Geography-Rivers and Coasts Flashcards
0
Q
What are the three different parts to the hydrological cycle?
A
The sea, the land and the atmosphere
1
Q
What does the hydrological cycle show?
A
How water moves around
2
Q
What sort of system is the hydrological system?
A
A closed system, there are no inputs or outputs (water going in/out), the water just flows around the cycle
3
Q
What is the first stage of the hydrological cycle?
A
Water evaporates from the sea and the land
4
Q
What is evaporation?
A
When water is heated by the sun and turns into water vapour
5
Q
What is transpiration?
A
The evaporation of water from plants
6
Q
What is evapotranspiration?
A
Evaporation and transpiration happening together
7
Q
What is the second part of the hydrological cycle?
A
Water vapour is moved inland by winds
8
Q
What is the third stage of the hydrological cycle?
A
The water vapour condenses to form clouds and then falls over the land as precipitation
9
Q
What is the fourth part of the hydrological cycle?
A
Water moves from one place to another (flows or transfers)
10
Q
What are the different ways that water moves around in the hydrological cycle?
A
Infiltration (water soaks into soil), percolation (water moves vertically down through soil and rock), through flow (water in the soil flows downhill), groundwater flow (water in rocks flows downhill), surface runoff (water flows overground), channel flow (flow of water in a river) and also the movement of water vapour by wind
11
Q
What else happens in the fourth part of the hydrological cycle?
A
Water can be held on the land in stores
12
Q
What are the different types of water stores?
A
Channel storage (water held in a river), groundwater storage (water stored underground in soil and rock(aquifer eg chalk)), interception storage (when water lands in things like plant leaves and doesn’t hit the ground), surface storage (water is held in things like lakes, reservoirs and puddles)
13
Q
What is a drainage basin?
A
The area of land drained by a river
14
Q
What part of the hydrological cycle involves drainage basins?
A
The part the happens on land
15
Q
What sort of system are drainage basins?
A
Open systems, there are inputs and outputs
16
Q
What is the input for drainage basins?
A
Precipitation
17
Q
What are the flows in drainage basins?
A
Surface runoff, channel flow, infiltration, through flow, groundwater flow and percolation
18
Q
What are the stores in drainage basins?
A
Channel storage, groundwater storage, interception storage and surface storage
19
Q
What are the outputs in drainage basins?
A
Evaporation, transpiration and river flow into the sea
20
Q
What are drainage basins separated by?
A
A boundary called a watershed (ridges of high land, water falling either side of these ridges will go into different drainage basins)
21
Q
What are the key features of a drainage basins?
A
A tributary (smaller river eg stream that joins a main river), the source (where a river starts, unusually in an upland area eg mountains), a confluence (a point where two rivers join) and the mouth (where a river flows into the sea or a lake
22
Q
What happens to rocks in a drainage basin?
A
They are broken down by weathering
23
Q
What is weathering?
A
The breakdown of rocks where they are (the material created doesn’t get taken away like with erosion)
24
What are the three types of weathering?
Mechanical weathering, chemical weathering and biological weathering
25
What is mechanical weathering?
The breakdown of rock without changing its chemical composition. Freeze thaw weathering is a type of mechanical weathering that happens in drainage basins
26
How does freeze thaw weathering work?
Happens when the temperature alternates above and below 0 degrees c. Water gets into rock that has cracks eg granite. When the water freezes freezes it expands which adds pressure on the rock, when the water thaws it contracts which releases the pressure on the rock. When this repeats, the cracks widen and the rock breaks up
27
What is chemical weathering?
The breakdown of rock by changing its chemical composition. An example is carbonate weathering which happens in warm and wet conditions.
28
How does carbonation weathering work?
Rainwater has carbon dioxide dissolved in it which makes it a weak carbonic acid. Carbonic acid reacts with rock that contains calcium carbonate eg limestone so the rocks are dissolved by the rainwater
29
What is biological weathering?
The breakdown of rocks by living things eg plant roots break down rocks by growing k to cracks on their surfaces and pushing them apart
30
What is a rivers course p?
The path of a river as it flows downhill
31
What sort of courses do rivers have?
An upper course, middle course and lower course
32
Where do rivers flow?
In channels, in valleys
33
What do the rivers do to the landscape?
They erode the landscape-wear it down then transport the material to somewhere else where its deposited
34
Why does the shape of the valley and channel change along the river?
