Coastal landscapes and systems COPY

Question 1

How can coasts be classified?

Answer 1

• geology (including lithology and structure, concordant and discordant)
• sea level changes (submergent or emergent)
• level of energy (high or low energy coastline)
• the dominant coastal process (landforms of erosion/deposition, sediment inputs)

Question 2

what are the long-term criteria for categorising coasts?

Answer 2

• geology - sea level changes

Question 3

what are the short-term criteria for categorising coasts?

Answer 3

• level of energy - sediment inputs (sediment added through deposition and removed by erosion)

Question 4

explain the structure of the littoral zone including some features

Answer 4

coast backshore (storm beach) foreshore (pebbles + berms) nearshore (runnels and ridges) offshore

Question 5

what is the littoral zone?

Answer 5

the boundary between land and seas and is the area of shoreline where land is subject to wave action. it is subdivided into: back shore, foreshore, nearshore and offshore

Question 6

why does the littoral zone vary?

Answer 6

due to short-term factors and long-term factors

Question 7

what are the short-term factors affecting the littoral zone

Answer 7

individual waves, daily tides, seasonal storms

Question 8

what are the long-terms factors affecting the littoral zone

Answer 8

changes to sea levels, climate change

Question 9

what areas of the littoral experience the most human activity?

Answer 9

the back shore and foreshore experience the most human activity

Question 10

what is the overall word to describe the state of the littoral zone?

Answer 10

DYNAMIC. because of the dynamic interaction between the processes operating in the seas, oceans and on land.

Question 11

what is the coastal system

Answer 11

inputs into process and then to outputs

Question 12

what are inputs in a coastal system

Answer 12

• marine: waves, tide, storm surges - atmospheric: weather and storm surges - land: rock type, tectonic activity - people: human activity and coastal management

Question 13

what are processes in a coastal system

Answer 13

• weathering - mass movement - erosion - transportation - deposition

Question 14

what are outputs in a coastal system

Answer 14

• erosional landforms - depositional landforms - different types of coasts

Question 15

explain Cornwall’s geology

Answer 15

Cornwall bears the worst of the weather from the Atlantic ocean but due to is geology, its rocky coastline can withstand frequent storms. much of Cornwall consists of: - igneous rock (such as basalt and granite) - older compacted sedimentary rocks (sandstone) - metamorphic rocks (slates)

Question 16

explain what rocky coastlines are like

Answer 16

• areas of high or low relief which usually form in areas with resistant geology in high energy environments, where erosion is greater than deposition - destructive waves - tend to be stretches of the Atlantic-facing coast, where waves are powerful

Question 17

explain what coastal plains are like

Answer 17

• (sandy and estuarine coastlines) at low reliefs - where the rate of deposition exceeds the rate of erosion - they result from the supply of sediment from different terrestrial and offshore sources, often in a low-energy environment - constructive waves, form sand dunes, beaches, mudflows and salt marshes - tend to be stretches of the coast where waves are less powerful or where it is sheltered from large waves, can form by sea level changes

Question 18

what is the word for a supply of sediment?

Answer 18

coastal accretion

Question 19

what are terrestrial sources of sediment?

Answer 19

from mass movement or rivers

Question 20

what are offshore sources of sediment?

Answer 20

from waves or currents

Question 21

what is the difference between rocky or cliffed coastlines vs coastal plain landscapes?

Answer 21

rocky or cliffed coastlines: when there is a clear distinction between land and sea, mainly because of the height of the cliffs. mainly in the north west , occupy 1000km of the UK’s coastline coastal plain landscapes: where the land slopes gently towards the sea and there is an almost imperceptible transition form one to the other. these are often maintained in a state of dynamic equilibrium from the sediment coming in and out. the wash is the largest estuary system in the UK, mainly in the east and south fo England.

Question 22

are coastlines always either high or low energy?

Answer 22

no. many coastlines are a mixture of big and low energy environments. for examples, areas such as holderness which hare predominantly low energy can experience short-term high energy erosion through winter storms.

Question 23

explain dynamic equilibrium

Answer 23

where erosion = deposition. there is a continuous flow of energy and material through the coasts but the size of stores (beach, salt marsh) remains unchanged

Question 24

what is geological structure?

Answer 24

refers to how the rock is arranged on a macro-scale and looks at the arrangement of different rock types in relation to each other. It looks at the rock strata, deformation and presence of faulting.It looks at the rock strata, deformation and presence of faulting.

Question 25

what are concordant coastlines?

Answer 25

• this is where rock starts runs parallel to the coast forming bays and coves - example: the souther coast of the isle of purbeck has formed lulworth cove and kimmeridge bay due to its concordant structure

Question 26

what are discordant coastlines?

Answer 26

• this is where the rock starts runs perpendicular to the coast forming headlands and bays - example: the isle of Purbeck’s eastern coast leading to headlands at peril point and durlston head, swanage bay has formed

Question 27

explain the formation of Dalmatian coasts

Answer 27

1) tectonic activity folded limestone layers so that ridges (anticlines) and valleys (synclines) formed parallel to the coast 2) sea level rose following the end of the ice age and drowned the valleys (creating a submergent coastline) 3) the tops of the ridges remained above the surface of the sea running parallel to the coast an example of this is the Croatian Dalmatian coast

Question 28

explain the formation of haff coasts

Answer 28

1) the build up of these sand dunes have created lagoons (haffs) between them and the shore 2) they form where deposition produces unconsolidated geological structures parallel to the coastline 3) this forms long sediment ridges topped by sand dunes that run parallel to the coast an example is chesil beach in Dorset which has formed in this way. shingle ridge reconnected island of portland bill to land (a tombolo)

Question 29

what are half coasts?

Answer 29

they are long spits of sand and lagoons aligned parallel to the coast

Question 30

what is beach morphology?

Answer 30

the shape of a beach including width and slope (profile) and other features such as berms

Question 31

explain the formation of headlands on discordant coastlines

Answer 31

1) wave action erodes the less resistant rock quicker due to hydraulic action and abrasion 2) the more resistant rock is left sticking out as a headland, causes waves to refract and as water becomes shallower and so waves energy is concentrated on the headlands and waves become higher increasing erosive power on the headland 3) the bay becomes sheltered as wave energy is dissipated, results in the formation of beaches as sediment is deposited in the low energy environment

Question 32

what does the morphology of discordant coasts lead to

Answer 32

the altering of the distribution of wave energy and rate of erosion through wave refraction

Question 33

explain swanage bay

Answer 33

• on the isle of purbeck in east dorset - formed by the erosion of less resistant Wealden clays - resistant limestone forms perril point headland to the south projecting out by 1km and the resistant rock forms the foreland headland which projects 2.5km to the north - structure is not the only factor influencing the indentation of swanage bay. since it faces east it is sheltered from the prevailing south westerly winds and highest energy waves

Question 34

what are cliff profiles influenced by?

Answer 34

• geology, especially the resistance to erosion of the rock
• the dip of rock strata in relation to the coastline

Question 35

explain joints

Answer 35

• (vertical cracks), these are fractures caused either by contraction as sediments dry out or by earth movements during uplift - they are fractures created without displacement and occur in most rocks, dividing rock strata up into blocks with a regular shape - jointing increases erosion rates by creating fissures which marine erosion processes such as HA can exploit example: in bantry bay, the limestone is heavily pointed, leading to more rapid fluvial and marine processes in adjacent sandstones

Question 36

explain faults

Answer 36

• formed when he stress of pressure not which a rock is subjected, exceeds its internal strength (causing it to fracture). the faults then slip along fault planes. - it significantly increases erosion since faulted rocks are much more easily jointed - huge forces are involved in faulting and displacing them and therefore either side of the fault line, rocks are often heavily fractured example: in bantry bay in cork in the republic of Ireland there is a major fault which runs SW-NE down the centre of the bays. the limestone is weakened allowing rapid fluvial erosion

Question 37

explain folds

Answer 37

• they are bends in rocks formed by pressure during tectonic activity which makes rocks buckle and crumple - the main two types are anticlines and synclines - folden rock is often more heavily fissured and jolted, meaning they are more easily eroded, also increases erosion by increasing angle of dip and causing joins through the stretching along anticline crests an compressed in syncline troughs

Question 38

explain dips

Answer 38

• refers to the angle at which rock strata lie (horizontally, vertically, dipping towards the sea or dipping inland) - its a tectonic feature, sedimentary rocks deposited horizontally can be tilted by faulting and folding by tectonic forces

Question 39

what is horizontal dipping

Answer 39

a vertical or near-vertical profile, notches reflect weathering and small scale mass movement

Question 40

what is a high angle of seaward dip

Answer 40

produces a sloping, low-angled profile with vulnerable rock layers, loosened by weathering

Question 41

what is a low angle of seaward dip

Answer 41

produces a steep profile that may even exceed 90 degrees, creating areas of overhanging rock, vulnerable to rock falls

Question 42

what is landward dipping strata?

Answer 42

produces steep profiles on 70º-80º as downward gravitational force pulls loosened blocks into place, very stable with few rock falls

Question 43

what is a cliff profile?

Answer 43

the height and angle of a cliff face, plus its features such as wave cut notches or changes in slope areas

Question 44

what are micro features?

Answer 44

• small-scale features such a scales and wave-cut notches which form part of a cliff profile - the location of these micro-features are often controlled by the location of faults and/or strata which have a high amount of joints and fissures

Question 45

what is the relief of an area affected by?

Answer 45

the relief or height and slope of land is also affected by geology and geological structure. there is a direct relationship between rock type, lithology and cliff profiles

Question 46

explain the different stages of a cliff profile

Answer 46

Question 47

what is lithology?

Answer 47

refers to the physical characteristics of the rock. igenous, metamorphic, sedimentary and unconsolidated rock each have different characteristics.

it also influences geological structure on a meso (medium scale) and micro scale (some types of rocks are more likely to have joints and bedding planes)

Question 48

how does lithology affect resistance?

Answer 48

1) mineral composition
2) rock type
3) structure

Question 49

how does mineral composition affect resistance?

Answer 49

• some rocks contain reactive minerals eaisly broken by chemical weathering, e.g. calcite in limestone
• other minerals are more inert that chemically weather more slowly

Question 50

how does rock type affect resistance?

Answer 50

• sedimentary rocks are clastic (sediment particles compacted together) and these are often reactive and easily chemically weathered
• igneous rocks are crystalline with strong chemcial bonding
• rocky coasltines differ in resistance

Question 51

how does structure affect resistance?

Answer 51

rocks with fissures or air spaces erode more easily

Question 52

what are rates of recession influenced by?

Answer 52

it is influenced by bedrock lithology (I,S,M) and the geology

• how reactive minerals in the rock are when exposed to chemical weathering
• whether rocks are clastic (less) or crystalline (more resistant)
• the degree to which rocks have cracks, fractures and fissures

Question 53

give examples of areas from the most resistant rock to the least resistant rock

Answer 53

most resistant: IGNEOUS- Land’s End, South Cornwall (granite)

resistant rock: METAMORPHIC- St Ives, Cornwall (slate)

resistant sedimentary rock: SEDIMENTARY- Blackers hole, south Purbeck, Dorset (Limestone)

least resistant rock: Holderness, NE Coast, (boulder clay)

Question 54

explain igneous rocks

Answer 54

• their crystalline structure (interlocking cystals) means they are well connected and impermeable with few lines of weaknesses (resistant)
• these rock types create rocky coastlines with steep profile cliffs
• erosion rates: 0.1-.0.3 cm/yr
• e.g. granite, basalt
• example: lands end, Cornwall (granite)

Question 55

explain metamorphic rocks

Answer 55

• they are also well-connected and impermeable
• however they are often folded and faulted so have weaknesses
• these rock types create rocky coasltines with steep profile cliffs (depending on folding and dip) and erode slowly
• erosion rates: 0.5-1 cm/yr
• e.g. marble, slate, schist
• crystalline rocks are resistant to erosion
• example: St Ives, Cornwall (slate)

Question 56

explain sedimentary rocks

Answer 56

• they are clastic meaning they are made up of cemented sediment particles rather than interlocking crystals
• formed in stratas (layers) with joints which provides weaknesses and makes limestone permeable along with other jointed sediemntary rocks whereas other ones are porous due to the presence of air spaces
• rocks that are younger erode faster than the others as they are softer and weaker, older sediment is buried deeper and is subject to more intense compaction with stronger sedimentation- making them more resistant
• limestone erosion rates: 1-2cm/yr, chalk erosion rate: 1-100 cm/yr
• example: Old Harry, Purbeck, Dorset (chalk)

Question 57

explain unconsolidated sediment

Answer 57

• they are the least resistant, they are not cemented together in anyway so are very vulnerable to erosion, fast recession rates
• can create slumped coastlines due to mudslides/landslides causing slumping
• the boulder clay of Holderness coast in Yorkshire retreats at a rate of 2-10 m p.a
• boulder clay erosion rates: 100-1000 cm/yr, sandstone rate: 10-100 cm/yr

Question 58

what are the factors influencing the rate of recession?

