Unit 1 - Section C - Physical landscapes of the U.K Flashcards
1
Q
Where are the majority of igneous rocks located?
A
North Scotland
Snowdonia
Wales
2
Q
Where are the majority of metamorphic rocks located?
A
North Scotland
3
Q
Where are the majority of sedimentary rocks located?
A
East England
4
Q
Where are the U.K upland areas found and what is the main rock type found?
A
-North and West of the country
-Igneous rocks (granite) and metamorphic (Slate) which are resistant to erosion
5
Q
Where are the U.K lowland areas located and what is the main rock type found?
A
-South and East of the country
-Sedimentary rocks like chalk and clay which erode easily
6
Q
What are examples of upland areas in the U.K.?
A
Lake district
7
Q
What are examples of lowland areas in the U.K.?
A
Lancashire
Chesire
8
Q
Define the term coast
A
The interface between land and sea. They are the dynamic zone where the land meets the sea and where coastal processes operate
9
Q
Define the term fetch
A
The distance the wind has blown the wave
10
Q
Define the term crest
A
Highest point on a wave
11
Q
Define the term trough
A
Lowest point on a wave
12
Q
Define the term wave length
A
Distance between each crest
13
Q
Define the term wave height
A
The distance between the top of the crest and the bottom of the trough
14
Q
Define the term breaking wave
A
A wave that has hit the beach
15
Q
Define the term swash
A
Water that travels up the beach after the wave has broken
16
Q
Define the term backwash
A
Water that travels back down to the sea by gravity
17
Q
What are the two types of wave
A
Constructive wave
Destructive wave
18
Q
What is a constructive wave?
A
Constructive waves are low waves that surge up the beach and spill with a powerful swash. They deposit large amounts of materials and construct the beach
19
Q
What is a destructive wave?
A
Destructive waves are formed by local storms close to the beach. They are close together and produce a swirling mass of water. They become high and steep but then plunge down onto the beach
20
Q
What are the properties of destructive waves?
A
-Close together
-Steep wave front
-Breaking wave plunges downwards
-Steep beach
21
Q
What are the properties of constructive waves?
A
Far apart
Gently sloping
Breaking wave spills forward
22
Q
Define the term hydraulic action
A
Waves crash against rock and compress the air in cracks. The air then expands and this puts pressure on the rock. This repeats and causes cracks to widen and bits of rock to break off
23
Q
Define the term abrasion
A
Eroded particles in the water scrape and rub against rock removing pieces
24
Q
Define the term attrition
A
Eroded particles in the water collide. They then break into smaller pieces and become more rounded and smooth
25
Define the term mechanical weathering
The breaking down of rock without changing its chemical composition
26
What happens in freeze thaw weathering
-Water enters the crack of a rock
-The water then freezes which expands the rock
-This puts pressure on the rock
-The water then thaws
-This process repeats and the crack widens causing some rock to break off
27
Define the term chemical weathering
The breakdown of rock by changing its chemical composition
28
What is mass movement?
The shifting of rocks and loose materials down a slope
29
How does chemical weathering occur?
Rainwater which is slightly acidic slowly dissolves certain rock like chalk and limestone
30
What are the three types of mass movement?
Slumping
Sliding
Rockfall
31
How does slumping occur?
-Since clay is **impermeable**
-If it rains water sits on top of the clay
-This adds **weight** to it and the combined weight of water and gravity causes the clay to **slump**
32
How does rockfall occur?
-Weathering causes rocks to become loose
-They then slide down the cliff if they break off
33
How does landslide occur?
-Material shifts in a straight line along a slide plane
-This often happens when there is a wave cut notch at the bottom of the cliff
34
What is longshore drift?
-Longshore drift occurs when the waves hit the coast at an **oblique angle**
-The swash carries material up the beach in the **direction of the wave**
-The backwash carries the material down the beach at **right angles** towards the sea due to gravity
-Over time material **zigzags** along the coast
35
What are the four transportation methds?
Traction
Saltation
Suspension
Solution
36
What is traction?
Large load like boulders are rolled along the sea bed by the force of water
37
What is saltation?
Pebble sized particles are bounced along the sea bed by the force of water
38
What is suspension?
Small particles are carried along the water
39
What is solution (transport)?
