1
Q
how can coasts be classified?
A
- formation processes (e.g. primary coasts are formed by land based processes such as river deposition whilst secondary coasts are formed by marine based processes such as wave action)
- balance between erosion and deposition creation varying landforms
- sea level changes produce submerging or emergent coastlines
- level of energy (high or low)
- geology (rock type, lithology and structure) this can influence if it is discordant of concordant or even if its rocky cliffed plains or coastal (sandy/estuarine) planes.
2
Q
what is the order of the littoral zone?
A
- (going out into the sea) back shore, foreshore, nearshore, offshore
- backshore and foreshore is where the greatest human activity occurs and so they experience the most change
3
Q
what are the inputs (external factors) to coastal landscapes?
A
- marine (waves, tides and storm surges)
- atmospheric (weather, climate)
- terrestrial (geology, tectonics)
- people (economic activity and coastal management)
4
Q
what are the processes to coastal landscapes?
A
- weathering
- mass movement
- erosion
- transportation
- deposition
5
Q
what are the outputs (outcomes) of coastal landscapes?
A
- erosional landforms
- depositional landforms
- different types of coasts
6
Q
what are submerging and emergent coastlines?
A
- emergent coastlines are those which have risen relative to the sea level
- submergent coastlines are those which have dropped and become drowned or flooded by the sea
7
Q
geological structure
A
how the rock is arranged on a macro scale, it looks at the arrangement of different rock types in relation to each other
8
Q
how do headlands and bay form at discordant coastlines?
A
- bands of alternating rock strata facing perpendicular to the coast
- wave action erodes the less resistant rock quicker due to hydraulic action and abrasion to produce bays. this becomes a sheltered low energy environment where wave energy is dissipated leading to deposition and beaches
- more resistant rock is less easily eroded so is left sticking out as a headland.
- this causes incoming waves to refract as water becomes shallower (wave refraction with a pincer like movement)
- wave energy is now concentration on the headlands, with waves becoming higher and steeper increasing the erosive power on the headland
- they will then eventually be eroded into a stack/stump
- in theory this may mean the process starts again as the coastline evens out
9
Q
what are the types of tidal change?
A
- microtidal coasts (range of 0-4m)
- mesotidal coasts (range of 2-4m)
- macrotidal coasts (range greater than 4m)
10
Q
what are the different wave energy environments?
A
- low energy sheltered coasts have limited fetches and low and speeds resulting in small waves
- high energy exposed coasts often face prevailing winds with long fetches creating powerful waves.
11
Q
how do coves form?
A
- at concordant coastlines rock strata is arranged in alternating bands parallel to the coastline
- initially, the outer layer of the coastline was a band of more resistant rock such as limestone
- as wave action was continually concentrated on the rock it weakened leading to faults and joints through processes like hydraulic action and abrasion
- as wave action forces it way through this more resistant rock which is easier to erode (e.g. clay) there is rapid erosion in all directions forming a cove.
- eventually erosion slows as more resistant rock layers have been reached
- this sheltered environment allows for deposition and the creation of beaches via constructive waves
12
Q
how do Dalmatian coasts form?
A
- type of submerging coastline
- tectonic activity folded limestone layers so that ridges (anticlines) and valleys (synclines) formed parallel to the coast
- sea levels rose following the end of the ice age and drowned the valleys (submerging coast)
- the ridges remain as islands running parallel to the coastline
- the best example of this is the Creation Dalmatian coast
- ice on land that melts causes sea levels to rise but ice in the water that melts doesn’t
13
Q
how do half coasts form?
A
- concordant coastlines (e.g. the south of the Baltic Sea)
- they are long sediment ridges (sand and mud) topped by sand dunes that run parallel to the coast
- the build up of these sand dunes have created lagoons (haffs) between them and the shore
- form in low energy environments due to deposition by onshore winds and low energy constructive waves
14
Q
meso structures
A
smaller stretches of cliff and their layers/ lithology
15
Q
micro structures
A
one cliff profile and its features
16
Q
coastal morphology
A
the shape and form of a coastal landscape and their features
17
Q
bedding planes
A
natural breaks in the strata caused by gaps in time during periods of rock formation
18
Q
folds
A
formed by pressure from tectonic activity which causes rocks to buckle and crumple
19
Q
dip
A
the angle at which rock strata lies (horizontal or vertical, island or outland)
20
Q
joints and faults
A
- joints (vertical cracks) are fractures caused either by contraction as sediment drys out or by earth movements during uplift
- faults form when the pressure or stress to which a rock is subjected exceeds its internal strength, it then slips or moves along fault planes
21
Q
what happens in rock dips towards the sea?
A
- if a rock layer dips towards the sea, it will be possible for blocks of rock to slide under there influence of gravity (mass movement). the steeper it is the softer the bade of the profile is and so this speeds up recession
- slight not so steep dipping, joints are often opened by weathering and pressure release
- if rock dips inland stable cliff profiles are creates yet if there are well developed faults and joints perpendicular to bedding planes they can act as slide planes
22
Q
what is the influence of horizontal strata?
A
this can lead to layers of differing resistances and therefore protrusions and indentations as well as small features such as caves, blowholes and geos
-if the layers of less resistant rock are at the base of the cliff it is likely to lead to caves and an overhand yet if it is at the top more so indentations due to weathering.
23
Q
how does mineral composition of the rock (micro) affect the rate of recession?
A
- in limestone there are reactive minerals such as calcite which are easily broken down by chemical weathering speeding up erosion. it is soluble in rainwater becoming dilute carbonic acid after having absorbed carbon dioxide from the air. this can create small pits and pinnacle
- yet in geology like sandstone there are more inert minerals such as quartz which weather and erode more slowly
- both are sedimentary so have the same inadvertent resistance yet other factors affect rate of recession
- this can make is subject to weathering such as carbonation or hydrolysis
24
Q
lithology
A
refers to the physical characteristics of the rock. this varies for igneous, sedimentary, metamorphic and unconsolidated rock.
