A beach is an expanse of sand or pebbles sloping gently down to a body of water. The term is most commonly applied to seashores, but beaches can also be found by rivers, lakes and oceans. They are a significant feature of many coastlines, and play important social, economic and environmental roles. A beach may be a place for swimming, walking, sunbathing or recreation. It is a habitat for plants and animals such as birds, insects, crabs and mollusks.
Beaches are dynamic landscapes, subject to constant change. This is partly because a healthy beach depends on accretion and erosion, and these two processes operate in opposite directions, with accretion occurring when swells or tides carry sediment up the beach or dune system. Erosion takes place when waves wash it away, but this can be slowed by the presence of beach vegetation. The shape and profile of a beach can change dramatically in the space of a few years due to events such as a storm surge or tsunami.
Sand on a beach is constantly moving north and south along the coast, a process called longshore drift. This movement is driven by swells and winds. The direction the sand moves depends on the location of the source, the nature of the rocks it passes through, and the size and velocity of the waves. The speed and turbidity of the water can affect the sand’s particle size, causing it to settle and compact as it travels through the surf zone or eroding it when it is carried by the wave.
Sediment on a beach can be further affected by the condition of the foreshore and the type of beach vegetation. Established beach vegetation slows the rate of erosion by absorbing rainfall and releasing it over longer periods of time. The removal or destruction of beach vegetation increases the speed and erosive power of runoff, carrying more silt and organic material to the beach.
The composition of a beach is also influenced by its geology and climate. Beaches made of black basalt, for example, tend to be dark in color, while beaches with white sand are lighter in shade. Other factors, such as the amount of coral or white quart in the source rock, can influence a beach’s color.
A beach can also be impacted by the use of facilities such as lifeguard posts, changing rooms and showers, and accommodation such as hotels, hostels or shacks. The use of cabanas (private covered areas for sunbathing or entertaining) is common at many beaches, particularly in resorts. Cabins can be built of timber, metal or composite plastic and are usually fitted with a roof, screens, fans and furniture. They can be designed for privacy, as part of a resort’s theme or for entertainment and can include such amenities as outdoor kitchens, barbecues and televisions. The secluded nature of a cabana makes it a popular choice for couples looking to enjoy a romantic beach escape.