Soluble materials are dissolved in the water and carried along
40
What is deposition?
When the sediment is placed down
41
When does deposition occur?
-Deposition occurs when the water carrying sediment loses energy and slows down
-There is erosion further along the coast as there's more material to place
-Lots of material is transported
42
What is a concordant coastline?
When the alternating bands of rock are parallel to the coast
43
What is a discordant coastline?
When the alternating bands of hard of soft rock are at right angles to the coast
44
What are some examples of erosional landforms on the coast?
Headlands
Bays
Cave
Arch
Stack
Stump
Wave cut platforms
45
Explain the formation of a headland and bay
-Headlands and bays form when there is a discordant coastline and there is less resistant rock in between more resistant rock
-The less resistant rock erodes quicker then the more resistant rock forming a bay with a gentle slope
-Because the more resistant rock takes longer to erode headlands form with steep sides
46
Explain the formation of the: Cave, arch, stack and stump sequence
-Headlands typically contain loads of cracks (lines of weakness)
-Waves crash into the headlands
-Because of abrasion and hydraulic action these widen the cracks
-This repeats forming a cave
-Abrasion and hydraulic action continue deepening and widening the cave
-As a result the water breaks through the cave forming an arch
-Abrasion and hydraulic action continue wearing down the rock supporting the arch
-Consequently because of gravity the arch collapses which forms a stack
-Eventually wave cut notches form causing the stack to to collapse which form a stump
47
Explain the formation of a wave cut platform
-Abrasion and hydraulic action occur at the foot/base of a cliff
-Consequently a wave cut notch forms over time
-Abrasion and hydraulic action cause the wave cut notch to enlarge
-Eventually the cliff will collapse and the material gets cleared
-This process repeats and consequently a wave cut platform is formed
48
Explain the formation of a spit
-Longshore drift occurs and transports sediment along the beach
-Consequently some sediment is deposited in the sea
-This process repeats making the spit longer
-Strong winds and waves can also form a recurved end
49
Explain the formation of a bar
-A bar forms when a spit joins across 2 headlands
-The bay gets cut off and this forms a lagoon behind the bar
50
Explain the formation of sand dunes
-Sand dunes are formed when sand deposited by longshore drift is moved up the beach by the wind
-Objects cause wind speed to decrease so sand is deposited forming embryo dunes
-These dunes are colonised by plants like Marram grass and consequently the roots help stabilize the dune
-More sand accumulates there forming foredunes
-Eventually a mature dune forms and new embryo dunes form in front of the foredunes
51
What are the 2 types of coastal defences?
Hard engineering
Soft engineering
52
Define hard enginerring
Man made structures built to control the flow of the sea and reduce flooding and erosion
53
Define soft engineering
Schemes set up using knowledge of the sea and its processes to reduce the effects of flooding and erosion
54
What are the benefits of a sea wall?
-Prevents erosion
-Acts as a barrier to prevent flooding
-Can be used as a promenade which can attract tourism
55
What are the drawbacks to a sea wall?
-Expensive to build and maintain
-Creates a strong backwash that erodes under the wall
-Looks unnatural
56
What are the benefits of gabions?
-Absorb wave energy which reduces erosion
-Cheap and easy to build
57
What are the drawbacks to gabions?
-They're ugly
-The wire cages corrode over time
58
What are the benefits to rock armour?
.Absorbs wave energy which reduces erosion
.Fairly cheap
.Can be used for fishing
.Can provide interest for the coast
59
What are the drawbacks to rock armour?
-Needs to be replaced as the boulders can move
-The rock type may not be the same as the typical coast rock type which makes them look obtrusive
60
What are the benefits of groynes?
-Creates a wider beach which slows down the waves
-Fairly cheap
-Provides useful structures for fishing
61
What are the drawbacks to groynes?
-They starve beaches further down the coast making them narrower
-They look unnatural
-They increase rate of erosion further down
62
What are the benefits of beach nourishment and reprofiling?
-Blends in with the existing beach
-Creates wider beaches and slows the waves
63
What are the disadvantages of beach nourishment and reprofiling?
-Very expensive as it has to be repeated
-Disrupt other envrionments
64
What are the advantages of dune regeneration?