25
igneous rock
- crystalline structure of interlocking crystals
- this makes sediment better connected with strong chemical bonding and therefore is less permeable and susceptible to erosion
- they have few points of weakness
- tend to form rocky coastlines with steep profile cliffs that erode very slowly
- rocks like granite in 'Lands End' Cornwall
- recede slowest at 0.1-0.3 cm/yr
26
metamorphic rock
- formed boy the recrystallisation of sedimentary and igneous rock under immense heat and pressure
- resistant due to crystalline structure yet less resistant than igneous as crystals are often orientated in the same direction (foliation) making them weaker than the interlocking crystals of igneous rock
- often heavily folded and faulted
- often recede slowly at about 0.5-1cm per year
27
resistant sedimentary rock
- strata is clastic and so made up of unconsolidated sediment particles making them subject to fissures
- strata is more porous as particles are less tightly compacted leading to air spaces between layers
- this means geology becomes more easily saturated lessening its ability to retain its structure
- limestone and chalk
28
less resistant sedimentary rock
- same structure as resistant sedimentary rock but with further reduced stability due to unconsolidated sediment which hasn't been cemented together by pressure
- e.g. boulder clay
29
differential erosion
different sections of a cliff eroding at different rates
30
how can the arrangement of rocks lead to differential erosion?
- if there is a porous rock above an impermeable rock water collects in the upper layer saturating it and usually leading to slumping and mass movement
- resistant rock creates a bench feature at the base leading to surface run off
31
what are pioneer species?
- marram grass (xerophyte) in a sand dune
- glasswort and cord grass (halophyte, resistant to salt) in a salt marsh
- they colonise an area meaning a plat community develops overtime helping to stabilise the cliff
- adds organic matter to the sand helping soil to develop which is less vulnerable to wind erosion
32
what does marram grass do?
- colonise the bare surface (sand) and reduce wind and water erosion
- long roots up to 3m long but also creeping stems called Rhizomes extend sideways below the surface creating a ladder like structure. This helps to bind sediment together to stop it being washed or blown away
- one the surface wind speeds are reduced as the vegetation acts like a wind break preventing sand from being blown away
- thrives in arid conditions on free draining sand preventing unnecessary water loss (e.g. waxy leaves are rolled inwards to prevent surface evaporation)
33
what does glasswort do?
- helps to trap and secure muds and slits to develop salt marshes
- when submerged plants provide a protective layer so that sediment isn't directly exposed to action from the tide
- succluent stem to store water
- adds organic matter helping to develop soil which is less vulnerable to erosion
34
what is succession?
the changing structure of a plant community overtime as an initially base surface is colonised by pioneer species and continues to develop
-they typically occur at coastlines where deposition is taking place in low energy sheltered environments
35
first four stages of sand dune succession
- psammosphere
- there is plentiful supply of sand, a large areas for sand to dry out and onshore winds that blow sand landwards. sand accumulates to form an embryo dune
- pioneer species like marram grass colonise the dune stabilising it and helping it to trap more sand
- a fore dune develops when enough sand has been trapped and the dune becomes more stable
- with soil now developed on the dune, it becomes a yellow dune. this is permanent and the conditions are suited to a greater variety of species including gorse and heather
36
last four stages of sand dune succession
- now an established dune will become more vegetated by marram grass. it provides dead organise matter to the sand and soil start to develop, improving conditions for other species. this is now a grey dune
- between dunes dune slack develops. wind erosion can deepen them and they ma be water logged in high tide conditions
- further inland is the climax community mature dunes. Here the soil is fully developed, the dune is fully stabilised and species diversity is at its highest. (e.g. trees can grow here)
37
first three stages of plant succession on a salt marsh
- form in low energy environments on estuaries, sheltered bays and behind spits
- river brings fine muds and slits and tidal conditions bring other sediments, all of which are deposited
- tiny sediment particles combine in a process called flocculation which increases deposition due to the weight. the area is colonised by algae which have to survive being submerged twice a day
38
last three stages of plant succession on a salt marsh
- the vegetation helps to trap more sediment and builds the height of the marsh, making more suitable for other species
- sediment becomes more stable and vegetation adds dead organic matter, making conditions better for more species to grow. conditions become less salty as the marsh is now only occasionally submerged
- at the inland end of the marsh, soil has developed and the climax community is established
39
structure of a salt marsh
- upper part is raised above regular inundation and may be dissected by small channels and creeks.
- this can help sustain less salt tolerant plants
- the lower part of the salt marsh is under water for longer periods and only hardy halophytic plants grow here
40
what are rocky coastlines and costal plains
```
Rocky coasts (high and low relief) result from resistant geology (to the erosive forces of sea, rain and wind), often in a high-energy environment
-whereas coastal plain landscapes (sandy and estuarine coasts) are found near areas of low relief and result from supply of sediment from direct terrestrial and offshore sources, often in a low-energy environment
```
41
coastal plains
- Coastal plain landscapes are relatively flat, low relief areas adjacent to the sea.
- They often contain freshwater wetlands and marshes due to the poor drainage of the flat landscape.
- Their littoral zone is composed of sand dunes, beaches, mud flats and salt marshes
42
examples of coastal plains
- sandy coasts, composed of sands, shingles and cobbles.
| - estuarine (alluvial) coasts composed of mud (clays and silts
43
movement of waves
- the force of the breaking wave pushes up the beach creating a swash at 45 degrees
- after reaching its furthest point on the beach, the wave runs back down at 90 degrees due to gravity. this is the backwash
44
destructive waves
- larger amplitude, smaller wavelength
- swash is bigger than backwash
- plunging breaker
- causes cliff retreat, flat beaches and degradation
- 13/15 per minute
- long fetch
- high energy
45
constructive waves
- smaller amplitude, longer wavelength
- backwash is bigger than swash
- spilling breaker
- steep beaches, scoured beaches, steep beaches
- aggrades beaches
- swash builds up the beach creating berms
- low wave energy
- short fetch
46
swell waves
- some waves originate in mid-ocean and maintain their energy for thousands of miles
- these mid ocean waves appear as larger waves amongst smaller locally degenerated waves (swell waves)
- swell is an ocean wave system not raised by the local wind blowing at the time of observation but rather raised some distance away. they continue to travel in the direction of the winds that originally formed
- may travel for thousands of miles before dying down
- as it advances, its crest becomes flattened and rounded, its surface smooth
- they are usually characterised by a relatively long and regular period
47
why are coastal landscapes different?
- east and west Britain have very different landscapes (rocky cliffed coasts v coastal plains)
- the affect of geological structure on a macro scale on coastal landforms (concordant and discordant coastlines)
- lithology
- vegetation
48
how are waves formed?
- as wind blows over the ocean, fiction occurs and energy is transferred to the water creating a wave
- the stronger the wind, the greater the wave power and size
- wind strength and wave strength and controlled by fetch (the distance over which the wind has blown)
- Cornwall and Devon face the longest fetches (Atlantic Ocean)
49
how do waves move across the ocean?
- waves move across the open ocean in a circular motion as ocean swell
- as they reach shallower water, the fictional drag on the seabed slows down the base of the wave causing the wavelength to reduce and the wave height to increase
- eventually the wave breaks as the top of the wave is moving faster than the base.
