A beach is a landform along a sea, lake or river shoreline that features sand and pebbles. It’s a depositional landform and is constantly changing due to erosion, sedimentation and tidal action. Beaches are a popular gathering place for recreational activities such as sunbathing, swimming and water sports.
The composition of a beach depends on where it is located and what types of sediments are available. The sand of beaches in temperate regions tend to be primarily quartz and may contain feldspars, while beaches in tropical waters have a more varied composition. Some beaches also feature skeletal remains of marine organisms or calcified algae. In addition, a beach’s sand quality can be affected by the type of wave it receives and how quickly the water is flushed back into the sea after a wave crashes ashore.
Beaches that are exposed to very energetic waves have looser, less compact sediments that can be eroded more readily. Conversely, if a beach receives little to no waves or wind, the sediment will become more compact and dense and be less erodable. Beach plants, like coconut palms and sea grasses, add stability to a beach by trapping sand and rainwater in their roots, slowing fluid flow through the sediment and increasing its resistance to erosion.
The area of a beach that gets wet each day is called the swash zone, and the part that dries up between each daily tide is known as the berm. Behind the berm is the wrack line, which contains natural things like seaweed and other debris. Sometimes, sand dunes are found behind the wrack line.
A beach can also be a host for human artifacts and materials. The Skeleton Coast of Namibia, for example, is dotted with bones of whales and seals and shipwrecks. In addition, many beaches accumulate a variety of manmade materials, such as plastics and garbage.
While most people think of a beach as a coastal landform, they can also be found in inland lakes and rivers. Some beaches, such as those in California, require a beach permit to be used by the public. Others have restrictions such as no dogs on the beach during certain times of the year.
Beaches can be improved by a process known as beach nourishment, which involves pumping new sand onto the beach to help it retain its shape and prevent it from becoming a dangerously eroded bar. However, it’s important to do this carefully so the new sediment can compact and stabilize before aggressive wave or wind action erodes it. Also, the material should be of a similar composition to the surrounding beach. Otherwise, it could introduce flora or fauna that are not typical of the local environment.