COASTS

• Explain the difference between concordant and discordant coastlines. You may use a diagram to help your answer.

  Concordant: run parallel to the sea, if hard rock it will be very resistant for the sea to break through. Soft rock is eroded very quickly. Hard limestone acts as a wall . At some point the sea will break through and soft rock erodes

  
  

  Discordant: Rock layers perpendicular to the coast. Hard rock is less resistant. Soft rock easily eroded. ]

  HR: Headlands

  SR: Bays
• Explain one reason one reason why some coastlines are protected whilst others are not.

  
  

  If the cost of protecting the land outweighs the benefit, then the land may be left naturally.
• Explain one way in which hard engineering can reduce coastal erosion.

  
  

  Concrete walls that are placed at the foot of a cliff to prevent erosion. They are curved to reflect the energy back into the sea. e.g sea walls
• Explain one way in which wave height affects the rate of coastal erosion.

  High-energy destructive waves with a large wave height hurl load items with greater force, resulting infaster rates of erosion by abrasion.
• Explain how coastal erosion creates cliffs.

  Waves crashing against the coastline erode until a notch is formed. The erosion of this notch undercuts the ground above it until it becomes unstable and collapses.
• Why might there be an increase in storms in the future?

  a warming atmosphere caused by emissions from burning fossil fuels will make storms more frequent and severe in the UK.
• Why groyones reduce coastal erosion

  prevents LSD, trap sand to build beach. Trap sediments from longshore drift so that the coast behind the sand layer is protected from erosion.
• Explain two reasons why protecting some coastlines from erosion may have more cots than benefits.

  Other areas of coastline may be used for low-land farming. There would be less benefit in protecting the land because it is not a heavily populated
• Difference in rock type affect the rate of erosion on the uk landscape

  More resistant rocks (e.g. chalk,) erode more slowly.

  Weaker rocks (e.g. clays ) have less structural, strength and are eroded easily, producing a lower cliff profile with mudslides and slumping.
• State two possible reasons why coastal erosion is rapid on this coastline

  More destructive waves are present near the coastline. The rock type is soft, because there is boulder clay
• State the process that moves sediment along this coastline

  Longshore Drift
• Identify whichoneof the following is the most likely direction of sediment movement along this coastline

  
  

  south to north

  
• Explain why there is an increasing risk of coastal flooding on many UK coastlines

  Climate change (1)

  caused by increasing levels of greenhouse gases (1)

  leads to sea-level rise (1)
• Explain one reason why high discharge is likely to increase erosion

  
  

  Increased discharge increases load (1) which in turn increases

  abrasion
• Identify which one of the following is the most likely cause of waves such as these

  a long fetch across the Atlantic Ocean

  
• Identify one type of hard engineering used to protect this coastline

  Sea wall

  
• Identify which one of the following is mostly to result in rapid coastal erosion

  .high wave energy and easily eroded rock
• How do caves form

  Waves often tend to find any weakness or crack in a rock and widen it by the process ofhydraulic action. This often results in the formation of caves on a headland.
• How do arches form

  Once the cave has formed, the waves are able to enter and continue eroding back into the headland until they eventually break through to form anarch(for example Durdle Door, Dorset, UK)
• Stacks and Stumps


  Eventually over time the roof will collapse due to continued erosion and weathering leaving a tall isolatedstack

  The stack is attacked at the base by the force of the waves (undercutting) and will eventually collapse to form astump.
• Cliffs


  Sea cliffs are the most common landform of coastal erosion.

  Cliffs begin to form when destructive waves attack the base of the rock face between the high and low water marks.
• How does longshore drift work?

  the movement of material along the shore by wave action. It happens when waves approach the beach at an angle. The swash (waves moving up the beach) carries material up and along the beach.
• How do spits form ?

  They are formed at bays, estuaries and where the coastline changes direction. Spits are long and narrow beaches of sand and shingle that is attached to the mainland.
• How do bars form?

  Formed when a spit grows the whole way across a bay, cutting off the water to form a lagoon behind the bar
• Backwash


  material moves back down the beach
• Swash


  pushes water onto the beach
• What is managed retreat?

  Managed retreat is the controlled flooding of low-lying coastal areas.

  Advantages: - This is a cheap option compared to paying for sea defences.- Creates a salt marsh which can provide habitats for wildlife and a natural defence against erosion and flooding.- Salt marshes are diverse ecosystems supporting many species.

  
  

  Disadvantages: - Land is lost as it is reclaimed by the sea.- Landowners need to be compensated - this can cost between £5,000 - £10,000 per hectare.
• What is ICZM?


  CZM - integrated coastal zone management:Means managing the coast as a whole over a large area - can be a combination of hard and soft engineering.

  
  

  Do nothing (DN) (Naish Farm - Christchurch Bay)

  No coastal management employed. Generally what happens in areas where there's no people, and so nothing of value (to the government) to protect.

  
  

  Hold the Line

  Where existing coastal defences are maintained but no new defenses are set up.

  
  

  Advance the Line

  New defences are built further out in the sea in an attempt to reduce the stress on current defences and extend the coastline slightly. VERY RARE

  
  

  Retreat the Line

  Move people out of danger zones and let erosion/destruction take place. > Unpopular with local residents.
• What types of soft engineering are there?

  beach replenishment

  What is it?>

  Sand is pumped onto an existing beach to build it up. £500-1000 per m+ looks nice and create beach

  - annual sediment replacement needed