How is a sand spit formed?
(Prevailing) wind approaches from an angle ;
Swash comes in at an angle/obliquely;
Backwash is vertical/straight out to sea;
Material is moved in zigzag manner;
(Known as) longshore drift;
Spit develops where there is a change in direction of coastline;
Recurved/hook by waves from other directions, etc.
Describe the processes of coastal erosion
Hydraulic action;
Air compressed in crack in rocks by power of waves;
Corrosion/solution;
Rocks like limestone dissolved by acids in sea water;
Corrasion/abrasion;
Waves pick up loose materials and use them to grind the cliffs;
Attrition;
Materials reduced in size as they hit each other when being carried or moved around by waves, etc.
What are waves caused by?
The wind drags the surface of the water
Definition of swash
The flow of water rushing up the beach when a wave breaks
Definition of backwash
the flow of water back to the sea after a wave breaks
Features of constructive waves
Carries out deposition Wide, gently sloping waves Less powerful waves Breaks on the shore Transports material
Features of destructive waves
Carries out erosion Storm conditions Lots of wave energy Long fetch Water plunges forwards Steep beach gradient High wave height
Definition of longshore drift
waves carry material along the coastline
Problems which coastal erosion may cause for people in the area
- damage of housing
- loss of farmland
- negative impact on tourism
- roads destroyed
- high cost of protection methods
Definition of headland and bays
Alternate layers of hard and soft rock
How are caves formed?
- hydraulic action
- causes cracks in the cliff to widen
- erosion continues, forming a cave
How are stacks and stumps formed?
- Erosion continues until the roof of the cliff collapses
- Too heavy to withhold
- Separated land = stack
- Weathering erodes the top = stump
How are sand dunes formed?
Sand blown by wind;
Obstruction/pebble/litter/plant blocks wind;
Causes velocity of wind to reduce/eddies;
Deposition;
Colonization by more plants;
Gets larger over time;
Hazards of coasts
Flooding - Death - Cost of flood defense - Destruction of farmland - Unemployment - Destruction of buildings - Lack of water and food supply - Schools and hospitals destroyed Tropical storms Erosion of land - Loss of land - Collapsed housing
Opportunities of living near a coast
- trading
- transportation
- tourism –> more job opportunities
- fertile soil –> farming
- renewable energy
- Abundant supply of water
- Leisure
- Diverse eco-system habitats
How are wave-cut platforms formed?
- Formed by weathering and erosion along the coast
How are beaches formed?
- Composed of shingle and sand
- Sand is deposited by constructive waves (calm water)
- Shingle is deposited by destructive waves (rough water) further into the bay
How are headlands and bays formed?
- In the beginning, the hard and soft rock are at the same level
- As the soft rocks erode faster, the layers of hard rock. are left jutting out. These are called headlands.
- The area where the soft rock has eroded is called the. bay
How are headlands and bays formed?
- In the beginning, the hard and soft rock are at the same level
- As the soft rocks erode faster, the layers of hard rock are left jutting out. These are called headlands.
- The area where the soft rock has eroded is called the bay
How are cliffs formed?
- Weathering and erosion
- The soft rock is eroded away by destructive waves and solution –> hard rock left forms a cliff