Answer 58

• geology
• lithology
• weathering
• mass movement

Question 59

what is differential erosion?

Answer 59

where cliffs are composed of differing lithology, leads to different sections of a cliff eroding/receding at different rates. it can also be produced when there are alternating permeable and non-permeable strata

they may form a ‘bench’ feature at the cliff base and further up overhanging sections until they collapse by mass movement.

however, the overall rate of recession is determined by the resistance of the weakest rock layer

Question 60

what are the 4 different examples of differential erosion?

Answer 60

• a spring creating erosion and saturation leads to slumping
• poor water pressure leads to slumping
• wave-cut notches from different rates of erosion
• resistant rock creating a bench feature at the cliff base

Question 61

explain a spring creating erosion and saturation leading to slumping for differential erosion

Answer 61

when groundwater flows through the permeable sands but cannot flow through the impermeable clay which leads to the permeable layer becoming saturated, weakening it and causing slumping

Question 62

explain poor water pressure leading to slumping in differential erosion

Answer 62

poor water pressure (the internal force within cliffs exerted by groundwater) in the saturated layers pushes rock particles apart, reduces friction and lubricates lines of weaknesses

Question 63

explain the formation of wave-cut notches in differential erosion

Answer 63

wave cut notches are created by erosion of the weak coal layer with more resistant siltstone overhanging the coal below

Question 64

explain the importance of permeability in differential erosion

Answer 64

permeable rocks allow water to pass throug them. groundwater flow through permeable rock can weaken the rock by removing the cement that binds the rock sediment. slumping is a common outcome.

Question 65

what are the two types of cliff profiles

Answer 65

1) steep, unvegetated cliffs
2) shallow-angled, vegetated cliffs

Question 66

explain steep, unvegetated cliffs

Answer 66

• produced where marine erosion dominates
• there is little or no debris at the base as it is broken by attrition and transported offshore or along the coast

Question 67

explain shallow-angled, vegetated cliffs

Answer 67

• they have a convex profile (curved like the interor of a circle)
• there is debris at the base becuase sub-aerial processes slowly move sediment downslope, but marine erosion is unable to rmeove it from base
• produced where there is little active marine erosion

Question 68

what is succession?

Answer 68

the changing structure of a plant community overtimes as an intially bare surface is colonised by pioneer species and continues to develop

Question 69

explain the role of vegetation in stabilising sediment

Answer 69

• vegetation can stabilise unconsolidated sediment and protect it from erosion
  1) plant roots bind together, making it harder to erode
  2) plant stems and leaves covering the ground surface protect sediment from wave erosion and from tides and currents when exposed at high tide
  3) prevent sediment from wind erosion at low tide
  4) plant stems interrput the flow of water and wind, encouraging deposition and when the vegetation dies it adds its organic matter (humus) into the soil

Question 70

what are pioneer plants?

Answer 70

• these are the first plants to colonise freshly deposited sediment
• they being the process of plant succession, during which other species and take over until a balance is reached, the changes allow other species to colonise
• they modify the environment by: stabilising sediment, adding organic matter that retains moisture and reduces evaporation in sand

Question 71

explain the pioneer plant present in sand dunes: marram grass

Answer 71

• xerophyte
• has extremely long roots which binds the dune together, up to 3m long
• it has rhizomes which helps it keep anchored into the ground
• holds the beach together, allows the dune to develop as it builds up dense vegetation
• leaves roll inwards to kepp in moisture
• when it dies out, it adds lots of organic matter in the soil, leading to further plant growth

Question 72

explain the pioneeer specie in salt marshes: glasswort

Answer 72

• when submerged, plants provide a protective layer so the sediment is not directly exposed to erosion by the tide
• succulent stems to store water, continues to grow
• dead organic matter is added to the sediment and helps to create soil which is less vulenrable than loose sediment
• halophyte as it may be on higher levels, lack water

Question 73

what are halophytes and xerophytes?

Answer 73

halophytes- salt-tolerant species

xerophytes- drought-resistant species

Question 74

what is each stage in plant succession called and what si the end stage called?

Answer 74

a seral stage

the end result is called a climax community

Question 75

what are sand dunes?

Answer 75

an accumulation of sand grains shaped into mounds and ridges by the wind in coastal areas

Question 76

what is plant succession on sand called?

Answer 76

psammosere

Question 77

what are the sections of a sand dune called?

Answer 77

embryo dunes

fore dunes

yellow dunes

grey dune

dune slac

mature dunes (climax community)

Question 78

explain plant succession on a sand dune

Answer 78

1) there is a plentiful supply of sand, a large area for sand to dry out and onshore winds to that blow sand landwards. sand accumulates to form an embryo dune.
2) pioneer species like marram grass colonise the dune, stabilising it and helps to trap more sand
3) a fore dune develops when enough sand has been trapped an the dune starts to become more stable
4) now an established dune will become more vegetated by marram grass which provides organic matter to the sand and soil to devleop, improving the conditions
5) with soil now developed on the dune, it becomems a grey dune. this is permanent and conditions ar suited to a greater variety of species including heather and gorse
6) between dunes, dune slack develops. wind erosion can deepen them and they may be waterlogged in high tide conditions.
7) furthest inalnd is the climax community. there the soil is fully developed and the dune is fully stabilised and biodiversity is at its highest, trees can grow (birch)

Question 79

how do the types of plants change during psammosere

Answer 79

at first, the succession starts with halophytic plants capable of growing in salty, bare sand. as they trap more sand it develops into an embryo dune that alters the environmental conditions to one where xerophytic plants can flourish

Question 80

what is plant succession called on salt marshes

Answer 80

halosere

Question 81

what are ideal areas for salt marshes to form

Answer 81

estuarine areas are ideal for salt marshes as theyre sheltered from strong waves (so sediment like mud and silt can be deposited) and rivers transport sediment to the river mouth which can be added by seidiment flowing into the estuary at high tide.

they form in low energy environments ir estuaries, sheltered bays and behind spits. rivers bring fine muds and silts and tidal conditions bring other sediments, all of which are deposited.

Question 82

explain plant succession along salt marshes

Answer 82

1) the mixing of fresh water and sea water causes clay particles to stick together and sink which is called flocculation. this areas is colonised by algae which have to survive being submergeed twice a day.
2) the algae helps to trap more seidment and builds the height of the marsh, making it suitable for other species. species are halophytic and include cordgrass and glaswort
3) sediment becomes more stable and vegetation adds dead organic matter, making conditions better for plant growth. conditions become less salty as the marsh is now only submerged occasionally (spring tides)
4) at the inland end of the marsh, soil has developed and he climax community is established (trees)

Question 83

what are blowouts?

Answer 83

they are created when storm events erode sections of the yellow dune through wind or wave erosion. however, over time, deposition of sediment and recolonisation of vegeation will rebuild the dune’s damaged areas.

Question 84

how are waves created?

Answer 84

waves are created through friction between the wind and water surface, transferring energy from the wind into the water. this generates ripples, which grows into waves whedn the wind is sustained.

Question 85

what does wave size depend on?

Answer 85

• the strength of the wind
• how long has the wind been blowing for
• the length of the fetch

Question 86

what is the fetch?

Answer 86

this is the uninterrupted distance across water over which the wind blows and therefore the distance waves have to grow in size

Question 87

which area suffers the greatest waves?

Answer 87

the southwest due to the long fetch along the atlantic

Question 88

explain wave formation and the breaking of waves

Answer 88

1) waves move across open ocean in circular motion as ocean swell
2) as the waves reach shallower water, when their wave height is less than half the wavelength then friction increases slowing the wave down for the circular oscillations to become more so elliptical
3) as the wavelength decreases due to the shallower water, wave height increases and eventually the wave breaks as the top of the wave is moving faster than the base
4) the waves then lose enrgy and gravity pulls the water back as backwash

Question 89

what are destructive waves like?

Answer 89

• they degrade a beach
• high waveheight, low wavelength
• backwash > swash
• drags sediment back to sea
• scours beach
• 13-15 break/minute
• high energy
• causes cliff retreat
• plunging breaker
• steep beach

Question 90

what are constructive waves like?

Answer 90

• they aggrede a beach
• low waveheight, long wavelength
• swash > backwash
• brings sediment back to the sea
• builds beach up
• 6-8 break/minute
• low energy
• spilling breaker
• flat beach

Question 91

what are swell waves like?

Answer 91

• waves formed by winds blowing over larger distances, they travel out of windy and stormy areas
• swell waves originate in mid-ocean and maintain their energy for thousands of miles
• is an ocean wave system not raised by the local wind blowing
• as swell waves advance, its crest becomes flattened and rounded and its surface smooth

Question 92

using cliff profiles explain how recession rates can differ

Answer 92

• recession rate increases if dip is towards so as weathering opens joints and gravity speeds mass movement
• steep dip to the sea increases erosion rate as gravity makes bedding planes unstable and slabs slide downslope. this increases recession rates
• a cliff with landward dipping bedding planes are relatively steep and stable whcih decreases recession rates
• landward dip with well-developed joints will increase recession rates as joints acts as slide planes

Question 93

what are the 4 erosional processes explained

Answer 93

abrasion- the rubbbing together of hard load, sand paper effect

attrition- rocks bashing into one another breaking them down

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 which can widen cracks and dislodge blocks friom the cliff face

solution- where water in waves dissolves rock minerals

Question 94

how are erosional processes influenced by wave type, size and lithology?

Answer 94

• most effective during high energy storm events with large destructive waves
• most effective in winter, in high energy storms
• faster when the tide is high

Question 95

explain the cave-arch-stack-stump sequence

Answer 95

• the headland protrudes out into the sea as it is more resistant which means wave energy is concentrated on it due to wave refraction
• wave action attacks weaknesses in the headland due to abrasion and hydraulic action leading to cavitation
• this widens cracks into crevices and into caves
• caves can be eroded to form blowholes as the ceiling collapses
• marine erosion deepens the caves until they connect up and an arch is created and erosion continues and the roof of the arch becomes unstable from the widening of the arch due to weathering and other sub-aerial processes
• the arch eventually collapses by blockfall to form a stack
• continual undercutting and HA in the joints at the base of the stack creating a stump like Old Harry’s wife

Question 96

explain the formation of old harry rocks

Answer 96

• wave refraction concentrates wave action on the headlnad, hydraulic action and abrasion slowly erodes the headland to form a series of landforms
  1) chalk headland leads to wave refraction
  2) deposited sand from nearby waters deposit to form beaches
  3) waves carved into rock to form chalk cliffs, undercut to form hollow until it becomes so unstable that it collapses
  4) pockets of air are compressed into the cracks with the water that it becomes unstable and falls
  5) wave quarrying forms arches

Question 97

what are blowholes?

Answer 97

• caves can partially collapse to produce a hole in the cliff
• waves hitting the base of the cliff can be forced through and sprout water at the top

Question 98

how do cliffs vary in morphology?

Answer 98

they vary in their morphology depending on lithology and weathering are actively eroded by wave action or they are affected by sub-aerial processes

Question 99

explain the formation of a wave-cut platform

Answer 99

1) wave action at the base of the cliff between high and low tide means that hydraulic action and abrasion undercuts the clif to form a wave cut notch
2) this continues and the cliff above the notch is left unsupported and eventually collapses
3) the cliff retreats leaving a wave cut platform which is the base of the cliff that is left
4) this process maintains a steep cliff profile

Question 100

what is a wave-cut platform?