- the circular movement of the wave acts in an increasingly elliptical orbit
50
types of erosion
-abrasion
-attrition
-hydraulic action
solution
-during winter marine erosion is often at its highest as winter storms produce more destructive waves
51
hydraulic action
- air trapped in cracks and fissures is compressed by the force of the waves crashing against the cliff face. when the wave retreats, pressure is released explosively (cavitation)
- this can widen cracks and dislodge particles/ rocks
52
how do headlands and bays form?
- bands of less resistant rock are more easily eroded and so form bays
- the chalk headland absorbs some of the wave energy causing them to refract around its curvature in a pincer like movement, growing in height and steepness
- this means wave energy becomes concentrated on certain parts of the cliff and fissures are attacked through abrasion and hydraulic action (caviation)
- this widens cracks into crevices and caves
- this continues in particular during winter storms
- these can be eroded to form blowholes and eventually when overlying rock becomes unstable due to continual undercutting and arch and then stack/stump
53
how do blowholes form?
- caves can partially collapse to produce a hole in the cliff
- waves hitting the base of the cliff can be force through and spout water at the top
- this can cause the top of the cave to collapse
- also known s marine geysers
54
what do cliffs dominated by marine erosion form?
-active undercutting, steep faces and limited cliff base debris
55
what do cliffs dominated by sub Ariel processes form?
-leads to curved slop profiles, lower angle faces and accumulated debris
56
how to form wave cut notches and platforms?
- wave action at the base of the cliff means that hydraulic action and abrasion undercuts the cliff to form a wave cut notch
- this continues and the cliff above the notch is left unsupported and eventually collapses
- the cliff retreats leaving a wave cut platform which is now the base of the cliff left. This maintains a steep cliff profile
- happens when there is less resistant rock at the base of the cliff
- e.g. dancing ledge purbeck Dorset
57
beach morphology
beach form and shape
- beaches consists of loose material and their morphology alters as wave change
- this leads to seasonal variations that create summer and winter gradients (e.g. sediment is dragged offshore by destructive waves during winter and returned by constructive waves in summer)
58
how does material on a beach vary due to constructive waves?
varies in size and type depending on the distance from the shoreline
- beach profiles are steeper in summer when constructive waves are more common. this means waves energy dissipates and deposits over a wider area (weakens backwash)
- the swash of a constructive wave deposits larger material at the top of a beach creating a berm
- as the berm builds up the backwash becomes weaker (draining by percolation rather than down the beach), only having enough energy to move smaller material. this means sediment becomes finer closer to the shoreline
59
how does beach morphology vary due to destructive waves?
- in winter waves occur at a higher frequency
- berms are eroded by plunging waves and high energy swash
- strong backwash transports sediment offshore (depositing it as offshore bars)
- sometimes the backwash exerts a current known as a rip of undertow, dragging sediment as the next wave arrives over the top
60
formations of beach morphology
- storm beaches result from high energy deposition of very coarse sediment during the most severe storms
- berms typically of shingle/gravel result from summer swell wave deposition
- the middle area of the beach is mostly sand but the sand is coarser where berms/ridges have been deposited than in channels and runnels
- offshore ridges/bar are formed by destructive wave erosion and subsequent deposition of sand and shingle offshore
61
how is sediment transported
- sediment is constantly moving at the coast due to waves, tides and currents
- the main process is LSD
- sediment is transported in the same way as in the river (traction, salutation, suspension, solution)
62
how does LSD transport sediment
- the prevailing wind and therefore the waves approach the coastline at an angle (SW)
- this means that the swash moves sediment up the beach at the same angle but backwash moves sediment straight down the beach under gravity
- waves carry large pebbles by rolling them (traction) small pebbles bouncing them (saltation) and finer particles line sand and silt by suspension
- as the process continues sediment is moved east and a drift aligned beach will form
63
what happens to sediment as it is transported?
-sediment will experience attrition and abrasion during it s transportation causing ti to become smaller in size and smoother in surface
64
swash aligned beaches
- waves approach the coastline perpendicular to the beach
| - the swash and backwash move sediment up and down the beach forming a stable, straight beach
65
drift aligned beaches
- waves approach at an angle and sediment is moved along by longshore drift
- this forms wide beaches but uneven in sediment
66
sources of sediment
- rivers
- constructive waves
- cliffs
- LSD from one area to another through transportation
67
why does deposition occur?
- deposition due to gravity settling occurs in low energy coastal environments. course dropped first, finer further away
- flocculation helps the process of depositing fine flay particles. this is because they are very light and so by clumping together in salt water they become heavier
- sediment is stabilised by vegetation (sand dune and salt marsh succession)
68
how do spits form?
- sediment is moved along the coast by LSD
- when there is a change in the direction of the coastline (e.g. the river mouth) longshore drift continues
- the waves loose energy in the slacker water behind the headland and the largest sediment is deposited here first in the same direction (gravity settling)
- as deposition continues, a spit is formed.
- finer material is carried further along the spit before being deposited as its lighter. flocculation helps with finer clay
- the spit grows and may form a hook if wind direction changes
- in the slack water behind a spit move deposition takes place and a salt marsh may develop with halophytic plants helping to trap sediment and allowing new land to develop.
69
why don't spits form across an estuary?
- spits don't grow across an estuary as the velocity of the river current prevents deposition
- in areas where there are no river currents to prevent LSD deposition in a straight line the spit can join with land to form a bar, damming water behind it forming a lagoon
- e.g. slapton sands, devon
70
how do Tombolos form?
- an island joined to the mainland
- it develops when deposition occurs behind and island due to the low energy sheltered environment it creates
- eventually the island will connect to the mainland
- these can also form by long shore drift and a bar forming or if there is a change in wind direction
- e.g. st Michaels Mount Cornwall
71
how do cuspate forelands form?
- a cuspate foreland is a low lying headland
- it is foamed when significant longshore drift is occurring from opposite directions resulting in the formation of two spits
- eventually the two spits converge and shelter the area behind the bay
- further coastal deposition in the slack water and alluvial deposits from small streams flowing into the former bay gradually causing the area to fill with sediment
- e.g. Dungess Kent the largest cuspate foreland in Europe
72
what does the formation process of a cuspate foreland result in?
- this results in mud flats and salt marshes that will eventually stabilise and result in a new area of low land
- here the prevalent and dominant wind direction is from the south west and has created long shore drift from the west to east along the south coast of England
- there is also long shore drift from the eats as the swell waves move through the English Channel, bringing sediment from the opposite direction
73
how do barrier islands form?
