Sand dunes—ridges or mounds of windblown sand—are an integral part of Virginia’s beach system. Dunes are vital to shoreline stability because they are protective features that also serve as reservoirs for sand. They are resilient natural barriers to the destructive forces of coastal storms and offer the least expensive and most efficient defense against flooding tides and waves. Coastal storms can destroy even well-established dunes. During storms, high-energy waves may wash against the base of the dunes, eroding sand and undermining the seaward dune face. In extreme storms, the dune face may recede significantly and the dune itself may be destroyed. During storm events, dune sand is removed and redistributed along the beach—essentially the dunes act as a sand storage system and a buffer between waves and coastal property. Depending on the size of the dune and intensity of the storm, high continuous dunes can provide a barrier to storm surge and overwash, thereby reducing flooding on the landward side.
Natural dune recovery after a storm depends on the severity of the storm and the initial condition of the dune. The front dunes can be severely eroded or completely flattened or overtopped during a storm. In the days and weeks after a storm, waves begin to push sand from nearshore bars back to shore to rebuild the beach. Eventually sufficient sand returns to the beach, and the dune begins to recover from storm damage as the wind blows sand up into the dune area. Natural dune rebuilding processes operate relatively slowly. Left solely to natural processes, dunes may take years or even decades to recover after a severe storm. Because dunes play such a direct role in providing storm and flood protection, it’s important to remember that removal of dune material will increase flood risk. The NFIP prohibits all manmade alteration of sand dunes within VE and V zones unless an engineering analysis demonstrates that the activity will not result in an increased flood risk.
There are many ways for individuals and communities to help protect Virginia dunes:
- Place signs on the dune to explain the importance of keeping off of the beach grass and dunes.
- Restore damaged dunes, plant vegetation, and put up dune fencing to restrict traffic. Do not remove any material from the dune—all sand should remain on the dune and beach system.
- Use designated dune walkovers and access points to control pedestrian and vehicular traffic flow across dunes. All planted areas should be protected from vehicles, pedestrians, and pets.
- Allow beach grass and dune vegetation to grow naturally. Mowing destroys the grasses’ ability to trap sand and may kill the plants.
- Maintain a clear, clean, and natural dune environment. Items such as Christmas trees, cut shrubs, and yard clippings will smother natural dune vegetation and may also become a fire hazard. This type of debris should not be placed on the dune or beach. Similarly, items such as cars, trucks, bikes, and boats should be kept off of the dune.
- Avoid hard landscaping such as railroad ties, flower boxes, retaining walls, piling tops, large stone, brick, cement blocks, and concrete. These items should not be placed in dune environments. They are easily lifted by storm waves, becoming debris that can batter your home and adjacent buildings and may cause severe damage or loss of property.