coasts

• Destructive Waves


  Erodes coastline, short wavelength, weak swash, strong backwash, steep gradient
• Constructive Waves

  Builds up coastline, long wavelength, strong swash, weak backwash, shallow gradient
• Coastline


  Transition zone between land and sea
• Intertidal zone


  The zone between high tide and low tide
• Erosion


  Wearing away and removal of material by a moving force, such as the sea
• Deposition


  Dropping of material that was being carried by a moving force, such as the sea
• Transportation


  The movement of material around coastlines by the action of the sea
• Swash


  The forward motion of a wave which tends to deposit sediment
• Backwash

  The backwards movement of a wave which tends to erode the coastline
• Hydraulic Action


  Force of waves hits cliffs forcing pockets of air into cracks causing minor explosions
• Corrosion (solution)


  Dissolving of rocks by salty sea water (esp. limestone)
• Abrasion (corrasion)


  Waves hurl pebbles at cliffs, thus eroding them and starting a cycle
• Attrition


  Material carried by waves becoming rounded and small as it collides with other material in sea
• Fetch


  The distance of open ocean over which waves are formed
• Prevailing wind


  The most common wind direction
• Slumping


  After heavy rain, rapid soil movement occurs when saturated soil flows over impermeable subsoil, leading to cliff collapse
• Weathering


  Breakdown of rocks on the spot without the agent of movement
• Bay


  Inlet formed of softer rocks
• Headland


  Land made of more resistant rocks jutting out to sea
• Cave


  Waves force their way into cracks in the cliff face
• Arch


  Waves erode through the back of a cave
• Stack


  Roof of an arch collapses due to gravity
• Stump


  Sea erodes base of stack and so top collapses due to gravity
• Wave cut platforms


  Rock shelf marking former base of cliff, exposed at low tide and covered at high tide
• Longshore Drift


  Loosened sediment is moved along a beach in direction of prevailing wind as swash carries it in at angle and backwash then carries it directly out to sea
• Beach


  Accumulation of coastal sediments, most often occurring in sheltered areas along coast
• Spits


  Long narrow beach attached to land at one end formed in shallow water were coastline changes direction due to longshore drift
• Bars


  Ridge of sediment formed when a spit continues across a bay
• Tombolos


  Spit connecting an island to mainland
• Salt marshes


  Formed when water accumulates
• Soft engineering


  A type of technique which uses nature against itself e.g. beach replenishment
• Hard engineering


  A type of technique which interrupts and works against nature e.g. sea walls
• Sea walls


  This is a type of hard engineering that involves the construction of a wall at the base of a retreating cliff or at the back of the beach. They often have a recurved face to deflect the waves back down the beach. They are durable and last a long time but are very ugly, so have to be buried under shingle
• Groynes


  These are a type of hard engineering which use Longshore Drift to trap sand behind them, leading to wider beaches. The side facing the waves suffers erosion but the other side traps sand due to deposition. They have a long lifespan but are vulnerable to erosion
• Revetments


  Structures built to protect embankments or slopes from erosion by absorbing and deflecting the force of water. They are commonly made of concrete, stone, or other durable materials
• Rip Rap


  Large boulders made of a resistant rock (e.g.granite) are dumped at the base of the cliff. The gaps between the rocks disperse the wave energy and reduce their erosional power. They are very effective but pose a risk to health and safety if tourists climb on them
• Gabions

  Small wire cages containing small boulders made of a resistant rock such as granite. They are then placed along retreating cliffs. This hard engineering technique is very long lasting but is also very ugly
• Concordant coastline


  Coastline where rock types lay parallel to sea
• Discordant coastline


  In this type of coastline, the layers of rock are perpendicular to the direction of the coastline
• Biological weathering


  Decomposition due to organic agents such as trees or creatures (eg. a tree growing through a rock)