- there are offshore sand bars thought to have formed when a plentiful supply of sediment was deposited in sand dunes along the eastern seaboard of the USA by waves and winds
- as sea level has risen, land behind was flooded to create a lagoon but the sand dunes themselves become elongated islands running parallel to the coast (Atlantic coast)
- as sea levels continue to rise they migrate inland
- they provide protection to the coastline during storms as they absorb wave energy
- submergent formation
74
how do offshore bars form?
- a long ridge of sand/pebbles found a short distance out at sea
- forms a shallow water offshore where slope is gentle
- following large erosion events during a storm
- beach and sand dunes can be scoured heavily by destructive waves
- extra sediment is deposited vertically offshore in a bar (may only be temporary)
- LSD can add to them or change their shape
75
how does a salt marsh form behind a spit?
- deposition occurred due to the sheltered conditions behind the spit
- this created a low energy environment and as a result gravity settling means sediment is deposited as the water doesn't have the energy to transport it
- flocculation can occur as clay from rivers has clumped together and become heavy enough to also be deposited
- The rate of sediment accretion is fastest on the lower part of the platform (Low Marsh), and so these areas are elevated at a much quicker rate, overtime making that platform almost horizontal.
76
sediment cell
an area of coastline that acts like a closed system
- there are sources, transfers and sinks within each one
- the UK is split into 11 sediment cells (lengths of relatively self contained coastlines with often natural barriers e.g. headlands)
- sediment cells are then split into subcells which are managed at a local level of an SMP (shoreline management plan)
77
sources in the sediment cell
- onshore winds
- constructive waves (swash)
- cliff
- weathering and cliff erosion
- human intervention (e.g. beach nourishment)
78
transfers in the sediment cell
- LSD
| - destructive waves (backwash)
79
sinks in the sediment cell
- sand dunes
| - offshore bars
80
positive feedback sediment cell
- positive feedbacks tend to increase the rate of erosion through changing the balance of sediment until a new equilibrium is reached, this can lead to degradation.
- For example, damage to sand dunes during storm conditions can create ‘blow outs’ allowing wind to move more sand away, preventing xerophytic plants such as marram grass from re-growing and therefore catalysing erosion and the rate of recession.
81
negative feedback sediment cell
- When there is negative feedback it often helps to maintain a balance within the system and therefore limits the rate of erosion, helping it to aggrade.
- For example, where when wave erosion causes rockfalls which then protect the base of the cliff from further erosion.
82
sediment budget
- sediment cell concept helps to understand coastal systems is because it allows for the representation of a whole cliff as whilst sediment cells are coined as closed systems, in reality transfers do occur between cells during certain conditions (e.g. erosion in one place will be balanced by deposition in another)
- One way this can be determined is through a sediment budget which can quantify the amount the input and outputs of sediment.
83
what can sediment budgets help with?
This can help coastal developers to critically evaluate the best places to construct infrastructure as they can see which areas are most likely to be starved of sediment and others which won’t.
-For example, an area with sink formations or negative feedbacks are far less susceptible to erosion and therefore will be more sustainable for development.
84
why do coastal processes vary from day to day?
- climatic oscillations which lead to stronger destructive waves due to more energy and longer fetches. erosional processes magnified. whereas warmer days fewer destructive waves with shorter fetches.
- different degrees of coastal development. high levels can leave land subject ti land subsidence meaning a greater proportion is affected by coastal processes increasing erosion. it also affects degree of coastal defences
85
sub-oriel processes
refer to processes which act on the cliff face rather than the base of the cliff
-they are erosional processes of weathering and mass movement
86
what is weathering
- the breakdown of rocks in situ, at or near the earth's surface, exploiting weaknesses in rocks over a long timescale
- it is done by mechanical, chemical or biological agents
- this is different to erosion as erosion doesn't happen in situ but also because erosion is done by external agents (wind, waves, river)
87
mass movement
the movement downslope of rocks, sinks, glacial till or soil
- it is caused by gravity once a slope has become stable
- weathering processes can help this to happen
88
what influence show vulnerable a cliff is to mass movement
- lithology and structure
- weathering
- water from rainfall
- angle of the slope
89
how do landslides and land flows form?
| mass movement
- form when rocks are jointed or have bedding plains parallel to the coastline
- material mains in tact as it slumps
- saturation of water can reduce friction lubricating impermeable sources.
- once enough of the rocks strength has been exceeded is slides/slumps at a slip plain
- landforms are the same but material is eroded and the flow is more mud and soil rather than rock
90
how does slumping occur?
| mass movement
- less resistant rock lying on top of more resistant rock
| - repeated slumping creates a terrace cliff profile and rotational scars
91
```
rock falls
(mechanical)
```
- appear on slopes over 40 degrees
| - rocks fall/ bounce to form scree at the foot of the slope and jagged surfaces on the slope itself
92
what is soil creep?
| mass movement
- slowest form of mass movement and is an almost continuous process
- it is the vert slow downhill movement of individual soil particles
93
what is soil fluction?
| mass movement
- movement averages between 5cm and 1m a year
- mainly in tundra arras where the ground is frozen. when the top layer thaws in summer but the Lowe layer remains frozen (permafrost). the surface becomes saturates and flows over the frozen subsoil and rock
94
what percentage of the world's cities are on the coast?