Answer 100

it is a flat rock surface exposed at low tide, extending out to sea from the base of a cliff

Question 101

what is a wave cut notch?

Answer 101

a curved indentation of about 1-2m high extending along the base of a cliff. it forms between the high and low tide marks, where destructive waves impact against the cliff.

Question 102

what are beach profiles like in summer?

Answer 102

• they are steeper in summer, where constructive waves are more common than destructive. wave energy dissipates and deposits over a wide area.
• as the berm builds up, the backwash becomes weaker and only has enough energy to move smaller material, so the beach material becomes smaller towards the shoreline

Question 103

what are beach profiles like in winter?

Answer 103

• destructive waves occur at a hgiher frequency
• berms are eroded by plunging waves and high-energy swash
• strong backwash transports sediment offshore (offshore bars are made)
• destructive, high-energy waves dominate in the winter, lowering angle of beach profile and spreading shingle over the whole beach

Question 104

how does the size of sediment vary on a beach?

Answer 104

as constructive waves have a weaker backwash can only transport smaller particles down the beach. this leads to the sorting of material with larger, heavier shingle at the back of the beach and the sand drawn back closer to the sea. the backwash only has enough energy to transport down smaller sediment. they also become more angular at the back of the beach and rounder at the front of the beach.

Question 105

what influences beach morphology?

Answer 105

1) sediment supply- if the supply is reduced from rivers, for example, due to the construction of dams on rivers that traps sediment upstream
2) human interference- often a result of coastal management in one place having an effect on processes further along the coast
3) climate change- if global warming made the UK climate on average stprmier, then destructive waves and ‘winter’ beach profiles would become more common

Question 106

explain morphology along cliff profiles

Answer 106

• storm beaches result from high-energy deposition of very coarse sediment during the most severe storms
• berms typically of shingle/graves, result from summer swell wave deposition
• the middle area of the ebach is mainly sand, but the sand is coarser where berms/ridges have been deposited than in chsnnels and runnels
• offshore ridges formed by destructive wave erosion and subsequent deposition of sand and shingle offshore.

Question 107

why is sediment constantly moving at the coast?

Answer 107

as a result of waves, tides and currents. the main process is LSD.

Question 108

what are the 4 methods of transportation?

Answer 108

traction- where large, heavy load items are rolled along the sea bed

saltation- where lighter sediment bounces along

suspension- where very light sediment is carried within a body of water or air

solution- where seidment is carried dissolved within the water

Question 109

explain the process of longshore drift

Answer 109

• the prevailing winds (in this case SW) mean that the waves approach the coastline at an angle
• this means 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) and small pebbles by bouncing them (saltation) and sand, silt and clay is suspension
• as the process continues, sediment is moved east and over time, a drift aligned beach will form.

Question 110

what are swash-aligned beaches?

Answer 110

waves approach the coasltine perpendicular to the beach. the swash and backwash move sediments up and down the beach = stable and straight beach

Question 111

what are drift-aligned beaches?

Answer 111

waves approach at an angle and sediment is moved along by longshore drift = wide beaches but uneven in sediment

Question 112

what are examples of sources of sediment?

Answer 112

• rivers
• constructive waves (from seabed)
• cliffs
• LSD

Question 113

why does deposition happen?

Answer 113

• deposition due to gravity settling occurs in low energy coastal environments, course dropped first, finer further away
• flocculation helps depositon of fine clay particles that are very llight. they clump together in salt water, making them heavier.

Question 114

explain the formation of a spit

Answer 114

1) sediment is moved along the coast by a process called LSD
2) when there is a change in the direction of the coastline (river mouth), longshore drift continues
3) the waves lose energy in the slacker water behind the headland and the largest sediments are deposited here first in the same direction (gravity settling)
4) as deposition continues, a spit is formed. finer material is carried along futher along the spit before being deposited as it is lighter (course dropped first, finer, further away). flocculation helps to settle fine clay
5) the spit grows and may form a hook if the wind direction changes
6) in the slacker water behind the spit, more deposition takes place and a saltmarsh may develop with halophytic plants helping to trap sediment (links to salt marsh succession). new land is eventually created. e.g. spurn head

Question 115

how does a bar form?

Answer 115

where there are no river currents, it prevents longshore drift depositing in a straight line across and so evenutally the spit joins with land to form a bar, e.g. chesil beach

it is when a beach or spit extends across a bay to connect two headlands,

Question 116

explain tombolos

Answer 116

• this is an island joined to the mainland. it develops when deposition occurs behind an island due to the low energy environment. eventually, the island becomes connected to the mainland.
• occur on drift aligned coastlines, when longshore drift builds a spit out from land until it contacts with an offshore island.
• they are linear ridges (bars) of sand and shingle connecting an offshore island to the coastline of the mainland.

Question 117

what are double spits?

Answer 117

• Double spits are where two spits extend out in opposite directions from both sides of the bay, towards the middle.
• They form where longshore drift is operating in different directions on opposite sides of the bay
• They can also form when rising sea levels drive ridges of material onshore from the offshore zone.
• Or, a barrier beach driven across a bay forms a bar (e.g. Haff coastlines) but a strong exiting river current may breach the bar to form a double spit.

Question 118

what are cuspate forelands?

Answer 118

• low-lying triangular shaped headlands, extending out from a dhoreline, formed from deposited sediment
• forms when longshore drift current from opposing directions converge at the boundary of two sediment cells
• The sediment is deposited out into the sea by both currents creating a triangular shaped area of deposited material.
• They can extend from a few metres to several kilometres.

Question 119

what are barrier islands?

Answer 119

• a ridge of material emerging just offshore to form a chain of beaches parallel to the coast
• these 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 became elongated islands running parallel to the coast (USA Atlantic coast)
• as sea level continues to rise, they migrate inland
• they provide protection to the coastline during storms as they absorb wave energy

Question 120

what are offshore bars?

Answer 120

• Offshore bars are ridges of sand or shingle running parallel to the coast in an offshore zone.
• forms in shallow water offshore where the slope is gentle
• following large erosion events during a storm
• beach and dunes can be scoured heavily by destructive waves and carried seawards by backwash
• They are also called breakpoint bars because the offshore/nearshore boundary is where waves first begin to break.
• They can sometimes be exposed by neap tide.
• LSD can add to them or change their shape and they can be temporary

Question 121

what is a sediment cell and explain it?

Answer 121

it is an area of a coastline that acts as a closed system, there are sources, transfers and sinks within each cell.

• they UK is divided up into 11 sediment cells (lengths of coastline that are relatively self contained). boundaries are often natural barriers, e.g. headlnads
• sediment cells are divided into sub cells
• the sub cells are then managed at a local level by an SMP (shoreline management plan)

Question 122

give 5 examples of sources

Answer 122

• deposition from rivers
• weathering and erosion of cliffs
• human intervention
• onshore winds
• onshore currents

Question 123

give 5 examples of transfers

Answer 123

• destructive waves (backwash)
• LSD
• ocean currents
• wind
• tidal currents
• swash

Question 124

give 5 examples of sinks

Answer 124

• Backshore depositional landforms

E.g. sand dunes

• Foreshore depositional landforms

E.g. beaches

• Nearshore depositional landforms

E.g. bars

• Offshore depositional landforms

E.g. barrier islands ​​

Question 125

explain the concept of the coast being a dynamic system

Answer 125

• they are dynamic because the sediment is constantly generated in the source region, transported through the transfer region and deposited in the sink region.
• dynamic equilibrium is achieved when inputs of sediment from the source region are balanced by the amount being deposited in sinks
• however, things like climate change creaitng more frequent and intense storms and seasonal change

Question 126

explain the sediment budget

Answer 126

• the amount of sediment gained from sources and lost to sinks can be quantified in a sediment budget
• if the sediment budget is negative, a coastline mya start to degrade (erode)
• if the sediment budget is positive, a coastline may start to aggrade (from accretion)

Question 127

what happens if the sediment budget falls or increases?

Answer 127

• if the sediment budget falls (more lost to sinks than gained from sources) then there may be more erosion from sources to balance the budget
• if the sediment budget increases (more gain from sources than loss to sinks) there will be more deposition in sinks

Question 128

explain cases when the sediment cells are positive or negative

Answer 128

• they may have positive feedback in damage to snad dunes during stormy conditions, which may create a ‘blow-out’, allowing the wind to move more sand away, preventing grasses from regrowing- which allows further erosion to occur
• there may be negative feedback through wave erosion causing rock fall which then protects the base of a cliff from further erosio

Question 129

what are sub-aerial processes?

Answer 129

they are processes that affect the cliff face rather than the cliff foot. they are land-based processes which later the shape of the coastline. they are a combination of weathering and mass movement

Question 130

what is weathering?

Answer 130

the decay and disintegration of rock in situ (where they are) by mechanical, biological or chemical agents.

Question 131

what is mass movement?

Answer 131

the movement of material downslope as the result of gravity. water commonly acts a lubricant in mass movement.

Question 132

how is weathering and erosion different?

Answer 132

erosion also involves the transport of sediment away from the cliffs, the erosion occurs by an external agent

Question 133

what might influence how vulnerable a cliff is to mass movement?

Answer 133

• lithology and structure of a cliff can determine mass movements it is vulnerable to
• weathering processes can contribute to the loosening of cliff faces so that mass movements are more likely
• water from rainfall is often a key cause of mass movements
• angle of the slope will also affect vulnerability

Question 134

what are the 5 different types of mass movement?

Answer 134

landslide

slumping

mudflow

rockfall

soil creep

Question 135

what are landslides?

Answer 135

rocks that have jointed or having bedding planes parallel to the slope are susceptible to landslides. increased water leads to less friction, leading to sliding

Question 136

what is rotational slumping?

Answer 136

common where softer rock overlies harder rock, it causes rotational scars, repeated slumping creates a terraced cliff profile

• A rotational scar is a fresh, curved, unweathered and unvegetated rock surface on the cliff face.
• The detached slope section, often with vegetation intact on top of the slump, forms a beach or terraced cliff profile.
• Slumping is facilitated by the presence of water, which adds weight (increasing the gravitational force) as well as lubricating it, reducing friction.

Question 137

what is a mudflow?

Answer 137

Flows occur when unconsolidated fine grained sediment, e.g. silts and clays, mix with large volumes of water. They’re common in weak rocks such as clay or unconsolidated sands. They become saturated, lose their cohesion, and flow downslope.

• difference between a slide and a flow is that in a slide the material remains intact but in a flow the material becomes jumbled up

Question 138

what is a rockfall/blockfall?

Answer 138

• most likely to occur when strong, jointed and steep rock faces/cliffs are exposed to mechanical weathering or marine erosion, happens on slopes over 40 degres
• once broken away, it can form scree at the bottom of the cliff

blockfalls- similar to rock falls but here a large block of rock falls away from the cliff as a single piece.

Question 139

what is soil creep?

Answer 139

the slowest form of mass movement, an almost continuous process, it is a very slow downhill movement of individual soil particles

Question 140

what are the different types of biological weathering?

Answer 140

plant roots

rock boring

seaweed acids

Question 141

what are the different types of mechanical weathering?

Answer 141

freeze thaw

salt crystallisation

wetting and drying

Question 142

what are the different types of chemical weathering?

Answer 142

carbonation

oxidation

Question 143

explain freeze thaw

Answer 143

• water gets into the cracks and freezes and expands 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.
• effects: creates angular rock fragments at the base of the cliffs called scree and a jagged cliff face. also can contribute to large rock falls.

Question 144

explain salt crystallisation

Answer 144

• salt spray or waves hitting cliffs makes them wet with seawater. this evaporates and leaves salt in cracks on the cliff. overtime, salt crystals form and grow, exerting pressure on the crakcs and pores which loosens and breaks apart rocks. most vulnerable are well jointed rocks (limestone) and porous rocks (sandstone). happens most in hotter climates
• effects: creates angular rock fragments at the base of cliffs called scree. some rock faces crumble away.

Question 145

explain wetting and drying

Answer 145

• rocks rich in clay expand when they get wet and contract when they dry. this repeated process causes them to crack and break apart
• effects: cracks form in cliffs so they become vulnerable to slumping.