-Relatively cheap
-Maintains a natural beach environment
-Helps absorb wave energy which prevents flooding and erosion
65
What are the disadvantages of dune regeneration
-Time consuming
-Can be easily damaged by storms
66
What are the advantages of managed retreat?
-Works with nature
-Cheap and easy
-Helps protect farmland from flooding
67
What are the disadvantages with managed retreat?
-People who live by the sea get nervous
-The salt water can damage ecosystems
68
Where are named examples of coastal landforms?
-**Durdle door** - Arch
-**Chesil Beach** - Bar which joins the Isle of Portland to the mainland and behind the bar is The Fleet Lagoon
-**Swanage bay**, Studland bay and The Foreland - Headland and bays. At the end of the Foreland is a stack called Old Harry and a Stump called Old Harry's wife
69
Why does Lyme Regis need to have its coast managed?
Lyme Regis has a population of over 3600 people and around **500,000** tourists each year
Around 900m of the A3052 road which links Lyme Regis to other towns would’ve been lost within 50 years
The local economy relies on tourism (Around **£42 million was spent by tourists in 2015**)
**Erosion would be a threat to the historic town center and the tourism industry**
70
What are the positive impacts to Lyme Regis' coastal defences?
The improved beaches have increased trade by 20% in some parts of the town
The rock armour absorbs the powerful wave energy protecting the harbour
People now feel more secure when buying properties in Lyme Regis as the defenses ensure that the houses are protected against coastal erosion and landslides
71
What are the drawbacks/disagreements to Lyme Regis' coastal defences?
Greater number of **tourists** increases traffic, litter and noise pollution
The defenses stop new fossils from being located
Some residents think it was **expensive** for the short-term solutions as the defenses may need **rebuilding** in 60 years time
72
What did Lyme Regis do to defend the coast (4 phases)?
**Phase 1** - Involved building new rock armour, a sea wall and a promenade. This finished in 1995
**Phase 2** - Work started in 2005 and ended in 2007. The **rock armour was extended** and the old wooden groynes were replaced with new **stone groynes** . Drainage systems were improved to reduce water build up and **prevent landslides**. The total cost was **£26 million**
**Phase 3** -Was meant to prevent landslides to the west however **was never carried out due to its cost**
**Phase 4** - Was completed in 2015 and cost **£19.5 million** . It included **390 metres of sea walls** and rock armour to protect roads into the town
73
What is hydraulic action in rivers?
The force of the river water colliding with rocks breaks rock particles away from the river channel
74
When do rivers deposit their load?
-The volume of water falls
-The amount of eroded material increases
-The water is shallower
-The river reaches its mouth
75
Describe the river's shape and gradient in the upper course
-Steep gradient
-V-shaped valley
-Steep sides
-Narrow
-Shallow
-Water velocity is low
-Vertical erosion is dominant
76
Describe the river's shape and gradient in the middle course
-Gently sloping valley sides
-Wider
-Deeper channel
-Lateral erosion is more dominant here
77
Describe the river's shape and gradient in the lower course
-Very wide
-Almost flat valley
-Very deep and wide
-Lateral erosion is dominant here
78
What is vertical erosion?
-Erosion that **deepens the river valley** and channel making it v-shaped
-It is dominant in the **upper course** of a river
-High turbulence causes the rough and angular particles to be **dragged** across the river bed causing vertical erosion
79
Define lateral erosion
-This widens the river valley and channel during formation of meanders
-It is dominant in the middle and lower course
80
Explain the formation of a gorge
-Waterfalls form when a river flows over an area of hard rock followed by soft rock
-The soft rock is eroded by **abrasion and hydraulic action** much quicker than the cap rock which is more resistant **(Differential erosion)**
-This forms an overhang
-Due to gravity and the weight of the water the overhang will collapse
-The hard rock will then collapse into the plunge pool
-Consequently it will break apart and because of abrasion and hydraulic action it will **widen and deepen the plunge pool**
-Over time this process **repeats** forming a gorge
81
What are interlocking spurs?
-Found in the upper course of a river where most erosion is vertically downwards
-This creates steep v-shaped valley sides
-In the upper course rivers lack the power to erode laterally so they wind around rocks and hillsides that stick out
-Those hillsides that stick out are interlocking spurs
82
Explain the formation of a meander
-Rivers develop large bends in the river called meanders in the middle and lower course
-The current is **faster on the outside** of the bend because the river channel is **deeper**
-Consequently **more erosion** takes place on the outside of the bend forming **river cliffs**
-The current on the inside of the bend is **slower** as the river channel is **shallower**
-Therfore the river **deposits** its material which forms **slip off slopes**
83
How are ox-bow lakes formed?