70%
| -very susceptible to sea level change
95
eustatic sea level change
- sea level changes relative to the land
- global process
- happens as ice melts from ice caps and glaciers as well as thermal expansion
- or forms due to global climate and the cycle of glacials and interglacials
- in the last ice age there was no North Sea and UK was joined to Europe
96
isostatic sea level change
land height changes relative to the sea
- local process
- large amounts of ice pressed down on land in previous glacial periods has led to glacial rebound and land masses to rise
- highland areas north of the Teex-ex line are rising due to glacial rebound due to warmer temps
- lowland areas are sinking as rivers in the SE deposit masses of sediment adding weight to estuaries and leaving them susceptible to flooding
- land also sinks due to the weight of infrastructure
97
what else changes sea level
- tectonics as land can be pushed up by plates in a series of earthquakes
- new islands can rise out of the sea in eruptions (e.g. Surtsey, Iceland)
- accretion (deposition of sediment) in a river estuary or delta can weigh down the crust band also cause sinking (subsidence) e.g. Thames estuary
98
submergent coastlines
produced by eustatic sea level rise
| -fjords, rias, Dalmatian coasts, barrier islands
99
emergent coastlines
produced mainly by isostatic readjustment (rebound)
| -relict/fossil cliffs and raised beaches
100
rias
- submergent river valleys
- drowned river valleys not glaciated in the last ice age before end of the last age, a small river with its tributaries met the sea
- the lowest part of the river's course and its floodplain may be completely drowned but the higher land remains exposed
- in plan view, they tend to be winding, reflecting the original route of the river and its valleys
- when sea level those ecstatically the main channel and drowned these areas, the sea advanced inland
- this created an estuary, at the mouth larger than the regional river valley
101
fjords
- submergent glacial valleys
- they have steep cliff sides valleys and the water is uniformly deep
- post glacial isostatic rebound occurred in many areas where they are present, slowly lifting them up from sea level, making them shallower by a few mm a year
- following an ice age eustatic sea level rise drowned the valleys
102
features of a fjord
- in plan views fjords tend to have much straighter routes than rias due to the erosive power of the glacier
- they often have a submerging lip at the seaward end of the fjord where the glacier ended and left a terminal moraine
- e.g. Milford Sand Fjord in New Zealand
103
raised beaches and relic cliffs
- emergent formation
- areas of former wave cut platforms and their beaches which are left at a higher level than the present coastline
- abandoned cliffs with wave cut notches, caves and arches can also be found
- southern tip of the idle of Portland, 15m above the present sea level, thought to have formed 125,000 years ago
- iceland too
104
formation of relic/fossil cliffs
- at the end of the last ice age, the ice melted and the land that was covered started to rebound slowly as the weight was removed, still rebounding today
- this meant beach platforms rose out of the sea to become new land (raised beaches) and their cliffs also rose to become stranded above the current sea level
- as the raised beach is no longer a beach, sediment is slowly removed by wind, rain and waves
- the relic cliff may still display features such as caves and stacks
105
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freeze thaw (mechanical)
(types of weathering at the coast)
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- Water gets into cracks, freezes and expands by up to 9%. This exerts pressure on the cracks which loosens and breaks apart rock. Most vulnerable are well jointed rocks. Only happens when daily temperatures fluctuate around zero degrees
- Creates angular rock fragments at the base of cliffs called scree and a jagged cliff face. Also can contribute to large rock falls.
106
salt crystallisation (mechanical)
- Salt spray or waves hitting cliffs make them wet with seawater. This evaporates and leaves salt in cracks on the cliff. Over time, salt crystals form and grow, exerting pressure on the cracks and pores which loosens and breaks apart rock. Most vulnerable are well jointed rocks (limestone) and porous rocks (Sandstone, chalk). Happens most in hotter climate
- Creates angular rock fragments at the base of cliffs called scree. Some rock faces crumble away
107
wetting and drying (mechanical)
- Rocks rich in clay expand when they get wet and contract when they dry. This repeated process causes them to crack and break apart
- Cracks form in cliffs so they become vulnerable to slumping.
108
carbonation (chemical)
- Limestone slowly dissolves as it reacts with weak carbonic acid in rainwater.
- Joints and cracks get wider on cliffs and wave cut platforms. This makes them more vulnerable to other weathering and mass movement processes.
109
oxidation (chemical)
- Oxygen combines with iron based minerals in a rock causing a chemical breakdown of the minerals shown by a red rusty colour on the rock face. Sandstones and shales often contain iron so are vulnerable.
- Leads to crumbling of the cliff as sections are no longer bonded together.
110
plant roots (biological)
- Tree and plant roots growing into cracks can slowly widen them and cause them to break apart. Important process on vegetated rock faces.
- can cause rock falls
111
rock boring (biological)
- Clams and molluscs bore (dig) into rock to make their homes. They can also secrete acids that dissolves rocks. Sedimentary rocks in the intertidal zone are vulnerable.
- Holes and weaknesses created are vulnerable to erosion and further weathering.
112
seaweed acids (biological)
- Some seaweed species like kelp contain pockets of sulphuric acid that can burst on rocks and dissolve them.
- Leads to crumbling of the cliff as sections are no longer bonded together.
113
coastal flood risk
the likelihood of flooding to occur at the coast
114
physical factors increasing coastal flood risk
- eustatic sea level rise (caused by global warming)is predicted by IPCC to be between 28 and 98cm by 2100
- coast topography. Bay of Bengal the coast narrows acting as a funnel for weather systems. increasing storm surge height
- low lying land especially islands (Maldives) and deltas (Ganges, nile) are most at risk
- global warming will increase wind speed, wave heights, magnitude and frequency of storms
115
human factors increasing coastal flood risk
- dams block sediment getting to deltas
- population increase at the coast. by 2060, 12% of the world will live in low elevation coastal zones increasing demand for water extraction and leaving people more at risk
- groundwater extraction can cause subsidence of the land
- destruction of mangroves for wood and charcoal exposed coasts to erosion. they can reduce wave height by up to 40%, stabilise sediment and reduce storm surge height (sundarbarns forest Bangladesh)
116
storm surges
- low pressure weather events creates a bulge in the sea
- strong winds drive bulge towards the coast
- land topography can funnel sea, increasing height further
- high tides can also increase height
- sea rushes onto land as a surge
117
North Sea storm surge
- January 1953 (worst ever recorded) and was repeated in December 2013
- killed 2500 people
- as the storm moved over Iceland it deepens dramatically with very low air pressure and storm surge potential of 5.8m. corresponded with high tide in many areas making the flooding worse
- winds of over 140mph were recorded in mountainous areas of Scotland.
- in some areas the storm surges were higher than in 1953 yet the economic and social impacts were lower due to better forecasting, warning and evacuation as well as improved defences.
- in 2013 Thames barrier defended London and 800,000 homes were protected
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Bangladesh storm surge
- particularly vulnerable as:
- much of the country is very low lying (1-3m above sea level)
- incoming storm surges often meet outflowing rivers from the Ganges meaning there is a greater capacity of water involved in flooding
- intense rainfall from tropical cyclones intensifies it
- deforestation of coastal mangrove forest has removed stability and the ability to dissipate wave energy
- triangular shape of the bay of bengal concentrates wav energy causing it to increase in height
- densely populated octaval areas for fishing
- shelter and aid has improved overtime
- estimated that a 1.5m sea level rise will flood over 20,000km2 of land (wetter areas are breeding grounds for disease) with higher sea level, rivers will flow more slowly, ponding back upstream and increasing the risk of river flooding
- dredging and channelisation as well as natural compaction of the delta has meant high tide levels are rising
- main port of Chittagong may be shut due to flooding and salt contamination reducing GDP and calling malnutrition
119
how does removing vegetation impact flood risk?
- essential to marine and terrestrial biodiversity as they stables against erosion, collect nutrients and provide a nursery for coastal fish as well as ptoetcion against coastal flooding
- satellite studies show 71% of Bangladesh's mangrove forested coastline is retracting by as much as 200m a year
- half of the world's mangroves have been lost since the mid 20th century
- converting the forests into lucrative shrimp farms accounts for 25% of the loss.
