Coasts Flashcards

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1
Q

litoral cell

A

area near coastline where high and low tide occur

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2
Q

sediment inputs

A

if deposition is bigger then coats is expanding
if erosion is bigger the coast is retreating

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3
Q

energy inputs

A

tides
currents
precipitation
gravity

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4
Q

foreshore zone

A

part of shore between high and low tide marks

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5
Q

nearshore zone

A

shallow waters nearest land

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6
Q

backshore zone

A

area furthest from sea
only affected by waves in big storms or spring tides

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7
Q

the 5 processes

A

weathering
erosion
deposition
transport
mass movement

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8
Q

outputs

A

erosional landforms
depositional landforms
different types of coasts

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9
Q

rocky coastlines

A

high relief
resistant rock
high wave height
destructive waves erosion is greater than deposition

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10
Q

sandy coastlines

A

low relief areas
not resistant rock
low wave height
constructive waves
deposition is greater than erosion

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11
Q

esturaine coastlines

A

low relief
salt marshes and mudflats
low energy
soft rock
constructive waves

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12
Q

example of discordant coastline and concordant coastline in Britain

A

d - holderness
c - dorset

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13
Q

concordant coastline

A

alternating bands of hard n soft rock parallel to coast causing lower rates of erosion

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14
Q

discordant coastline

A

alternating bands of hard and soft rock at 90 degrees to coast

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15
Q

what forms at concordant coastline

A

Dalmatian coats

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16
Q

what forms at discordant coastline

A

headlands and bays

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17
Q

igneous rocks

A

formed by magma crystallization the crystals interlock , resistant to erosion, contain few joints and weaknesses (Basalt and Granite)

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18
Q

metamorphic rocks

A

formed by change in heat and pressure, resisant to erosion as crystals overlap but don’t interlock . (Slate and Marble)

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19
Q

sedimentary rocks

A

formed by build up of sediment , not resistant to erosion . Limestone and chalk

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20
Q

permeable rocks

A

poreous - contain pores that allow water
numerous joints
less resistant to erosion as surface vulnreable to chemical weathering is increased

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21
Q

dune order

A

embryo , fore , yellow, grey, mature

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22
Q

what dunes to sea rocket and crouch form in

A

embryo and fore dune

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23
Q

how dunes change as you get further away from coast

A

stronger
more vegetation
more sheltered

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24
Q

embryo dunes

A

form at coastline
have pioneer plants - these increase soil nutrients and allow other plants to grow

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25
Q

xerophyetes

A

tolerate dry conditions

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26
Q

halophyetes

A

tolerate salt

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27
Q

constructive waves

A

strong swash
weak backwash
deposition greater than erosion

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28
Q

destructive waves

A

larger height
shorter wave length
strong backwash, weak swash
create steep, narrow beach

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29
Q

erosional processes - hydraulic action

A

wave gets into cracks of cliff and widens them - force of water breaks rocks
destructive waves are more effective

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30
Q

erosional processes - abrasion

A

pieces of rock hit against the sea bed
destructive waves are more effective

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31
Q

erosional processes - attrition

A

pieces of rock hit against eachother becoming smaller and more rounded
destructive waves are more effective

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32
Q

erosional processes - corrosion

A

chemical reaction between sea water leaving minerals and a solution
susceptible rock such as limestone
constructive waves are more effective

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33
Q

mechanical weathering

A

application of force onto rock
( freeze thaw weathering , wetting and drying , salt crystal growth)

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34
Q

chemical weathering

A

a weak chemical reaction between water and rock where rainwater mixed with carbon dioxide forms carbonic acid , this reacts with carbonate in limestone to form bicarbonate which is soluble.

