COASTS

• how a bay is made: soft rock is eroded quicker creating a bay
• how a bay is made: hard rock sticks out (headland) as ts not eroded
• beaches: made from eroded material transported elsewhere and then deposited by the sea
• constructive waves- strong swash and weak backwash, wave crests are far apart, beach gains sediment
• destructive waves- weak swash and strong backwash, waves are close together, beach looses sediment
• swash- movement of waves up the beach
• backwash- movement of the wave going back down the beach (always at a right angle)
• weathering- break up of rocks due to the exposure in the atmosphere
• chemical weathering- involves a chemical change taking place
• biological weathering- caused by organisms
• physical weathering- break up of rocks with no chemical change taking place
• formation of spit: 1- prevailing winds push waves at an angle towards the shore
• formation of spit: 2- waves pikc up sediment and swoosh it up the beach
• formation of spit: 3- waves retreat down at right angles dragging sediment as its backwash
• formation of spit: 4- process of longshore drift continues in a zig-zag movement along the beach
• formation of spit: 5- where river enters the sea it slows the wave causing sediment to deposit
• formation of spit: 6- deposited sediment builds up forming a spit with a curved end
• formation of spit: 7- behind this a salt marsh can form
• formation of coastal bar: 1- created when theres a gap in the coastline with water in it
• formation of a stump: 1- a joint or fault in resistant rock is found
• formation of a stump: 2- abrasion and hydraulic action widen the joint to form a cave
• formation of a stump: 3- waves make the cave larger until it cuts through the headland making an arch
• formation of a stump: 4- arch is eroded as the roof becomes too heavy and collapses
• formation of a stump: 5- leaves a tall stack
• formation of a stump: 6- stack is eroded and collapses leaving a stump
• erosion- wearing down of rock soil and other materials
• transportation- movement of materials in the sea along the coast
• deposition- when material is deposited or left behin
• attrition- material carried by waves bump into each other and are smoothed and broken into smaller particles
• hydraulic action- waves enter faults in coastline and compress the air within the crack, when the wave retreats the air expands quickly
• solution- acids in water slowly dissolve rocks on the coast
• abrasion- coast is worn down by material carried by waves hitting against the rocks
• transportation- movement of sediment along the coast
• formation of sand dunes: 1- marram grass act as a high wall preventing the sea from reaching buildings
• formation of sand dunes: 2- formed by mound of sand and winds
• hard engineering: rock armor- piles of rock dumped at cliff, rocks absorb energy from waves protecting cliffs

  ad- cheap, can be used for fishing

  dis- rocks arnt local and look out of place, expensive to import
• hard engineering: gabions- wire cages filled with rocks providing a buffer between the sea

  ad- cheap to produce, improve drainage of cliffs, merge into landscape

  dis- very unattractive, dont last very long before rusting
• hard engineering: sea wall- concrete barrier against the sea, has a curve to reflect waves back to sea

  ad- creates walkway for people, effective

  dis- look obtrusive and unattractive, expensive, high maintenance
• hard engineering: groynes- timber or rock structures built out to sea, trapping sediment being moved by longshore drift making a wider beach acting as a buffer reducing wave damage

  ad- creates wider beach (popular with tourists), cheap

  dis- starves beaches stopping longshore drift, increases rate of erosion, unnatural looking and unattractive
• soft engineering: beach nourishment- sand is pumped into beach to build it up stablising the coastline and supports in case of a flood

  ad- blends in, larger beaches appeal to tourists

  dis- needs to be constantly replaced, sand is brought from elsewhere