coastal environments Flashcards
dune succession?
1
Q
name some coastal processes
A
erosion
mass movement
weathering
transport
deposition
2
Q
what are some inputs into coastal environments?
A
marine e.g., waves, tides, storm surges
atmosphere e.g., weather, climate, climate change, solar energy
land e.g., rock yupr, structure, techtonic activity
people e.g., coastal management and human activity
3
Q
what are some outputs of coastal environments?
A
erosional landformas like arches, stumps, stacks, headlands, and bays
depositional landforms like splits tombolos and beaches
different types of coasts like sandy beaches, coastal wetlands, and others
4
Q
what factors influence variation in coastal environments?
A
human activity can change coastal environments, sea lewvel and changes in the level can create either emergent of submergent coastlines
wave energy can crease high or low energy coatlines
geology can affect rates of erocion aswell as concordant/discordant coastlines
balaance between erosion and deposition can create either erosional or depositional coastlines (dynamic equilibrium)
- vegetation can also infulence the types of coastal ecosystems like sand dunes
5
Q
what is dynamic equilibrium?
A
it is a pweriod in a system when is inputs and outputs of energy and matter are balanced. this can stay steady for a long period of time but short term changes can still occur which systems can adjust to by a process of negative feedback
- beaches are an example of dynamic equilibrium because htey adjust to changing energy inputs. thius is. adelicate equilibrium between the amount off sand and erosion
6
Q
what is a littoral zone? how is the coast a littoral zone?
A
it is the transition zone betwen the land and the sea and consists fo 2 parts, onshore and offshore
7
Q
name some different types of beaches
A
rocky headlands, land reclamation, coastal plains, salt marshes, sand dunes, fjords, sandy beaches, rocky headlands
8
Q
what causes waves?
A
- waves come from the transfer of energy from the wind. this causes friction with the surface of the sea, and the water begins to move in a circular motion. the amount of energy gained depends on
- wind speed, length of time the wind has been blowing for, distance the wind has been blowing
- firciton wiht the seabed slows the wave at the base, but the top of the wave doesnt slow down. therefore the top becomes higher and steeper until it breaks
- the wave moving up the beach is called the swash whereas the wave flowing back down to the sea is called backwash and this is due to gravity
9
Q
what happens when waves reach the coast? describe the process step by step
A
- in th eopen sea, despite the wavy surface, there is little horizontal movement in water
- only when the waves approach the shore is there forward mvement of water as waves break and surge up on the beach
- the seabed interrupts the circular movement of the water
- as the water becomes shallower, the circular motion becomes more elliptical
- this causes the crest of the wave to rise up and eventually collapse on the beach
- the water thatrushes up the beach is called the swash
- the wateer that flows back into the sea is called backwash
10
Q
what are the number of wave crests hat break per minute equivalent to?
A
wave frequency
11
Q
describe the relationship between wind speed and wave height
A
- strong relationship
- as wind speed increases, wave height increases in general as there is more energy in the wave
12
Q
what are the features of a constructive wave?
A
- long wavelength, weak backwash, shallow wave gradiwnts, stron swash, orbit becomes eliptical due to the shore friction at the base of the wave
- the beach is built up by a deposition of material brought in by the swash
- shallow and gently sloping beach profile
spilling type of wave break
low frequecny of wave
13
Q
what are the features of a deconstructive wave?
A
- tall waves, short wavelength, steep gradient waves, weak swash, stron backwash
- beach eroded as material is dragged back and moved along by longshore drift
- rbit becomes eliptical due to friction
- basically short and tall waves with higher frequency. they have a plunging wave break and have a steep beach profile
14
Q
what is the difference between beach profiles in the summer versus in the winter?
A
in the summer:
- beaches are steeper
- berms are built up
- more sediment is deposited and backwash is weaker
- usually ocnstructive waves as there is lower enerfy
- water level is lower
in winter:
- more enrgy due to weather meanders there are destructive watves, leading to more erosions na dsteeper beach profiles
- there are bars
- destructive plunging waves
15
Q
what is erosion?
A
the wearing away of the land by an external agent. (e.g., water, wind, humans, ice). material is removed
16
Q
what is hydraulic action?
A
the power of the waves forces the water into the cracks in a cliff. this compresses the air in the cracks. When the wave retreats the compressed air blasts out forcing the rock apart (cavitation)
17
Q
what is solution?