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35
Q

biological weathering

A

rocks broken down by living things
( plants roots widening cracks in rocks, rock boring where animals live in a rock)

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36
Q

inputs / sources of a sediment cell

A

cliff erosion
subaerial processes
onshore currents

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37
Q

transfer’s of sediment cell

A

processes that move sediment between sources and sinks
( LSD , swash , backwash , wind)

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38
Q

sinks of sediment cell

A

areas and landform where sediment is stored
( sand dunes , beaches , barriers)

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39
Q

eustatic change

A

rising of sea level due to ice age - ice melts and sea rises

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40
Q

isostatic change

A

rise in land as ice was sat on it and melts so land rebounds

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41
Q

tectonic change

A

land rises and sinks at boundaries

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42
Q

emergent coastlines

A

coast line rises relative to sea level

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43
Q

submergent coastlines

A

coast being flooded by sea due to rising sea levels

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44
Q

5 depositional landforms

A

Spits, Bars, Bayhead Beaches, Tombolos, cuspate forlands

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45
Q

depositional landforms- spit

A

long finger of sand sticking out from beach caused by LSD ( Duriston head)

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46
Q

depositional landforms- bar

A

spit grows accross a bay ( start bay devon)

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47
Q

depositional landforms - curved spit

A

spit curves inland due to prevailing winds

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48
Q

depositional landforms - cuspate foreland

A

triangle shape caused by LSD from 2 directions

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49
Q

depositional landforms- bayhead beach

A

beaches formed in bays by constructive waves
( Durdle door)

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50
Q

depositional landforms- tombolo

A

spit that has joined two landscapes ( portland bill)

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51
Q

Caves

A

weakness in a cliff widens

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52
Q

Arches

A

cave erodes whole way through
( durdle door)

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53
Q

stack

A

top of arch collapses

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54
Q

stump

A

stack erodes futher

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55
Q

Longshore drift

A

wave approaches at an angle , backwash pushes it straight, difference in angles between swash and backwash mean sediment is transported along the coast

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56
Q

wave cut notch and wave cut platform

A

sea attacks base of cliff which then collapses and creates an overhang
overhang eventually collapses
once this has collapsed the rubble watches away and creates a wave cut platform

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57
Q

3 soft engineering strategies

A

beach nourishment , cliff regrading, dune stabilisation

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58
Q

beach nourishment and a positive and negative ( Lyme Regis)

A

transporting sediment from elsewhere to beach.
Costs - £300,000 for 100 metres
positive - cheap and easy to maintain, looks natural , increases tourism
negative - needs constant maintenance because of erosion

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59
Q

cliff re grading and a positive and negative

A

reducing angle of cliff to help stabilise it
positive - works on clay or loose rock where other methods don’t work
negative - can cause cliff to retreat

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60
Q

marsh creation and a positive and negative

A

allowing low lying areas to flood so land becomes a salt marsh
positive - cheap , creates natural defence and habitat to wildlife
negative - agricultural land is lost

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61
Q

dune stabilisation and a positive and a negative

A

creation or restoration of dunes by either fencing them off or planting maram grass
positive - maintains environment for wildlife and is cheap
negative - planting marram grass is time consuming

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62
Q

5 hard engineering strategies

A

sea walls , rip rap , groynes , revtments, off shore breakwater

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63
Q

sea walls and a positive and negative

A

concrete walls that refract wave energy
positive - little maintainence
negative - expensive

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64
Q

rip rap and a positive and negative

A

pile of boulders to reduce energy
positive - cheap
negative - limit beach access

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65
Q

revetments and a positive and negative

A

angled sea wall
positive - most cost effective
negative - regular maintenance

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66
Q

offshore break waters and a positive and negative

A

pile of rocks parralell to coast
positive - calm beach conditions
negative - expensive

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67
Q

groynes and a positive and negative

A

wooden posts at 90 degree to coast which aim to trap sediment and widen the beach
positive - widen beach
negative - beach further down narrows

68
Q

Cost benefit analysis

A

determines economic value of coastline to see if intervention is necessary

69
Q

Environmental impact assessment

A

asses long and short impacts on enviroment

70
Q

ICZM

A

looks for most effective management, considers social and economic factors

71
Q

managed realignment ( Abbots hall farm)

A

allowing coastline to retreat but in a managed way such as breaching flood banks to low quality land
pros- reduces flooding in important areas
cons- difficult to sell houses that are unprotected

