A beach is a landform that occurs along the shoreline of a body of water. It consists of sand, small rocks, gravel, or other sediment that has been eroded by the water and wind. People visit beaches for many different reasons, including to relax, play, fish, or swim.
There are a wide range of sizes and shapes of beaches, as well as varied compositions. Some are very broad, others are narrow, and some have a lot of shell content. There are also many different kinds of sand, such as white, black, tan, and yellow. The color of the sand is based on the type of rock that the beach is made from.
The sand on a beach is formed when sand is carried from mountains and rivers by the wind and water and deposited on the ocean bottom. The process is called sand stripping and it takes place over many years.
Erosion, or the wearing away of a surface, can take decades to occur, but it is often faster and more dramatic in some places because of human activities. Dams, which block river sediment from reaching the coast, can speed up the erosion of beaches.
Beaches are threatened by climate change, sea level rise, and erosion from humans. Changing weather conditions, such as the El Nino-Southern Oscillation, can lead to rapid coastal erosion.
During stormy seasons, waves can break more quickly on a beach, which can cause the sand to move inward, forming a beach berm. The crest of the berm is above the water (depending on tide), and the face is a slope that drops down to the water level. The beach berm may be a small hill that appears above the high-water line, or it may extend offshore to form offshore bars.
These offshore bars can move onto a beach in a matter of weeks or months. As they get closer, the observant beach stroller will notice the sand accumulating on the crest of the berm.
The sand accumulated on the crest of a berm is gradually pushed inland and becomes the dune. Eventually, the dune will become a natural barrier to wave crashing over it.
In some parts of the world, especially in the Pacific, a dune can grow into an island. In other areas, it can be a sandbar.
Sandbars are a type of sand formation that can be found on beaches throughout the world. They form where the waves first start breaking on a beach and can be up to a few miles long.
They are usually found at the mouth of a bay. There are two types of sandbar: the bay-mouth bar and the bay-head bar.
Another type of sandbar is the lagoon bar. These are formed at the heads of large bays or in the open waters near a coast. The lagoon bar is typically a very narrow, circular feature that encircles the head of the bay.
Sandbars can sometimes be a very interesting part of a beach to look at. They can be shaped like an animal, such as a turtle or a dolphin, or they can be simply a pile of sand. During a storm, they may be formed into a sand sculpture that can look very beautiful.