Posted on February 25, 2020
Why Do You Need to Fortify Your Dunes?
It is a well-established fact that sand dunes are the coastline’s first line of defense against the destructive forces of wind and waves. They are absolutely vital in not only protecting your property but also in the construction/conservation of an ecosystem that supports native plants and wildlife.
Wind and waves are not only the forces that erode dunes but also some of the very forces that build them. This is where proactive human intervention plays a crucial role in establishing dunes and helping them grow. We are the stewards of the dunes, and as such, it is our responsibility to fortify, protect, and maintain them.
Natural sand dunes form in sporadically scattered mounds all along the coast. By themselves, these dunes are fragile and don’t offer any significant protection for your investment. As multiple forces combine to cause the continual reshaping and erosion of these dunes, the water inches its way closer to your property. Sand fencing is the most economical and effective method of fortifying and sculpting dunes into a continuous berm that will retain its linear shape and build a line of defense against the impact storm surges can have.
How Do Sand Dunes Form?
Much like an oyster creates a pearl from a grain of sand, anything on the beach, from a piece of driftwood to a piece of washed-up seaweed, can be a catalyst for sand dune creation. Sand fences trap blowing and drifting sand at their location thus causing a sand dune to effectively form and build. To promote optimal dune formation while maintaining a neutral impact on wildlife, extensive planning is needed to design the layout of the fences.
It takes extensive planning to design the layout of the fences to promote optimal dune formation while maintaining a neutral impact on wildlife. It can take years to build up protective dune berms from scratch. If adequate dunes don’t already exist, one option to accelerate the process is to haul in the sand by tractor to provide a starting foundation. One critical factor is to have native vegetation simultaneously installed to anchor the forming dune. The plants’ deep root systems form a web that helps hold the sand in place. The vegetation also acts as a further means to trap sand carried over the dunes by wind.
In the wake of Hurricane Ivan, one of the projects Dune Doctors tackled was a coastal restoration project for Heritage Dunes Subdivision. The property owners incurred an extensive loss of sand due to erosion from storm surge. The pounding waves eroded away over 150 feet of the depth of the beach relocated the sand offshore on a sandbar. The first part of the emergency restoration was the placement of roughly 2,000 cubic yards of sand along a 400-foot stretch of shoreline. The sand was then stabilized with plants and a row of sand fences was added at the toe of the newly created slope.
Over time, the fences became buried under sand brought there by the wind. Once the first row was buried, Dune Doctors added a new row of fences and plants, further seaward. Thirteen years later, the dune field now includes 3 lines of dunes, which increased the width of the original dune by over 80 feet.
Why Are Sand Fences Necessary?
The coastal ecosystem relies on “sand banking” similar in process to the way we humans rely on regular (financial) banking. It is in your best interest, with regular banking, to accumulate as much wealth as possible to provide for future withdrawals. Likewise, in the case of sand banking, it is most definitely in your best interest to accumulate as much sand as possible in order to mitigate future erosion.
It should be noted that as important as the elevation of the dunes is, the continuous nature of the barrier they create is critical. Powerful waves can push their way through grooves and passages between dunes, creating blowouts and damage landward. With the end goal of creating a continuous berm, we can use sand fences to initiate the location where the accumulation (accretion) of sand needs to begin. The installation of sand fencing helps to accrete sand in a specific place to limit dune movement while still providing beachgoers ample access to recreational beach areas.
Are You Following Federal Guidelines?
Finally, fences should never be installed on the beach with the purpose of sectioning off your property as wildlife may find its way there and become disoriented and trapped by the fencing. We always recommend following all the guidelines put out by local and federal regulating authorities. As per those guidelines, our sections of fences are angled to allow the free movement of animals to ensure they pose no threat to turtles during nesting season. At Dune Doctors, we can help you navigate the policies put in place to protect the wildlife with which you share this unique environment.
The coastline, as in all things, is in a constant state of change. Sand movement is the major cause of this change, and it is always at work. The challenge is designing and implementing ways to channel sand relocation and determine where its placement will be the most helpful.
Source: dunedoctors.com
