A beach is a sandy or pebbly strip of land that stretches along a body of water such as an ocean, lake or river. Beaches are made of materials such as sand, seashells and rocks that have been worn away by the action of waves over long periods of time. Beaches change every day as wind and waves deposit new material, move materials around and take away old material. The materials that make up a beach are often derived from faraway places, carried by tides and currents.
Beaches are usually narrow and gently sloping. They are often lined with a variety of plants and animals. They may be rocky, reef-like or covered by sediments such as sand, gravel, silt, pebbles, cobbles and boulders. Beaches are the product of thousands of years of weathering and erosion.
Waves pound beaches and coastlines, wearing away at cliffs and forming dunes. Over time, the constant beating of waves breaks down sand and rock and deposits sediment. Most beaches are composed of both sand and rock. Sand can be geological in origin or biological, coming from the breakdown of coral skeletons, shells and other hard body parts of marine organisms.
Ocean and river currents also play a major role in shaping and changing beaches. They push cold and warm water toward different areas of the world ocean, causing a lot of the movement of swells that we see as surf on the beach. Beaches that face very strong waves and winds tend to erode, while those facing less energetic conditions accrete.
A beach’s shape, behavior and consistency are determined by the location and strength of the surf break. These surf breaks can be natural (from a jetty, submerged shipwreck or a headland) or manmade (from a concrete groin or rip rap).
A surf break creates a certain type of wave. Spilling, surging, mushy or plunging waves are the result of a variety of factors such as the size and intensity of the swell, the length of time between swell arrivals, wind speed, bathymetry, what lies beneath the water and other variables. Understanding how a surf break works will help you read the sea and improve your surfing performance. You’ll have more fun, catch more waves and ride bigger and better surf!