Coast

Question 1

4 types of erosions

Answer 1

Abrasion, Attrition, Hydraulic Action, Solution

Question 2

What is Abrasion

Answer 2

The waves containing eroded materials such as rocks and sand are being throw against the cliff with great force, breaking more rocks off

Question 3

What is Attrition

Answer 3

Rocks that had been eroded from the cliff falls in the sea. They will collide with each other. Overtime, they become smaller and smoother

Question 4

What is hydraulic action

Answer 4

Destructive wave repetitively hit against the cliff face until the cliff developes cracks. Overtime, the crack will be windened. Some water will be trapped inside the crack which causes the air of the crack contract, which makes the crack bigger and eventually the rock will break.

Question 5

What is solution

Answer 5

The acid and salt in sea water reacts with the soluble rock on the cliff face which cause them to dissolve.

Question 6

What are the four types of marine transportation

Answer 6

Traction - (Stones rolling along the sea-bed)

Supension - (Fine materials being carried by the sea)

Saltation - (Small pebbles bouncing along the sea-bed)

Solution - (Dissolved materials being carried by the sea)

Question 7

What is mass movement

Answer 7

The downhill movement of material under the influence of gravity

Question 8

What are the three types of mass-movement?

Answer 8

Slumping
Landslides
Rockfall

Question 9

What is slumping

Answer 9

When a large area of land on a cliff becomes saturated and heavy “slumps” down the cliff in one peice with the assistance of gravity, leaving a curved surface

Question 10

What are landslides?

Answer 10

when a section of material slides down a slope, the section of material will stay together until it hits the bottom of the slope

Question 11

What is rockfall

Answer 11

When fragments of debris break away from a cliff and fall quickly down a cliff- face and land at the bottom of the cliff

Question 12

explain the formation of a spit

Answer 12

A spit is a depositional landform that forms by longshore drift. The prevailing wind pushes constructive waves up the beach at an angle as the swash. The waves then travel at a 90 degrees angle back down the beach as backwash. This process is repeated and continues down the beach. The beach will then be extended which forms a spit.

Question 13

3 soft engineering defense methods

Answer 13

• Beach replenishment: Sand is pumped back onto a beach to replace eroded material
• Cliff regrading: The angle of a cliff is reduced to reduce mass movement
• Managed retreat: Existing coast defenses are abandoned allowing the sea to flood inland until it reaches higher land or a new line of defence

Question 14

Advantages and disadvantages of beach replenishment

Answer 14

Advantages:
- Beaches absorb wave energy,
- Widens beachfront

Disadvantages:
- Has to be repeated regularly which is expensive.
- Can impact sediment transportation down the coast

Question 15

Disadvantages and Advantages of cliff regrading

Answer 15

Advantages:
-Prevents sudden loss of large sections of cliff
-Regrading can also slow down wave cut notching at the base of cliffs as wave energy is slowed

Disadvantages:
-Does not stop cliff erosion

Question 16

Advantages and disadvantages of managed retreat

Answer 16

Advantages:
- No expensive constructions cost
- Creates new habitats such as salt marches

Disadvantages:
- Disruptive to people where land and homes are lost
- The cost of relocation can be expensive

Question 17

Name the six hard engineering strategies for coastal defence

Answer 17

-Sea Wall
-Groynes: Rocks built at right angles to the shore which traps beach material being moved by longshore drift
- Rip Rap: Rocks piled up the protect a stretch of coast
- Gabions: Wired cages filled with stones
- Revetments: Sloping wooden fence with an open plank structure
Tetrapods: Made of concrete which absorbs wave energy

Question 18

Advantages and disadvantages of Sea wall

Answer 18

Advantages: Most effective at preventing both erosion and flooding

Disadvantages:
-Very expensive to build and maintain
- Restricts access to the beach
- Ugly to look

Question 19

Advantages and disadvantages of Groynes

Answer 19

Advantages:
-Slows down beach erosion
-Creates wider beaches

Disadvantages:
-Makes walking along the shoreline difficult
-Stops material moving down the coast where the material may have been building upon and protecting the base of a cliff elsewhere

Question 20

Advantages and disadvantages of Rip-rap

Answer 20

Advantages:
-Cheap
- Works to absorb wave energy from the base of cliffs and sea walls

Disadvantages:
- Rocks can be eroded during heavy storms

Question 21

advantages and disadvantages of gabions

Answer 21

Advantages:
- Cheap
- Cages absorb wave energy

Disadvantages:
- Wire cages can break and they need to be securely tied down
- Not as efficient as other coastal defenses

Question 22

Advantages and disadvantages of Revetments

Answer 22

Advantages:
- Breaks the force of the waves
- Cheap

Disadvantages:
- Not effective in stormy conditions
- Can make beach inaccessible for people
- Regular maintenance is necessary
- Ugly

Question 23

Advantages and disadvantages of tetrapods

Answer 23

advantages:
- Breaks wave energy before reaching the shore
- Low maintenance

disadvantages:
- Expensive to build
- Can be unattractive
- Can be removed easily to prevent storms