Dunes

Coastal Dune Protection and Restoration: Case Study 3 – Dunes in Massachusetts

Sand dunes are common features in coastal zones and desert environments. Along the coast, dunes can protect beaches from erosion during storms and supply sand to a beach that is eroding. Dunes also provide habitat for highly specialized plants and animals, including rare and endangered species. Because of threats by both intentional and unintentional human activity and because of the benefits they offer, such as storm protection and sediment cycling between dune and beach evironment, many countries such as the Netherlands, United Kingdom, and the United States employ dune protection programs. These include stabilization programs and restoration efforts centered on building or re-building dunes. Protection, stabilization, and restoration methods utilize measures to reduce the transport of sand by wind and water, such as planting vegetation, constructing sand fences, and selecting access areas that avoid damage to dunes and dune vegetation from foot traffic.

It is important to consider dune structure when planting dune vegetation. Dunes are composed of the foredune (the part that faces the ocean), the sand plain (the dune crest or top) and the backdune (the side facing away from the ocean). The micro-environments of these dune components limit the types of plants that can thrive on them. For instance, foredune plants need to be tolerant to salt spray, strong winds, and some burial by wind-blown sand from the berm and beach environment, while sand plain and backdune plants can be less tolerant of these stresses because they are typically protected from salt spray and sand burial.

Managing coastal dunes for use as part of a flood protection and mitigation strategy involves an integrated management approach or plan, which follows closely on some of the principles we introduced for soft shoreline engineering. These are to:

• Restore and preserve natural processes (that is, work with nature)
• Create conditions and opportunities for establishing future natural processes (that is, maintain mass and energy flow)
• Prevent land use practices that hinder any of the above

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Figure 7.15: A: view of recently planted vegetation on the foredune and sand plain, showing remnants of sand fencing, and enclosure to protect plants against foot traffic. B: backdune view of bushy vegetation, and walkways that restrict human activity on the dune.
Credit: Left: "Spencer Park" by Emma Kelland https://creativecommons.org/licenses/by-sa/3.0/ CC BY-SA 3.0, Right: "Spencer Park 2" by Emma Kelland CC BY-SA 3.0