Question 146

explain carbonation

Answer 146

• limestone slowly dissolves as it reacts with weak carbonic acid
• This attacks calcium carbonate in limestones, other carbonate rocks and sedimentary rocks with calcite sediment.
• effects: joints and cracks get wider on cliffs and wave cut platforms. this makes them more vulnerable to other weathering and mass movement processes

Question 147

explain oxidation

Answer 147

• oxygen combines with iron based minerals in a rock causing a chemical breakdown of the minerals shown by red rusty colour on the rock face. it produces iron oxides and increases in volume, leading to mechanical breakdown. sandstones and shales often contain iron so are vulnerable.
• effects: leads to crumbling of the cliff as sections are no longer bonded together

Question 148

explain the effects of plant roots

Answer 148

• tree and plant roots growing into cracks can slowly widen them and cause them to break apart. important process on vegetated cliff faces.
• seeds falling into cracks in rocks can germinate, nourished by rainwater and nutrients from wind-blown sediment. as the plant grows its roots expand and thicken, tree roots exert sufficient tensional force to widen the crack
• effects: eventually angular fragments of rock break away as cobble or boulder-sized sediment, rock falls

Question 149

explain rock boring

Answer 149

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.

• piddocks drill depressions into sock rocks by rotating their shell equipped with sharp edges
• effects: holes and weaknesses created are vulnerable to erosion and further weathering

Question 150

explain seaweed acids

Answer 150

• some seaweed species like kelp contain pockets of sulphuric acid that can burst on rocks and dissolve them
• when the cells break sulphuric acid attacks rock minerals like calcium carbonate leading to a chemical reaction similar to carbonation
  effects: leads to crumbling of the cliff as sections are no longer bonded together

Question 151

what is a talus scree slope?

Answer 151

The angular blockfall debris accumulates at the cliff foot to form a talus scree slope, a fan shaped mound of material.

formed from a blockfall

Question 152

what is a statistic on cities on coasts?

Answer 152

70% of cities are on the coasts, major economic hubs

Question 153

what is isostatic change?

Answer 153

an isostatic change is a change in local land level

rising or falling of a land mass relative to the sea which can result from the release of the weight of the ice after the last ice age (isostatic rebound)

rises in local land level causes a fall in local sea level. this can be caused by:

• post-glacial adjustment
• accretion (sink regions in the sediment cell are experiencing net deposition, land is built up, leading to a fall in sea level)
• tectonics

a fall in local land level causes a rise in local sea level. this can be caused by:

• post-glacial adjustment
• subsidence (caused by heavy buildings, the deposition of sediment or from the lowering of the water table through increased evaporation leading to settling of overlying sediment and land subsidence as pore water pressure is removed

Question 154

what is eustatic change?

Answer 154

• it is a change in global sea level
• variations in relative sea level resulting from changes in the amount of liquid water entering the oceans, e.g. melting ice caps
• eustatic fall in sea level occurs during glacial periods when ice sheets form on land in high latitudes, and water evaporated form the sea is locked up on land as ice, leading to a global fall in sea level, the sea bed is exposed as land (marine regression)
• eustatic rise in sea level occurs at the end of a glacial period when melting ice sheets return water to the sea and sea levels rise globally. global temp increases, leading to the volume of ocean water to increase (thermal expansion) leading to sea level rise

Question 155

what are sea levels?

Answer 155

the realtive position of the sea versus the land

Question 156

how are sea levels changing in the different parts of the UK?

Answer 156

the tees-exe line separates the highland and lowland areas, the NW is facing rising due to isostatic recovery and the south and east UK is sinking due to isostatic subsidence, the rising amount of sediment coming down leading to higher sea levels, isostatic subsidence is accelerating a rise in sea level produced by global warming (eustatic)

Question 157

what are the overall factors determining sea level change?

Answer 157

• tectonics, land can be pushed up by plates in a series of earthquakes
• accretion (deposition of sediment) in a river estuary or delta can weigh down the crust and also cause sinking (subsidence), e.g. thames estuary
• isostatic change/eusostatic change

Question 158

what are submergent coastlines?

Answer 158

they are produced by eustatic sea level rise. they produce fjords, rias, dalmatian coasts and barrier islands

• an example is the sognadjord, norway

Question 159

what are emergent coastlines?

Answer 159

they are produced mainly by isostatic readjustment (rebound)

they produce relcit/fossil cliffs and raised beaches

example: Vik, South Iceland

Question 160

explain the formation of rias

Answer 160

• submerged river valleys
• the lowest part of the rivers course and its floodplain may be completely drowned, but the higher land becomes exposed
• in plan view they tend to be winding, reflecting the original route of the river and valley
• before the end of the last ice age, a small river with its tributaries met the sea, creating an estuary at the mouth that is larger than the original river valley
• e.g. kingsbridge estuary, devon

Question 161

explain the formation of fjords

Answer 161

• submerged glacial valleys
• they have steep, cleiff-like valleu sides and the water is uniformly deep
• these were formed when glaciers eroded below sea-level. when the ice melted the valleys were flodoed to form the fjords
• in plan view, fjords tend to have much straigther routes than rias due to the erosive power of the glacier
• they often have a submerged lip at the seaward end where the glacier ended and left a terminal moraine.
• example: milford sound fjord, new zealand

Question 162

explain the formation of raised beaches

Answer 162

• areas of former wave-cut platforms and their beaches which are left at a higher level than the present coastline
• a flat surface covered by sand or rounded pebbles/boulders
• usually vegeatted by palnt succession

Question 163

explain the formation of fossil cliffs/relic cliffs

Answer 163

• a steep slope found at the back of a raised beach exhibiting evdience of formation through amrine erosion but now above hgih tide level
• they may contain wave-cut notches, caves and arches providing evidence of formation by marine erosion
• episodic nature of isostatic recovery allows marine processes to erode cliffs and deposit beaches when sea levels are stable. relatively rapid drop in sea level then elaves relict coastline abandoned above high tide and some distance inland

Question 164

explain what is happening to sea level changes

Question 165

explain the formation of lulworth cove on concordant coastlines

Answer 165

these occur on concordant coastlines and through destructive waves hitting the resistant limestone and it creates joints through hydraulic action and abrasion eroding the resistant rock. the erosion then becomes more rapid when it reaches the band of softer rock where it creates the cove shape through the erosion of the softer clays. erosion is rapid in all directions and eventually the erosion slows down as the more resistant chalk strata is reached.

Question 166

how can geological structure influence cliff profiles?

Answer 166

Geological structure largely influences cliff profiles in terms of the landforms that form as a result. If it is a discordant coastline then they are to see headlands and bays but if it is a concordant coastline they will see haffs and coves. Geological structure closely relates to the resistance of the rock and so it determines the rate of coastal recession in the different areas also.

Question 167

describe the essential features of the backshore

Answer 167

• It is a part of the beach above the high-tide mark and abutting the cliff base. It is only affected by exceptionally high tides and during severe storms. On the backshore we see a storm beach and pebbles.
• area between the high water margin and the landward limit of marine activity. Changes only happen here in storm events.

Question 168

describe the essential features of the foreshore

Answer 168

the area between the HWM and the LWM. The most important zone for marine processes. Only exception is during storm events (the tidal range), if it is a small tidal range there are fewer processes.

-

Question 169

describe the essential features of the nearshore

Answer 169

• it is the zone extending seaward from the low water line beyond the surf zone, it defines the area influenced by the nearshore or lowshore
• Shallow water close to the tide line but covered by water at normal low tides Here we see the formation of ridges and runnels.

Question 170

describe the essential features of the offshore

Answer 170

beyond the point where waves cease to impact upon the seabed and in which activity is limited to deposition of sediments.

Question 171

what is the breaker zone?

Answer 171

the zone in which waves approaching the coastline begin breaking (typically between 5 and 10 metres) however this depends on coastline, steeper vs shallow and type of seabed (rocky vs smooth)

Question 172

explain the profiles of two high-relief cliffs- one which is being actively eroded and the other not

Answer 172

Eroded- this will have a very steep profile and will show evidence of joints and have a wave-cut platform, there will be scree at the bottom of the cliff

Non-eroded- here we will see a much gentle and smooth profile. It will be curved at the top by sub aerial process and at the base by the accumulation of cliff debris.

Question 173

examine the influence of dips on cliff profiles

Answer 173

Landward dipping- they are relatively steep and stable, decreasing recession rates

Seaward dip- high angle produces low-angle profile with one rock layer facing the sea, low angle produces steep face with overhanging rocks

Horizontal dipping- vertical profiles with notches where weaker strata have been eroded, reflecting weathering and small scale mass movement

Question 174

what are the micro features of a cliff and how are they formed?

Answer 174

These are small-scale features such as wave-cut notches, caves, stacks or blow holes. They are normally formed through the presence of faults and strata which have a high amount of joints and fissures.

Question 175

describe how the differential erosion of alternating and contrasting rocks affects the coastline

Answer 175

This leads to a series of different landforms forming along the coastline and differing rates of recession. Higher rates of erosions will lead to the formation of bays whilst areas with more resistant rock will simply see faults and joints. It produces complex cliff profiles through the variety of different rock types. Headlands are likely to coincide with resistant rocks and will be characterised by relatively slow rates of recession.

Question 176

explain why estauries are ideal for the development of salt marshes

Answer 176

• Estuarine conditions compromise of calm and low-energy waters where deposition is high. This means that they are perfect conditions for saltmarshes as these calm conditions encourage the deposition of salt.
• The sediment is supplied to an estuary through the river and the plants that are able to grow along the estuary and salt marsh allow for further deposition of salt, thus building up the salt marsh further. -
• Mudflats are gradually built up in the sheltered water and they will eventually be colonised by pioneer plants. Those plants prosper in the sheltered conditions and help trap more sediment. So the plant succession is set in motion.

Question 177

explain the formation of embryo dunes

Answer 177

Embryo dunes form thanks to the blowing of sand from the onshore winds and through plant succession and the halophytic plants which are able to sustain the salty conditions.

The plants trap the sand and once established this forms the embryo dunes.

They are early accumulations of sand at the backshore, but prone to wind and wave erosion during strong storms.

Question 178

explain the formation of dune slacks

Answer 178

These are the areas between dunes. Wind erosion can deepen them and they may become waterlogged in high tide conditions. It is caused by strong winds blowing away sand at the water table. Damp sand is less easily blown away.

Question 179

apart from colour, what is the difference between yellow dunes and grey dunes?

Answer 179

Grey dunes are much more developed and are permanent whereas yellow dunes are less stable.

Grey dunes are part of the fixed dunes due to the developing vegetation cover. Due to that, the characteristic yellow sand of the mobile dunes is less visible.

Question 180

why is marram grass so important to the formation of sand dunes?

Answer 180

These are a form of pioneer species. This means that they are essential to the first stages of sand dune succession. It is very effective in stabilising blown sand.

It has tough, long and flexible waxy leaves which can cope with being sand blasted. It has roots of up to 3m long so it can tap water below the surface of the dune and can survive temps of up to 60ºC. They trap the sand and the sand can build up amongst it.

It allows the dune to develop as the more marram grass present, the increased amount of organic matter that is added to the sand and the soil is able to develop, improving the conditions and allowing for further development.

They are essential for the growth of sand dunes

Question 181

explain contemporary sea level change

Answer 181

• sea levels have fluctuated and since 1850 they have been rising
• the IPCC prediction models suggest that mean sea levels will rise by between 0.45m and 0.74m by 2100 and will continue rising for centuries
• the low emission estimate for sea level change by 2100 is 28-61cm and the high emission estimate is 52-98cm
• global sea levels have risen about 7cm over the past 22 years

Question 182

what are the different things contributing to sea level rise?

Answer 182

thermal expansion (40% so far), predicted to be 53%

melting of glaciers (27% so far)

melting of major ice sheets (Antarctic 10% so far, Greenland 15% so far)

Question 183

why is there debate about how much sea levels will rise?

Answer 183

• unclear about how much temps will rise and so how much thermal expansion there will be
• unclear as to how rapidly the ice sheets will melt. greenland ice sheet is more vulnerbale than antarctic as it is smaller and not as close to the pole
• sea level rise is not equal all over the world
• if greenland was to completely melt, sea level would rise by up to 7m, global warming melts the glaciers, ice caps and ice sheets and thaws permafrost, more water is then added leading to sea level rise

Question 184

what is thermal expansion?