-Abrasion and hydraulic action cause the outside of the bends to get closer
-The **neck consequently gets shorter**
-During a flood, storm or when river **velocity is at its fastest** the neck of the meander gets cut off
-The river takes the shortest route and consequently deposition occurs which cuts off the old meander
-This forms an ox-bow lake
84
Explain the formation of a floodplain
-The floodplain is a the wide valley floor on either side of a river
-When rivers flood, water loses energy and deposits the material it's transporting
-This helps build up the floodplain
-The deposition that happens on slip off slopes also builds up flood plains
85
Explain the formation of a levee
-Levees are natural embankments along the edges of a river channel
-During a flood eroded material is deposited over the whole flood plain
-The heaviest material gets deposited closest to the river channel
-Over time the deposited material builds up creating levees along the edges
86
Explain the formation of mudflats
-Estuaries are found at river mouths
-The river level rises and falls each day (tidal)
-When the water floods over the banks of a river it carries silt and sand onto the valley floor
-As the tide reaches its highest point it **deposits its sediment**
-Over time more builds up creating mudflats
87
What is an estuary?
Tidal areas where the river meets the sea
88
What are the factors that affect flood risk by increasing river discharge?
Heavy rainfall
Geology
Prolonged rainfall
Relief of the land
Land use
89
How does heavy rainfall lead to floods?
Heavy rainfall means that water arrives too quickly to infiltrate so there is more surface runoff which increases river discharge
90
How does the geology increase river discharge?
Some rocks like clay are impermeable. This means infiltration doesn't take place so therefore more runoff takes place
91
How does prolonged rainfall increase river discharge?
Prolonged rainfall can saturate soil. Any further rainfall can't infiltrate which means runoff is increased
92
How does relief increase river discharge?
If a river has steep valley sides water will get to the river quicker as it can flow faster. This increases discharge
93
How does land use affect river discharge?
-Buildings are made from **impermeable** surfaces like concrete aswell as surrounding roads. This increases runoff. In addition man-made drains quickly transport water **increasing discharge**
-Trees **intercept** rainwater on their leaves which then evaporates. If you cut down trees (deforestation) this increases discharge as more water enters the channel
94
What is peak discharge?
The highest discharge in the river in the period of time you're looking at
95
What is lag time?
The delay between peak rainfall and peak discharge
96
What is the rising limb?
The increase in river discharge as rainwater flows into the river
97
What is the falling limb?
The decrease in river discharge as the river returns to its normal state
98
What are the benefits of dams and reservoirs?
-Reservoirs store water after heavy rain, control water flow and prevent floods downstream
-They also create man-made habitats for wildlife
-They can be used to generate hydroelectric power
99
What are the benefits of channel straightening?
.Water leaves the area more quick;y therefore flood risk is lower
100
What are the benefits of enbankments?
The river can hold more water so floods are less common
101
What are the benefits of flood relief channels?
Gates on channels mean that the release of water can be controlled reducing flood risk
102
What are the benefits of flood warnings and preperation?
Warnings give people time to move possessions upstairs, put sandbags in place and even evacuate
This reduces the impact of flooding
103
What are the benefits of floodplain zoning?
Flood risk is reduced as there are fewer impermeable surfaces near the river
The impact of flooding is reduced
104
What are the benefits of planting trees to reduce flood risk on rivers?
Discharge and flood risk is reduced
Vegetation reduces soil erosion and provides habitats for wildlife
105
What are the benefits of river restoration?
Discharge is reduced so there is less risk of flooding downstream
Little maintenance is needed and there are better habitats for wildlife
106
What are the drawbacks of dams and reservoirs?
-Dams are expensive to build
-The creation of a reservoir can flood settlements
-Material is deposited in the reservoir not along the river's course so the land becomes less fertile
107
What are the drawbacks of channel straightening?
-Flooding may happen downstream instead
-Fast flowing water may cause erosion downstream
108
What are the drawbacks of embankments?
