Physical Landscaoes In The Uk - Coasts And Rivers - Not Finished Flashcards
1
Q
What is relief
A
The physical features / shape of land
2
Q
What is the highest mountain in the uk
A
Ben nevis at 1344m (scotland)
3
Q
What is the relief like in the uk
A
The south and east of england is quite low lying and is made of softer rock like chalk and clay
The north west and south west of the uk is made from harder rock -like granite and limestone - mountains are formed
4
Q
What mountain range is Ben Nevis in
A
The grampian mountains
5
Q
What is the name of the mountain range just north east of wales
A
The pennines
6
Q
Name a mountain range in scotland
A
Cambrian mountains
7
Q
What is the Tees-exe line
A
An imaginary line splitting the relief of the uk into two parts
8
Q
What is fetch
A
The distance wind blows over the water
9
Q
What is swash
A
The movement of waves up a beach
10
Q
What is backwash
A
The movement of a wave back down the beach
11
Q
What is a crest
A
The top of a wave
12
Q
What is a trough
A
The base of a wave
13
Q
What is wavelength
A
The distance between crests of a wave
14
Q
What are constructive waves
A
Low waves with a powerful swash
They deposit large amounts of sediment
They have a weak backwash
Cause by a weak fetch - each wave is far apart
15
Q
What are destructive waves
A
Formed by strong winds or storms
They have a strong backwash and weak swash
High and steep
Close together
16
Q
What is suspension
A
Particles carried by the water
17
Q
What is solution (transport)
A
Dissolved chemicals often limestone or chalk (in water)
18
Q
What is traction
A
Large pebbles rolling along the seabed
19
Q
What is saltation
A
Hopping / bouncing motion of particles do heavy to be carried
20
Q
What and how do mudslides occur
A
Occur on a steep long coastline, if there is limited vegetation binding the soil
Heavy rain saturates the soil and it becomes heavy, causing it flows over the edge of the cliff at a fast speed
21
Q
What and how do landslides occur
A
Rocks and unconsolidated (loose) material on the cliff face are saturated with water
Eventually the water slips down the slope
Occurs more often on soft rock coastlines where natural joints are easily accessible
22
Q
What is rotational slumping and how does it happen
A
Heavy rain is absorbed by unconsolidated material
cliff face become heavier and separate from the material
Occurs at concave cliffs
23
Q
What is rockfall and how does it occur
A
Occurs when rocks are separated from a cliff face by freeze thaw weathering
Material is vulnerable to the elements and falls from the cliff face into the sea
24
Q
Give examples of mass movement
A
Longshore drift
Mudslides
Landslides
Rotation slumping
Rockfall
25
What is longshore drift and how does it occur
It is the movement of sediment up or down a beach
The waves hit the coast in the direction of the prevailing wind, so the swash pushes sediments in that direction.
The backwash is always at 90° so sediment is taken back up to sea.
This happens in a zig zag pattern and pushes sediment up the beach
26
What is hydraulic action
'water in cliff'
The water slams into the rocks and traps air in cracks.
The waves compress the air which causes great pressure overtime causing the rocks to crack
27
What is weathering
The breaking down of rock in situ (where it is)
Rain is a form of weathering
28
What is attrition
'Rock on rock'
Particles carried by the waves crash against each other and are broken up into smaller particles
This also causes them to be smoother
29
What is abrasion
'Rock on cliff'
Particles carried by the waves hit the cliffs damaging and breaking the rock
30
What is solution / corrosion
'chemical on cliff'
Salt from the sea water is forced into the cliff when it is hit by a wave.
The salt slowly dissolves the cliffs and the material produced is carried away
31
Chemical weathering (carbonation)
Carbon dioxide from moisture in the air reacts with carbon in the rock breaking it down (forms carbonate)
32
What is biological weathering
Plant roots break up rock with roots or exudates (similar to sap)
This process occurs over a long period of time as roots take years to grow and as they do they slowly push the rock apart causing it to crack
33
What is mechanical freeze thaw watering
Occurs on permeable or porous rocks.
Water enters cracks in the rocks and freezes when the temperature drops.
The ice expands widening the crack in the rock.
