coasts

• Fetch = distance between two islands. (this means that a greater amount of wind can pass through between the islands which allow it to build wave energy).
• Wavelength = distance between each crest.
• Wave height = distance between trough and crest.
• Wave frequency = number of wave crests passing through a particular point each second.
• Wave period = the time required for the crest at point A to reach point B.
• Swash = waves moving up the beach.
• Backwash = waves moving away from the beach and back into the ocean.
• Constructive waves:

  • Short wave height.
  • Long wavelength.
  • Gentle sloped profile.
  • Gentle wave.
  • Stronger swash.
  • More deposition.
  • Low energy.
• Destructive waves:

  • Large wave height.
  • Short wavelength.
  • Steep beach profile.
  • Powerful waves.
  • Stronger backwash.
  • More erosion.
  • High energy.
• Hydraulic action = wave hitting the cliff causing air to be compressed into the cracks of the cliff, slowly opening up the cracks.
• Abrasion = waves carrying sediment crashing into the cliff, the sediment adding more force, eroding the cliff at a faster rate. When the rocks from the cliff break down into the water, it adds more sediment and force.
• Attrition = breaking down of large sediment into smaller and rounder sediment. This will eventually turn into sand.
• Solution = when the water dissolves certain rocks such as limestone.
• Traction = heavy sediments being dragged along the seabed.
• Saltation = sediment bouncing along the seabed.
• Suspension = small sediments being carried in the water.
• Concordant coastline = consistent (same type) of rocks throughout the coast. Takes longer to erode, same rate of erosion.
• Discordant coastline = inconsistent type of rocks throughout the coast. Soft rock will erode faster than hard rock. Different rates of erosion.
• Spit = narrow depositional landform that forms as a result of longshore drift and change in wind direction.

  -> hook end, salt marsh.
• Longshore drift causes the formation of a spit due to sediments transported from the beach down the shoreline.
• Headland changes direction but longshore drift continues, extending the beach into the ocean.
• Wave energy is reduced once it enters the ocean, causing sediment to be deposited due to low energy.
• Sediments build up over time, creating a salt marsh due to the evaporation of water and the spit blocking waves from passing through.
• Change in wind direction in the prevailing wind causes the spit to form a hook end.
• The spit is unable to build across the river estuary due to the wind, causing some material to be eroded away.
• formation of a spit key words:

  1. longshore drift, swash, backwash, transport.
  2. headland, direction, coast, transport, continue.
  3. energy, low, wave, deposit, sediment, buildup.
  4. salt marsh, form, evaporation.
  5. change, wind.
  6. river, estuary, sediment, removed.
• spit case study -> spurn head, along the holderness coast.
• spit

  
• beaches are accumulations of sand and shingles (pebbles) found where deposition occurs.
• deposition is the main process that creates a beach.
• why people would choose to live in a coastal environment?

  • tourism (job opportunities) - attractions such as jet ski.
  • fishing.
  • residential attractions (hotels).
  • gift shops - commercial industry.
• challenges to those living in coastal area:

  • flooding - destroys properties, kills.
  • coastal erosion.
  • tropical storms.
• coast opportunity and challenges case study -> east coast australia.
• opportunities - east coast australia:

  • the great barrier reef add 5.7 billion dollars to the economy each year.
  • 10,000 ships travel through the reef for trade.
  • 6000 mega watts of energy from onshore and offshore wind.
• challenges - east coast australia:

  • coastal erosion affects up to 85% of the coastline.
  • 18,000 people were evacuated due to flooding and landslides.
  • thousands of homes and businesses were damaged due to flooding and landslides, the cost estimated to be billions of dollars.
• a sand dune is an accumulation of sand formed by the wind, usually along the beach or desert.
• what are required for a sand dune to form?

  • wide beach.
  • onshore wind.
  • large amounts of sand.
  • dry sand.
  • flat beach.
  • obstacle to form against.
• embryo dune -> fore dune -> yellow dune -> grey dune -> mature dune.
• mature dunes have the most vegetation coverage.
• sand dune case study -> sefton sand dunes liverpool:

  • stretches for 22 miles along the coast.
  • some dunes can reach heights up to 100 feet.