beach

Waves sometimes hit the beach at an angle. The incoming waves (swash) carry sand and shingle up onto the shore and the outgoing wave takes some material away with it. Gradually material is carried down the shoreline in the same direction as the longshore current.

Seven Mile Beach, Negril, Jamaica. Now a major tourist attraction, the beach was once enclosed the Great Morass swamp until a road was built through the swamp from the town of Green Island to Negril in 1959.

The shingle beach at Lulworth Cove, Dorset, England. Wave action wears down rugged, sharp stones into smaller rounded pebbles. As the process of attrition continues, the pebbles become progressively smaller and smoother.

Track marks from vehicles are clearly visible on the sand dunes at Studland Beach, Dorset, England. Sand dunes are vulnerable ecosystems. They are easily disrupted by activities such as trampling, camping, and driving. The concentration of people and vehicles at particular places can cause great ecological damage.

A sign requests visitors to refrain from lighting fires or having barbecues on the sand dunes. The ecosystem of the beach can be easily disrupted by fire. Fire destroys the vegetation, which can take up to 50 years to recover. Part of the site has been fenced off, to prevent people from walking over it and thus preserve the dunes.

Wide sandy beaches, such as this one at Formby in Lancashire, England, are formed along parts of the coast where there is a large supply of sand, strong offshore winds, and a large tidal range. These areas are very attractive for tourism and recreation; the holiday camp in the background dominates the area behind the beach.

Blackpool Sands, at Dartmouth in Devon, was voted the best kept beach and resort in the United Kingdom in 1999. It has also been granted a prestigious European Blue Flag Award. Mentioned in the Domesday Book, Blackpool Sands was also the site of the last highwayman's coach hold-up in England.

Strip of land bordering the sea, normally consisting of boulders and pebbles on exposed coasts, or sand on sheltered coasts. Beaches lie between the high- and low-water marks (high and low tides). A berm, a ridge of sand and pebbles, may be found at the farthest point that the water reaches, generally at high tide.

The material of the beach consists of a rocky debris eroded from exposed rocks and headlands by the processes of coastal erosion, or material carried in by rivers. The material is transported to the beach, and along the beach, by longshore drift.

When the energy of the waves decreases, more sand is deposited than is transported, building depositional features such as spits, bars, and tombolos.

Artificial barriers In some places attempts are made to artificially halt longshore drift and increase deposition on a beach by placing barriers (groynes) at right angles to the beach. These barriers cause sand to build up on their upstream side but remove the beach on the downstream side, causing beach erosion. The finer sand can also be moved about by the wind, forming sand dunes.

The beach cycle Beach erosion also occurs due to the natural seasonal beach cycle. Spring high tides and the high waves of winter storms tend to carry sand away from the beach and deposit it offshore (as an offshore bar). In the summer, calmer waves and neap (low) tides cause increased deposition of sand on the beach.

Commercial threats to beaches Apart from the natural process of longshore drift, a beach may be threatened by the commercial use of sand and pebbles by the mineral industry, and by pollution (for example, by oil spilled or dumped at sea).

Beach replenishment Although it is expensive, the high value of tourism, industry, and residential property can make beach replenishment a feasible solution. Miami Beach, Florida, is an excellent example. Between 1976 and 1982 an 18 km/11 mi long, 200 m/656 ft wide beach was constructed using 18 million cubic metres/24 million cubic yards of material dredged from a zone offshore. It replicated a natural beach as far as possible.