Answer 184

as seawater heats up by absorbing heat from the atmosphere, its volume expands. the ocean has stored 90% of the increased heat energy of the climate system in recent decades.

Question 185

which areas at most at risk from sea level rise

Answer 185

low lying areas are most at risk. these include the maldives, bangladesh and cities like Miami, New York and Tokyo. these risks are often increased by a dense population.

Question 186

what are two things that the IPCC predicts to happen to the sea due to global warming

Answer 186

• wave heights will increase in the arctic ocean as sea ice melts, increasing wave erosion will happen on Arctic coasts
• there will be stormier seas, leading to more destructive waves. this combined with higher sea levels will make it easier to predict that erosion rates and coastal change will increase in the future

Question 187

evaluate the contribution that sea level change makes to the formation of coastal landscapes (20)

Answer 187

YES: eustatic sea level rise, formation of rias, fjords, dalmation coast

YES: isostatic sea level rise, fossil/relic cliffs, raised beaches

NO: tectonic changes, during earthquakes it can jolt

NO: geological structure

NO: lithology

Question 188

why is coastal flood risk becoming an increasingly large problem?

Answer 188

becuase many people have settled at the coast. By 2060, 12% of the world’s population will live in low elevation coastal zones.

flood risk increases in coastal zones thar are experiencing isostatic sinking

Question 189

what is coastal flood risk?

Answer 189

the likelihood of flooding taking place at the coast

Question 190

what are the three global factors that influence flood risk

Answer 190

1) eustatic sea level rise- caused by global warming, predicted by IPCC to be between 28 and 98cm by 2100
2) some evidence that global warming will increase wind speeds, wave heights, frequency of storm surges and the magnitude of tropical storms
3) population increase at the coast- by 2060, 12% will live in low elevation coastal zones. this increases demand for water extraction and means more is at risk.

Question 191

what are the 6 local factors that increase coastal flood risk?

Answer 191

1) dams- they block sediment getting to deltas to replace what is lost by erosion
2) groundwater extraction- can cause subsidience of land at the coast, reduces sediment volume, this is the sudden sinking or gradual downward settling of the ground’s surface
3) isostatic sinking- is causing south eastern Britain to sink
4) shape of the coast (topography)- in the case of the North Sea and the Bay of Bengal, the coast narrowing, acting as a funnel for weather systems, increasing storm surge heights, funnelling effect
5) height- low lying land especially islands (like the Maldives) and deltas are most at risk from sea level rise, temporary flood risk from storm surges and permanent flooding from SLR, archipelagos
6) vegetation removal- the destruction of mangrove forests food wood and charcoal exposes the coast to erosion. mangroves can reduce wave heights by 40%, stabilise sediment

Question 192

what are depresssions?

Answer 192

depressions are areas of low air pressure generating surface winds that spiral into the centre of low pressure in anti-clockwise directions. they occur in mid-latitudes, like the UK.

Question 193

what is a storm surge?

Answer 193

it is a temporary rise in local sea level produced when a depression, storm or tropical cyclone reaches the coast

Question 194

explain the formation of a storm surge

Answer 194

1) low pressure weather event (depression) creates a bulge in the sea
2) strong winds drive bluge towards the coast
3) land topography can funnel sea, increasing the height further
4) high tides can also increase height
5) sea rushes onto land as a surge

Question 195

what are the 7 factors contributing to coastal recession?

Answer 195

LSD

erosional processes/resistance

length of fetch

mass movement

type of waves

tides

dredging

Question 196

what problems might using old maps bring for assessing coastal recession?

Answer 196

• they are outdated and so it doesnt show the real size of the coastline, e.g. the area of mappleton used to be far inland but now it is right on the coastline
• may not be done as accurately doesnt show everything, different scales

Question 197

how might methods of measuring erosion changed through time?

Answer 197

• posts in the ground were used as reference points before GPS was invented in the 90s
• old maps were used to look at changes before this
• LIDAR used in combination with GPS now

Question 198

explain the use of LIDAR for measuring erosion

Answer 198

• LIDAR (light detection and ranging) is a 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 from a distance of 100-150m
• it scans a swathe of cliff up to 800m in width, collecting 2000 individual measurements of the cliff face per minute
• data collected in the field by laser scanning and GPS are entered into a modelling package which calculates cliff top recession rates

Question 199

explain what happened in the village of Hallsands (coastal recession)

Answer 199

a storm ripped apart almost the whole village in 1917 as the natural shingle beach defence was dredged in the 1890s in order to create a new navel dock in Plymouth. this meant that there was nothing to dissipate wave energy.

• this has led to high amounts of recession with homes being destroyed due to the recession rates

Question 200

what are the 4 physical causes of coastal recession

Answer 200

subaerial processes

wind direction

tides

weather systems and global warming

Question 201

explain the human cause of coastal recession: coastal management

Answer 201

• the building of groynes will deprive beaches of sediment downdrift for beach building leading to the beach becoming narrower and will be less able to absorb wave energy and so waves will hit the backshore with a stronger force
• this has been seen at Dunwich, south (downdrift) of southwold on the Suffolk coast

Question 202

explain the human cause of coastal recession: offshore dredging

Answer 202

• dredging removes sand and gravel for construction purposes to deepen entrances to ports or to supply seidments for beach nourishment
• deeper water caused by dredgig will also allow waves to maintain the circular motion and energy closer inshore and have a more destructive impact on the coast
• e.g. dredging off the North Norfolk coast has been blamed for increased erosion rates, as the supply of sediments to beaches has been altered
• it can have a negative impact on the natural environment such as removing benthic species and communities, increasing turbidity, which can damage coral reefs and sediments

Question 203

explain the human cause of coastal recession: river dams

Answer 203

they reduce the supply of sediment to the coast (e.g. the impact of the Aswam High damn on the Nile Delta)

Question 204

explain the physical cause of coastal recession: subaerial processes

Answer 204

• weathering weakens rocks found at the coast and allows erosion rates to increase
• mass movement moves sediments to the base of coastal slopes where wave action and LSD can carry material away, this then exposes the base of coastal slopes, resulting in further cliff recession
• rainwater directly impacts cliff slops with the formation of rills and then gullies in unconsolidated materials or at weak points in rock
• mass movement is more strongly linked than wave action to seasonal climate changes
• cliff failures in the chalk cliffs on the french side of the English Channel were found to be due to weathering rather than marine erosion

Question 205

explain the physical cause of coastal recession: wind direction

Answer 205

• as there is a clear relationship between wind and wave direction and wind direction changes daily, it means there is a complex pattern of wave activity and erosion
• the dominant wind produces strongest waves, in Land’s End in Cornwall it comes from the SW and on the North Norfolk coast it comes from the N
• max erosion will happen with these winds, less erosion when winds and waves are from other directions
• coasts with longer fetches are likely to retreat faster as waves will be more powerful
• for North Norfolk, the dominant winds and waves fro mthe north are rare due to the westerly prevailing winds for the UK taking waves offshore, but when they occur erosion rates may reach a rate of over 8m per year
• Birling Gap in Sussex has shorter fetches and chalk rocks and has eroded at a rate of 0.58m per year
• when wind blows from prevailing wind direction, strong winds produce large destructive waves and rapid recession

Question 206

explain the physical cause of coastal recession: tides

Answer 206

• extreme high tides (spring tides) occur when the sun and moon are aligned so their gravitational pull is strongest, the lowest tides (neap tides) occur when they are at right angles, these spring and neap tides occur twice a year
• at high tides, waves are more likely to reach the backshore and erode the land faster. if high tides coincide with destructive storm waves, erosion will be at its max
• four times a year, the moon is closest to the earth creating higher high tides called ‘perigean spring tides’
• high tides occur twice each day, 12 hours apart

Question 207

explain the physical cause of coastal recession: wetaher systems and global warming

Answer 207

• in the UK there is a seasonal weather pattern based on high-pressure areas (anticyclones) and low pressure areas (depressions)
• high pressure brings calmer conditions and smaller waves, low pressure brings a mixture of air masses at different temps and air rises rapidly, so this leads to strong winds rotating in an anticlockwise direction, creating larger waves
• in winter, the diff in temp at the equator and the poles is greatest so depressions are strongest, with lower AP and faster wind speeds, which creates larger destructive waves and fastest recession rates
• depressions form in the north atlantic and take days to pass across the UK from the SW to NE. As they pass the spiralling inflow air produces changes in wind direction
• global warming has added more heat to the atmosphere which has intensified the low pressure systems. the UK now faces stronger winds and therefore waves, coastal erosion is likely to increase with recession being visible. the IPCC says 1cm rise in SL will erode a beach by about 1m horizontally.

Question 208

explain the case study of the nile delta for coastal flood risk

Answer 208

• the 240km coast sees holiday beach resourts, coastal defences, general tourism, marine recreation, fisheries, land reclamation, agriculture, settlements and transport and port infrastructure
• the delta area is where 95% of Egypt’s pop live
• they have been experiencing retreat with salt inrustion due to SLR and coastal flooding will become more frequent due to CC
• as sea levels rise and protective offshore bars are eroded, 3.3% of the delta will be lost due to this
• the building of the aswan dam in 1964 reduced terrestrial sediment supplies
• a 2015 study classified 32.4% of the nile delta coast as highly vulnerable with only 26% being low vulnerability
• if sea levels rise by 1m by the end of the century and no action is taken, 2 million hectares of fertile land will be lost and at least 6 million displaced, including 30% of the city of Alexandra
• the UNDP habe placed an ICZM programme for the nile delta

Question 209

explain the coastal risk on the holderness coastline

Answer 209

on the holderness coast erosion is not constant. average annual erosion is 1.25m per year but we can see that there are wide spatial variation from 0m per year to 6m per year

the variations are due to :

• coastal defences in locations such as Hornsea, Mappleton and Withernsea which ahve eliminated erosion
• starvation of sediment further south due to groynes and breakwaters that interrupy LSD but lead to greater erosion just south of these defences
• sediment starvation, erosion rates generally increase from north to south
• variations in cliff height and the susceptibility to erosion of some areas of boulder clay compared to others
• mass movement susceptibility in some locations, as well as debris from previous erosion

Question 210

what are the three human causes of coastal recession?

Answer 210

offshore dredging

coastal management

dams

Question 211

how does the holderness coast see differing erosion rates over time?

Answer 211

erosion of Holderness varies over time. measuring erosion every six months at Hollym between 1999 and 2014 showed variations from 0m to 11m.

these variations are due to:
- winter storms, which cause most erosion, especially when these coincide with a high spring tide

• storms are rare in summer months so erosion rates measured in autumn are lower
• north easterly storms cause most erosion due to long fetch

Question 212

how does the shape of the coastline at the holderness coast influence erosion?

Answer 212

the shape of the beach in front of the Holderness boulder clay cliffs can change and promote erosion

• ords are deep hollows on the beach running parallel to the cliff line, they seem to concentrate erosion in particular areas by allowing waves to directly attack the cliff with little energy dissipation
• ords migrate downdrift by about 500m per year so the locations of most erosion may change over time
• ord locations erode 4x faster than locations without ords

Question 213

what is hard engineering and what are the 5 methods

Answer 213

hard engineering is the use of built structures (rocks or concrete). it aims to protect the coast by working against the forces of nature.

sea walls

rip-rap

rock breakwaters

revetments

groynes

Question 214

what is soft engineering and what are the 3 methods?

