A beach is a strip of unconsolidated sediment (usually sand) along a body of water. It may be covered at high tide, leaving only a narrow path for walking. Occasionally, it extends far out to sea, creating islands which appear only during low tide. Some beaches are rocky, but most are composed of sandy sediments. Beaches are often popular vacation spots, and many people have different ideas of what makes a good one. Some enjoy the idea of a jam-packed beach, full of activity, while others prefer deserted islands where they can relax and sunbathe in peace. There are also surfers who want to ride big waves, and families who want sheltered areas where children can play safely in the water.
The characteristics of a beach are determined by its substrate, the water, the landscape, and the vegetation. Some of the more desirable features include:
Beaches are created by erosion and movement of sediments by wind, waves, and currents. Erosion can occur from the mechanical action of attrition and abrasion, or the chemical action of weathering and corrosion. Beaches can also form through biological action, such as the deposition of algae.
Many beaches are made of sand, which is mainly composed of quartz. However, the sediment can also be a mixture of rock fragments, carbonate skeletons of marine organisms, or fragmented shells. In the tropics, the beach may be covered with a more finely grained material that is primarily calcium carbonate.
Sand is transported from inland to the beach by longshore drift, and it can be deposited on the shore in shallow water or as fingerlike bars that extend into the ocean. These sandbanks may be connected to the mainland by a tombolo, or they might stand alone as offshore islands.
Another characteristic of a beach is its color, which can be determined by the composition of its substrate and the presence of seaweed. Most beaches have a bright tan color, while some have dark gray or black sands. The beach’s slope is also an important feature, as most people prefer a gently sloping beach to a steep, rugged cliff.
There are many things to consider when describing a beach, including its accessibility, size, shape, surface texture, temperature, and tidal fluctuations. It is essential that a beach be able to cater to the needs of all types of people, including swimmers, sunbathers, fishermen, snorkelers and divers, and birdwatchers.
Beaches are natural environments, and they should be allowed to function as such, even though this can conflict with human activities. For example, tidal movements can create a shifting sand surface, which is not always convenient for beachgoers. Beaches are also affected by the dissolved oxygen and salt levels in the ocean waters that they border, so it is important that they be kept in good condition for their ecosystems. The environmentalists who promote green beaches are trying to balance these concerns.