It changes depending on whether the erosion or deposition is having the most impact
35
What does the long profile of w river show you?
How the gradient change over the different courses
36
What does the cross profile of a river show you?
What a cross section of the river looks like
37
What is the upper course of a river like?
Steep gradient. v shaped valley, steep sides. Narrow, shallow channel
38
What is the middle course of a river like?
Medium gradient. Gently sloping valley sides. Wider, deeper channel
39
What are meanders?
Large bends in a river
39
What are meanders?
Large bends in a river
40
What is the lower course of a river like?
Gentle gradient. Very wide almost flat valley. Very wide, deep channel
41
Where do meanders develop?
In a rivers middle and lower couses
41
Where do meanders develop?
In a rivers middle and lower couses
42
How do meanders develop?
The current is faster on outside of bend (river channel is deeper there as there is less friction to slow the water) more erosion takes place on outside of bend forming river cliffs. Current slower on inside as channel is shallower, more friction, slowing water. Eroded material is deposited on inside of bend forming slip-off slopes
42
How do meanders develop?
The current is faster on outside of bend (river channel is deeper there as there is less friction to slow the water) more erosion takes place on outside of bend forming river cliffs. Current slower on inside as channel is shallower, more friction, slowing water. Eroded material is deposited on inside of bend forming slip-off slopes
43
What are ox-bow lakes?
They are formed by meanders that get larger and eventually separating from the rest of the river
43
What are ox-bow lakes?
They are formed by meanders that get larger and eventually separating from the rest of the river
44
What is the process of an ox-bow lake forming?
Erosion causes outside bends to get closer until small bit of land left called a neck between the bends, river breaks through this land usually in a flood and the river flows along the shorter course. Deposition cuts off meander-forming an ox-bow lake
44
What is the process of an ox-bow lake forming?
Erosion causes outside bends to get closer until small bit of land left called a neck between the bends, river breaks through this land usually in a flood and the river flows along the shorter course. Deposition cuts off meander-forming an ox-bow lake
45
What are flood plains?
Flat areas of land that flood
45
What are flood plains?
Flat areas of land that flood
46
Where are flood plains usually located?
The wide valley floor on either side of a river which occasionally get flooded
46
Where are flood plains usually located?
The wide valley floor on either side of a river which occasionally get flooded
47
What happens when a river floods onto the flood plain?
The water slows down and deposits the eroded material that its transporting, this builds up the flood plain-makes it higher
47
What happens when a river floods onto the flood plain?
The water slows down and deposits the eroded material that its transporting, this builds up the flood plain-makes it higher
48
How else can flood plains be built up?
Meanders migrate across the flood plain making it wider, the deposition that happens on the slip-off slopes of meanders build up the flood plain
48
How else can flood plains be built up?
Meanders migrate across the flood plain making it wider, the deposition that happens on the slip-off slopes of meanders build up the flood plain
49
What are levees?
Natural embankments along the edges of a river channel. During a flood, eroded material is deposited over flood plain, heaviest material is deposited closest to river channel as its dropped first when river slows down. Over time the deposited material builds up creating levees along the edges of the channel
49
What are levees?
Natural embankments along the edges of a river channel. During a flood, eroded material is deposited over flood plain, heaviest material is deposited closest to river channel as its dropped first when river slows down. Over time the deposited material builds up creating levees along the edges of the channel
50
What are deltas?
Low-lying ayes where a river meets the sea or a lake
50
What are deltas?
Low-lying ayes where a river meets the sea or a lake
51
What happens when rivers are forced to slow down when they meet the sea or a lake?
They deposit the material that they're carrying
51
What happens when rivers are forced to slow down when they meet the sea or a lake?
They deposit the material that they're carrying
52
What happens if the sea doesn't away the deposited material?
it builds up and the channel gets blocked, this forces the channel to split up into lots of small rivers called distributaries. Eventually the material builds up so much that low lying areas of land called deltas are formed
52
What happens if the sea doesn't away the deposited material?
it builds up and the channel gets blocked, this forces the channel to split up into lots of small rivers called distributaries. Eventually the material builds up so much that low lying areas of land called deltas are formed
53
What are the three types of deltas?
Arcuate, Cuspate and Bird's foot
53
What are the three types of deltas?
Arcuate, Cuspate and Bird's foot
54
What are arcuate deltas?