Answer 214

it makes use of natural systems such as beaches, sand dunes and salt marshes to help with coastal defence

beach nourishment

cliff regrading and drainage

dune stabilisation

Question 215

explain groynes and their advantages and disadvantages

Answer 215

they are wooden (or rock) structures that are positioned along a beach at right angles from the coast. they trap sediment that is moved by LSD and build up the beach. the beach absorbs wand increases its recreational value.

example: holderness coast

advantages:

• the built-up beach increases tourist potential and protects the land behind it
• groynes work with natural processes to build up the beach

disadvantages:

• can starve areas downdrift of sediment
• wood can rot and so may not be a good long-term solution, high levels of maintenance
• groynes are unnatural and rock groynes can be very unattractive

Question 216

explain revetments and their positives and negatives

Answer 216

they are concrete or wooden structures that are placed across a beach or coastline to take the full force of the wave energy, preventing further erosion of the coast. air spaces allow the backwash of the wave to drain away but the sedimemnt is trapped behind, reducing removal by destructive waves.

example: Overstrand, North Norfolk

advantages:

• they are relatively inexpensive to build
• effective for many years

drawbacks:

• wood can rot so may not be a good long-term solution, high levels of maintenance
• does not cope well with powerful storm waves so needs maintenance
• not aesthetically pleasing
• reduced access to the beach

Question 217

explain gabions and their positives and negatives

Answer 217

they are cages of small rocks stacked to make a wall along the coast. the small boulders are contained within stel wire-mesh cages and can be joined together to form larger structures or walls.

example: Overstrand, Norfolk

advantages:

• cheap, approx £100/metre
• flexible as can be added in different places
• absorbs wave energy

disadvantages:

• not suitable for high energy coasts as cages can break and spill contents
• unnatural, not aesthetically pleasing

Question 218

explain rip rap and its positives and negatives

Answer 218

large boulders dumped in front of a cliff or sea wall to take the full force of the waves.

example: Minehead, Somerset

advantages:

• their large surface areas means they absorb wave energy
• the gaps left are able to let water filter through, again mitigating thieir impact on the coast
• it’s often used for fishing from or for sunbathing by tourists

disadvantages:

• can be under scoured by strong backwash, could be moved during weather events
• some erosion will still occur on the backshore in storng storms
• the rocks used are usually from somewhere else so they don’t fit in with the local geology and so can look out of place
• decreased access to beach

Question 219

explain a recurved sea wall and the positives and negatives

Answer 219

it is a concrete barrier that is recurved to reflect the waves and their energy. sea walls must have a continuous facing because any slight gap will be exploited by HA. they also need drian outlets so that if water does get over them it doesnt accumulate inland.

example: Minehead, Somerset

advantages:

• they often have a promenade for people to walk along
• effective prevention of erosion, long-lasting
• gives people confidence on the future of the coastline

disadvantages:

• most expensive defense (£5000/linear m)
• they can be intrusive, unnatural
• need deep foundations to stop being undercut by waves
• destruction of the natural cliff face and foreshore environment
• they reflect the wave energy rather than absorbing it

Question 220

explain breakwaters and the positives and negatives

Answer 220

they are granite rock boulders that are dropped and aligned in short lengths in shallow offshore waters parallel to the coast.

example: Sea Palling, Norfolk

advantages:

• an effective permeable barrier
• create sheltered areas for recreation and boats and a tombolo effect
• they absorb and dissipate waves before they reach the foreshore

disadvantages:

• may look unaesthetically pleasing during low tides
• still may need further hard engineering
• it’s a potential navigation hazard
• expensive (between £1m and £2m)

Question 221

explain beach replenishment and what are the positives and negatives

Answer 221

sand is dredged from the seabed and pumped onto the beach to replenish it from the effect of LSD or destructive waves. the beach can be ‘reprofiled’ to recreate its original shape.

example: Pevensey Bay, Sussex

advantages:

• it looks natural and blends in with the existing beach
• it increases tourist potential by creating a bigger beach
• beach absorbs wave energy

disadvantages:

• will need to be done every few years as LSD/destructive waves will continue to remove beach sediment, ongoing costs are high
• can disrupt the marine ecosystem or the natural sediment cycling and deepening offshore so waves have more energy

Question 222

explain cliff regrading and the positives and negatives

Answer 222

if the cliff lithology is unstable and vulnerable to slumping after heavy rainfall, 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.

example: Barton-On-Sea, Hampshire

advantages:

• regrading can work on clay or loose rock where other methods won’t work
• allows the build up of the beach

disadvantages:

• very expensive (about £1 million)
• unaesthetically pleasing, not natural, can be disruptive during construction
• cliff line retreats into valuable land land when constructed
• not full proof in extreme conditions, other measures needed

Question 223

explain cliff drainage and the positives and negatives

Answer 223

if the cliff consists of a permeable layer above an impermeable layer it can become unstable after heavy rain due to pore pressure. so by inserting pipes to take out the water that has percolated through, saturation is prevented and it is less likely to slump

example: Barton-On-Sea, Hampshire

advantages:

• drainage is cost-effective
• In-cliff drainage reduces pore-water pressure and mass movement risk

disadvantages:

• not aesthetically pleasing
• can weaken the cliff when inserted, they dry outleading to them to collapse
• cannot prevent weathering and subsequent rock fall
• difficult to insert enough without disturbing the cliff stability

Question 224

what is dune restoration and what are the positives and negatives?

Answer 224

protecting this ecosystem can provide natural protection for the coastline. it is mainly damaged by vegetation removal which can lead to blowouts. strategies include:

• geotextile netting can reduce erosion but still allow water in
• vegetation planting (marram grass) to encourage sand deposition
• fences and boards put up so tourists don’t stand on the dunes, they are given an area to walk on
• afforestation with quick-growing conifers
  example: Studland, Dorset

advantages:

• can be very cost effective in the long term
• it provides important wildlife habitats

disadvantages:

• only effective if public access controlled by fences and signs which reduces amenity value
• strong storms can still cause damage
• time consuming to plant marram grass
• people may respond negatively to being kept off certain areas

Question 225

epxlain developing natural defences/managed retreat and its positives and negatives

Answer 225

natural ecoysystems such as sand dunes and salt marshes help to stablise coastlines and act as natural buffrs against SLR and storms. managed retreat involves abandoning the cirrent line of sea line defences to then be colonised by natural barriers such as marsh. it also accepts that the coast is retreating but by enhancing its natural defences, this can be slowed down

advantages:

• it is relatively cheap because it often involves land reverting to its original state before it was managed for agriculture
• it creates a natural defense providing a buffer to powerful waves
• it creates an important wildlife habitat

disadvantages:

• needs agreement from land owners
• does not prevent land being lost
• Landowners need to be compensated - this can cost between £5,000 - £10,000 per hectare.

Question 226

explain coastal management in place in Happisburgh

Answer 226

• a wooden revemtnet stretched from happisburgh to the cart gap seawall but in 1990 a storm destroyed about 300 metres of revetment to the east of Happisburgh. this led to rapid erosion of the cliffs which had agricultural land on top. the remaining revetment was damaged by storms and by 1996, another length was lost.
• in 2007, the council spent £200,000 on emergency works where an extra 1000 tonnes of rip rap were placed on the beach
• in 2008 Natural England said they plan to allow the sea to flood the area, covering six villages and creating a new bay

Question 227

who are the winners and losers of the coastal management plans in Happisburgh

Answer 227

• in 2010, the North Norfolk District Council offered to buy 10 homes in most risk of danger for demolition, there were conflicts
• 94% of land in North Happisburgh is agriculture and so the biggest losers will be the farmers, source of income gone
• local heritage sites will be lost if not protected
• many homes are at risk, “when i bought this house there was another row of home between us and the sea. Today the sea is only 20m away”

Question 228

what are the shoreling management plan reccomendations/drawbacks in Happisburgh

Answer 228

• not appropriate to defend the area due to the impact on the shoreline, the coastal retreat would lead to the formation of a healand, significantly impacting LSD
• although they will see a loss of residential properties and amenities, these are not sufficient to economically justify building new defences
• the existing rock armour will continue to have a limited effect on the rate of retreat in the short trm (5-10 years) but will not prevent cliff erosion

Question 229

explain the coastal management in Sea Palling

Answer 229

it is a small settlement on a low-lying area of the North Norfolk coast with a sea with a line of sand dunes and if the sea were to break through tge dunes, 6000 hectares of land could be flooded with salt water. 95% of coastal strip agriculture

groynes were built along the coast at Eccles and so prevented lots of sediment reaching sea palling which posed threats to their sea wall.

• 150,000 tonnes of rip rap placed at the foot of the sea wall to prevent undercutting
• 1.4 million cubic metres of sand added to beach
• offshore bars built in 1995, length of 240m and cost £5.9 million
• in 1996, 5 more reefs built 160m long, cost £10.5 million

Question 230

what is the shoreline management plan reccomendation for Sea Palling

Answer 230

• their policy is to hold the line due to the considerbale assets at risk and the uncertainty of how the coastline could evolve
• their policy is likely to include maintaining their sea walls and reef structures (bars), replacing groynes and continuing to renourish beaches with dredged sand

Question 231

what are the pros and cons of coastal management at sea palling

Answer 231

not many complaints

• “it is now wide and very long with golden sand which the kids love”
• “the larger beach means we can make more money”
• “we even get people kite surfing”

BUT:

• residents whose homes are dissapearing are the losers
• “the reefs are too far appart so the sea stilll eroded the beach between them”
• “they have spent millions of pounds on defences”

Question 232

explain coastal management in minehead and its drawbacks/losers

Answer 232

• in 1990 its beach was washed away leading to £2 million floods
• sea walls being built to protect the coast from storm events
• rock armour (each 7 tonnes) being placed in front of the curved concrete wall (1.8km) to deflect wave energy, cost for both at £12.5 million
• butlins brings in £90 million and so defences are needed, it is seemed as economically viable to install defenses, without it the resort could flood
• the area is prone to floods and high tides

drawbacks/losers:

• constant improvement needed to make sure they dont wear down
• ALOT of money needed, needs to be balanced by the money coming from Butlins
• council lose

Question 233

explain coastal management in Porlock bay and the drawbacks/losers

Answer 233

• no massive man-made degences, they use nature as a natural form of protection
• shingle has been used as a natural seawall, barrier to protect the agricultural land behind from storms
• winter gales have destroyed shingle wall and now areas are becoming flooded
• the National Trust wonde whether they should spend millions on rebuilding or do nothing and let nature take its course
• they found that due to LSD, shingle would be pushed to the north and less in the south leading to water flooding through the gap
• it has been decided to do nothing, the area will become marshland which will absorb the energy and imapacts, MANAGED RETREAT

drawbacks/losers:

• farmers, residents, local gov
• the valuable assets of farmland lost, source of income gone
• the shingle ridge which protects marshalnd has been breached by storms
• locals argue it would cut the bus service in two
• no investment to come to the area as it floods

Question 234

explain coastal management on Holderness coast, NE Yorkshire

Answer 234

it is the fastest eroding coastline in Europe, eroding at 1.8m a year. due to less resistant lithology of boulder clay, naturally narrow beaches (less protection), the presence of man made structutres (groynes) and powerful waves

• Bridlington has a 4.7km long sea wall as well as groynes
• sea wall, wooden groynes and rock armour at Hornsea
• in Withernsea, there are groynes and a sea wall. some rock armour was placed in front of the wall after it was damaged in severe storms in 1992
• eastern side of Spurn Head protected by groynes and rip rap. this also protects the Humber estuary behind Spurn Head
• defences include two rock rocks which were built in Mappleton in 1991 and cost £2 million.

Question 235

drawbacks and losers of coastal management on the holderness coast

Answer 235

drawbacks

• the groynes built at Hornsea starved Mappleton (further south) of sediment. By 1990s nearly 4m of cliff were being eroded at Mappleton each year
• Hornsea’s defences have changed the natural pattrn of erosion and transferred the problem further south
• Golden Sands holiday park have seen 100 chalets fall into the sea despite management strategies
• sea defences at Mappleton are causing problems further along the coast as there is less sediment to travel down
• some sea defences negatively impact tourism and reduce the amount of money coming in

losers

• residents (some disagree on where defences are being placed, benefitting some and not others)
• business owners
• holiday parks
• farmers

Question 236

what are the social impacts of flooding and recession

Answer 236

HARD TO QUANTIFY

• loss of livelihoods
• health and well-being (stress, worry)
• relocation (break up community)
• property insurance does not cover losses from coastal erosion. so there are high costs of relocation (no compensation) and breaks up community
• environmental refugees created
• the Environment Agency estimates that 800 properties will be lost by 2035

Question 237

what are the economic impacts of coastal flooding and recession?

Answer 237

EASY TO QUANTIFY

• loss of property, business
• damage to infrastructure
• loss of farmland
• falling property values
• fall in amenity value
• south devon railway line at Dawlish was destroyed in Feb 2014 by storms (£35 million)
• homeowners on the norfolk coastline have properties now worth £1
• collapse of Holberk Hall Hotel in Scarborough 1993 after 2 months of heavy rainfall. no compensation

Question 238

what are the environmental impacts of coastal flooding and recession?

