Alongshore sed. transport, refraction, rocky coasts - Lecture 8

Question 1

What determines wave breaking height and angle?

Answer 1

Refraction
Waves slow down in shallow water, different parts of crest encounter different depths on bed, slower movement results in bending of wave

Question 2

What is refraction?

Answer 2

Crests bend parallel to beach

Swells - faster velocity, slows down more therefore bends more

Question 3

What does the amount of waves bending depend on?

Answer 3

Velocity differences
Angle angle of approach
If crest is stretched, wave height decreases

Question 4

Why do cliffs occur on some coasts and barriers on others?

Answer 4

The Bruun rule

Difference is a matter of slope

Question 5

What is the Bruun rule?

Answer 5

Coastal profile will move up/down, whilst maintaining it’s shape

Question 6

What does the profile have to look like to create a cliff?

Answer 6

If the landscape slope is greater than the shoreface slope and erosional rate determines some beach, no beach or wide beach