Rounded shape and lots of distributaries eg the Nile delta
54
What are arcuate deltas?
Rounded shape and lots of distributaries eg the Nile delta
55
What are cuspate deltas?
Triangular shape and few distributaries eg the Tiger delta
55
What are cuspate deltas?
Triangular shape and few distributaries eg the Tiger delta
56
What are bird's foot deltas?
Shaped like a bird's foot eg the Mississippi delta
56
What are bird's foot deltas?
Shaped like a bird's foot eg the Mississippi delta
57
What do contour lines tell you about a river?
The height and steepness of land by how close the lines are, so you can tell the direction of the river because they can't uphill
57
What do contour lines tell you about a river?
The height and steepness of land by how close the lines are, so you can tell the direction of the river because they can't uphill
58
What do contour lines look like on a map?
Orange lines
58
What do contour lines look like on a map?
Orange lines
59
How can you identify a river's upper course on map?
Blue line representing a river and close contour lines showing steepness
59
How can you identify a river's upper course on map?
Blue line representing a river and close contour lines showing steepness
60
How can you identify a waterfall on a map?
Black block lines that symbolise a cliff and close contour lines
60
How can you identify a waterfall on a map?
Black block lines that symbolise a cliff and close contour lines
61
How can you identify a river's lower course?
Low land, if the river only crosses one contour line showing only a gentle slope, if it joins a sea or a lake, if it has large meanders, if there is a thick blue line showing a wide river
61
How can you identify a river's lower course?
Low land, if the river only crosses one contour line showing only a gentle slope, if it joins a sea or a lake, if it has large meanders, if there is a thick blue line showing a wide river
84
What are the four processes of erosion?
Hydraulic action (force of water breaks rock particles away from river channel), Corrasion (Eroded rocks picked up by river scrape/rub against channel wearing it away-most common), Attrition (Eroded rocks picked up by river smash into each other, break into smaller fragments, edges get rounded) and Corrosion (River water dissolves some types of rock eg chalk and limestone)
85
What is transportation?
The movement of eroded material
86
There are four processes of transportation, what is traction?
Large particles like boulders are pushed along the river bed by the force of the water
87
What is saltation?
Pebble-sized particles are bounced along the river bed by the force of the water
88
What is suspension?
Small particles like silt and clay are carried along by the water
89
What is solution?
Soluble materials dissolve in the water and are carried along
90
What is deposition?
When a river drops eroded material, when the river slows down
91
What are he reasons why a river can slow down?
Volume of water in the river falls, the amount of eroded material in the water increases, the water is shallower eg inside of the bend And the river reaches it's mouth
92
What part of a river are waterfalls and gorges found in?
The upper course of a river
93
When do waterfalls form?
Where a river flows over an area of hard rock followed by an area of softer rock, softer rock erodes more than hard rock making a step in the river, water goes over step, eroding it more, steep drop is eventually created which is a waterfall
94
How are gorges formed?
Hard rock is eventually undercut by erosion, becomes unsupported and collapses, collapsed rocks swirl around foot of waterfall where they erode the softer rock by corrasion creating steep plunge pool, over time, more undercutting = more collapses, waterfall will retreat living behind a steep-sided gorge
95
How are steep sided, v-shaped valleys formed?
In the upper course of a river most of the erosion is vertically downwards, creating these valleys
96
How do interlocking spurs then occur?
The river aren't powerful enough to erode laterally they have to wind around the high hillsides that stick out onto their path either side. The hillsides that interlock with each other as the river winds around them are called interlocking spurs
97
What is river discharge?
The volume of water that flows in a river per second. It's measured in cumecs (cubic meters per second)
98
What do hydrographs show?
How the discharge at a certain point in a river changes over time
99
What do Storm hydrographs show?
The changes in river discharge around the time of a storm
100
What is peak discharge?
The highest discharge in the period of time you're looking at
101
What is lag time?
The delay between peak rainfall and peak discharge
102
What is rising limb?
The increase in river discharge as rainwater flows into the river
103
What is falling limb?
The de tease in river discharge as the river returns to its normal level
104
Why does lag time happen?
Because most rainwater doesn't land directly in the river channel. It gets there by flowing quickly overland (surface runoff) or by soaking into the ground (infiltration) and flowing slowly underground
105
What are factors that increase discharge and make the hydrograph steeper?