A
some rock types like limestone, are dissolved by a chemical reaction between salt and other acids in sea water
18
Q
what is attrition?
A
it is when material carried by the waves will collide together causing them to become rouder and smaller over time
19
Q
what is abrasion?
A
this is caused by the waves picking up sand and pebbles and hurling them at the cliffs with force, wearing away the cliff
20
Q
draw a discordant coastline
A
different layers of rock are exposed to rock (perpendicular to) and will erode at different rates
21
Q
draw a concordant coastline
A
on the left you can see the concordant coastline. the layer of rock is parallel to the coastline and only one type of rock is exposed . they will erode at the same rate
22
Q
what will happen to the rock on a discordant coastline?
A
- where rock is more resistant, it will be eroded less, leaving a headland that sticks out
- where there is less resistant rock, the material is eroded more quickly by:
abrasion, which is where pebbles and rocks are hurled at the cliff by destructive waves, weakeneing the rock,
and hydraulic action where waves compress air into cracks in the rock and blast it apart - this leads to the fromation of a sheltered bay and sediment from the eroding headland helps to from a beach, the headland protects the beach from the full force of the waves. attrition breaks down the boulders into pebbles and eventrually sand to form thebeach
- the headland is now exposed to the full force of the wavws and is vulnerable to erosion
23
Q
describe how coastal processes can transform cliffs into caves, arches, stacks and stumps
A
large crack is opened by hydraulic action.
the crack grows into a cave by hydraulic action and abrasion
- the cave becomes larger
- the cave breaks throguh the headland forming a. natural arch
- the arch is eroded and collapses
- this leaves a tall rock stack and rthe base of the stackcontinues to erode
- the stack is eroded as it falls and collapses and a stump is formed (by hydralic action)
24
Q
how do wave cut platforms and wave cut notch form?
A
- the erosion or a clidd is greatest at its base where large waves break- hydraulic action, abrasion, constantly undercut the foot of the cliff forming a ‘ wave cut notch’
- the undercutting continues and eventually the overhanging cliff becomes so heavy it collapses downwards- this process continues over time and the cliff gradually retrreats and becomes steeper
- as the cliff retreats, a gently sloping rocky platform is left at the base, this is known as a wave cut platform which is exposed at low tide
if the sea level were to rise significantly… the same process would happen but higher up on the cliff and create another step. if it were to dall… areas are raised out
25
how are coves formed?
if a more resistant layer is breached in the front of a less resistant layer, it may form a cove (concordant)
26
name the different types of weathering process'
mechanical:
freez-thaw, salt crytalisation, wtting and drying
chemical:
carbonation, oxidation
biological:
plant roots, animals
27
name come different types of mass movement:
rock fall, slide, slump, topple, flow
28
what is freeze-thaw? what type of process is it? explain it.
it is when water colleects in the crack of a rock
water expands as ifreezes, forcing the crack to open
explanation:
- the ice thaws, contracts, and water gets deeper into the crack again. this repeated expansion and contraction (aka freeze thawing) causes further cracks until the rock splits
- mechanical weathewring
29
what is salt crystalisation? what type of process is it? explain it.
- mechanical weathering
when the salts evaporates, it leaves salt crystals behind. these can grow over time and exert stresses in the rock which causes it to break up
30
what is wetting and drying? what type of process is it? explain it.
- mechanical weathering
frequent cycles of wetting drying are common on the coast. rocks rich in clay expand when wet and contract as they dry causing them to crack and break up
31
what is carbonation? what type of process is it? explain it.
- chemical weathering
slow dissolution of limestone due to rainfall (weak carbonic acid, pH 5-6)
32
what is oxidation? what type of process is it? explain it.
- chemical weathering
- addition of oxygen to minerals especiallu iron compounds also known as rusting
no erosion
33
what is plant roots? what type of process is it? explain it.
- biological weathering
- trees and palnts grow into small cracks which causes rocks to break them apart
34
what is animals? what type of process is it? explain it.
- biological weathering
- diffferenty birds like puffins and animals like rabbits dig burrows in clifs, causing them to break
35
describe rock fall
- most liekly to occur when strong, jointed, and steep rock faces are exposed to mechanical weathering
- occur on slopes over 40 degrees
- the material either rbounces or falls vertically to form scree
- block falls are similar
A rockfall is the fastest moving type of mass movement where rocks break away from the cliff face and fall, bounce or roll downslope.