72
Q

hold the line - pros and cons

A

maintaining current position of coastline ( using hard engineering)
pros - good for residents
cons- expensive and needs maintaining

73
Q

advance the line

A

construct new defences

74
Q

no active intervention - pros and cons

A

letting nature take it’s course and allowing sea to erode
pros- free , not affecting environment
cons- whoever uses the land loses out

75
Q

Maldives - coastal flooding

A

removal of mangroves led to increase flooding, relys on tourism , meant fresh water supply was limited, fish farms ruined

76
Q

Studland - contemporary sea level rise

A

sea level is rising so low lying areas such as Studland are vulnerable to flooding

77
Q

Kirabati - contemporary sea level rise

A

sea level is rising 1cm a year
this means Kiribati is likely to disappear
Kiribati have purchased land in Fiji to use for farming and if necessary move people to

78
Q

Abbots hall Farm ( Essex) - coastal management ( managed retreat)

A

RSPB breached parts so sea could go in which reduces pressure on coast and attracted wildlife.
Created 200 acres of mudflats, salt marshes and coastal grassland

79
Q

Netherlands Delta project

A

a hard engineering mega project which began after 1953 floods
built an open barrier to remain tidal movement for birds benefit but could close during storm surges
cost $5 billion

80
Q

morphology

A

shape and form of coastal landscape

81
Q

lithology

A

physical characteristics of particular rocks

82
Q

erosion

A

action of surface processes that removes soil, rock or dissolved material from one location and transports to another

83
Q

weathering

A

decay and disintegration of rock

84
Q

cliff profiles - relief

A

angle at which cliff lies to sea
affected by geology

85
Q

subaerial cliff profile

A

curved and sloped
lower angle face
accumulated debris

86
Q

marine cliff profile

A

steep face
limited cliff base debris

87
Q

4 factors affecting rate of erosion

A

geology, lithology, weathering, mass movement

88
Q

freeze thaw weathering

A

water gets into cracks of rocks and freezes making the rock expand and become brittle

89
Q

mechanicalweathering - wetting and drying

A

clay rich rocks expand when wet and contract when dry
this results in cracks

90
Q

mass movement - soil creep

A

continous however slowest form of mass movement where individual particles move downhill

91
Q

mass movement - soliflucation

A

movement is 5cm to 1m per year
occurs in areas of permafrost where top layer melts in warmer temps and slides over lower frozen layer

92
Q

mass movement - mudflow / landslides

A

downslope movement of blocks down moderately flat plain
chemical weathering causes rocks to weaken and gravity slowly pulls them down

93
Q

mass movement slides - rock fall

A

occur on slopes over 40 degrees
rock weakens due to erosion and weathering
and drops down vertically leaving a talus scree slope

94
Q

mass movement - rotational slumps

A

rock failure and movement along a curved slope
occurs in weak unconsolidated material
rocks fall in rotational movement

95
Q

strata

A

layers of rocks

96
Q

bedding planes

A

horizontal , natural breaks in strata caused by gaps in time during periods of rock formation

97
Q

geological structures - joints

A

vertical cracks created by rock not moving
igneous it occurs during magma cooling
sedimentary it occurs due to compression of overlying rock

98
Q

geological structures -folds

A

bends in rock caused by sedimentary rocks layering

99
Q

dip

A

refers to the angle at which the rock strata lies

100
Q

geological structures - faults

A

large fractures caused by tectonic plates
make the rocks easily erodable

101
Q

erosion- hydraulic action

A

air trapped in cracks is compressed by force of waves crashing against cliff face causing cracks to open
destructive waves are most effective

102
Q

erosion - abrasion

A

sediment is thrown against cliff face or sea bed which causes it to break down

103
Q

erosion- attrition

A

collisions between loose sediments and makes sediment smaller and more rounded

104
Q

erosion - corrasion

A

solution by rainwater causing rocks to break down

105
Q

fetch

A

length of water that is uninterupted

106
Q

tides

A

changes in water level caused by gravitational pull of the moon

107
Q

Jurassic coast - how geology has effected features - Lulworth cove

A

a concordant coastline
soft rock is chalk which is poreous
rocks vary in resistance to erosion
sea broke through portland stone to create horseshoe shape

