A beach is the land along the edge of a body of water, usually a sea. It is a dynamic environment made up of varying materials such as sand, gravel, and rock. As a result, beaches never stay in the same location for long periods. They are continuously changing due to the action of wind, waves, and the tides, and can be hundreds of kilometers long.
In most countries, sand is blown out to sea, forming small hummocks called foredunes and rows of dunes. Some dunes bury woods, fertile soil, or buildings. This dynamic process is called longshore drift. Beaches vary in size, shape, and height depending on the season.
Erosion is also a major threat to coastal areas where people live. It can expose rocks and soil that are less resistant to weather. In extreme cases, the overburden can collapse, destroying the beach and its ecosystem. It can also alter the habitat of marine animals, such as corals. In addition, houses can interfere with the beach’s natural balance and cause significant problems.
A beach, also known as a strand, is a gently sloping strip of land that is filled with sand, pebbles, and seashell fragments. The majority of these materials come from erosion of the land over many years. The action of waves on cliffs may also create loose rocks. Even huge boulders can be eroded down to grains of sand.
A beach’s ecosystem can repopulate itself with sand crabs or other animals. Sand crab larvae drift with ocean currents and can return to the beach within a year. However, frequent episodes of nourishment can delay the recolonization process. In addition, frequent nourishment can also damage the ecosystem, reducing its ability to rebuild.
A typical beach will have a berm, a beach face, and a shallow offshore bar. In addition to these, beaches will vary in length and shape. Some beaches will be long and narrow, while others will be short and sloping. The shape of a beach will depend on its location.
Beaches in low-lying areas can be prone to erosion and large cyclonic storms. These large storms typically cause large waves and high tides. These storms will alter a beach’s profile and shape, and may also erode the beach’s sediment. A beach with a poorly-stabilized foreshore is vulnerable to erosion and sea level rise.
Pollution in the ocean is one of the greatest threats to beaches. A recent NRDC report found that 20,000 beaches were closed or inspected in 2013, and 80% of those were due to near-shore bacteria levels exceeding public health standards. These closures directly impact the economy of coastal cities. Almost 900 million Americans visit coastal areas each year, and a staggering $44 billion dollars is spent on tourism each year. As a result, the economy of beachside cities is directly affected by the quality of the beaches.
Although beaches can occur anywhere, they are typically narrow, and the configuration of their topography determines whether they are rocky or sediment-filled.