Because of the many problems with Maintaining Seawalls and Other Structures, there has been a shift in recent years toward non-structural shore stabilization techniques. Non-structural shore protection measures generally seek to enhance the natural ability of shorelines to absorb and dissipate storm energy without interfering with natural beach, dune, and bank processes.
For an overview table of shore protection options in Massachusetts, see the Massachusetts Coastal Hazards Commission’s final report—Preparing for the Storm: Recommendations for Management of Risk from Coastal Hazards in Massachusetts (Appendix C).
In addition, CZM has produced a Coastal Landscaping website, which provides information on storm-damage prevention and other benefits of appropriate landscaping approaches, along with detailed information on how to effectively landscape coastal banks, beaches, and dunes.
CZM has also produced a StormSmart Properties website, which provides important information on a range of measures that can effectively reduce erosion and storm damage while minimizing impacts to shoreline systems. This information is intended to help property owners work with consultants and other design professionals to select the best option or combination of options for their circumstances.
Fact sheets are currently available on the following techniques:
- Artificial Dunes and Dune Nourishment - Sand, cobble, or other sediment (of appropriate size) is brought in from offsite to build a new dune (i.e., mound of sediment) or add to an existing dune to protect inland areas from erosion and flooding. Dune projects are appropriate for almost any area with sufficient space to maintain some dry beach at high tide.
- Controlling Overland Runoff to Reduce Coastal Erosion - Runoff is water from rainfall, snowmelt, irrigation, and other sources that flows over the ground surface where it can cause erosion. Runoff flowing over a coastal bank, dune, or beach can exacerbate other coastal erosion problems. Runoff control reduces the quantity and speed of water flow and changes its direction to reduce erosion.
- Planting Vegetation to Reduce Erosion and Storm Damage - Plants can help control erosion by stabilizing soil and sediments with their roots, breaking the impact of raindrops and wave splash, and trapping sand to build dunes. Vegetation projects are appropriate for virtually any dune or bank with exposed sand or other sediments (although their effectiveness as a stand-alone option can be limited in locations regularly inundated or overwashed by tides and waves).
- Bioengineering/Coir Rolls on Coastal Banks - Coastal bioengineering projects use a combination of deep-rooted plants and erosion-control products made of natural, biodegradable materials, such as coir rolls. Coir rolls are long, cylindrical rolls of mesh packed with coir fibers (i.e., coconut husk fibers). They can be stitched together to provide a continuous physical barrier that helps reduce erosion of exposed sediments on a bank. Coir rolls can be used on both sheltered and some exposed sites where there is dry beach at high tide, but may require more frequent maintenance in exposed conditions.
- Bioengineering/Natural Fiber Blankets on Coastal Banks - These bioengineering projects combine the use of erosion-control plants with mats made of natural fibers (such as straw and coconut husk) that help reduce erosion of exposed sediments from wind, waves, and overland runoff. These blankets can be installed on almost any coastal bank but are most effective where the toe of the bank is not constantly subject to erosion from tides and waves.
- Sand Fencing - Sand fencing (also called snow fencing) helps capture sand to build dunes. It is typically made of thin, wooden slats that are connected with twisted wire to wooden or metal stakes. Because of its relatively low cost and minor impacts, sand fencing is appropriate at almost any site not reached by daily high tides and waves from minor storms, except areas with endangered or threatened shorebird or turtle nesting habitat.
Some additional non-structural shore protection techniques for your community to consider include:
- Creating or restoring wetlands. See the Massachusetts Division of Ecological Restoration website.
- Prohibiting or more stringently restricting the infill of wetlands. Your community may wish to adopt a local wetlands bylaw or ordinance to do this. See the Massachusetts Association of Conservation Commission’s model wetlands bylaw/ordinance.