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Beach

2007 Schools Wikipedia Selection. Related subjects: Geology and geophysics

   The Beach in Calella, Spain.
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   The Beach in Calella, Spain.

   A beach or strand is a geological formation consisting of loose rock
   particles such as sand, gravel, shingle, pebbles, cobble, or even shell
   along the shoreline of a body of water.

Components

   A view from above of Waikiki Beach
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   A view from above of Waikiki Beach

   Some geologists consider a beach to be just this shoreline feature of
   deposited material, but William Bascom (1980) has argued that a beach
   is the entire system of sand set in motion by waves to a depth of ten
   meters (30+ feet) or more off ocean coasts. Submerged, longshore bars
   are therefore also part of the beach. In the Bascom approach, beaches
   can be viewed as either:
     * small systems in which the rock material moves onshore, offshore,
       or alongshore by the forces of waves and currents; or
     * geological units of considerable size.

   90 mile beach Australia
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   90 mile beach Australia

   The former are described in detail below; the larger geological units
   are discussed elsewhere under bars. Both types can be viewed as
   "beaches."

   There are several conspicuous parts to a beach, all of which relate to
   the processes that form and shape it. The part mostly above water
   (depending upon tide), and more or less actively influenced by the
   waves at some point in the tide, is termed the beach berm. The berm is
   the deposit of material comprising the active shoreline. The berm has a
   crest (top) and a face — the latter being the slope leading down
   towards the water from the crest. At the very bottom of the face, there
   may be a trough, and further seaward one or more longshore bars:
   slightly raised, underwater embankments formed where the waves first
   start to break.
   Lanikai Beach on Oahu. This gently-sloping beach face is topped by a
   beach crest onto which a salt-tolerant grass (Sporobolus virginicus) is
   spreading from the incipient dune
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   Lanikai Beach on Oahu. This gently-sloping beach face is topped by a
   beach crest onto which a salt-tolerant grass ( Sporobolus virginicus)
   is spreading from the incipient dune

   The sand deposit may extend well inland from the berm crest, where
   there may be evidence of one or more older crests (the storm beach)
   resulting from very large storm waves and beyond the influence of the
   normal waves. At some point the influence of the waves (even storm
   waves) on the material comprising the beach stops, and if the particles
   are small enough (that is, are sand), winds shape the feature. Where
   wind is the force distributing the grains inland, the deposit behind
   the beach becomes a dune.
   A view from the rocks at Tamandaré Beach in Brazil
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   A view from the rocks at Tamandaré Beach in Brazil

   The line between beach and dune is difficult to define in the field.
   Over any significant period of time, sand is always being exchanged
   between them. The drift line (the high point of material deposited by
   waves) is one potential demarcation. This would be the point at which
   significant wind movement of sand could occur, since the normal waves
   do not wet the sand beyond this area. However, the drift line is likely
   to move inland under assault by storm waves.

How beaches are formed

   Beach in Long Branch, New Jersey
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   Beach in Long Branch, New Jersey

   Beaches are deposition landforms, and are the result of wave action by
   which waves or currents move sand or other loose sediments of which the
   beach is made as these particles are held in suspension. Alternatively,
   sand may be moved by saltation (a bouncing movement of large
   particles). Beach materials come from erosion of rocks offshore, as
   well as from headland erosion and slumping producing deposits of scree.
   A coral reef offshore is a significant source of sand particles.

   The shape of a beach depends on whether or not the waves are
   constructive or destructive, and whether the material is sand or
   shingle. Constructive waves move material up the beach while
   destructive waves move the material down the beach. On sandy beaches,
   the backwash of the waves removes material forming a gently sloping
   beach. On shingle beaches the swash is dissipated because the large
   particle size allows percolation, so the backwash is not very powerful,
   and the beach remains steep. Cusps and horns form where incoming waves
   divide, depositing sand as horns and scouring out sand to form cusps.
   This forms the uneven face on some sand shorelines.

   There are several beaches which are claimed to be the "World's
   longest", including Cox's Bazar, Bangladesh (120kms), Fraser Island
   beach, 90 Mile Beach in Australia and 90 Mile Beach in New Zealand and
   Long Beach, Washington (which is about 30km). Wasaga Beach, Ontario on
   Georgian Bay claims to have the world's longest freshwater beach.

Beaches and recreation

   A beach is a popular form of recreational "park"; here, Sunset Beach
   Park on O'ahu
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   A beach is a popular form of recreational "park"; here, Sunset Beach
   Park on O'ahu
   A surfer carries a surfboard along the beach.
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   A surfer carries a surfboard along the beach.