The ice will melt and the water goes deeper into the rock.
The process then repeats
34
What is salt weathering
When salt spray from the sea gets into rocks it can crystallize
This puts pressure on the surrounding rocks and weakens them
35
What is wave refraction and what does it have to do with costal deposition
When waves hit a headland they lose energy and flow towards more sheltered areas.
They travel parallel to the cliff until reaching bays, slowly dropping sediment as they lose more energy
36
What are erosional landforms
Landforms created by destructive waves wearing away rock by hydraulic action and solution
Headlands and bays are examples
37
What is a discordant coastline
A coastline made from different types of rock, hard and soft, which erode at different rates
38
What is a concordant coastline
A coastline made of the same type of rock
39
How are headlands and bays formed
They are only formed on discordant coastlines
The soft rock erodes faster than the hard rock and forms bays.
The hard rock slowly erodes to form a headland (sticks put futher at sea).
Overtime due to wave refraction a beach is formed in the bay
40
How are caves, arches, stacks and stumps formed - like old Harry Rocks
Cracks occur where geology has natural joints. They expand due to erosion and weathering
As erosion continues the cracks continue to expand to form a cave
Abrasion and hydraulic action erode the back of the cave through the cliff, forming an arch
Erosion continues and the arches base gets wider until the roof of the arch becomes too heavy and collapses, leaving a stack
The stack is eroded at the base by abrasion and hydraulic action (mini wave cut notch formed) and eventually collapses into a stump
A stump can eventually disappear due to too much errosion
41
What is a wave cut notch
This is a dent in the cliff usually at the level of high tide (where erosion occurs most consistently)
42
How are cliff and wave cut platform formed
Sea attacks a headland / hard rock cliff and undercuts the cliff forming a wave cut notch
Eventually the notch becomes too large and the cliffs weight causes it to collapse
The rubble is washed away by the waves and corrosion eventually smooths out the base left behind, forming a wave cut platform.
When the cliffs collapse the coastline retreats backwards
43
How do spits form
They form where there is a change in the landscape
Sediment is carried by longshore drift and deposited when there is a change in the coastline
This causes a long thin ridge to be deposited (a spit)
44
How do bars form
When a spit grows across a bay and joins to headlands together a bar is formed
The shallow body of water behind it is a lagoon
Eventually lagoons are filled up with water
45
Example of headland and bay stacks and bar
Swanage bay
Old harry rocks
Chesit beach
All on the dorset coastline
46
What are the 5 types of sand dunes
Embryo dune
Fore dune
Yellow dune
Grey dune.m
Mature dune
47
What conditions are needed for dunes to form
A large supply of sand
A large flat beach
Onshore wind
Time for sand to dry
An obstacle for dunes to form against
48
How do dunes form
Sand builds up in an obstacle due to onshore wind
Larger particles build up in front and the smaller ones behind
Salt resistant plants like maryam grass trap more sand, so dunes can grow in height
More mature dunes are found futher away from the beach
49
What is hard engineering
Using concrete or large artificial structures to defend against costal errosion
50
What is soft engineering
Managing erosion by working with the natural process to help restore beaches and costal errosion
51
What is managed retreat
A deliberate policy allowing control of flooding low value, low level areas or cliff collapse
52
What is a sea wall
A hard engineering strategy to protect the coast
Concrete / rock wall built to absorb and reflect energy from waves, is curved to reflect the waves
Often built at the vase of rocks
Average cost of £5 to 10k per metre
53
What are groynes
A hard engineering strategy to protect the coast
Timber or rock structures that jut out to sea.
They stop the movement of sediment via longshore drift
£150k each placed every 200m
Create a wider beach but are unattractive
Good fishing spots
Starve beaches futher up from sediment
54
What is rock armour
A hard engineering strategy to protect the coast
Gradual slopes of rocks that absorb energy from waves and protect the cliff
£200k per 100m.
Relatively cheap / provide interest to the coast
Can be dangerous / doesn't fit in with local geology
55
What are gabions
A hard engineering strategy to protect the coast
Wire cages filled with rocks, placed at the bottom of cliffs to support it
£50k per 100m
Cheap, will eventually become vegitated and blend in with the environment.
