Along New Jersey’s coast, sand dunes are much more than a scenic natural feature—they serve as a vital line of defense against tides, waves, and wind erosion. Constantly shaped and reshaped by winds, storms, and human activity, dunes are dynamic systems that help protect both our shoreline and the communities behind them.
Once established, dunes can absorb the impacts of moderate storms. Vegetation, particularly American beachgrass (Ammophila breviligulata), plays a key role by anchoring sand in place with its extensive root network. The New Jersey Soil Erosion and Sediment Control Standards, Section 2: Dune Stabilization, provides proven methods for establishing and maintaining these natural barriers. Understanding these standards, and the role of vegetation, fencing, and other stabilization practices, is essential for building resilient coastal landscapes.
According to the NJ Standards, dune stabilization reduces the risk of wind erosion, storm surge, and sand encroachment in oceanfront, bayfront, and back bay areas. Dunes typically form perpendicular to prevailing winds and expand toward their source of sand. Healthy vegetation on these ridges binds the unconsolidated sand together, helping dunes withstand harsh coastal conditions.
- American beachgrass is the dominant species on New Jersey’s frontal dunes. The best planting window is from October 15 through April 1, as long as soils are not frozen.
- Coastal panicgrass thrives on dune crests and inland sites.
- Salt meadow cordgrass grows well in secondary or back dunes.
- Shrubs and trees are most successful in the sheltered back dune environment.
When American beachgrass is combined with other native dune species and structural measures, such as sand fencing (see Figure 2-1 from the state standards), a strong and well-anchored storm barrier is created.
Sand fencing is a simple yet effective tool for building and strengthening dunes. When installed correctly, it slows wind speeds at ground level, causing sand to accumulate around the fence and gradually form a dune. The NJ Standards recommend that dunes be located at least 100 feet landward of the mean high tide line (MHT), therefore sand fencing should also be set back this far. Fencing should be positioned in a zig-zag or linear pattern parallel to the shoreline. Over time, sand fencing works in combination with dune vegetation to create a sturdy, well-anchored dune system.
The NJ Standards note that temporary sand dunes may be mechanically excavated when needed.
In addition to storm protection, dunes provide critical habitat to various types of wildlife such as birds, mammals, amphibians and insects that use sand dunes as nesting and foraging areas. Many species depend on the unique conditions found in these sandy ridges. The American Oystercatcher, for example, sometimes nests in sparsely vegetated foredunes, while the Saltmarsh Sparrow forages among grasses in back dune areas. The Northeastern Beach Tiger Beetle, a federally threatened insect, relies on sandy dune habitats for burrowing and hunting. In addition, the Seabeach Amaranth (Amaranthus pumilus) a federally threatened plant, thrives in the lower dune zone where shifting sands create open conditions. Each of these species highlights the ecological importance of protecting and maintaining dune systems.
For more information about dune stabilization practices, planting recommendations, and seeding mixtures, click to view the Standard for Dune Stabilization (Section 2-1). For a comprehensive collection of all NJ Standards, click to view the complete NJ Soil Erosion and Sediment Control Standards.