High/intense rainfall (more runoff/shorter lag time). Impermeable rock (water cant get in rock so more runoff/shorter lag time). Previously wet conditions (water cant get in wet soil...) Steep slopes. Less vegetation (less interception and through flow isn't slowed by roots)
106
What are factors that decrease discharge and make the hydrograph gentler?
Low/light rainfall (less runoff/longer time). Permeable rock (water infiltrates rock so less runoff/longer lag time). Previously dry conditions (water infiltrates soil so...) Gentle slopes. More vegetation (more water is intercepted and evaporates-less water reaches channel. Roots slow down throughflow so longer lag time)
107
Why are hydrographs steep for rivers in urban areas?
Urban areas have drainage systems and covered with impermeable materials so they increase discharge
108
Why are hydrographs gentler for rivers in rural areas?
Rural areas have more vegetation which decreases discharge also more reservoirs which store water and release it slowly, decreasing discharge in the river below
109
When does flooding occur?
When the level of a river gets so high that it spills over its banks onto the flood plain
110
What are the physical causes of flooding?
Prolonged rainfall, Heavy rainfall, snowmelt, Relief (how the height of the land changes), Geology
111
What are the human causes of flooding?
Deforestation and urbanisation
112
How does prolonged rainfall cause flooding?
After lots of rain, the soil becomes saturated, any further rainfall cant infiltrate which increases runoff into rivers increasing discharge quickly which can cause a flood
113
How can heavy rainfall cause flooding?
Heavy rainfall means there's a lot of runoff increases discharge quickly, which can cause a flood
114
How can snowmelt cause flooding?
When a lot of snow or ice melts it means that a lot of water goes into a river in a short space time. Increases discharge quickly, which can cause a flood
115
How can relief cause flooding?
If a river is in a steep-sided valley, water will reach the river channel much faster because water flows more quickly on steeper slopes. This increases discharge quickly which can cause a flood
117
How can geology cause flooding?
When a river is in an area of permeable rock like limestone, more water percolates into the rock instead of flowing on the surface. This means there's less runoff so the risk of flooding is lower. When a river is in an area of impermeable rock like clay water doesn't percolate into the rock but flows on the surface this means there's more runoff, the risk of flooding is higher.
118
How can deforestation cause flooding?
Trees intercept rainwater on their leaves which evaporates and take up and store water from the ground. Cutting down trees increases the volume of water that reaches the river channel-increasing discharge making flooding more likely. Deforestation also causes soil erosion where soil ends up in the river-raising the riverbed, reducing the volume of water that the river can hold
119
How can urbanisation cause flooding?
Urban area=lots of buildings made from impermeable materials e.g. concrete. surrounded by roads made from tarmac (impermeable) These surfaces increase runoff and drains take the runoff to the rivers quickly. Quickly increases discharge which can cause a flood
120
What are serious impacts of flooding?
Death by the flood or diseases when water supplies are contaminated, Buildings are damaged/destroyed (homelessness, businesses shut down) Jobs are lost due to damaged buildings, damaged equipment or pollution of farmland
121
Why are the effects of flooding worse in LEDC's than MEDC's?
Because theres less money to spend on flood protection and on help after the flood. Also there are more people living and working in areas that are more likely to flood and poorer transport links make it more difficult to get help to affected places
122
What is hard engineering?
Man-made structure built to control the flow of rivers and reduce flooding
123
What is soft engineering?
Schemes set up using knowledge of a river and its processes to reduce the effects of flooding
124
What are hard engineering flood management strategies?
Dams and reservoirs, channel straightening, man made leaves
125
What are dams and reservoirs?
Built across rivers-upper course, reservoir formed behind dam, store water, release it slowly(reduces flooding), can be used for fun, can be used to drink and generate energy. Bad-very expensive, creating it foods existing settlements, eroded material deposits in river, not natural course, makes farmland downstream less fertile
126
What is channel straightening?
Rivers course is straightened, meanders are cut out. Good-water moves out quickly as doesn't travel as far. Bad-flooding can happen downstream instead as flood water is carried there faster
127
what are man-made leeves?
Man-made embankments-both sides of the river. Good-river channel can hold more water, cheap. Bad-Leeves can fail and cause catastrophic flooding
128
What are soft engineering flood management strategies?
Flood warnings, preparation and flood plain zoning
129
What is flood warnings?
