Introdcution to Coastal Environments

Question 1

What are the 3 inputs of a coastal system?

Answer 1

River sediment
Sediment from cliffs that have been eroded
Sediment that have been transported craves from offshore

Question 2

What are the 6 coastal processes?

Answer 2

Wave action
Tidal movement
Erosion
Weathering
Transportation
Deposition

Question 3

What are the 2 coastal outputs?

Answer 3

Sediment washed out to sea

Sediment deposited further along the coast

Question 4

Define a coastal sediment cell.

Answer 4

Lengths of a coastline that are self-contained for the movement of sediment

Question 5

What are waves responsible for?

Answer 5

Erosion and deposition of beach sediment

Question 6

How are waves created?

Answer 6

By the wind blowing over the surface of the sea.

Friction between the wind and the surface of the sea gives the water a circular motion

Question 7

What determines the affect a wave has on a coastline?

Answer 7

The height of the wave

Question 8

Hat affects the height of the wave?

Answer 8

Wind speed

Fetch of the wave

Question 9

Define fetch.

Answer 9

Maximum distance of sea the wind has blown over in creating the waves

Question 10

What are the characteristics of a high waves

Answer 10

High wind speed

Long fetch

Question 11

What is the process of a wave?

Answer 11

Waves approach shore and they break

Friction with sea bed slows the bottom of the waves (makes motion more elliptical)

Crest of the wave rises up and then collapses

Question 12

What are the two types of waves?

Answer 12

Constructive

Destructive

Question 13

What are the characteristics of a constructive wave?

Answer 13

Low frequency (6-8 waves a minute)

Low and long - elliptical cross profile

Strong swash, weak backwash

Deposits material on the beach

Question 14

What are the characteristics of a destructive wave?

Answer 14

High and steep - circular cross profile

Higher frequency (10-14 waves a minute)

Strong backwash, weak back swash

Takes material away

Question 15

What are tides?

Answer 15

The periodic rise and fall of the ocean surface

Question 16

What causes tides?

Answer 16

The gravitational pull of the moon and the sun

Question 17

What do tides affect?

Answer 17

The position at which waves break on the beach

A high tide = break higher up the shore

Question 18

Where are landforms created in relation to tides?

Answer 18

Between maximum high tide and minimum low tide

Question 19

What are sub-aerial processes?

Answer 19

They describe coastal processes that are not linked to the action of the sea

Includes free-thaw and salt weathering

Question 20

What can make cliffs more unstable

Answer 20

Through flow and runoff caused by heavy rain

Increases likelihood of mass movement

Question 21

Define mass movement.

Answer 21

The movement of material downhill due to gravity

Includes landslides, slumping and rockfalls

Question 22

What are the 5 ways that waves erode the coastline?

Answer 22

Abrasion/corrosion
Hydraulic action
Quarrying 
Corrosion/solution
Attrition

Question 23

Describe abrasion/corrasion

Answer 23

Bits of rock and sediment transported by the waves smash and bring against rocks and cliffs, breaking bits off and smoothing surfaces

Question 24

Describe hydraulic action

Answer 24

Air in cracks in cliffs is compressed when waves crash in, pressure exerted by the compressed air break off rock pieces

Question 25

Describe quarrying

Answer 25

Energy of a wave as it breaks against a cliff is enough to detach bits of rock

Question 26

Describe corrosion/solution

Answer 26

Soluble rocks (limestone) get gradually dissolved by the seawater

Question 27

Describe attrition

Answer 27

Bits of rock in water smash against each other and break into smaller bits

Question 28

What are the 5 factors affecting the rate that the coastline is eroded

Answer 28

Width of beach
Breaking point of the wave
The aspect
Rock type 
Fetch of the waves

Question 29

Describe how the width of the beach affects erosion rates

Answer 29

Beaches slow down waves, reducing heir erosive power

Wide flat beach will protect cliffs more than a narrow steep beach

Question 30

Describe how the breaking point of the wave can affect the rate the coastline is eroded

Answer 30

Waves breaking at foot of cliff transfers most energy to the cliff, causes most erosion

Waves breaking earlier on sill cause less damage

Question 31

Describe how the aspect of a beach can affect the rate the coastline is eroded

Answer 31

If coastline faces dominant wind and wave direction, erosion will be faster

Question 32

Describe how rock type of a beach can affect the rate the coastline is eroded

Answer 32

Hard rocks (granite) are more resistant to erosion than softer rocks (clay).

Question 33

Describe how fetch of the waves can affect the rate at which the coastline is eroded

Answer 33

Waves with larger fetch are much higher and steeper, more energy, causes most erosion

Question 34

Define currents

Answer 34

General flow of water in one direction

Question 35

What do currents do?

Answer 35

Move material along the coast through longshore drift

Question 36

Explain process of longshore drift

Answer 36

Swash carries sediment (shingle) yo the beach, parallel to the prevailing wind.

Backwash carries sediment back down the breach, at right angles to the shoreline.

When there’s an angle between the prevailing wind and the shoreline, a few rounds of swash and backwash move the sediment along the shoreline

Question 37

What does a coastal system have?

Answer 37

Inputs
Processes
Outputs