Terra Sea Technical Solutions Ltd. -

Decoding Nature’s Coastal Defense

What is the first thing that comes to mind when we hear the word ‘dune’? Perhaps the recent movie adaptations of Frank Herbert’s Dune novels? Or do you picture those prickly, grass-covered piles of sand that either burn our feet on the way to the beach or conveniently elevate our umbrellas as we enjoy cool beverages?

Beach dunes are, in fact, more than just big piles of sand; they are complex and dynamic landforms and ecosystems that form a crucial buffer between the ocean and inland areas. These dunes, which often appear as ridges or small hills, are typically found in deserts and along coastlines where wind patterns facilitate the movement and deposition of sand particles. They can vary significantly in size and shape, influenced by factors such as wind direction, sand availability and the presence of vegetation – resulting in diverse and dynamic landscapes.

Beach with dune and vegetation preventing incursion by the ocean. Photo credit: AXISIMA

The increasing threat posed by our changing climate, particularly rising temperatures and sea levels, makes it more crucial than ever to protect our infrastructure and recreational areas from coastal erosion. The impact of storm surges and coastal flooding, when unchecked, exposes buildings and foundations to wave action, leading to the erosion of supporting soils, reduced stability, and eventual structural failure. Additionally, seawater intrusion poses a significant risk to inland biodiversity, as the native flora and fauna are often ill-equipped to handle high salinity levels.

Luckily, beach dunes serve as effective natural defenses against the erosive forces of waves and coastal hazards such as storm surges and coastal flooding. They act as natural, elevated barriers, effectively absorbing and dissipating wave energy and holding back storm surges and preventing related coastal flooding – a function often replicated by man-made seawalls. The height and width of a dune system directly correlate with its ability to provide effective protection; larger, healthier dunes offer greater resistance to coastal hazards and are more resilient against severe events.

Effect of flooding by seawater intrusion due to lack of a healthy dune system. Photo credit: AXISIMA

Furthermore, dunes serve as a dynamic sand reservoir. They play a vital role in maintaining the balance of coastal ecosystems by storing sand and releasing it as needed. During periods of erosion, such as storms, sand from the dunes is transported to the beach, replenishing what has been lost. Conversely, during calmer periods, windblown sand is trapped by dune vegetation, allowing the dunes to rebuild and grow.

Beyond the protective function of beach dunes, they also serve as habitats for a variety of highly specialized plant and animal species that depend on dune systems for survival. Beach dunes are thus highly valued as special areas of conservation.

This is the first post in our Dune Systems Series. Further topics regarding dune formation, dune stabilization and more, will be discussed in future posts in the Dune Systems Series.

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