1.1.2 Temporal variations and their influence on coastal environments

Question 1

Describe the formation of a wave

Answer 1

The bottom of the wave touches the sand and slows down due to increased friction (wave length decreases). The top of the wave becomes higher and steeper (wave height), overtaking the bottom as the water gets shallower until it topples over (breaks).

Question 2

What are four factors that influence the formation of a wave?

Answer 2

1. Wind speed
2. Fetch
3. Time duration the wind has blown over a given area
4. water depth

Question 3

Describe destructive waves

Answer 3

Created in stormy conditions, when wind is strong, high wave energy, long fetch, erosional, backwash is stronger than swash, high frequency (10-12 per minute), high gradient.

Question 4

Describe constructive waves

Answer 4

Created in calm weather, depositional waves, low gradient, swash is stronger than backwash, long wavelength and low in height, low frequency (6-8 per min).

Question 5

What is wavelength or amplitude?

Answer 5

The distance between two successive crests or troughs

Question 6

What is wave period?

Answer 6

The time in seconds between two successive between two successive crests or troughs

Question 7

What is wave height?

Answer 7

The distance between the trough and the crest

Question 8

What is fetch?

Answer 8

The amount of open water of which the wave has passed.

Question 9

What is velocity?

Answer 9

The speed a wave travels at and is influenced by wind, fetch, and the depth of water

Question 10

What is swash?

Answer 10

The movement of water up a beach

Question 11

What is backwash?

Answer 11

Movement of water down the beach

Question 12

What are the three energy inputs?

Answer 12

waves, tides and current

Question 13

When are destructive waves more likely to form?

Answer 13

During spring tides due to the higher nature of the tide peak

Question 14

When are constructive waves more likely to form?

Answer 14

During neap tides