   Beaches have long been a popular attraction for tourism and recreation.
   Especially popular are seaside resorts and large white sand beaches.
   Residents and tourists alike use beaches as a place for leisure and
   sport. The relatively soft formation of sand is comfortable to sit or
   lie on, and entering and exiting the water is far easier across a sand
   beach than a rocky shore. The waves present at beaches add to the
   enjoyment and make the sport of body surfing and related activities
   possible. One of the many attractions of a sand beach, especially for
   children, is playing with the sand, building sand castles and other
   constructs.

   Towels and mats are typical beach " furniture". In the Victorian era,
   many popular beach resorts were equipped with bathing machines because
   even the all-covering beachwear of the period was considered immodest.
   This social standard still prevails in some Muslim countries. At the
   other end of the spectrum are clothing-optional beaches, where swimwear
   is optional.
   Recreation on a California beach, first decade of the 20th century
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   Recreation on a California beach, first decade of the 20th century

   A walk along the beach is also popular, including a long walk in the
   case of a long beach, for example from one seaside resort to the next.
   People usually walk the beach with bare feet. It is typically done near
   the shore line, where the sand is wet and therefore more convenient to
   walk on. One may or may not walk with the feet in the water, and this
   may also alternate with the waves

   In more than thirty countries in Europe, South Africa, New Zealand,
   Canada, South America and the Caribbean, the best recreational beaches
   are awarded Blue Flag status, based on such criteria as water quality
   and safety provision. Subsequent loss of this status can have a severe
   effect on tourism revenues.

   Due to intense use by the expanding human population, beaches are often
   dumping grounds for waste and litter, necessitating the use of beach
   cleaners and other cleanup projects. More significantly, many beaches
   are a discharge zone for untreated sewage in most underdeveloped
   countries; even in developed countries beach closure is an occasional
   circumstance due to sanitary sewer overflow. In these cases of marine
   discharge, waterborne disease from fecal pathogens and contamination of
   certain marine species is a frequent outcome.

Artificial beaches

   Girls Having Fun At Messila Beach, Kuwait
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   Girls Having Fun At Messila Beach, Kuwait

   Some beaches are artificial; they are either permanent or temporary
   (For examples see Monaco, Paris, Rotterdam, Hong Kong and Singapore).

   The soothing qualities of a beach and the pleasant environment offered
   to the beachgoer are replicated in artificial beaches, such as "beach
   style" pools with zero-depth entry and wave pools that recreate the
   natural waves pounding upon a beach. In a zero-depth entry pool, the
   bottom surface slopes gradually from above water down to depth. Another
   approach involves so-called urban beaches, a form of public park
   becoming common in large cities. Urban beaches attempt to mimic natural
   beaches with fountains that imitate surf and mask city noises, and in
   some cases can be used as a play park.

   Beach nourishment involves pumping sand onto beaches to improve their
   health. Beach nourishment is common for major beach cities around the
   world; however the beaches that have been nourished can still appear
   quite natural and often many visitors are unaware of the works
   undertaken to support the health of the beach. Such beaches are often
   not recognised as artificial.

   A concept of IENCE has been devised to describe investment into the
   capacity of natural environments. IENCE is Investment to Enhance the
   Natural Capacity of the Environment and includes things like beach
   nourishment of natural beaches to enhance recreational enjoyment and
   snow machines that extend ski seasons for areas with an existing snow
   economy developed upon a natural snowy mountain. As the name implies
   IENCE is not quite mainstream natural science as its goal is to
   artificially invest into an environment's capacity to support
   anthropogenic economic activity. An artificial reef designed to enhance
   wave quality for surfing is another example of IENCE. The Surfrider
   Foundation has debated the merits of artificial reefs with members torn
   between their desire to support natural coastal environments and
   opportunities to enhance the quality of surfing waves. Similar debates
   surround Beach nourishment and Snow cannon in sensitive environments.

Sounds of the beach

   Gentle waves at the beach
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   Gentle waves at the beach

   Beaches are noted for their sometimes serene stillness and the rhythmic
   sound made by waves crashing upon the sand. To experience, listen to
   this sound file sound recording (1.00MB) made on a South Carolina beach
   at night.

Beaches as habitat

   Flooded beach at Shell Bay, on Studland, Dorset, UK, with Marram grass
   beds in foreground
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   Flooded beach at Shell Bay, on Studland, Dorset, UK, with Marram grass
   beds in foreground

   A beach is an unstable environment which exposes plants and animals to
   harsh conditions. Some small animals burrow into the sand and feed on
   material deposited by the waves. Crabs, insects and shorebirds feed on
   these beach dwellers. The endangered Piping Plover and some tern
   species rely on beaches for nesting. Sea turtles also lay their eggs on
   ocean beaches. Seagrasses and other beach plants grow on undisturbed
   areas of the beach and dunes.

   Retrieved from " http://en.wikipedia.org/wiki/Beach"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