108
Q

cuspate foreland

A

formed when sediment comes from 2 directions to form an accumulation of sediment creating a triangular feature

109
Q

Hallsands - lost village ( South Devon)

A

example of village built on a source zone where they dredged the shingle to be used for buildings, the beach dropped and village got destroyed

110
Q

3 causes of land rising and falling

A

weight of ice
tectonic movement
sediment build up

111
Q

3 things that form at a submergent coastline

A

dalmation coasts
fjords
rias

112
Q

dalmation coasts formation

A

concordant coastline or submergent coastline

113
Q

Fjords formation

A

formed when glacial troughs are flooded by rise in sea level

114
Q

Rias formation

A

when valleys in dissected uplands are flooded, providing a natural harbour with a deep mouth , due to submergent coastline

115
Q

emergent coastline - raised beaches

A

as land rose as a result of isostatic change, former shorelines and their beaches were raised above present sea levels

116
Q

what is causing contemporary sea level rise

A

glaciers melting
ice sheets melting ( antarctic)
thermal expansion ( hot water takes up more space)

117
Q

Hard engineering Vs Soft engineering

A

hard engineering is contructing something new whereas soft engineering involves working with nature

118
Q

depressions

A

intense low weather systems that occur when fast moving cold air moves into a region of warm air

119
Q

5 causes of coastal flooding

A

land subsidence
removal of vegetation
building sea defences
storm surges
climate change

120
Q

storm surge

A

short term change in sea level caused by low pressure and wind

121
Q

2 things causing a storm surge

A

depression and cyclone

122
Q

2 things making storm surges worse

A

strong winds that push waves onshore
high/spring tide occurring at the same time

123
Q

1953 storm surge Canvey islands and Netherlands

A

winter storm over 2 day period with no planning in place
Canvey island had no defences and was mainly bungalows
killed 306 in UK
killed 1800 in Netherlands

124
Q

2013 storm surge Canvey islands and Netherlands

A

surge combined with high winds and high tide
killed 2
flooded 1400 homes
£100 million of damage

125
Q

4 local factors affecting risk of coastal flooding

A

low lying land
coastal topography ( narrow causes funnel affect)
subsidence ( sinking of land relative to sea level)
removal of coastal vegetation

126
Q

2 global factors affecting risk of coastal flooding

A

eustatic sea level rise caused by global warming
thermal expansion and ice sheets melting causing rising sea levels

127
Q

climate change and tropical storms

A

27.5 degrees is temp needed for tropical storm and climate change has resulted in more oceans being over this

128
Q

3 types of vegetation that protect a coastline

A

mangroves
salt marshes
sand dunes

129
Q

sediment is protected by plants in 2 ways

A

roots of plants bind sediment together
plants protect sediment from sand erosion

130
Q

3 causes of coastal subsidence ( sinking land)

A

destruction of vegetation exposing to erosion
groundwater abstraction
river straightening causes sediment to be propelled too far offshore

131
Q

where do salt marshes develop

A

sheltered areas where deposition occurs
where salt water meets fresh water

132
Q

`human causes of coastal retreat

A

coastal defences
offshore dredging

133
Q

physical causes of coastal retreat

A

destructive waves
subaerial processes
geology

134
Q

UK and coastal erosion

A

occurs along 17% of UK coastline
2300km of UKs coastline is protected

135
Q

Erosion at Holderness

A

Holderness is one of Europe’s fasting eroding coastlines
erodes 2m a year
29 villages have been lost

136
Q

Coastal defences of Holderness

A

Has invested in sea walls, groynes and rock armour
They have caused problems south of coast as starved them of sediment

