Constructing Dunes

Extensive root system on American beach grass.

Extensive root system on American beach grass. Photo: Juliana Barrett

Property owners can work together to increase or create dunes as a protective measure. Teaming with your neighbors can help defray construction costs, and create a more storm-resistant dune. Dune construction may require an individual permit or a Certificate of Permission from the Connecticut DEEP. You should consult with staff from Office of Long Island Sound Programs (OLISP) to determine the appropriate permit process. Dune activities are limited by specific timing windows, mostly related to seasonality of plants and threatened or endangered species such as least terns or piping plovers. If these species are present, you will need to submit a Request for Natural Diversity Data Base (NDDB) State Listed Species Review Form (DEP-APP-007), and all required attachments, including maps, to the NDDB for further review. The process is designed to assist in complying with the State Endangered Species Act program. Maps have been developed to serve as a pre-screening tool to help applicants determine if there is a potential impact to state listed species. You can find these pre-screening maps at CT DEEP NDDB.


When is it appropriate to construct a dune?


Dune construction is not appropriate for all coastal sites as dunes are not simply piles of sand (e.g. a berm) or rocks covered with sand or soil. Natural sand dunes usually start as windblown sand that accumulates in a sheltered area behind some type of obstacle such as piles of seaweed. The obstacle slows down or blocks the wind, causing sand to accumulate behind it. In Connecticut, dunes are often colonized by American beach grass. As the plants grow, they trap additional windblown sand with their stems and their extensive root systems hold sand in place.

Because vegetation and sand fencing take a long time to build a new dune, bulldozing has become a common form of artificial dune construction. However, bulldozed piles of sand are not the same as natural dunes. Natural dunes require a source of sand transported to the beach by waves and currents. Over time, windborne sand causes the dune to grow and move with the local conditions. Lack of a natural source of sand means the constructed “dune” may be just a very expensive and temporary pile of sand.


More Dune Creation Techniques


Other dune creation techniques involve using long geotextile tubes that are filled with sand and then placed so as to create a dune system. The tubes are then covered with sand and planted with American beach grass. This technique has been used successfully in several coastal Connecticut locations but siting of the dune location is critical and requires input from coastal engineers and other experts, as well as possible permitting from state and local officials.

Historical aerial photos and maps can help property owners determine if dunes once existed naturally at their site. Alternatively, a section of dune fencing can be set up to see if it successfully traps sand. The Connecticut Natural Diversity Data Base (NDDB) should be checked to ensure fencing is allowed at the site since fences can disturb nesting birds. In addition to a source of sand, constructed dunes must be placed far enough landward on the beach to withstand the average storm wave run-up. Many beaches are too narrow to support the construction of a stable, artificial dune. For more information on sand dunes and their formation, see Sand Dunes.