People warned about possible floods via various media. Good, impact of flooding reduced, people can move valuables and evacuate. Bad-flood isn't actually stopped, people, especially in LEDCS, may not receive any warnings
130
What is preparation?
Buildings are modified to reduce damage, plans are made in case of flood. Good-impact of flooding is reduced, buildings are less damaged, people know what to do. Bad-Doesnt guarantee safety, could give false sense of security, expensive to modify homes and businesses
131
What is flood plain zoning?
Restrictions prevent buildings on places likely to flood. Good-Impact of flooding is reduced, impermeable surfaces aren't created. Bad-Expansion os urban area is limited, doesn't help areas that have already been built on
132
What is a sustainable strategy?
Something that meets the needs of people today without stopping people in the future getting the things they need (not using up resources or damaging the environment)
133
What is mechanical weathering?
Breakdown of rock without changing its chemical composition-mainly freeze-thaw weathering
134
What is chemical weathering?
Breakdown of rock by changing its chemical composition e.g. carbonation weathering
135
What is carbonation weathering?
Carbonic acid from rainwater reacts with rocks that contain calcium carbonate
136
What are the four processes of erosion (waves)?
Hydraulic action, Corrasion, attrition and corrosion
137
What are destructive waves?
Waves that carry out erosional processes
138
What are the properties of destructive waves?
High frequency, steep and high
139
How are destructive waves destructive?
Backwash is more powerful than their swash, more material is moved away than it is given
140
What are two main factors that affect the size and power of destructive waves?
Wind and fetch (distance of water which the wind has blown to produce a wave
141
CASE STUDY FOR RIVER VALLEY
The River Clyde
142
How long is the river clyde?
About 160km long
143
Where does the river flow?
North-west through Motherwell and Glasgow
144
Where is the rivers source?
In the southern Uplands region of Scotland
145
Where is the rivers mouth?
It is an estuary on the west coast of Scotland
146
Where is the rivers estuary?
About 34km west of Glasgow, its about 3km wide
147
Where does the river join up to?
It joins the Fifth of Clyde which eventually becomes the Irish Sea
148
What is Glasgow built on?
It is built on the flood plain of the River Clyde so the land is about 5m above sea level on either side of the river
149
Where in the river is an ox-bow forming?
Near the village of Uddingston
150
What are the falls of clyde?
Four waterfalls near Lanark, the highest fall is Corra Lin (about 27m high)
151
Why is there gorge?
It is caused by the waterfalls retreating
152
Where does the river meander?
Between Motherwell and Glasgow
153
Where are there interlocking spurs?
At Crawford between 300 and 500m high
154
How is the river clyde formed?
Two tributaries coming together
155
CASE STUDY FOR FLOODING IN AN MEDC
Carlisle, England. 8th January 2005, caused by River Eden
156
What were the causes?
Heavy rainfall 200mm in 36 hours (rainfall saturated soil, increasing runoff into river Eden). Carlisle is large urban area (impermeable material increase runoff). 1520 cumecs is what he discharge reached
157
What were the primary effects?
3 deaths, around 3000 people were made homeless, 4 schools severely flooded, 350 businesses shut down, 70,000 addresses lost power, some roads and bridges were damaged, rivers were polluted with rubbish and sewage
158
What were the secondary effects?
Children lost out on education (one school closed for months), Stress-related illnesses increased after the floods, around 3000 jobs were at risk in businesses affected by floods
159
What flood protection measures were put into place?
The environment agency monitors river level and makes flood warnings, leaflets issues to explain flood warning and ways to prepare beforehand, A scheme called Eden and Petteri flood alleviation scheme in 2008 for building defence walls and levees to prevent flooding. And the local council distributed sandbags
160
CASE STUDY FOR FLOODING IN LEDCS
South Asia (Bangladesh and India), July and August 2007, caused by rivers Brahmaputra and Ganges
161
What were the causes?
Heavy rainfall (in one place 900mm in July saturating the soil increasing runoff into rivers). Melting snow from glaciers in the Himalayan mountains increased discharge and the peak discharge of both rivers happened at the same time caring increased discharge downstream
162
What were the primary effects?
Over 2000 deaths, around 25 million people were made homeless, 44 schools were totally destroyed, many factories closed, livestock were killed, 112000 houses destroyed in India, 10000km of roads were destroyed, rivers were polluted with rubbish sewage
163
What were the secondary effects?
