Sand dunes play an important role in the stabilization of the coastline of the New Jersey Shore.
It is the nature of sand to shift in reaction to its environment. In desert areas of the world, such as western and northern China, sand is moving to overcome towns at the alarming rate of twenty meters per year.*1
The forces of nature have long been a subject of study due to the potential impact on human life and health. As more and more people become permanent residents of the Jersey Shore, the protection of sand dunes and the need to foster their development as a stabilizing feature of the coastline could never be clearer.
The New Jersey Department of Environmental Protection is charged with the overall responsibility for setting dune maintenance standards. Any construction or maintenance changes to the beach area require a CAFRA permit.
The County of Monmouth contains some of the most traveled beaches on the New Jersey Shore. Fortunately for New Jersey this county is dedicated to preserving and enhancing the beaches of the New Jersey Shore for all to enjoy.
Their document on building and maintaining sand dunes can be viewed at: http://www.visitmonmouth.com/03230planboard/EnvirGenReports/DunProtWeb.pdf (Must have Adobe Reader to view)
Essentially there are three areas of concern. The first is to protect both the coastline and the development along it by stabilizing the existing dune structures. This is done with dune fences and dune grass plantings. At the same time new sand dunes are created from natural forces of wind and rain. The sand dune system is an ever changing, growing, moving and disappearing structure.
There is no other system that responds to aerodynamics and fluid dynamics quite like shifting sand. At any point in time a granule of sand may be in contact with as many as twelve other grains of sand. The movement of air around those grains causes a volume of sand to be transported to a new location and to come in contact with many new granules.
Physicists have formulae for the behavior of solids, liquids, and gases but do not have an adequate scientific description of granular motion. Granular behavior doesn’t fit neatly into a single physical theory.
Consider the effect on a sand dune of a change in temperature, moisture or wind velocity. In spite of all this uncertainty, there are a few things we do know.
We know, for example, that as sand moves inland, it begins to nurture root grasses that stabilize its movement. Because of this stabilization, there are fewer collisions between sand granules so dunes that are anchored in this manner protect the homes and developments of the New Jersey Shore they front.
We also know that dunes can be influenced and in some cases created by dune fences and regular plantings sponsored by local town governments.
There are apparently three types of dune structures. A curved shape dune results from constant winds in a single prevailing direction. A line type structure is caused by winds that change seasonally and a star type structure is caused by constantly changing winds.
(Sand Dunes information and resources bibliography) |