Cages only last 5-10 years
56
What is beach nourishment
A soft engineering strategy to protect the coast
Addition of sand or shingle to an existing beach making it higher or wider
Blends in with existing beach
Up to 500k per 100m
Needs constant maintenance as sediment will be lost via longshore drift
57
What is Sand dune regeneration
A soft engineering strategy to protect the coast
Vegetarian or maram grass is planted in dunes to keep them stable and help the develop
Fences are placed to prevent people from climbing on them
Maintains a natural environment
£200-2000 per 100m
Time consuming to plant the grass which some people then trample
58
What is sand dune fencing
A soft engineering strategy to protect the coast
Fences are constructed on a sandy beach along the seaward face. This encourages new sand dunes to form
These new dunes also help protect existing dunes
minimum impact on the ecosystem.
Easily damaged by storms
£400 - £2000 per 100m
59
What does a river long profile show
The steepness in the upper lower and middle course
The steepness of the gradient decreases as it goes to the lower course
60
What is a drainage basin
An area of land drained by a river and it tributaries
61
What is the source
Start of a river
62
What are tributaries
A small stream that joins to a river
63
What is the watershed
The edge of a drainage basin
64
What is the river mouth
The end of the river / where it meets the sea / a body of water
65
What what is verticle erosion
Downward erosion on a river bed
66
What is lateral erosion
Erosion of river banks rather than the bed (creates a wider river)
67
What is discharge (rivers)
Quantity of the water that passes a given point on a stream or river banks within a short period of time
68
What are the properties of the upper course
Steep sided v shaped valleys
Shallow fast flowing
Carries large sediment
Predominantly vertical erosion
69
What are the properties of the middle course
Wide, flat (in a floodplain)
The rover is wider and deeper.
High risk of flooding.
Predominantly lateral erosion
70
what are the properties of the lower course
The valley is wide and flat
The river is wide and deep with a large sediment load
(Wider and deeper than in the middle course)
Waters velocity is lower
71
What are interlocking spurs
A landform in the upper course
The river cuts down the valley through hydraulic action
The water will bend around areas of hard rock
This creates interlocking spurs of land which link tightly together
72
What are waterfall and gorges / how are they formed
The river flows over bands of less resistant soft rock and resistant hard rock
The less resistant rock is worn away faster due to errosion
The river undercuts the harder rocks leaving an overhang which becomes unsupported and collapses into the plunge pool below
After the collapse the rocks are swirled around creating a deeper plunge pool below the waterfall
It is also deepend as the river discharge is greater
The waterfall moves upstream creating a steep sided gorge ( tall walls in front of where the waterfall use to be)
73
What are gorges
Steep sided valleys showing how a waterfall has formed
74
What is a meander in a river
Bends in the river found in the middle course
75
What is the thalweg
The line of fastest flow in a river. Found in the outside of the bend
76
What are levees / how are they formed
Raised banks caused by deposition of sediment.
During a flood the thickest sediment is deposited at the channel edge, and finer sediment builds up further away, on the outer parts of the flood plane
After many floods levees are naturally built up by repetitive deposition
77
What is needed for levees to form
Repetitive flooding
High velocity river with a high carry capacity
Wide valley
78
What is an estuary / how is it formed
A drowned part of a river valley in lowland areas.
They form if land sinks or sea levels rise
For example, during an ice age most of the water in the sea evaporates, and snow falls onto mountains
This snow turns into ice, and doesnt reach the seas causing the sea level to fall
Rivers then cut deeper into their beds in order to flow down to the new sea level
When the ice age ends the ice melts and the sea rises
The new rovers / valleys by the sea become floded creating a drowned river or estuary
79
What is a fjord
A drowned river in mountainous regions
It is formed when a valley is flooded by ice that melts
80
Why are flood plains good for farming
The soil is very nutritious as nutrients are spread when the floodplain floods
81
What is flocculation
A process where the mixing of fresh water and seawater, causes clay particles to clump together
This makes them heavier and they sink,
This builds up overtime and can form sand bars and lead to braiding
82
What are the 3 natural factors that effect the risk of flooding
Precipitation - torrential rainfall can lead to sudden flash floods as rivers cant contain the sudden increase of water.