Children lost out on education-400 schools affected, around 100000 people caught water-borne diseases like dysentery and diarrhoea, Flooded fields reduced rice yields so prices rose 10%, many farmers and factory workers became unemployed
164
What flood protection measures were put into place after the flood?
Bangladesh has a flood forecasting and warning system with 85 flood monitoring stations, these warnings can give 72 hour warnings before a flood, but they don't reach many rural communities, there are around 6000km of man-made leaves to prevent flooding but they're easily eroded and aren't properly maintained so are often breached by flood waters, they also cause sediment to build up and raise the level of the river bed, increasing flooding They allow floods in controlled conditions in some areas called controlled flooding so sediment build up in channels are reduced, reducing flooding
165
Why do cliffs retreat?
As a result of erosion, weathering and mass movements
166
what causes most erosion at the foot of a cliff?
Waves
167
What does erosion at the foot of a cliff cause?
A wave-cut notch which is enlarged as erosion continues, making the cliff above the notch unstable
168
How is the part of the cliff above sea level affected?
By mechanical and chemical weathering processes, making the cliff more unstable until it eventually collapses
169
What happens to the collapsed material?
It is washed away and a new wave-cut notch starts to form
170
What does repeated collapsing repeat in?
Cliff retreating
171
What is a wave-cut platform?
The platform that's behind as the cliff retreats
172
What does the rate of retreat depends on?
The geology of the cliff and vegetation
173
How does the geology of the cliff affect the rate of retreat?
Cliffs formed from soft rock or loose material can retreat very quickly e.g. several meters a year. Cliffs formed only from hard rock can be eroded over thousands of years
174
How does vegetation affect the rate of retreat?
Cliffs covered in vegetation are more stable so they're eroded less easily and more slowly
175
What are cliff collapses?
Mass movements (the shifting of rock and loose material down a slope) that happen when the force of gravity acting on a slope is greater than the force supporting it e.g. when the notch has made the cliff above unstable
176
What are the three types of mass movement that can affect cliffs?
Slides (material shifts in a straight line), Slumps (material shifts with a rotation) and Rockfalls (material shifts vertically)
177
Where do headlands and bays form?
Where there are alternating bands of resistant and less resistant rock along coast
178
How are bays formed?
The less resistant rock e.g. clay, is eroded quickly forming a bay with a gentle slope
179
How are headlands formed?
The resistant tock e.g. chalk is eroded more slowly and its left jutting out forming a headland its steep sides
180
What are good examples of headlands and bays?
The Foreland and Swanage Bay in Dorset, UK
181
Headlands erode to form what?
Caves, arches, stacks and stumps
182
How are caves formed?
The resistant rocks have weaknesses like cracks, waves crash into the headlands and enlarge the cracks mainly by hydraulic action and erosion, repeated erosion and enlargement of the cracks causes a cave to form
183
How is an arch formed from a cave?
Continued erosion deepens the cave until it breaks through the headland, forming an arch e.g. Hurdle Door in Dorset
184
How is a stack formed from an arch?
Erosion continues to wear away the rock supporting the arch unit it eventually collapses forming a stack, an isolated rock thats separate from the headland e.g. Old Harry in Dorset
185
How is a stump formed from a stack?
The stack is eventually worn away to give a stump, which can be covered by the water at high tide e.g. Old Harrys wife in Dorset
186
What is a cove?
A cove is a wide, circular bay with a narrow entrance
187
Where are coves formed?
They form where there's a band of hard rock e.g. limestone, along a coast with a band of softer rock behind it e.g. clay
188
How do coves form?
Where theres a weakness in the band of hard rock a narrow gap will be eroded. The softer rock behind will then be eroded much more to form the cove
189
What is an example of a cove?
Lulworth Cove in Dorset
190
How is material transported along coasts?
A process called longshore drift
191
How does longshore drift happen?
Waves follow the direction of the prevailing wind, they usually hit the coast at an oblique angle (not a right angle), the swash carries material up the beach in the same direction as the waves. The backwash then carries material down the beach at right angles back towards the sea, over time material zigzags along the coast
192
What are the four other processes of transportation?
Traction, saltation, suspension and solution
193
What is traction?
Large particles like boulders are pushed along the sea bed by the force of the water
194
What is saltation?