120
how is Kiribati affected by climate change?
-most people live in Tarawa just 3m above sea level
-rising temperatures have led to bleaching of coral areas, the health of which is vital for the island's growth via atolls
bleaching = addition ocean heat stresses coral polyps causing them to exert their symbiotic zooxanthellae, loosing their food supply and colour
-the gov is looking to relocate the population, creating environmental refugees
121
how is the Maldives affected by flooding
- highest point above sea level is 2.3m so very small changes in sea level translate to huge losses of land
- Malé is ringed by a 3m high sea wall
- Hulhumalé is anew artificial island built form coral and sediment dredged from the seabed (costs $32 million)
122
how did people previously measure coastal recession?
- posts in the ground are used as reference points before GPS was invented in the 90s
- old maps are used to look at changes before this. yet, urbanisation has meant there may be new roads/infrastructure not shown. coastal erosion may mean cliffs have receded and so there is now less land in the area
123
how is LIDAR used to measure costal recession?
light detecting and ranging
- land based laser scanner that takes several scans and combines info with GPS
- equipment is set up on the beach in front of the eroding cliff line at a distance of 100-150m
- it scans a swatch of the cliff up to 800m in with, collecting 2000 individual measurements of the cliff face per minute
- data collection in the field by laser scanning and GPS are entered into a modelling package which calculate clip top recession rates
124
village of Hallsand
- in 1917 a storm ripped apart almost the whole village of Hallsand because of the village's natural shingle beach defence was dredged in the 1980s out to create a new naval dock in Plymouth
- this left nothing to dissipate wave energy
125
human causes of coastal erosion
- coastal defences built at one location will stop or limit the supply of sediment to a cell meaning another areas downdraft may be starved. when the supply is cut off the beach gets narrower and is less able to absorb energy meaning the waves hit back shore with more force
- offshore dreading may increase costal retreat as it removes sand and gravel to depend entrances to ports or to supply sediment to beaches via beach nourishment (this has been blamed for recession in Norfolk)
- deeper water caused by dreading also allows waves to maintain their circular motion and energy closer in shore, having a more destructive impact on the coast
126
how dod sub areal processes causes coastal erosion
- both weathering and mass movement accelerate recession rates. weathering weakens the rocks found at the coast and allow erosion rates to increase
- rainwater creates rills and gullies in unconsolidated material or weak points in harder rock, increasing poor pressure and leading to slumping
- mass movement is more strongly linked to seasonal climate change (Norfolk, hard engineering put in place but cliff retreat still takes place)
- mass movement moves sediment at the base of coastal slopes where wave action and long shore drift can carry material away, exposing the base.
127
how can wind direction cause coastal erosion
- coasts will experience maximum erosion at those times and less erosion when winds and waves are from other directions.
- the longer the fetch, the larger and more powerful the waves will be causing faster retreat. e.g. Lands end has waves from The Atlantic
- wind changes daily meaning there is a complex pattern of wave activity. The dominant wind produce the largest waves
- in North Norfolk, dominates waves and winds from the north are very rare as the westerly prevailing winds to the UK take waves offshore. when they do occur erosion rates may reach a rate of over 8m a year
128
how do tides effect coastal recession?
- two tides a day. extreme high tides known as spring tides occur when the sun and moon are aligned so their total gravitational pull is at it's strongest.
- lowest tides known as neap tides occur when the.sun and moon are perpendicular to each other and so their total gravitational pull is weakest. these occur twice every lunar cycle
- tides determine where waves will hit the shore. 4 times a year the moon is at its closest to earth and this creates slightly higher high tides called Pengean Spring Tides
- at high tides waves are more likely to be able to reach the back shore and erode the land faster. If high tides coincide with restrictive storm waves, erosion will be at a maximum
129
weather systems
- in the N Atlantic and consequently the UK, there is a seasonal weather pattern based on a sequences of anticyclones and depressions
- high pressure brings calmer conditions and smaller waves. low pressure has a mixture of air masses at different temperatures and air rises rapidly. this creates stronger winds rotating an anticlockwise direction and so larger waves are created.
- in winter, the difference between the temperature at the poles and the equator is greatest meaning depressions are strongest, larger waves and more recession
- Global warming has added more heat to the atmosphere, intensifying the low pressure systems. UK experiences stronger winds and waves and so recession is more visible.
130
the nile delta
- 240km coast of the Nile Delta in the eastern Mediterranean
- holiday beach resorts, coastal defences, settlements, fisheries
- delta area is where 95% of the area's population live. this area is retreating significantly (33.4% of the delta is classed as highly vulnerable)
- salt intrusion into the delta due to sea level rise and coastal flooding will become more frequent
- the building of the Aswan Dam in 1964 reduced sediment supplies
- if sea level rises by 1m, 2 million hectares will be lost
- UNDP has implemented an ICZM project to ensure environmental stability
131
hard engineering
the use of build structures (rocks/concrete) aims to protect the coast by working against the force of nature
132
soft engineering
makes use of natural systems such as beaches, sand dunes and salt marshes to help with coastal defence
133
sea palling Happisburgh - background
- retreated approximately 1-2km over the last 900 years. Land lost due to eroding cliffs and low lying flooding
- cliffs made of sand and clay making them soft and susceptible to erosion
- in 1953 natural defences were broken during the North Sea flood storms from the north west combined with high spring tides
- coastline divided by a number of different management strategies
- line of properties on the cliff edge
- isn't enough beach to protect base if the cliff leading to regular undercutting and the cliff to often fall
- there had been a wooden revetment yet this was destroyed in 1990
134
sea palling - issues
- there is a line of sand dunes which if broken, 6000 hectares of land could be flooded with sea water
- in 1953, a storm surge in the North Sea caused major flooding along the east coast and sea broke through the dunes
- in 1954 sea wall was constructed in front of the dunes
- further along the coast a number of groins are built to trap sediment being moved southward by LSD
- 1992 new beach management plan was proposed
- 14 million cubic metres of sand were added to the coast and 150,000 tonnes of rock armour. this allowed for a tomoblo to develop, interrupting the process of LSD increasing erosion downstream
135
local opinions about sea palling
- uncertainty has meant people are trying to hold the line (maintenance of existing sea walls and bars) providing an adequate level of protection
- the beach is wide and very long with golden sand that kids love to play on. this also makes it an attractive tourist destination
- general positivity
136
local opinions about Happisburgh
- not be suitable to defend as the impact this would have on the shoreline as a whole as the coastal retreat on either side would result in the development of a headland making it harder for LSD to occur.