Answer 238

DIFFICULT TO QUANTIFY

• loss of coastal ecosystems and habitats
• loss of farmland?
• as sea levels rise, salt water will be pushed higher up estuaries and damage fragile ecosystems

Question 239

what are the social, economic and environmental impacts happening to australia due to coastal flood risk and recession?

Answer 239

social:

• 250,000 homes will be at risk leading to some relocation, breaking up communities
• 75 hospitals and health services are within 200m of the coasline

economic:

• a 1m SLR will expose more than US$162 billion of industrial, commercial, transport and housing infrastructure to flooding and erosion
• a 0.2m SLR would cause US$1.4 billion for SE Queensland
• tourism industry contributes US$30 billion to GDP, employs 8% of workforce
• expenditure on beach nourishment increase by US$39 a year
• AUS$72 billion of homes at risk

environmental:

• groundwater supplies may be affected by salt intrusion
• great barrier reef and ecosystems like mangrove forests and salt marshes trapped between rising SL and coastal protection measures
• SLR will push salt water further up estuaries, affecting freshwater habitats in Kakadu national park
• coral reefs may not be able to grow fast enough to keep up with SLR, those more than 50m deep will die

Question 240

what are the social, economic and environmental impacts of coastal flood risk and recession to the Philippines?

Answer 240

social

• in san fernando it is estimated that by 2100, the city will lose 300 buildings , over 283,000 m squared of land and over 123,000 m squared of beach
• social amenity losses of schools, churches and beaches
• up to 2.3 million people could be affected, 63% in manila

economic

• the costs of damage due to SLR expected to be $6.5 billion a year without adaptation costs
• high poverty means they are economically vulnerable (90% of wealth held by 15% of pop)
• in San Fernando property losses to be $2.5 million and land loss of $2.1 million
• loss of fishing jobs, hard to find alternative jobs, estimated welfare lost to the local community of $168,000 a year

environmental

• in manila bay the natural ecosystem of mangroves, corals and seagrass have been damaged by pollution, over-exploitation and siltation, which greatly reduces their ability to protect the backshore from SLR
• rate of SLR is higher than global average because the pacific ocean currents and trade winds move water towards the islands

Question 241

what are the social, economic and environmental impacts of coastal flood risk and recession on the maldives

Answer 241

social:

• their population of 400,000 is difficult to relocate to mainland countries, they are trying to relocate the residents
• growing amount of environmental refugees having to flee their area due to environmental risks

economic:

• as it is a small country, no one has homeowners insurance and so when their homes are destroyed they will have nothing
• a new artificial island called Hulhumalé has been built from dredging coral and sediment from the seabed between 1997 and 2002 at a cost of US$32 million
• economy based on toursim and fishing and so many jobs are to dissapear

environmental:

• a SLR of 50cm by 2100 would mean the maldives losing 77% of its land area
• very small changes in sea level translate into major losses of land because of the country’s unusual topography

Question 242

explain environmental refugees

Answer 242

• they are people and communities forced to abandon their homes due to natural processes. these processes may be sudden as with landslides or volcanic eruptions, or gradual such as rising sea levels
• between 2008 and 2013, the philippines had the 3rd largest number of internally displaced people due to natural hazards with 94% of these displacements in 2013- due to ‘storms’
• in 2005, over 1 million people evacuated from New Orleans due to hurricane katrina and went to other places across the USA, 30% did not return and became environmental refugees
• the UK does not include fleeing from climate change as being a refugee but most are to be those fleeing from sea level rise

Question 243

what is sustainable coastal management?

Answer 243

it is about meeting the needs of today’s coastal areas as well as those of the future. you must take into consideration the three strands of social, econmic and environment.

it is increasingly based on adaptation strategies due to increasing recession rates, ICZM takes a holistic approach to a coastline and it required cooperation from stakeholders so conflcit is inevitable

Question 244

how should sustainable management be done?

Answer 244

by taking the area as a whole, taking into consideration each littoral cell and how they interlink. it requires makinguse of the cocnept of intergrated coastal zone management.

coastal communities face the dynamic nature of the coast’s everyday environment and the threats we face such as rising global sea levels and increased frequency of storms and increased erosion and flooding

Question 245

what are the strategies used to help and adapt in sustainable coastal management?

Answer 245

1) educating communities to understand why change is needed and how to adapt
2) monitoring coastal change and adapting to unexpected trends
3) creating alternative livelihoods before existing ones are lots to the sea
4) managing natural resources (fish,farmland,water supplies) to ensure long-term productivity
5) managing flood and erosion risk where possible, managed retreat and soft engineering
6) adapting to rising sea levels by relocating, alternative building methods and water supplies

Question 246

what does sustainable coastal management require?

Answer 246

it requires co-operation from people in order to ensure the well-being of people and the coastal environment. the management needs to be sustainable in the sense of ensuring that the coastal zones and all its inhabitants havea. reasonably secure future.

Question 247

why does adopting sustainable coastal managemetn lead to conflict?

Answer 247

• coastal natural resources may have to be used less in order to protect them (loss of income)
• relocation may be needed where engineering solutions are too costly
• some erosion/flooding will always occur, as engineering schemes cannot protect against all threats
• future trends such as SLR may change, creating uncertainty and the need to change plans

Question 248

why is coastal management increasingly following an ‘adaptation’ policy and what does it involve and what does it lead to?

Answer 248

• in order to use the latest scientific understanding
• evaluate new coastal developments
• ensure that any necessary developments provide social and economic benefits
• ensure the overall long-term sustainability of coastal areas

leading to:

• the high costs of building and maintaining a coastal defence against large-scalel natural processes means that some locations will not be supported by gov funding
• the potential loss of property and cultural heritage has led to conflict between govs and communities
• the UK gov, through the environment agency and Defra encourages local communities and council to adapt themselves, e.g. through the ‘pathfinder initiative’

Question 249

what are holistic coastal management strategies?

Answer 249

• the physical processes operating in a sediment cell and interlinked for long stretches of coast
• to manage a coast effectively it is important to consider a long length as well as all stakeholders using the coastal environment
• you must consider a long timescale in coastal management as physical processes take hundreds/thousands of years to complete (climate change)

Question 250

what is integrated coastal zone management?

Answer 250

it dates from the Rio Earth summit in 1992 and it has three main features:

• that the entire coastal zone needs to be managed
• the importance of the coastal zone to people’s livelihoods and well-being
• the need to make the management of the coast sustainable

ICZM works well with the concept of sediment cells, each cell can be managed as a holisitc unit.

Question 251

what are the 4 things that an ICZM should incorporate?

Answer 251

• plan for the long term
• involve all stakeholders and ensure that they have a say in any policy decisions
• follow an ‘adaptive’ approach to unforseen changes
• try to work with natural processes rather than against them

Question 252

what are the 4 possible actions for a SMP and what is the hardest part?

Answer 252

the hardest part is the decision making process to decide what actions to take. in the UK there are four different management options to follow:

1) no active intervention
- no investment will be made in coastal defences
- letting nature take its course and allowing the sea to erode and flood low-lying land
2) hold the line
- trying to eliminate any further retreat of the coast, involves a mixture of hard and soft engineering
- maintaining the current position of the coastline
3) advance the line (build new coastal defences on the seaward side of the existing coastlines. this usually involves land reclamation.)
- may involve drainage as well as other hard engineering techniques
- extending the coastline out to sea through encouraging the build up of a bigger beach

the choice is generally not straightforward due to a number of factors:

• the economic value of the assets that might be protected
• the technical feasibility of different engineering solutions
• the environmental sensitivity
• the cultural and ecological vaule of the land that might be protected
• pressure from local communities, developers and environmental groups
  4) managed realignment/retreat
• involves allowing the coastline to retreat but in a managed way
• removal of existing hard engineering defences and using more natural and sustainable techniques including protection, management or restortion of coastal ecosystems such as salt marshes and sand dunes, e.g. porlock bay

Question 253

what has been put into place to prevent the concept of winners and losers for ICZM?

Answer 253

the EU adopted the Reccomendation on ICZM in 2002 and the Marine Strategy Framework of 2008 also emphasised a comprehensive and integrated approach to protect all european coasts and seas

Question 254

expalin the coastal realignment in Essex and the players involved

Answer 254

• they have adopted a ‘finding space for water’ philosophy which involves managed retreat
• coastal squeeze due to future sea level rise and storm surges make maintaining flood embankments unsustainable
• 5 breaches in the embankemnts 2002
• the Essex Wildlife Trust purchased the Abbot’s Hall estate in Essex on Blackwater estuary and convered more than 84 hectares of farmland into salt marsh and greenland by breaching old embankments in 4 places in 2002, farmers were compensated
• it is sustainable as the 49 ha of additional mudflats and saltmarshes absorb incoming higher seas and storm surges without any local damage
• wading birds and other wildlife returns for feeding and nesting
• CBA showed that sea wall was not cost-effective, soil quality poor

players

• landowners
• the RSPB (royal society for the protection of birds)
• the essex wildlife trust
• fisherman

Question 255

what were the conflicts of interests and winners and losers in the coastal realignment in essex

Answer 255

conflicts

• the west mersea fisherman were concerned that sediments could choke and kill oysters and water sea level changes could remove oyster habitats
• the RSPB were concerned about the increased erosion and flooding of their site opposite the farm which could change bird habitats

winners/losers

• however, all conflicts were resolved, research showed that the sediment didnt affect the oysters and bird habitats actually improved as a result
• landowners and farmers have discussed giving up land to sea
• a CBA concluded that since the soil quality and land value were low, it was not worth maintaining the embankments
• it was the largest coastal realignment project in europe, costing £645,000, CHEAP
• reduces the volume of water travelling up the essex estuaries and creeks which could flood settlements

Question 256

explain Namibia’s different land uses and their national policy on climate change of 2011

Answer 256

• it is called the skeketon coast due to Benguela current causing thousands of shipwrecks
• Namib desert runs all the way along the coast creating very inhospitable currents
• Henties bay is an important high end tourist destination
• Walvis bay is an important port

Namibia’s national policy on climate chnage in 2011 said:

• emphasisd sustainable adaption measures to reduce vulnerability
• launched in 2013, it aims to improve QOL and maintain ecosystems

Question 257

what were the different management strategies put into place in Namibia in the 3 different areas?

Answer 257

1) Skeleton coast in the Namib desert with isolated rural settlements and many wildlife areas

LOW COST MANAGEMENT OPTIONS

• prevent future development of coasal buffer zone experiencing recession
• conserve wetland habitats
• stabilise and protect sand dunes
• monitor SLR for future planning
• reduce poverty so people are able to prepare themselves (build better homes)
  2) Small tourist settlements like Henties Bay

MODERATE COST OPTIONS

• beach nourishment
• protecting Kelp beds and restoring sand dunes
• rehabilitation of wetland ecosystems
• early warning systems for residents of high tides
  3) Larger settelemt important for industry and trade like Walvis bay

EXPENSIVE OPTIONS

• sea walls
• relocation of vulnerable communities
• raising of infrastrcture (ports and roads)
• building barrages and barriers

Question 258

explain what’s happening for mangroves for the future in the maldives

Answer 258

• in the maldives there is conflict over adaptation to SLR. CUrrently the gov have prioritised protecting the capital city of Malé and its tourism industry but is not prioritising smaller communities that rely on traditional industries (farming,fishing)
• mangroves for the future is an organisation that promotes sustainable development and is helping the maldives to become more sustainably managed for the future by:
  1) educating communities on the importance of maintaining coastal mangrove swamps as a natural defence against coastal erosion and flooding
• the Global Environment Facility (GEF) has provided small grants to islanders to help them develop sustainable and organic farming as an alternative food and income source to coral reef fish (threatened by both overfishing and global warming)
• the Japanese gov have funded mangrove nurseries on the maldives so that damaged mangrove areas can be replanted

Question 259

what is the funnelling effect?

Answer 259

when the land is in a triangle shape and so it becomes narrower and shallower towards the coast it means that wave height increases as the volume of water is in a smaller space. this is seen at the bay of bengal in bangladesh

Question 260

how is coastal management changing?

