The dynamics of a beach depend on a number of factors. The waves, tidal height, sediment composition and distribution influence the form and dimensions of a beach. The sand deposited on a beach often forms a terrace or series of ridges or berms. Dunes may also bury fertile soil, woods, or buildings.
The temperatures of the water at a beach are usually in the mid-forties, but they can be dangerously cold for swimmers. Sneaker waves can hit the beach without warning, so it’s vital to wear life jackets. Children should be supervised near the water’s edge, so that they don’t trip or fall. Also, be cautious about large logs and rocks. In case of an emergency, call 911 or immediately seek medical attention.
The materials found on a beach vary considerably in size, shape and color. Some beaches are wide and sandy, while others are narrow and rocky. There are also beaches that contain large amounts of shells and seaweed. The colors of these materials vary from beach to beach, and are dependent on the geology of the area. Most beaches are some shade of brown or tan, but extreme colors can occur when there is a uniform source of sediment.
Beaches are also subject to erosion by inland water bodies. Human activity, such as the building of dams, can exacerbate the effects of coastal erosion. In the 1990s, Tuvalu’s beaches began receding quickly. The erosion was linked to the El Nino-Southern Oscillation (ENSO).
Besides being important recreational and cultural features, beaches also drive local economies. Some have man-made structures such as lifeguard posts, showers and changing rooms. Some may even be developed into housing or hotels. So, when determining the location of a beach, it’s important to understand its configuration and tidal patterns.
In temperate and tropical climates, beach sands are primarily composed of quartz, with some feldspars and heavy minerals. In tropical regions, beach sands often contain the skeletal remains of marine organisms. In addition, some beaches are called storm beaches because of the large size of the waves.
Beaches have an interesting feature called cusps. These features are located on the outer rim of the berm of the beach. They alternate with small embayments to give a beach its characteristic wavy appearance. The size and shape of cusps vary widely with different tidal conditions. During high tide, they are more prominent than at low tide. They also migrate back onto the beach during low waves.
Erosion causes a beach to deteriorate. This process is a combination of attrition, abrasion, sediment, and chemical breakdown of sediment. In many cases, the softer a rock is, the faster it is worn away.