137
Q

Key players of Holderness - Central government agencies

A

responsible for coastal management

138
Q

Key players of Holderness- Local government

A

joint responsible for coastal management with Environment agency

139
Q

Key players of Holderness- stakeholders in local economy

A

tourist industry want greater spending
farmers want protect their land
residents want to protect their homes
insurance companies won’t insure vulnerable properties

140
Q

Why is erosion such a problem at Holderness - Lithology

A

much of coast consists of boulder clay which is structurally weak and not resistant to erosion
soft poreous rock , weak joints , they dip seawards and are heavily faulted

141
Q

Why is erosion such a problem at Holderness- Fetch

A

fetch of about 500-800km which is small but the waves have huge power due to currents and a deep water floor

142
Q

Why is erosion such a problem at Holderness- longshore drift

A

not enough sand to stop waves reach cliffs as tide flows south which transports material by longshore drift

143
Q

Holderness - Economic Loses

A

owner of golden sands lost 100 sea chalets in 15 years
by 2100 predicted 200 homes will fall into sea
between 2010-2012 Yorkshire council spent £1.2million on helping people live with erosion

144
Q

Holderness - social losses

A

homes and businesses lost

145
Q

managing coastlines - engineering feasability

A

what’s the best method
is it achievable
is it within budget

146
Q

managing coastlines - environmental sensitivity

A

does the coast include protected sites
( Flamborough and Spurn head are considered heritage coasts)

147
Q

managing coastlines - land use and value

A

what is the land used for and how much is it worth

148
Q

managing coastlines - impacts on coastal processes

A

doing nothing means sediment continues to be supplied to the right places
holding the line starves other areas of sediemnt

149
Q

managing coastlines - political, social and economic reasons

A

agriculture and tourism are key industries
costs must be acceptable to the government

150
Q

adaptation

A

making changes to lessen the impact

151
Q

mitigation

A

making effort to reduce GG emission so sea level rise stops

152
Q

Bangladesh - Eco engineering

A

working with the environment by building 4000km of embankments and planting mangroves
LIC so needed cheap protection

153
Q

sustainable coastal management

A

designed to cope with future threats (increased storm events, rising sea levels) but its implementation can lead to local conflicts in many countries.

154
Q

coastal communities face the threat of

A
  • rising global sea levels, but there is uncertainty about the scale and timing of the rise
  • increased frequency of storms and the possibility of increased erosion and flooding
155
Q

4 egs of sustainable coastal management

A
  • managing natural resources ( fish, farmland)
  • managing flood and erosion risk
  • creating alternative livelihoods
  • educating communities to understand why change is needed
156
Q

3 reasons sustainable management coastal can create conflict

A
  • coastal natural resources may have to be used less - people use less income
  • relocation may be needed
  • some erosion and flooding will always occur as engineering can’t protect against all threats
157
Q

Holderness - Mappleton

A

hold the line - a rock groyne
- This has protected the main road, homeowners can still get a mortgage, businesses can stay in the area.
- cost benefit analysis found this was viable to protect

158
Q

Holderness - Withernsea

A

-hold the line has been selected including a sea wall and rip rap.
-Residents can stay in their homes
- but the council must cover the cost of keeping the coastal management in place.

159
Q

Holderness - Easington

A

-hold the line has been selected including rip rap.
- British consumers and the gas industry have benefited since the gas station hasn’t needed to be relocated.

160
Q

Holderness - Kilnsea

A

-managed retreat has been selected.
- A caravan owner was able to buy the land behind him and rollback. They get 5 pitches for every 4 lost previously.

161
Q

Holderness - Bridlington and Hornsea

A

far up the coast
two seaside towns
hold the line

162
Q

Holderness - Ringborough farm

A

farm land , no active intervention
farmers have had to move back and build new land

163
Q

Holderness - Sprun head

A

managed retreat as important for shipping and SSSI
( science)

164
Q

Holderness - sediment cell

A

spurn head is the sink as the depositional landforms form here
Flamborough head is the source - where the sediment is coming from

165
Q

why understanding sediment cells is important

A
  • if you don’t understand you put wrong protection in wrong place , increases erosion ( Sidmouth)