Answer 260

it is increasingly using the concept of littoral cells to manage extended areas of coastline. throughout the world, countries are developing schemes that are sustainable and use holistic ICZM strategies

• littoral cells are natural subdivisions of the coastlines containing sedimetn sources, transport paths and sinks.

the second round of SMPs in 2004 changed many HTL strategies to MR and do nothing perhaps due to the fact that they were not aware of the rapid recession rates that were to happen due to climate change.

Question 261

what needs to be considered before making a shoreline management plan?

Answer 261

1) CBA- value of the land (properties and business that would be lost) vs the cost of the proposed management strategies
2) Environmental sensibility through EIA- short and long term positive and negative impacts on environment: changes to flora and fauna, impacts on water and air quality
3) technical feasibility- it is not possible to hold the line in all areas, e.g. fynamic deposition features such as spits
4) social and political factors- imapct, pressure from communities: campaigning and loss of property, business and stress

any decision also needs to be informed by the results of objective investigations, such as a CBA and EIA

Question 262

what is a cost benefit analysis and how is it difficult?

Answer 262

it is worked out by seeing if the benefits outweigh the costs and so a value of the land is a key consideration in the decision making process

• it is controversial as the value of property is dependant on how at risk it is as a home, at very high risk it could be worth norhing whereas a very similar house which is safe could be worth £300k
• some human costs (worry, stress) and environmental costs (value of biodiversity) are very hard to quantify in financial terms

Question 263

what is the CBA in Happisburgh?

Answer 263

• they chose the ‘no active intervention’ in the immediat efuture as defending the area would have an impact on the wider coastal management plan. it would block LSD and cause further erosion downdrift.
• longer term plan is managed realignment
• the median cost of building defences here is £6 million. this is very close to the value of property that could be saved and much higher than the compensation costs payable to local residents
• coastal managers argue that the area should be seen in the wider context of the whole SMP, further justifying the decision not to defend the village

Question 264

what are the costs and benefits of erosion for happisburgh

Answer 264

costs

• affected residents could get up to £2k each in relocation expenses plus the cost of the council to find plots of land to build new homes
• grade 1 listed St Mary’s church and Grade 2 listed manor house lost
• social costs as the village is slowly degraded, including health effects and loss of jobs

benefits

• by 2105, 20-35 properties would’ve been saved from erosion with a combined value of £4-7 million
• aorund 45 hectares of farmland would be saved, with a value of £945,000
• the manor caravan park would be saved, which employs local people

Question 265

explain an environmental impact assessment

Answer 265

any type of coastal management usually requires an EIA

it is a process that aims to identify:

• the long term impacts of building new sea defences or changing a policy from hold the line to no active intervention or managed realignment
• the short term imapcts on the coastal environment of construction

EIA involves assessments of:

• impacts on water movement (hydrology) and sediment flow which can affect marine ecosystems
• impacts on water quality, which can affect sensitive marine species
• possible changes to flora and fauna including marine plants and marine mammals
• wider environmental impacts such as air quality and noise pollution during construction

Question 266

explain the shoreline management plan in happisburgh, north norfolk

Answer 266

• by 2105, the shoreline may recede by 200m
• they have repeatedly failed to quanitfy for gov grants for coastal defences. managed retreat has been operated which has caused conflict among locals and especially residents of beach road on the coastline
• the gov started proviidng grant aid of £5000 to assist with demolition costs and £1000 for relocation costs
• £1.4million was set aside for ‘purchase and lease-back’ of 11 houses on beach road to create a buffer zone between the eroding cliff and the main village
• they have spent lots of money relocating important sites like the caravan park (450k) and taking out the defences
• lobbying by the CCAG and others have led to a change in the SMPZ policy for them to follow ‘managed realignment’ which allows for some coastal defences if funding can be found

Question 267

what are the positives and negatives and winners and losers of SMPs in happisburgh

Answer 267

positives:

• the gov started providing grant aid of £5000 to assist with demolition costs and £1000 for relocation costs
• they obtained a gov allocation of £3 million partly because of its emphaiss on ICZM and stakeholder engagement
• all but caravan park were able to relocate due to difficulties of finding an alternative site
• the community remains the same size and profits from the sale of the new houses will be used in the future to buy properties of those under threat from CE

negatives

• by 2105, the shoreline may recede by 200m with a loss of a further 50 homes, caravan sites and property losses totalling £6m
• in 2003, the lifeboat and beach access ramp were lost, prompting concerns for their tourism
• house values are very low and people cannot afford to move elsewhere
• there is no national system of compensation but campaigning led to pathfinder project where people along beach road were offered half the non blighted value of thri home to help them relocate, houses now demolished to create buffer, all but one took it
• there could be a promontary effect where erosion comes either sides and comes round the back
• the existing rip rap will have limited effect on the rate of recession in the short term

winners:

• those who have successfully relocated
• losers:
• those who are closest to cliff face
• businesses relying on tourism industry
• local council, large costs of relocating

Question 268

explain the shoreline management plan in chittagong, bangladesh and why they are so vulnerable

Answer 268

a coastal climate resilient infrastructure project (2012) supported by the Asian Development Bank (ADB) aims to ‘climate-proof’ the area

this involves:

• improving road connection for farmers and markets whilst raising embankments to 60cm above normal flood levels and making them resilient to CE
• creating new market areas with sheds raised on platforms above the expected 2050 sea level
• constructing, improving or extending 25 tropical cyclone shelters, taking account of SLR and higher wind speeds
• training in climate resilience and adaptation measures
• it was loaned US$60 million by the IFAD and project was rated as satisfactory
• 1.5m rise in sea level would flood 22,000km sqaured and displace 15 million people
• 40% of farmland will be lost (salt water intrusion and directly)
• mangroves dissapearing, reducing protection from surges
• funnelling bay of bengal

Question 269

what are the positives and negatives and winners and losers of the SMP in chittagong, bangladesh

Answer 269

positives:

• helped alleviate poverty by 10% by generating income opportunities
• reduced disaster risk, road flooding 5 days a year rather than 20
• environmental enhancement through growing trees

negatives:

• disturbance of people and habitats especially during construction
• permanent removal of natural vegetation
• relocation of 200 people by road realignment
• slow progress on road embankments

winners:

farmers, local community seeking jobs

losers:

environmentalists to some extent, community who are relocated, market sellers

Question 270

How can conflicts between players develop over management decisions? give case studies

Answer 270

Essex

• the west mersea fisherman were concerned that sediments could choke and kill oysters and water sea level changes could remove oyster habitats
• the RSPB were concerned about the increased erosion and flooding of their site opposite the farm which could change bird habitats

Chittagong, Bangladesh

• environmentalists concerned about the permanent removal of natural vegetation
• local communities concerned about the fact that 200 people would have to be relocated, breaking up communities
• there is conflict over adaption to SLR. Currently the government have prioritised protecting capital city of Malé and its tourism industry but it is not prioritising smaller communities that rely on traditional industries (farming, fishing)

Here they have chosen no active intervention approach as they have used a CBA in order to justify that the cost of protecting is much higher than its worth however this will cause conflicts between local residents and the authorities as they will lose their home and community. They would argue that their homes are worth a lot more.

Question 271

How can conflicts be reduced through sustainable management strategies?

Answer 271

MFF, Maldives

• the japanese gov have funded mangrove nurseries on the Maldives so that damaged mangrove areas can be replanted

Chittagong

• they improved road connections for farmers and markets and lifted embankments, this reduces conflicts as it brings social, economic and environmental benefits
• constructing, improving or extending 25 tropical cyclone shelters, in their strategies they ensure the longevity of their plans, ensure that the area is protected in the long term, the community will be protected from hazards

Namibia

• the way they went about management through low cost soft engineering methods in the desert and wildlife areas would reduce conflicts as they are trying to protect these areas even though they don’t have a very high value, they are to conserve wetland habitats and prevent future development of coastal buffer zone experiencing recession in order to ensure long-term protection

Question 272

Why are there different ways to manage a coastline?

Answer 272

• range of stakeholders so needs a holistic strategy that takes all of them into account (ICZM), e.g. Namibia
• land value, e.g. london (thames barrier vs blackwater estuary)
• feasibility with rapidly retreating coastlones, it is not viable to protect them, e.g. maldives
• environmental sustainability: blackwater estuary, whether it is in a protected area
• impact on downdrift areas

Question 273

what is the difference between macro, meso and micro scales?

Answer 273

macro scale- concordant and discordant coastlines (encourages headlands and bays or coves)

meso scale- dip of strata (bedding planes), differential erosion from mixed lithology layers

micro scale- joints, these are vulnerable to HA, freeze thaw, salt crystallisation and bio weathering

Question 274

explain the problem of coastal flood risk for Kiribati

Answer 274

• composed of 33 atolls, low-lying pacific island nation
• most of their 112,000 peole live on tarawa which is only 3m above sea level
• they have already seen some islands sinking
• rising sea surface temps also affetcing coral reegs, these are critical to sustaining atolls and their islands, coral bleaching
• projections that by 2080, the risk of flooding here is likely to be 200x greater than at the start of the century
• without adaptation, kiribati coud lose 34% of its 1998 GDP by 2050 due to SLR and climate change

Question 275

explain the north sea storm surges of 1953 and 2013

Answer 275

• 1953 storm and high tides caused a 3m surge at night killing 307 people along the east coast (2100 in the netherlands)
• 20,000 homes flooded and damage estimated at £1.2 billion (our prices), farmland destroyed
• no flood warning or forecasts, basic technology
• 2013 similar event with 6.4m storm surg on some places in yorkshire
• only 1400 homes flooded and no deaths, better monitoring to warn people for evacuation, sea defences protected 800,000 homes
• thames barrier protected london

Question 276

explain the impact of the storm surge of typhoon haiyan in the philippines

Answer 276

• cat 5 2013, waves of up to 7m
• economic impact estimated at $5.8 billion
• fishing communities severly affected, sotrm destorying 30k boats and equipment
• 7000 people died, 4 million displaced
• 71,000 hectares of farmland affected
• damage to oil barge led to over 1 million tonnes of oil leaking into the sea

management:

• PAGASA gave warnings two days before, evacuation of 750k people
• emergency shelters put up but not high enough to escape 5m surge
• storm protection shelters destroyed due to poor construction
• rebuilding efforts very slow, not much progress after one year
• gov criticised for poor management (corruption)

Question 277

what is a rotational scar?

Answer 277

A rotational scar is a fresh, curved, unweathered and unvegetated rock surface on the cli

Question 278

what are the 4 things that influence sediment transportation?

Answer 278

• the angle of wave attack
• the process of longshore drift
• tides
• currents

Question 279

how does the angle of wave attack affect sediment transportation?

Answer 279

​This is the main determinant of the direction of sediment transport (in the foreshore zone).
Where the wind is blowing directly onshore, the incoming swash transports the material direction up the beach at 90’ to the coastline.
Backwash then transports sediment perpendicularly back down to the beach to its original starting position.
Sediment is moved up and down the beach, but there is no net lateral movement.

A wave angle 30’ to the coastline produces the strongest longshore drift movement.
On most coastlines there is a dominant prevailing wind, so over time there is a dominant direction of longshore drift.

Question 280

how do currents infleunce sediment transportation

Answer 280

This is the flow of water in a particular direction, and they can transport sediment in the nearshore and offshore zones.
They can be driven by winds, or initiated by differences in water density, temperature or salinity.
​Currents transport sediment over a variety of spatial and temporal scales:

The global thermohaline circulation connects four oceans and takes 500 years for one complete circuit.

Rip currents on the beach transport sediment a few metres out to sea for a few hours when the wind is blowing direcly onshore with the right strength.

Question 281

how do tides influence sediment transportation?

Answer 281

Tides are changes in sea level produced by the gravitational pull of the moon and the Sun.

The incoming and ebbing tide can create tidal currents in the nearshore and offshore zones that transport sediment.

Question 282

explain how tides work

Answer 282

The Earth’s rotation combined with the gravitational pull of the Moon and Sun causes bulges in the water surface to shift position within each ocean or sea basin.

The tidal bulge in the water surface rotates around a location called a amphidromic point, which is determined by the morphology of the sea bed.

The sea may contain several separate amphidromic points.

Tidal range is the distance between high tide and low tide.

Tidal range is determined by the distance from an amphidromic point (range decreases with distance) and the shape of the coastline.