Our Environment

Coastal Dunes: Nature’s Coastal Defense and Sand Keeper

Coastal dunes play an important role in protecting the coastline as they are a natural barrier to wind and waves

DATOEver wonder why some locations have lost their pretty white beaches?  I ask you, do you see sand dunes above the beach line? Do you see mangroves nearby? Most likely your answer would be: nope.

Coastal sand dunes are (usually) a common feature along the shoreline and fringe thousands of kilometers of coastline around the world. Most beaches are backed by vegetated sand ridges (dunes), built up by dry sand blown inland and trapped. Plants play a vital role in this process, acting as a windbreak and trapping sand particles. As sand accumulates, the dunes become higher and wider.

Coastal dunes play an important role in protecting the coastline as they are a natural barrier to wind and waves. Coastal dunes (and mangroves) are our first line of defense against storms and beach erosion. They absorb the impact of storm surge and high waves, preventing or delaying flooding of inland areas and damage to inland structures. They are also sand storage areas that supply sand to eroded beaches during storms and buffer windblown sand and salt spray.

Coastal dunes are vulnerable and are threatened by human activity. They are eroding due to increased sediment loss because of increased coastal human activities, and they need to have limited interaction with humans to survive. Structures built too close to the shoreline are inhibiting the landward movement of the dune. Driving and walking on the dunes causes deterioration of beach grass and other vegetation that help trap and hold the sand in place. Without vegetation, the dune is exposed to wind erosion and without the sand-catching dunes (and mangroves), the beach has no way to replenish its sand.

To avoid this, protecting the vegetation and the ecosystem is vital. Damaged and sensitive dunes might need to be fenced and access tracks for vehicles and people provided. However, the success of restoration and dune management depends a great deal on public education because not all aspects of dune management are obvious or important if the public does not understand why. To preserve any ecosystem, improvement and protection efforts should not only be the responsibility of the governmental entities involved. The efforts of those individuals who live on and use the shoreline can be even more valuable.

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