How are barrier beaches formed?

Barrier Beaches are dynamic strips of coastal dunes and beaches that are formed by long shore currents depositing sand across the mouth of an inlet or harbor. Barrier beaches are divided into frontal beach, dune, and inland beach, usually with a marsh or estuary system in the sheltered zone behind the barrier.

These beaches are extremely dynamic systems that are constantly subjected to wind and wave energy. Well-vegetated areas on the barrier are somewhat stable, but sandy areas migrate significantly and large storms can rip holes right through the barrier. Inland areas are buffered by the barrier beaches, which dissipate storm wave energy by their shifting sands.

Barrier beaches provide nesting sites for certain rare species of birds including piping plovers (Charadrius melodus) and roseate terns (Sterna dougallii). (.jpg - 35k) Barrier beaches are too unstable to build on, and yet many people do just that. Any structure, whether a house or a jetty, that impedes the movement of a barrier beach will cause undesirable changes in the beaches ability to dissipate wave energy. No structure is permanent if built on a barrier beach.