. That doesn’t mean that they are going to disappear anytime soon, but it does point to how delicate the dance is among the forces at work.
Humans have done a fairly remarkable job of stabilizing the Outer Banks, and have used a number of tool to do so. Certainly in the past 80 years we have become more effective at stopping encroachment from the ocean—first with a line of sand dunes created in the 1930s by the WPA, and more recently through the use of beach nourishment.
On the soundside of the Outer Banks, things are more complicated.
There is a tendency to focus on the Atlantic Ocean as the great threat to shorelines; and wave energy from storms and sea level rise are issues that every community on the North Carolina coast is confronting and developing plans to mitigate.
But water seeks its own level, and there is encroachment on the sound side as well.
Loss of land on the shorelines of our Outer Banks sounds is, in some ways, more complex than what is occurring in the ocean. The loss of beach and shoreline on the ocean has the advantage of brutal simplicity—waves crash into the shore and remove sand. Ultimately it is more complex than that, but reduced to basic concepts, this is what we see happening.
In the sounds though, there are quite a number of environmental factors at work. Wave energy still drives shoreline loss, but how much energy reaches the shoreline is determined by how healthy the marsh and wetlands are that are a part of the shoreline.
In a healthy estuarine environment, much of the energy contained in waves is dissipated by the subaquatic vegetation that thrives along the shoreline and the grasses and vegetation that are typical of a marsh.
When we build in a marsh—and that is what we have done along the sounds—a natural process of shoreline protection is disrupted.
A number of steps have been taken over the years to offset the loss of land by sound front property owners. Most involve hardened structures of some sort—either riprap or bulkheads.
Bulkheads in particular, can create longterm problems.
A bulkhead does work well at first, but over time, there will be loss of land either to the sides of the structure or beneath it.
Hardened structures do not change the energy in a wave—they simply move it. Either the energy goes left or right, or it goes down. If the energy goes to either side, neighboring property owners are going to lose shoreline. If the energy goes down, the bulkhead will be undermined, and there is a very good possibility of loss of land behind the bulkhead.
Because of the potential environmental damage hardened structures represent, living shorelines are becoming more popular.
A number of them have been installed on the Outer Banks, and currently there are two large projects under CAMA review. One is a joint project of the Town of Kitty Hawk and the North Carolina Coastal Federation and the other is a joins the Coastal Studies Institute with North Carolina Sea Grant.
The Kitty Hawk project is about 500’ long and is designed to protect Moor Shore road from Kitty Hawk Bay flooding.
The CSI project addresses loss of over 100’ per year on the north end of the property.
Living shoreline use a number of techniques to break up the wave energy as it approaches the shore. There are constructs that are used, but they are beneath the surface of the water, and they are placed in such a way that the wave energy is dissipated instead of transferred.
Typically sills of approved materials are placed in parallel lines with offset gaps between the lines.
Because the wave energy of the waves has been weakened, a number of things begin to happen. Subaquatic vegetation returns, enhancing the effect of the sills. As the vegetation thrives, fish and marine life come back, as well as a migratory waterfowl that require those plants for their diets.
A living shoreline is generally not a project an individual property owner can take on. Even though it has been shown to be more effective than a bulkhead, and more cost effective over time, it does require a major CAMA permit. A bulkhead permit, by comparison, is considered a general permit by CAMA and is “… issued for certain types of projects with little or no impact on the environment.”
Will that change over time? That’s hard to say. However, towns and the state of North Carolina are increasingly looking toward living shorelines as an effective way to protect infrastructure.