Coastal Erosion

Question 1

What does water do in terms of coastal erosion

Answer 1

• Wave erosion: waves represent energy moving through water
• some of this energy expended at coast breaking down coastal cliffs, removing materials

Question 2

explain what wave axtion does in terms of erosion

Answer 2

results in eroding backwards (landward retreat of cliffs)
- this is increased by sea level rise

Question 3

how do waves approach coast line?

Answer 3

hit as an angle which results in wave refraction (waves bend)

Question 4

What is longshore Transport?

Answer 4

movement of sand parallel to shore

Question 5

What is Longshore current

Answer 5

waves approach shore at an angle (refraction occurs)
- creation of current that paralleles the coast

Question 6

What is Longshore Drift

Answer 6

waves run up beach face at an angle (called Swash)

Question 7

What is Backwash?

Answer 7

Water returns to ocean perpendicular to shore - (Backwash)

Question 8

What is a “Jetty” and what does it do?

Answer 8

• blocks sediment transport
• built in pairs to protect harbour entrance
• perpendicular to shore

Question 9

What is a starved beach?

Answer 9

increased erosion; resulting in coastlines moving inland

Question 10

Explain the coastal erosion occurring in Pacifica CA

Answer 10

coastal erosion of cliffs retreat 0.5 M/Y
- accelerated rate during uears with high amounts of storm activity

Question 11

what were the causes of Pacifica CA coastal erosion

Answer 11

• Undercutting of cliff by wave action
• Reduction in beach width over time
• Reduction in cliff stability due to heavy rains

Question 12

Explain issues with Thawing Permafrost

Answer 12

• stronger coastal waves and storm surges
• less ice
• warming air temperature

Question 13

what are the approachs to stabilize coastlines/beaches and prevent erosion?

Answer 13

• Hard stabilization measures
• Soft stabilization measures
• Measured retreat

Question 14

Explain Hard stabilization

Answer 14

• engineered structures built to prevent erosion and protect harbours
• they work by absorbing wave energy preventing erosion
• can also protect against coastal flooding

Question 15

What are “Seawalls”

Answer 15

they bounce waves back from shore increasing beach erosion
- also loss of biodiversity

Question 16

explain issue with seawall

Answer 16

• waves can overtop seawalls resulting in flooding and increased pressure from land side
• increased erosion

Question 17

What are Groynes?

Answer 17

• Prevent longshore transport of sediment, can preserve beach and protect harbour access, but creates issues in direction of transport

Question 18

What is terminal groyne syndrome?

Answer 18

• Accelerated erosion of the down current beach, recieves little or no sand from longshore transport

Question 19

How can be prevent coastal erosion (soft stabilization)

Answer 19

• plant and maintain dune vegetation
• restore salt marches, oyster reefs
• Beach nourishment (artifically place sand on a beach)
  - This can protect against eorsion