Beaches are gentle slopes that contain loose sediment, such as coarse gravel, cobbles, and sand. Which are moved by the waves. One of the natural characteristics that helps protects beaches from coastal erosion are dunes. The two pictures above show an example of a dune. Dunes are made of sand and deposits carried by the wind.
Dunes are important for gathering and keeping sand together.
A dune can grow to be very large. On average they are 3 to 100 meters high. Local winds may be the contributing factor to the size of a dune. Dunes are the natural barrier that dissipates all the wave strength. This helps to protect the back beach.