A beach is an area of sand located next to a stretch of water, usually the sea. The beach is a natural phenomenon that forms as waves wash up and reshape the coastal areas, break rocks into smaller fragments, and bring sediment onto shore. Beaches are also a popular destination for recreational activities like swimming, surfing, sunbathing and fishing. In addition, beaches are used as a place to relax and unwind with family and friends. The beach landscape can differ based on the type of water body, weather and other geological factors.
A sandy beach is characterized by an abundance of fine, well-rounded, sand particles. This type of beach typically exists in coastal regions with a temperate climate and is often backed by dunes and marshes. The sand particle size is larger than that of gravel or cobblestones, making the sand more resistant to erosion. Beach sands tend to be composed of quartz and feldspars with a small percentage of heavy minerals, such as micas.
Marine beaches are primarily influenced by tides and sediment being brought onto the shore. In contrast, freshwater beaches are mainly affected by cross-shore and longshore processes. Generally, long-term coastal erosion is caused by a structural imbalance between the supply and export of sediment in a certain coastal section. This deficit can be due to both cross-shore processes and littoral drift, e.g. by a down-drift increase of longshore sediment transport (see littoral drift and shoreline modelling).
The beach is divided into several zones depending on its physiographic character. Beaches consist of the beach face, the foreshore, and the backshore. The beach face is the portion of the beach that is exposed during low tide. The foreshore is the part of the beach that is covered by water during high tide.
A sand bar is an elongated sand feature that develops naturally in tidal lagoons and estuaries in relation to flow convergence zones. It can also occur in ebb- and flood-dominated channels in the case of swash bars. Other sand features that are common in coastal systems are swash- and dune ridges, beach berms and intertidal flats.
Beach nourishment is a process that involves the delivery of new sand to a beach, in order to protect it from the impact of wave erosion. It is a method of beach management that is becoming increasingly common, and it can be applied to a wide range of beach types. In addition, beach nourishment can contribute to the ecological sustainability of a beach. Beach nourishment is especially important when sand loss has occurred in the past, as it can slow down the rate of erosion and restore the original beach profile. In the long run, this can also help to reduce the risk of flooding and protect coastline infrastructure.