Long lasting storms also cause a build up of water
Geology - impermeable rocks do not allow water to pass through, so there is more surface run off into rivers
Relief - steeper areas encourage a rapid transfer of water, and the banks fill faster
If the land is very flat flooding may occur if the ground becomes too saturated
83
Give an example of a porous and non porous rock and there used
Slate - non-porous - used in house roofs to prevent water entering
Chalk - porous, allows water to be absorbed
84
What 3 human factors increase the risk of flooding
Urbanisation - building on floodplains created impermeable surfaces like tarmac roads and concrete driveways
Deforestation - most water that falls on trees is temporarily stored or evaporated
Trees also use up water as they grow
Removing trees causes more water to be available
Agriculture - in arable farming the soil is left exposed which can lead to more surface run-off
Ploughing land also increases this as water can easily travel along the furrows
Cattle also eat vegitation
85
What is a flood hydrograph
A graph that displays the rain fall and river discharge over a certain time, they can be used to predicted floods
86
What are the features of a flood / storm hydrograph
Rising limb - river level is increasing
Falling limb - decreasing
Peak discharge
Lag time - time between peak discharge and peak rainfall
87
What is a flashy hydrograph
A hydrograph that shows a river that is likely to flood
It would have a high peak discharge and shorter lag time
88
What are dams and reservoirs
A hard engineering strategy to reduce the risk of river flooding
They are concrete structures that prevent water from flowing downstream, as they reduce discharge they reduce the risk of flooding.
They can also be used to generate energy
They are very expensive (farmoor - oxford cost 3mil)
89
What is channel straightening
A hard engineering strategy to reduce the risk of river flooding
Cutting off meanders allows the river to flow downstream faster
This diverts flow away from urban areas, preventing flooding
Also improves shipping roots
Silt collected can be used as fertilizer
Increases downstream flooding and disrupts natural habitats
90
What are embankments
A hard engineering strategy to reduce the risk of river flooding
They are similar to natural levees, and increase the capacity of the river before it floods
3k per m - cheap
Contains flood water within the natural river
Looks unnatural
Reduces access to the river
91
What are flood relief channels
A hard engineering strategy to reduce the risk of river flooding
A man-made channel that diverts discharge from the main river.
It reduces the amount of water in the river by splitting the discharge
Increases tourism potential as there are two rivers
Natural habitats are not effected
When the relief channel meets the main river again flooding is likely
92
What is flood warning and preparation
A soft engineering strategy to reduce the risk of river flooding
Used to prepare / inform people about a flood in their area
Gives people time to save valubles
Warnings dont stop a flood
People may not gear the warnings
93
What is floodplain zoning
A soft engineering strategy to reduce the risk of river flooding
This process is used by planner when making a town in a floodplain
More expensive buildings will be placed further away, so less at risk
Playing fields would be closer as they are less important
Limits development to specific areas
94
What is afforestation / how does it help prevent flooding
A soft engineering strategy to reduce the risk of river flooding
It decreases surface run off as the trees intercept more water
Trees also stabilise soil which reduces the effect of hydraulic action and abrasion
Trees take up space, and in large cities there is no room for afforestation
95
What is river restoration
A soft engineering strategy to reduce the risk of river flooding
The process of managing rivers to reinstate natural processes and restore biodiversity.
Provides healthy habitats
Ensures long term recovery + vegetation reduces flooding
Can take time for vegetation to grow
Not always possible to restore a river
96
What is High Force
A waterfall on the river Tees, with a 22m drop (largets in the uk)
It is made of hard whinstone and carboniferous limestone, a soft rock
97
Where can a managed retreat be seen
In Medmerry
A flat low lying area of low value land mostly used for farming and caravan parks
£28 million had to be paid to farmers in compensation
That was significantly cheaper than fixing the sea wall.
The scheme started in 2013 and will create
A salt marsh that acts as a natural buffer to the sea, protecting nearby areas
It will also establish a valuable wildlife habitat and encourage visitors to the area
