The coast

The coast

1. Defenition: The coast is the area of contact between the land and the sea. These can be narrow strips, with cliffs, or expansive areas, such as wide sandy beaches or mudflats

2. Waves

   • The fetch - longer = powerful
   • The strength of the wind
   • The duration of the wind
   • Britain's biggest wave: the Cribbar off Fistral Beach, Newquay, Cornwall
   • Constructive
     • Smaller in height
     • 'A powerful wave with a strong swash that surges up the beach'
     • They carry large amounts of sediment and 'construct' the beach
     • Distance storms can be 100s of Km away
     • 6-8 per minute, loved by surfers, frequent in summer and well spaced apart, push them up the beach
   • Destructive
     • Taller
     • 'A wave formed by a local storm that crashed down onto a beach and has a strong backwash
     • They 'destroy' the beach when they pull the sand back with strong backwash
     • 13-15 per minute
     • Local storms close to the coast

3. Marine/wave processes

   • Coastal erosion
     • Hydraulic action
       • The sheer power of the waves lashes the coast, forcing air into tiny cracks. The pressure of the compressed air, blasted into holes and cracks in the rocks weakens it and eventually causes the rock to break apart
     • Corrasion and abrasion
       • corrasion: the sea hurls fragments of rock at a coast which scrape and gouge the coast
       • Abrasion: a sandpapering effect of pebbles grinding over a rocky platform making it smooth
     • Corrosion/solution
       • Dissolving of rocks such as limestone and chalk. Calcium carbonate in these rocks reacts with the slightly acidic sea water
     • Attrition
       • Rocks and stones carried by the sea are knocked into one another, making themselves smaller and more rounded, helps to form out beaches
   • Coastal transportation
     • Traction
       • Large pebbles are rolled along the seabed
     • Saltation
       • A 'hopping' or 'bouncing' motion of particles too heavy to be suspended
     • Suspension
       • Particles carried/suspended within the water
     • Solution
       • Dissolved chemical often derived from limestone or chalk
     • Longshore drift
       • Transportation along the coast
   • Coastal deposition
     • When the sea loses energy it drops the sand, rock particles and pebbles it has been carrying
     • It occurs when:
       • Swash is stronger than the backwash
       • Waves enter an area of shallow water
       • Waves enter a sheltered area e.g. cove/bay
       • There is little wind
       • There is a good supply of material