Coastal landscapes

Question 1

what 3 factors is the energy of a wave determined by

Answer 1

• strength of wind
• duration of wind
• distance / fetch

Question 2

how does wave height increase

Answer 2

the wind pulls waves the surface through friction causing ripples to form

Question 3

give me 3 features of constructive wave

Answer 3

• depositional
• strong swash weak backwash
• low frequency
• low wave height
• large wavelength

Question 4

give me 3 features of a destructive wave

Answer 4

• strong backwash weak swash
• short wave length
• high wave height
• erosional

Question 5

what are the 3 erosional process along a coastline and define them

Answer 5

abrasion - when sediment scrap and bang against coast wearing it away
attrition - rocks and pebbles hit each other wearing each other down and get smaller
hydraulic action - waves cause air to force through cracks the high pressure cause it to crack open and widen and air expands

Question 6

give me a example of mechanical weathering and define it

Answer 6

freeze thaw - water enters cracks and freezes and expands to up to 10% causing more cracks to grow due to pressure and fragments to break away over a repeated cycle

Question 7

give me a example of chemical weathering with an example

Answer 7

carbonation - this is when acid rain reacts with calcium carbonate to form soluble which is carried away by water

Question 8

What are some common forms of mass movement

Answer 8

rockfall
landslides
mudflow
rotational slump

Question 9

what is a rockfall

Answer 9

fragments and chunks of rock falling off a cliff face resulting in freeze thaw

Question 10

what is landslide

Answer 10

sliding of chunks of rock due to lack of friction as water lubricates

Question 11

what is mudflow

Answer 11

when saturated soil flows down hill /slumping causing bulge at bottom

Question 12

what is rotational slump

Answer 12

when soil and rock fragments become saturated due to water and instead create a head at the bottom of cliff

Question 13

tell me the 4 method of transportation in rivers

Answer 13

traction
saltation
suspension
solution

Question 14

what is traction

Answer 14

the rolling of large boulders along seabed

Question 15

what is saltation

Answer 15

the bouncing of pebbles too heavy

Question 16

what is suspension

Answer 16

the particles suspended under the water / float

Question 17

what is solution

Answer 17

the chemicals dissolved in water

Question 18

what is longshore drift

Answer 18

this is the movement of sediment along coastline due to wind direction if prevailing winds which pushes the sediment in direction of wind due to swash then carry back due to back wash in zig zag
- longshore drift form spit and beaches

Question 19

what is coastal deposition

Answer 19

where sediment is dropped off by waves which have low wave energy normally constructive waves

Question 20

What is a headland

Answer 20

bit of coast jutting out to sea exposed to high energy waves and contain landforms such as cliffs , wave-cut platforms stacks

Question 21

what is a bay

Answer 21

sheltered by headlands , experienced by low energy waves resulting in deposition and beaches

Question 22

how are wave cut platforms formed

Answer 22

• when waves erode a cliff forming wave cut notch due to hydraulic action and abrasion
• undercutting the cliff causing it to collapse through mass movement
• cliff line retreats leaving behind rocky wave-cut platform which is smoothed by pebbles due to abrasion

Question 23

What are caves arches and stacks stumps

Answer 23

1. crack formed in headland due to hydraulic action
2. crack grows and become cave
3. wave pressure causes caves to break through and from arch which is widen due to erosion
4. weathering (freeze-thaw) cause it to become unstable and top collapse into sea leaving behind stack
5. stack is eroded at base to make it unstable
6. stack is collapsed into sea forming stump

Question 24

how are beaches formed

Answer 24

depositional landforms of sand and pebbles

Question 25

what are sandy beaches

Answer 25

low energy constructive waves deposit sand

Question 26

what are pebble beaches

Answer 26

when high energy destructive waves remove sand and leave behind pebbles

Question 27

what are sand dunes

Answer 27

formed at back of beach due to prevailing winds

Question 28

what are spits

Answer 28

extended stretch of sand or shingle jutting out into the sea from the land. Spits occur when there is a change in the shape of the landscape or there is a river mouth. Sediment is carried by longshore drift. When there is a change in the shape of the coastline, deposition occurs. A long thin ridge of material is deposited. This is the spit. A hooked end can form if there is a change in wind direction.

Question 29

what are bars

Answer 29

Sometimes a spit can grow across a bay, and joins two headlands together. This landform is known as a bar. They can trap shallow lakes behind the bar, these are known as lagoons

Question 30

describe the erosional and depositional landforms at Dorset coast

Answer 30

Swanage is an example of a headland and bay Old Harry Rocks is an example of caves, stacks and stumps at Chesil Beach there is a bar

Question 31

what are three ways to manage coasts

Answer 31

soft hard and managed retreat

Question 32

what are sea walls and advantages and disadvantages

Answer 32

structure placed at barrier of sea absorb and reflecting wave preventing erosion - expensive - unattractive - successful

Question 33

what are rock armour

Answer 33

Large boulders placed at the foot of a cliff. They break the waves and absorb their energy. - Cheaper than a sea wall and easy to maintain. - They look different to the local geology, as the rock has been imported from other areas. The rocks are expensive to transport

Question 34

gabions

Answer 34

``` Rocks are held in mesh cages and placed in areas affected by erosion. Cheap - approximately £100 per metre. Absorbs wave energy. Not very strong. Looks unnatural. ```

Question 35

Groynes

Answer 35

Wooden or rock structures built out at right angles into the sea. - Builds a beach - which encourages tourism. They trap sediment being carried by longshore drift - By trapping sediment it starves beaches further down the coastline, increasing rates of erosion elsewhere. They look unattractive

Question 36

what is beach nourishment and the advantages and disadvantage

Answer 36

``` when addition of sediment and sand is added to beach to replace material via erosion good for tourism cheap to start and maintain natural look regular requirements of sand ```

Question 37

What is dune regeneration

Answer 37

``` marram grass being planted to stabilise dunes and fences catch wind cost effective biodiversity and develop habitats tourism time consuming damage by storms ```

Question 38

what is managed retreat

Answer 38

``` when sea is eroded and flooded - decisions made prior cost effective land owners compensated low land value locals lose land long term good for tourism attractive sustainable ```

Question 39

why is managed retreat popular

Answer 39

too costly so efficient methods for local councils