36
describe slide
- rocks that are jointed or have bedding planes roughly parrallel to the slope of cliff surface, are succeptible to land slides. an increase in the amoutnof owater can reduce friction in a rock or land slide, slabs or rock can slide over and underlying rocks laong a slide of slip plane
37
describe slump
these often occur in saturated conditions. slips occur on moderate to steep slopes. they are common where softer material overly more resistant or impermeable rock like limestone of granite. it causes rotational scars on the bind and repeated slumping causes terraced cliff profiles
- often happens in clay, mud and sand stone
38
descripe topple
- this is influenced by the geological structure of the rock face where the rock strata have a steep seaward dip, undercutting buy erosion will quicklu lead to instability and block of material falling seawords
(google:
a rock, earth, or debris mass rotates forward around a pivot point at or near the base of a slope, often resulting in a talus cone at the base.
)
39
what is flow?
an increase int he amount of waer and that can reduce fricitona nd cause mud and earth to flow over the underlying bedrock.
- the difference between a slide and a flow is that in a slide the material remains intact and in a flow it just becomes jumbled up
40
what are the features of hard rock?
cliff face: rugged and bare rock
shape fo cliff: steep and high
foot of cliff: boulders and rocks
41
what are the features of soft rock?
cliff face: smoth and evidence of slumping and mass movement
shape fo cliff: generally lower and less steep
foot of cliff: few rocks and some mud
42
what are the different types of transportations (hint: 4)?
suspension
solution
saltation
traction
43
what is suspension?
small particles are carried in water e.g., silts and clays, which can make the water look cloudy
t
44
what is traction
pebbles and larger seidment are rolled along the seabed
45
what is solution?
minerals are dissolved in the sea water and carried in solution
46
what is saltation
load is bounced along the sea beg e.g., small peices of shingle or large sand grains
47
what is longhsore drift?
the process where waves transport eroded material along a beach and deposit it futher down the coast
48
describe longshore drift step by step + diagram.
1. the prevailing wind direction changes the direaction of wave and so it isi at an angle, approaching the coast
2. the wave (Swash ) is carried by the wind and the sediment is moved back perpendicularly because there is no more energy from the wind. only gravity
3. this process continues and longshore drift occurs
49
what is a spit? how are they fromed?
an accumulation of sand and shingle with one end attatched to the land and the other reaching out across and estuary or into the sea. they are features of coastal deposition.
- they are fromed when arge amounts of sediment are transported by longshore drift and where the coastline suddenly changes direction to leave a sheltered, shallow area of water
- due to an increase in friciton, more deposition can occur in the water sheltered by the headland and the spit slowly builds up to sea level and extends in length
- when the wind changes direction it causes the waves to alter their direction and this may result in some of the material at the end of the spit being forced inland to form a curved end
- salt marsh oftewn develops behind the spit and it cant grow across and esuary as the river current carries the material out to sea
50
descfribe the process that leads to the formation of a bar
1. longhsore drift makes a spit which covers the bay making a bar and lagoon because theybay cant force out the water like a river
- sometimes a spit may grow and extend and this is a tombolo
51
name some reasons for eriosion
lack of coastal management, longshore drift, concordant, discordant coastlines, wave refraction leading to a more concentrated force and energy at a specific point
52
what is a berm?
a terrace on a beach that has formed in the back shore. it is formed by constructive waver
note and underwater berm is a bar
53
what is a cuspate foreland?
- triangular shaped sand and shingle that accumulates and is extended seawards
- caused by longshore drift occuring in 2 different directions and change in directional coastline and brings sediment up causing it ot develop
54
what 3 factors influence the size and shape of a spit?
amount of longshore drift (speed)
prevailing wind direction
change in estuary, current of river
55
what is an emergent coastal landform? how can you identify it?
falling sea levels -Emergent coastline features. Landforms that exist because of a reduction in sea level are called emergent landforms. This happens during isostatic recovery.
(or uplift of land)
- relict wave cut platforms, relict cliffs, relict cave
56
what is a submergent coastal landform? how can you identify it?
rising sea levels
- flooded valleys, fjords
57
what is a fjord
it is formed when deep glacier troughs are flooded by a ride in sea level
they are long steep with a u shaped crossection
58
what does relict mean?
a landform, feature, or organism that is a remnant of a past geological or biological process, persisting in a landscape or ecosystem where the original conditions or processes are no longer active.
it becomes relict when you can see vegetastion forming
59
what does eustatic change in sea level mean?
is is the changw in sea level due to the changing volume of water (of oceans) - usually caused by a global influence
60
what is an isotatic change in sea level?
change in sea level due to changing elevation of land- ususally caused by a more local influence (land rises and fals relative to the sea)
61
what happens when there is a eustatic fall in sea level?
melting of land based ice puts water into oceans causing a rise in sea levels
if ore ice is formed then sea levels will go down (if the climate cools)
62
what happens when there is a eustatic rise in sea level?
as the ocean warms, the water expands because the rising temp causes rising sea level
63
what happens when there is a istotatc fall in sea level?