Pebble sized particles are bounced along the sea bed by the force of the water
195
What is suspension?
Small particles like silt and clay are carried along in the water
196
What is solution?
Soluble materials dissolve in the water and are carried along
197
What is deposition?
When material being carried by the sea water is dropped on the coast
198
How are coasts built up?
When the amount of deposition is greater than the amount of erosion
199
When does the amount of material thats deposited on an area of coast increases?
When theres lots of erosion elsewhere on the coast so theres lots of material available, and when theres lots of transportation of material into the area
200
What are low energy waves?
Low energy waves/slow waves, carry material to the coast but they're not strong enough to take a lot of material away, this means theres lots of deposition and very little erosion
201
What are constructive waves?
Waves that deposit more material than they erode and build up the coast
202
What are properties of constructive waves?
Low frequency (6-8 waves per minute), low and long, powerful swash that carries material up the coast, weaker backwash that doesn't take a lot of material back down the coast. This all means material is deposited on the coast.
203
How are constructive waves made?
By weaker winds and having a shorter fetch than destructive waves
204
Where are beaches found?
On coasts between the high water mark (highest point on land the sea level gets to) and the low water mark (the lowest point on the land the sea level gets to)
205
How are beaches formed?
By constructive waves depositing material like sand and shingle
206
What are the characteristics of sand beaches?
Flat and wide-sand particles are small and the weak backwash can move them back down the beach, creating a long, gentle slope
207
What are the characteristics of shingle beaches?
Steep and narrow-shingle particles are large and the weak backwash can't move them back down the beach, The shingle particles build up and create a steep slope
208
What are spits?
Beaches that stick out into the sea-they're joined to the coast at one end.
209
How are bars formed?
If a spit sticks out so far that it connects with another bit of mainland, it'll form a bar
210
How are both spits and bars formed?
By the process of longshore drift
211
Where are spits formed?
At sharp bends in the coastline e.g. at a river mouth
212
How are spits formed?
Longshore drift transports sand and shingle past the bend and deposits it in the sea, strong winds and waves can curve the end of the spit forming a recurved end. The sheltered area behind the spit is protected from waves-lots of material accumulates in this area which means plants can grow there. Over time, the sheltered area can become a mud flat or a salt marsh
213
How are bars formed (in detail)?
When a spit joins two headlands together e.g. theres a bar at Slapton in Devon. The bar cuts off the bay between the headlands from the sea. This means a lagoon can form behind the bar. A bar that connects the shore to an island, often a stack, is called a tombolo e.g. Chesil Beach in Dorset joins to the Isle of Portland
214
How can you identify caves, arches and stacks on a map?
Caves and arches cant be seen on a map because of the rock above them. Stacks look like little blobs in the sea
215
How can you identify cliffs and wave-cut platforms on a map?
Cliffs and other steep slopes are shown on maps as little black lines. Wave-cut platforms are shown as bumpy edges along the coast
216
How can you identify beaches on maps?
Sand beaches are shown on maps as pale yellow. Shingle beaches are shown as white or yellow with small dots on it
217
How can you identify spits on a map?
Shown by a beach that carries on out to sea, but is still attaches to the land at one end. There might also be a sharp bend in the coast that caused it to form
218
What is the case study for a coastal area with coastal landforms?
The Dorset Coast
219
What is the Dorset coast like?
Made from bands of hard rock like limestone and chalk, and soft rock like clay. The rocks have been eroded at different rates giving headlands and bats and lots of other coastal landforms
220
What are the coastal landforms on the Dorset coast?
Durdle door, Lulworth Cove, Chesil Beach and Swanage Bay and Studland Bay
221
What is durdle door?
A good example of an arch. Erosion by waves opened up a crack in the limestone headland, which became a cave and then developed into an arch
222
What is lulworth cove?
A cove formed after a gap was eroded in a band of limestone. Behind the limestone is a band of clay, which has been eroded away to form the cove. The shame is now starting to happen at Stair Hole further west along the coast
223
What is Chesil beach?
A tombolo formed by longshore drift. It joins the Isle of Portland to the mainland. Behind Chesil beach is a shallow lagoon called The Fleet Lagoon
224
What is swanage bay and studland bay?
These are two bays with beaches. They're areas of softer rock (sandstone and clay). In between them is a headland called The Foreland made from a band of harder rock (chalk). The end of the headland has been eroded to become a stack called Old Harry and a stump called Old Harrys Wife
225
What are the economic factors for human reasons to protect coastlines from flooding and erosion?
