A beach is a landform along the edge of a body of water, usually the ocean. It consists of loose material such as sand, cobbles, pebbles, and shells. It may also include clay, silt, gravel, shingle, and larger rock fragments. It can be found worldwide. Beaches are popular places for recreational activities like swimming, sunbathing, and playing beach games. They can be crowded with people and are sometimes used for fishing. Beaches can be affected by erosion, wind, and waves.
Beaches form from the movement and depositing of sediment particles. The size of the particles depends on the type of sediment, their source, and the forces that act on them. Sand particles can be produced from the erosion of rocks offshore, from beachhead slumping and headland erosion, or from rockfalls. Other important sources of sand are coral reefs, which produce sand by the process of abrasion, and the sand-making activity of fish as they feed.
Unlike the seashore, which refers to all lands at the edge of a body of water, the term beach implies that the beach is mainly made of specific materials – sand, cobbles and shells. Beaches can be long or short and have wide or narrow widths, steep or gentle slopes, a high or low percentage of shell content, etc.
As their name suggests, beaches are always moving – the beach width and slope change as the wind, rain and tide move material from or to the beach. Beaches can be very short or hundreds of kilometers long, and their composition and shape vary over time. A beach that is bare and sandy in the summer is often muddy and covered by vegetation in winter, as storm winds toss sand into the air and the beach is washed away or eroded.
In addition, beaches can be contaminated with waste materials from human activities. Wastewater from drainage pipes and rivers can wash sewage, toxic chemicals, and other pollutants to the shore. In some areas, trash from cities and towns can also wash up on the beach, including plastic bags, cans and other containers, medical waste such as needles, and discarded garbage.
The flora that grows on the dunes and foredunes of a beach is also an important part of a healthy beach. The roots of these plants help to stabilize the foredunes and prevent them from collapsing and shifting inland. In addition, some coastal flora species have the ability to trap sand particles and other materials as they grow. In some cases, these flora can even be transported by the winds and waves to other parts of the beach or by boats from other locations. Beach nourishment, which involves pumping sand onto beaches to improve their health, is a common practice for many large beach cities around the world. This practice can make a beach look quite natural, and many people are unaware that the sand they are walking on was actually shipped in from another location.