- could be caused by techtonic activity - can cause an area to be uplifted or decreased)
- couls aos be caused by volacnism, causing laa to build up new land
- isotatic remound is where ice that wss pushing land down melts, meaning the land level rises up because there is nothing pushing it down
64
will poorer places be more vulnerable to sea level rise?
yes - dont have the means necessary to combat issue
movement inland may lead ot overcrowdinh
65
what are the different shoreline management plans?
do nothing, retreat, hold the line, advance the line
66
what are the different factors to consider when choosing an SMP?
environmental impact analysis (would it affect surrounding environemtn and habitat or pollution and loss of heritage?does it mantain regulations? is it safe and sustainable? will it maintain environmental quality?),
feasability (engineering) studies,
risk management,
cost beenfit analysis (land use and value - if the land is worht alot then they may invest
impacts on coasral processes- also linked to environment (rick of pollution, does i affect longshore drift, does it interrupt natural systems, if rate of erosion decreases, some areas may be starved of sediment)
political, social and economic reasons
(how many people does it affect, expensive?, woudl it impact toursits, fishing inductry ro otehr industries based on coast?, does it protect their livelyhood? will citizens want to relocate - sentimentality? what is mosst important to polititians?)
67
what is an SMP?
a plan that assesses the risk of humand, and the developed historical and natural environment, and creates a strategy for floods and coastal defences
68
what is hold the line?
maintianing or upgrading the level of protection provided by defencesd
- envirnemtnally acceptable, used for towns and areas with higher land values, most resistant to erision, hard engineering, technically and economically viable,
69
what is no active intervention?
a decision not to invest in providing or mantaining defences
- only monitor the situation
- need ot have a designed area to hol the brunt of the erosion, mantians sediment movement, deasible, when rates or erosiona nre rapid and chellenges of engineering is too great this option is used
70
what is managed relaignment or retreat?
allwing the retreat of the shoreline, with management to control or limit movement
it is a compromise (loss of land), environmentally effective when biuilt, maintains EU regulations, you must pull back and rebuilt main road and networks and electrical lines
71
what is advance the line?
building new defences seaward of the existingdefence line
- ti mantains regulations, will still erode, environmetnally acceptable, rare deciciton as it is so cotly, adding sediment to coast, liekty not ot work, usually done for tourism, protects other parts of land a bit,
72
suggest 2 reasons conflict may arise in areas porne to coasral erosion
- many locals liek home owners and farmers will be upset if an SMP dfoesnt benefit them e.g., farmers wont be happy with groynes in highly populated areas because this puts pressure on lesser populated parts (which may not be protected as they are worth lewss) and cause increased erosion
73
what is the case study in the uk for coasts?
holderness coast
74
where is holderness coast?
it is in East Yorkshire. it has a soft geology and flat relief. atleast 30 vilalges have been lost in the last 1500 years
75
what are the areas of conflict in holderness coast?
social - home owners, businesses, local authorities, famers, fishers, people with emotional attatchments
environmental- environmental pressure groups, destruction of habitats and biodiversity, local environments doesnt have its own voice, difficult to attribute the impact and finanicial calue to an area
economic - can impact be economically damaging to tourims, fishing, agriculture, oil or gas related to coasts, house prices decrease, spending money on coast rather than population, many can't afford to relocate, lanf quality and cna the council pay for this?