- though there may be a loss of social amenity the area holds little economic value
- has a number of local heritage sites that will be lost
- happisburgh is a thriving community with local facilities and a worthwhile tourist industry so should be saved.
137
holder ness coastline - reasons for management
- rock type - the cliffs are made from less resistant boulder clay which slumps when wet
- naturally narrow beaches = gives less protection to cliff
- manmade structure = groins have been installed to stop LSD, this narrows unprotected areas
- powerful waves with long fetches
138
management strategies at the Holderness coast
- 4.7km long sea wall
- Hornsea is protected by sea wall, groynes and rock armour
- mappleton is protected by rock greens
- spurn head by rock groynes and armour
139
conflicts over the holderness coast
- increase in erosion at Great cowed because of groynes at Mappleton has led to farms being destroyed by the erosion. loss of 100 chalets at golden sands holiday park
- some people disagree on the location of defences
- some negatively impact tourism and reduce money inflows
140
groynes
- structures positioned perpendicular to the beach that trap sediment moved by LSD and build up the beach
- beach absorbs wave energy and increases recreational value
- can starve areas downdraft of sediment
- wood rots but rock is more expensive
141
revetments
- ramps that line the coast and absorb wave energy and air spaces that flow the back wash of the wave to be drained away leaving the sediment trapped
- wood rots, rock is expensive
- do not cope well with powerful storms waves so need maintenance and they are unsightly
142
gabions
cages of small rocks, stacked to make a wall along the coast and absorb wave energy
- flexile as can be added to different places as well as being easy to maintain
- lightweight so can be moved in storms and not suitable for high energy coasts as cages can break and split
143
rip rap
large boulders positioned along the coastline to absorb wave every and to hold back mass movement
- expensive if transport costs are included and can be underscored by strong backwash
- decrease access to beach and some erosion can still occur in the back shore.
144
recurved sea wall
- concrete barrier that is recurved to reflect the waves and their energy and can be stepped to dissipate energy
- gives people confidence and topics are used as promenades
- long lasting
- most expensive and technical to build and foundations can be undermined so they are expensive to maintain
145
breakwaters
- granite rock boulders dropped and aligned in short lengths in shallow offshore waters parallel to the coast
- absorbs and dissipate waves before waves reach foreshore
- creates sheltered areas for recreation and boats
- expensive and make look unsightly at low tide as geology doesn't match
146
beach nourishment
- sand is dredged from the sea bed and pumped onto the beach to absorb wave energy
- beach can be reprofiled to recreate its original shape
- looks natural
- will need to be done every few tears so lots of maintenance required
- can disrupt natural sediment cycling and is expensive
147
cliff regrading
- engineers calculate a stable angle for the particular rock and the cliff is artificially cut back, changing its shape and reducing its angle to make it more stable
- very expensive and unnatural
- not full proof in extreme conditions so other methods needed
148
cliff drainage
- pipes bust through it ti take out the water that has percolated through
- prevents it from becoming saturated and so is less likely to slump
- unsightly and can weaken the cliff the inserted. cannot prevent wearing and difficult to insure
149
dune restoration
- geotextile netting can reduce erosione but still allow water in
- erected vegetation planted to encourage sand disposition to build up
- broadwalks made for people to walk across so they don't trample on the dunes
- looks natural
- only effective if public walk in correct places and strong storms can still cause damage
150
manage retreat
- natural ecosystem such as sand dunes and salt marshes help to stabilise coastlines and acts as natural buffers against storms
- accepts retreat is happening but slows it down
- needs agreement from land owners and doesn't prevent land from being lost
151
main economic impacts of coastal recession
- south Devon main train line at Dawnish was destroyed in Feb 2014 by severe coastal storms
- developed countries will need to offer assistance to environmental refugees from less developed countries (e.g. New Zealand has accepted 3000 people from Tuvala as part of a labour migration plan)
- loss of infrastructure and business. easy to quantify
152
main social impacts of coastal recession
- death, health (stress and physical), bereavement and amenity value. difficult to quantify
- homeowners on the Norfolk coast have properties worth £1 meaning if they are destroyed they will get little, if any compensation
- property insurance in the Uk doesn't cover loss from coastal erosion. There is no compensation provided by the government either meaning people will lose their assets.
- collapse of Holbert Hall Hotel in Scarborough in 1993 after two months of heavy rainfall and no compensation was given
153
main environmental impacts of coastal recession
loss of ecosystems and habitats. difficult to quantify
- Great barrier reef in Australis could perish as sea levels rise as they require a certain amount of light for photosynthesis
- as sea level rises, salt water will be pushed higher up estuaries and damage fragile ecosystems
154
what happened in Australia regarding flooding?
- more than half are vulnerable to erosion and retreat, especially in Victoria state where 80% is at risk
- it is expected that a 10cm rise in sea level, will triple the risk of flooding, affecting cities like Sydney
- 1m rise will expose more than US$162 billion of infrastructure
155
main impacts with Australian flooding
- tourism industry that contributes over $30 billion to Australia's GDP in 2013 and employed 8% of the workforce (gold coast). this could mean expenditure on beach nourishment has to increase
- many of the areas famous natural landmarks like the GBR and mangrove forests will be damaged. estuaries are damaged affecting freshwater habitats in Kakadu National Park in the Northern Territory
- fisheries may be affected, 25000 homes at risk, $11 billion of road at risk leaving people isolated
156
how is the Philippines at risk from flooding?
- loses predicted at $6.5 million a year without adaptation costs
- rate of sea level rise is 5.8mm per year, higher than the global national average. this is due to the currents in the Pacific Ocean and trade winds that move water towards the islands
- the country's high level of poverty (90% of the country's well is controlled by 15%) leaves it vulnerable
157
main impacts of Philippine flooding
- property loses set at about $2.5 million and loss of recreational value
- bay on which the city's located is also used for mooning fishing boasts. the loss of employment because of this could create a welfare loss of $168,000
- parts of the urban area around Manila Bay like Las Pines would be flooded by 2100 with just a 1m sea level rise
- San Fernando is estimated to lose 300 buildings
- mangroves have been destroyed by increased pollution, overexploitation and siltation, reducing their ability to protect the back shore
158
how are the Maldives affected by flooding
- after Boxing Day tsunami, gov started to move people from the lowest 200 islands away and is looking to buy land elsewhere (e.g. Australia or Sri Lanka) and to make new areas to live (e.g. Hulhumalé is an artificially constructed island)
- average ground elevation just 1.5m above sea level
- population of nearly 400,00 means other countries will struggle to facilitate everyone
- no insurance
159
how is New Zealand dealing with coastal flooding?