-They're expensive
-Risk of severe flooding if the water rises above the embankments
109
What are the drawbacks of flood relief channels?
-There will be increased discharge where the relief channel joins the river
110
What are the drawbacks of flood warning systems?
-They don't prevent floods
-People may not have access to the warnings
-They may not be taken seriously
-It may give people a false sense of security
111
What are the drawbacks of flood plain zoning?
-The expansion of urban areas is limited
-It can't help sites that have already been built on
112
What are the drawbacks of planting trees?
Less land available for farming
113
What are the drawbacks of river restoration?
Local flood risks can increase especially if nothing is done to prevent major flooding
114
Why were river management schemes put in place for Oxford?
Oxford is situated right at the **confluence** of the River Thames and the River Cherwell
These 2 rivers are at huge risk of flooding especially during heavy rainfall
In 2007, river discharge increased rapidly causing **flash floods**
This meant over **250 homes** had to be evacuated
In 2014 a later flood caused trains to be cancelled and drains to overflow
These floods restricted people’s access to work and services as well as damaging the local economy as they prevented tourists visiting Oxford’s historic centre
115
What were the flood management schemes put in place in Oxford?
Increasing water storage in the floodplain and in the existing bypass channel - **400000 metres cubed of earth will be dug up** to increase capacity
Planting 20000 trees - **20,000 trees** will be planted to slow runoff and **decrease peak discharge**
**Flood walls** - Reused excavated material to build flood walls and embankments to protect at risk areas
116
What are the social impacts of the flood management schemes in Oxford?
Construction may disrupt residents' lives because of **noise pollution**
The scheme will improve public footpaths providing more **opportunities for recreation**
Residents feel more **confident** their home won’t flood
117
What are the economic impacts of the flood management schemes in Oxford?
The total cost is **£120 million** and not all the funding is secured
Over 1000 homes and businesses will be better protected so there is **less risk of expensive damage to property**
118
What are the environmental impacts of the flood management schemes in Oxford?
Over **2000 trees will be removed** and 2 hectares of rare grassland will be removed. They will be replanted but it will take a while to regrow
The scheme will create over **20 hectares of riverside habitats** which will increase biodiversity
119
What was phase 1 of the Lyme Regis' coastal defence?
**Phase 1** - Involved building new rock armour, a sea wall and a promenade. This finished in 1995
120
What was phase 2 of the Lyme Regis' coastal defence?
**Phase 2** - Work started in 2005 and ended in 2007. The **rock armour was extended** and the old wooden groynes were replaced with new **stone groynes** . Drainage systems were improved to reduce water build up and **prevent landslides**. The total cost was **£26 million**
121
What was phase 3 of the Lyme Regis' coastal defence?
**Phase 3** -Was meant to prevent landslides to the west however **was never carried out due to its cost**
122
What was phase 4 of the Lyme Regis' coastal defence?
**Phase 4** - Was completed in 2015 and cost **£19.5 million** . It included **390 metres of sea walls** and rock armour to protect roads into the town
123
What did the River Tees do in order to manage floods?
-Cow Green reservoir
-Tees Barrage
-Dredging
-Cutting of meanders
-Yarm flood defence scheme
124
How did the Cow Green reservoir impact the River Tees?
-It was built in 1970
-It can store water and release water at will
-Is used to store water in order to prevent flooding
125
How has the Tees barrage impacted the river Tees?
-A man made barrier built across the river
-It was made for recreational purposes and to help make water quality better
-Completed in 1995 and it costed **£54 million**
-The water is cleaner as it doesn't mix with any salt water at the estuary
-It helps act as a flood defence during storms
126
How did dredging impact the river Tees?
-The lower parts of the River Tees are dredged periodically
-This increases the river capacity and therefore decreases flood risk
127
How has cutting off meanders impacted the River Tees?
-In 1810 the neck of the **Mandale loop** was cut off
-This shortened the river by **4Km** and increases river velocity therefore decreasing flood risk
128
How has the flood defence scheme in Yarm affected the river Tees?
-Since **1995** flood defence scheme costing **£2.1 million** has been built
-**Flood warning systems** have been implemented and building on low lying land has been prohibited
-In the Yarm area the environmental agency have:
-Introduced **gabions**
-Added concrete walls with metal flood gates
-Used natural earth **enbankments**
