Coasts

Question 0

What is backwash?

Answer 0

Waves moving down the beach at a right angle due to gravity.

Question 1

What is a swash?

Answer 1

Waves moving up the beach.

Question 2

What are the properties of constructive waves?

Answer 2

Strong swash and weak backwash, causing deposition.

Question 3

What are the properties of destructive waves?

Answer 3

Weak swash and strong backwash, causing erosion.

Question 4

What are landforms on a destructive coastline?

Answer 4

1) Headlands and Bays
2) Cliffs and wave-cut platforms
3) Arches and stacks

Question 5

What are landforms on a constructive coastline?

Answer 5

1) Beaches
2) Spits
3) Tombolos

Question 6

How are headlands and bays formed?

Answer 6

On coastlines with alternating soft and hard rock, the soft rock is worn away rapidly creating a bay and leaving the more resistant hard rock in headlands sticking out to sea.

Question 7

How are cliffs and wave cut platforms formed?

Answer 7

Erosion is greatest at cliff foot, undercuts to create wave cut notch. As notch grows, cliff is unsupported and falls. Over time the cliff retreats and at the foot of the retreating cliff is a wave cut platform.

Question 8

How are arches and stacks formed?

Answer 8

A crack in a headland is eroded by sea to make a notch, further erosion creates a cave. Sea breaks through headland making arch, roof of arch unsupported and falls, leaving stack. Stack eroded leaving stump

Question 9

How are beaches formed?

Answer 9

In sheltered areas such as bays, constructive waves cause deposition. Longshore drift also contributes to the formation of beaches.

Question 10

How are spits formed?

Answer 10

Sediment is moved by longshore drift and deposited where waters are sheltered by a headland. A hook is created when wind changes direction. Salt marshes often develop behind a spit.

Question 11

What are Tombolos?

Answer 11

Where deposited sediment joins a mainland to an island.

Question 12

What is beach replenishment and why is it sustainable?

Answer 12

When specially adapted boats, eg Sospan Dau, dredge sediment from sea bed and spray back to develop beach.

Sustainable as doesn’t damage the environment, attracts visitors to see the boat and creates beach for tourists.

Question 13

What is beach reprofiling and why is it sustainable?

Answer 13

When sediment at sea edge is moved back up beach by trucks to form a slope, old tyres are used to form shape.

Sustainable as works with environment and uses tyres which would otherwise be waste. However, visual pollution by trucks.

Question 14

What is beach reprofiling and why is it sustainable?

Answer 14

When sediment moved east by longshore drift is distributed evenly over beach so no area is susceptible to wave attacks.

Sustainable as does not damage environment and ensures no area is particularly at risk of wave damage

Question 15

What are groynes and how sustainable are they?

Answer 15

Wooden walls build across beach to trap sediment.

Not greatly sustainable as stopping sediment building up further along coast to protect cliffs / £200,000 each / need to be maintained.

Question 16

What are sea walls and how sustainable are they?

Answer 16

Curved concrete walls to deflect wave power from coastal buildings

Very effective but not sustainable as cost £500,000 per metre / unnatural and unsightly / restrict beach access.

Question 17

What are revetments and how sustainable are they?

Answer 17

Slated sloping wooden fences to break wave force and trap beach material behind them.

Quite sustainable as cheaper than sea walls but not as effective.

Question 18

What are gabions and how sustainable are they?

Answer 18

Cages of boulders built up at cliff foot or sea walls.

Are sustainable as are cheaper than sea wall or revetments and are quite effective.

Question 19

What is rip rap and how sustainable is it?

Answer 19

Piles of boulders protecting cliff from wave power

Quite sustainable as cheapest hard engineering method but still expensive, also quite effective.

Question 20

What is Managed Retreat and how sustainable is it?

Answer 20

When the sea is allowed to erode the coast but is constantly monitored.

Cheapest method but very disruptive to people in area who have to leave homes and land. However builds up salt marshes to stop future erosion and provide a habitat for wildlife.