- Pacific access category ballet allows 400 citizens to be granted residency status each year and the seasonal worker programme allows employers to use labour from pacific islands
- 3000/10,800 Tuvala's population have moved to NZ
- some families have been granted residency on exceptional humanitarian grounds
160
environmental refugees
- can happen nationally or internationally
- between 2008-2013, the Philippines had the third largest number of internationally displaced people due to natural hazards
- in 2005, over 1 million people evacuated from New Orleans to escape hurricane Katrina. 30% of them didn't return and became environmental refugees leaving NO a partially abandoned city
- currently not influenced in UN definition of refugee but by the end of the 21st century major cities like London wand Shanghai will be affected in a similar way
161
what does sustainable coastal management entail?
-meeting the needs of today without jeopardising those of the future. also important to consider a long time scale and physical processes take hundred of years to complete
considering all three strands
-coastlines are best managed as a whole, taking into consideration each littoral cell and how they interlink.
-it can sometime mean abandoning certain areas, despite this contradicting with social beliefs
162
what has adaptation in the UK involved?
- policy change away form hard engineering defences towards more sustainable ones
- has included the second stage of shoreline management plans which reflect predictions of sea level rise by 2100 (e.g. Thames estuary 2100 project)
- the UK government through the environmental agency and DEFRA encourages local communities and councils to adopt coastal change themselves
163
integrated coastal zone management
- 1992 at the Earth Summit meeting and aims to bring together economic decision makers such as tourism, fishing and ports
- emphasises cooperation between stakeholders so that everyone benefits
- dynamic process due to changing demands at the coast and decisions are increasingly centred around sustainability
- the EU adopted the recommendation of integrated coastal zone management in 2004 and the marine strategy framework in 2008 emphasised this comprehensive approach
- ICZMs can now be found worldwide at varying states of sophistication and action (e.g. Philippines emphasises environmental management but little focus on climate change)
164
essex coastal realignment
- Essex wildlife Trust purchased Abbot's Hall estate on the Blackwater estuary, converting more than 84 hectares of farmland into salt marsh and grassland by breaching embankments in 2002 (cba was low so was worth it)
- largest coastal realignment project in Europe costing £645,000. it provides sustainable sea defences for the future as additional hectares of salt marshes absorb incoming storm surges and mudflats allow for wildlife development
- two stakeholder groups were concerned that the plans would change the local water environment
- west Mersey fishermen who carry out oyster fishing in the estuary were concerned that sediment could destroy habitats and RSPB concerned that erosion would change bird habitats.
- encouraged wading birds and other wildlife to return for feeding and nesting
- farmers compensated for lost land
165
what have the Maldives done to protect the coast?
- gov prioritised protecting the capital city and tourism as oppose to smaller traditional communities (e.g. overlooking fishing)
- Mangrove for The Future is an organisation that promotes sustainable development
- new islands constructed
- the organisation MFF is working with Maldivian communities to educate them on the importance of maintaining coastal mangrove swamps as a natural defence against flooding
- global environmental facility (GEF) has provided small grants to islanders to help them develop sustainable and alternative organic farming
166
sustainable strategies on the Namibian coast
- skeleton coast with rural settlements has taken low cost management options. prevent future development, conserve wetland habitats, stabilise and protect sand dunes, monitor sea level ruse for future planning, reduce poverty so people can prepare themselves
- Henties bay (tourist settlements) moderate cost options involves beach nourishment, restoring sand dunes, rehabilitation wetland ecosystems, early warning systems
- Walvis bay which is important for trade, expensive option involves sea walls, relocation of communities, raising of infrastructure and building barrages
167
what are the four coastal management options (SMPs)
- controlled by DEFRA
- do nothing
- hold the line (picture of hard and soft engineering)
- advance the line (often soft engineering to reclaim land followed by hard engineering strategies to hold it)
- managed retreat (removal of hard engineering strategies and replaced by natural more sustainable ones)
168
points of conflict in coastal decisions making
- CBA, the value of property set against the cost of a proposed management strategy
- EIA short and long term impacts on the environment
- social and political factors such as campaigning, stress and pressure groups
- technical feasibility, it isn't possible to hold the line in all areas (e.g. in area of dynamic deposition features such as splits)
169
cost benefit analysis
- the value of property depends on how at risk it is, identical houses where there is an imminent threat of destruction vs isn't will value differently
- some human and environmental costs are hard to quantify in financial terms
170
why was Happisburg not defended?
- defending the village would have an impact on the wider coastal management plan. it would end up as a promontory blocking LSD and causing further erosion downdrift
- median cost of building defences is around £6 million. very close to the value of property that could be saved and much higher than compensation costs payable to local residents
- campaigns by the CCAG started and raised awareness of the coastal erosion issue, locally and nationally. the N N Norfolk district council pathfinder bid covers six settlements and obtained £3million finding by emphasising stakeholder engagement
- owners were offered halftone non blighted value of their home (all but one accepted the offer)
171
environmental impact assessment
- aims to identify the short term impacts of the coastal environment
- long term impacts of building new sea defences or chaining a policy from hold the line to no active intervention
- it is wide ranging including an assessment of: impacts of water movement and sediment flows, impacts of water quality, possible changes to flare and fauna; wider environmental impacts such as noise and air pollution (mainly during construction)
172
winners/ pros of Happisburgh defences
- planning rights funded the purchase of farmland on the landward side of the village allowing it to remain the same size
- profits from sale of new houses will be used to buy properties on the seaward side that become under threat
- lobbying from CCAG changed the management strategy do nothing to manage retreat
173
costs/losers
- by 2015, shoreline may reduce by 200m, loss of 50 homes
- in 2003 the life boat and beach access ramp were lost, prompting concerns that tourism would be affected
- forced relocation
174
coastal management in Chittagong Bangladesh
- coastal climate resilient infrastructure project (2012)wa supported by the Asian development bank and aims to climate proof the area
- improve road connections so they flood 5 times a year not 20, and raising embankments 60cm above normal flood level
- creating raised markets above 2050 sea level rise
- creating 25 tropical cyclone shelters to withstand higher sea levels and stronger winds.
- training in resilience measures
- alleviated poverty by 10% by generating income, adapting to climate change and reducing risk
- IFAD loaned the project US$60 million
175
drawbacks of management in Chittagong Bangladesh
- disruption of people's living conditions (200 people relocated) especially during construction
- permanent removal or vegetation
- IFAD rated progress as satisfactory but with slow progress on road embankments
A Level Geography
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