Loss of tourism, businesses near cliffs may collapse, coastal flooding damages agricultural land and property prices can fall
226
What are the social factors for human reasons to protect coastlines from flooding and erosion?
Deaths, water supplies are affected, loss of housing, loss of jobs and damage to infrastructure
227
What are the environmental factors for environmental reasons to protect coastlines from flooding and erosion?
Ecosystems are affected and some SSSIs (sites of special scientific interest) are threatened by coastal erosion
228
What is hard engineering?
Man-made structures built to control the flow of the sea and reduce flooding and erosion
229
What is soft engineering?
Schemes set up using knowledge of the sea and its processes to reduce the effects of flooding and erosion
230
What are hard engineering strategies?
Sea wall, rip rap, groins, revetments, gabions and breakwaters
231
What is a sea wall?
A wall made out of hard material like concrete that reflects waves back into sea. Prevents erosion of coast and acts as a barrier to prevent flooding. However creates strong backwash, erodes under wall. Also very expensive to build and maintain
232
What is rip rap?
Boulders that are piled up along the coast. The boulders absorb wave energy and so reduce erosion and flooding. However boulders can be moved around by strong waves so they need to be replaced
233
What are groynes?
Wooden or stone fences built at right angles to coast, trap material transported by longshore drift. They create wider beaches which slow the waves, giving greater protection from flooding and erosion. However they starve beaches further down the coast of sand making them narrower which doesn't protect the coast as well leading to greater erosion and floods
234
What are revetments?
Slanted structures made of concrete, wood or rocks built at the foot of cliffs. They absorb wave energy and so reduce erosion. However expensive to build and they create a strong backwash that erodes under the barrier
235
What are gabions?
Rock filled cages built at foot of cliffs. They absorb wave energy and so reduce erosion. However they look ugly
236
What are breakwaters?
Concrete blocks or boulders deposited on the sea bed off the coast. They force waves to break offshore so their erosive power is reduced before they reach the shore. However they're expensive and can be damaged by storms
237
What are soft engineering strategies?
Beach replenishment and managed retreat
238
What is beach replenishment?
Sand and shingle from elsewhere thats added to beaches. Creates wider beaches which slow the waves giving greater protection from flooding and erosion. However taking material from seabed can kill organisms like sponges and corals. Its expensive and has to be repeated
239
What is managed retreat?
Removing an existing defence and allowing the land behind it to flood. Over time land becomes marshland, creating new habitats. Flooding and erosion are reduced behind marshland and its fairly cheap. However people may disagree over what land is allowed to flood.
240
What is meant by a sustainable strategy?
Sustainable strategies meet the needs of people today without stopping people in the future getting the thins they need. This means not using up too many resources or damaging the environment
241
Why are hard engineering strategies less sustainable?
They generally cost more money to build and maintain and they damage the environment more
242
What is the coastal management case study?
Hard engineering along Holderness
243
Why is hard engineering being used along the Holderness coast?
There's rapid erosion along the coast, about 1.8m per year
244
What have been the impacts of this erosion?
Homes near cliff (Skipsea) at risk of collapsing in sea, Businesses at risk of erosion so people lose jobs (seaside caravan park losing average of 10 pitches a year), The gas terminal (Easington) at risk which accounts for 25% of Britains gas supply, and 80000m2 of farmland is lost each year, huge effect on farmers' livelihoods
245
How is Bridlington protected from erosion and flooding?
By a 4.7km long sea wall as well as wooden groynes
246
What defences are at Hornsea to protect the village from erosion and flooding?
A sea wall, wooden groynes and rip rap
247
What defences are a Withernsea?
Groynes to create wider beaches and a sea wall. Some rip rap was placed in front of the wall after it was damaged in severe storms in 1992
248
What defences are at Mappleton?
Defences including two rock groynes were built in 1991 costing £2 million and built to protect the village and a coastal road from erosion and flooding
249
How is the eastern side of Spurn Head protected?
By groynes and rip rap, also protects the Humber Estuary behind Spurn Head
250
What problems do the groynes cause?
They cause narrow beaches to form further down the Holderness coast, increasing erosion down the coast e.g. Cowden Farm (South of Mappleton) is now at risk of falling into the sea
