Introduction to Coastal Environments

Question 1

What is a sediment cell?

Answer 1

Coastal sediment cells are are lengths of the coastline that are pragmatically self contained for the movement of sediment.

Question 2

What are inputs?

Answer 2

Inputs include river sediment, sediment from cliffs that have been eroded, sediment transported by waves from offshore

Question 3

What are processes?

Answer 3

Wave action, tidal movement, erosion, weathering, transportation and deposition.

Question 4

What are outputs?

Answer 4

Sediment washed out to sea, or deposited further along the coast.

Question 5

How are waves created?

Answer 5

Waves are created by the wind blowing over the surface of the sea. the friction between the wind and the surface of the sea gives the water a circular motion.

Question 6

What changes the effect of the wave on the shore?

Answer 6

The waves height. This is altered by the wind speed and fetch of the wave.

Question 7

What are constructive waves?

Answer 7

Constructive waves are waves which are low and long. They have a long frequency (6-8 per minute. The powerful swash carries sediment up the beach and deposits it.

Question 8

What are destructive waves?

Answer 8

They are waves which have a high steep frequency. They have a high frequency (10-14 per minute) Their strong backwash removes sediment from the beach.

Question 9

What are tides?

Answer 9

Tides are the periodic rise and fall of the oceans surface.

Question 10

What causes tides?

Answer 10

They are caused by the gravitational pull of the moon and sun.

Question 11

What is sub-aerial weathering?

Answer 11

It describes the coastal processes that are not linked with the actions of the sea. Including freeze-thaw weathering. Weathering weakens the cliffs making them more vulnerable to erosion.

Question 12

What is mass movement?

Answer 12

It is the movement of material downhill due to gravity. This includes landslides and rockfall.

Question 13

What are the 5 main ways to erode the coastline?

Answer 13

Abrasion, hydraulic action, quarrying, corrosion and attrition.

Question 14

Describe abrasion.

Answer 14

It is when bits of rock and sediment transported by waves smash and grind against rocks and cliffs, breaking bits and smoothing surfaces.

Question 15

Describe hydraulic action.

Answer 15

It occurs when air in cracks in cliffs is compressed when waves crash in. The pressure exerted by the compressed air breaks off rock pieces.

Question 16

Describe quarrying.

Answer 16

The energy of the wave as it breaks against the cliffs is enough to detach bits of rock.

Question 17

Describe corrosion.

Answer 17

When soluble rocks such as limestone get gradually dissolved by the seawater.

Question 18

Describe attrition.

Answer 18

It is when bits of rock in the water smash against each other, breaking into smaller bits.

Question 19

Which factors effect the rate that the coastline is eroded at?

Answer 19

The width of the beach,the breaking point of waves, the aspect , the fetch of the waves and the rock type.

Question 20

Draw a diagram of longshore drift