A beach is a landform formed by the accumulation of materials that have washed ashore from the sea. Waves and tides deposit this material on the shore, and it often has a curved or concave shape. A beach will gradually change in shape and location as it extends inland from the low water line.
Sandy beaches are located along coastal areas around the world and play important cultural and recreational roles. They are also important drivers of local tourism industries. Some of these beaches have man-made infrastructure, such as lifeguard posts, showers, and changing rooms. Others have housing and hotels on them. These developments have contributed to the evolution of the modern beach.
While some sand beaches have minor relief forms, others are very dynamic. Depending on the gradient of the shore, waves may break over the crest of a bar, or a shallow depression. A broad banded edge wave may break as a spilling breaker, a plunging wave, or a surging wave. During a large storm, the highest sea level can reach the upper limit of the swash line. The lower margin of the beach, on the other hand, is the line where the largest waves no longer move sand. The lowest beach margin occurs at a depth of approximately one third of the wavelength of a wave.
In addition to humans, the ocean’s beaches are home to a wide variety of creatures, including sand crabs. These fascinating creatures live in the intertidal zone and are often visible along the coast. The tides change the intertidal zone, and the animals living in it change constantly as they follow the tides. These creatures feed on the materials left by the waves and clean up the beach.
The shape and size of the beach depends on its geology, wave height, and sediment composition. During high tide, the sand deposits a terrace or berm and then migrates onto the beach during low tide. This is how a beach develops. You may see a large beach with large sandbars or long shore bars.
In addition to erosion, the composition of a beach depends on the composition of sediments upstream from the shoreline. The particles’ size and compaction also influence how resistant they are to erosion. Generally, more compacted sediments are more resistant to erosion than sediments that are still suspended in water. The presence of vegetation will also slow the flow of fluids at the surface layer.
Sand, pebbles, rocks, and seashell fragments are common on a beach. Most of the materials in a beach come from the weathering of land over centuries. Higher waves, meanwhile, move smaller grains offshore. In addition, dune sand is consistently finer grained than the sand on other beaches. Unlike most beaches, dune sand only carries the fine grains of sand.
Storm season can reduce the profile of a beach. In temperate climates, storm season occurs during winter months. Storms cause higher wave energy and shorter periods between breaking wave crests. The waves lift the sediment up the beach and deposit it along the berm when the water recedes. Winds from the ocean also carry sediment farther inland, enhancing the dune system.