76
how does vegetation influence the coast?
coastal landform - stabilises sediment and reduces/low risk of mass movement
ecosystems - vegetation provides habistats e.g., mangroves for fish nurseries, can influence local climate e.g., mangroves transpire and release water vapour making it more humid
physical process'- reduces wave energy as it reaches coast (absorbs) - reduces erosiona dn traps sediment
77
what is the SMP in hornsea?
promenade, sea walls, groynesv(losing beach due to longshore drifgt and winter storms), and rock armour (high masonry)
- £5.2 million spent on hold the line
- a rock armour groyne wa built between hornsea and withenrsea which accelerated erosion south in mappleton to 10 m a year
78
what is the SMP in Mappleton?
rip rap, rock groynes, increasing rate fo cliff erosion and revetment
79
what is the SMP in withernsea?
promenade, walls, timber groynes which threats holiday business and promenade
80
what is the SMP at Spurn Head?
nothing as there is no practical solution, leads ot loss of comunity, lifeboad and guard station
but it walso saves money and the area my recover
- little comfort to people who have homes
81
what have many locations in holderness decided to do?
nothing as the population is low density and mostly agriculture
82
what type of vegetation my stabilise loose material and reduce erosion?
sand dunes, salt marshes, mangrove swamps
83
what are specialised pioneer plants?
Specialized pioneer plants are the first species to colonize barren or disturbed areas aqnd can live in ahrsh conditions. tjhey cna often grow quickly
84
what are some specialised pioneer plants?
halophytes - can tolerate salt water
xerophytes- can tolerate very dry conditions e.g., sand dunes
85
what are some factors that are necesssary for sand dunes to form?
- storn onshore wind,
- plentiful supply of sand or sediment otherwise it woudl disappear
- space intensive backshore area where sand can accumulate
- variation or high and low tide (intertidal range) to allow sand to dry and dry can is easier to move by wind
- strong onshore wind
- soem sort of obstacle that would trap the sand e.g., sliff, driftwood
86
what do you expect to happen to vegatation density and diversity of species with increasing distance from the coast? why?
vegetation density- increase inland becausd the plants are more protected by wind however pioneer plants grow fast and can endure extreme conditions
more diverse- because contidiont are more stable so thwy can grow more easily and be protects
87
how could oyu measure vegetation?
carry out a vegetation transect through sand dunes or salt marshes. this can be done along a line or withing. abelt usually moving inland form the sea. having set out a transect line a half or metre quadrat could be used to sample vegetation species, and how frequently they pccur at points along the line. this allows easy calculation of % cover. the sampling procedure will affect the usevfulness and reliability of reuslts
- you can also contruct a kite diagram to show variation in vegitation
88
how are dunes formed/ stages? - dune succession
building: plants trap sand and grow with it, binding the sand together with their roots
(sand building up, seaweed, transient alkline sand. palnts are scattered and low growing protate habitat and wacxy leaves)
2. climax: taller plants rthat are more complect can grow. plants from ealier stages die out. the vegetation is at equilibrium
(surface is continually blown away and replenished by fresh sand. salt inolerant plants thruve on ebing burie by sand, they have introlled leaves, long trap roods, underground rhizomes to stabilise sand e.g., maram grass)
3. pioneer stage - sweds are blown in the wind or washed in your the sea and rooting sconidiotns are poor due to the drought, strong winds, saly sea water immersion and alkali conditions created by sea shells. the wind moves sand dunes meaning rain water can soak in more rapidly
(increased humus content, surgace lichens and sand no longer accumilating. maram grass cant rrally compete. many plants coexist and many prerennials ansd stabilising plants like increased organis matter content e.g., lichen and heather)
4. plant succession - sequance of plant communities inhabiting the same site
( loq lying, samp hollows, high water table in winter, soild acidic and pH variable. plants are moitrue loving)
the final characteristic is heath and woodland where there is more acidic soild and increased organic matter content. it is nurtriend rich and a shelter is developed. the plants are acidic loving and coexisting. there are woddy perenialls and undersotry species like heather
89
whwere are magnroves found?
THYE GROW IN SHELTERED WARM WATERS of tropical and subtropical areas. they susually fgrow within the latitudes of 25 N - 25 S some species can grow at 32 N (Florida) and 38 S (Australia)
foudn in over 100 different nations and over 90% are found in developing countries.
90
what are mangrove made up of?
woody treea, shrubas which are able to grow in oxygen poor soils and salt water.
they aere able to survive in saline and brackish conditions within intertidal zone of coasts and estuaries.
They live in low oxygen soils and can cope with changes of tide.
91
what are the benefits of mangroves?
- provide habitat for animals
- sources for food and raw materials for local populations
- natrual ay to increae reislience against threats posed by the impacts of climate change. It also provides protection tion from natrual storms as they prevent sea level rise.
- important part of the global carbon storage system
92
what are some threats to mangroves?
- threatenedby population growth and developement
- deforestation , overfishing
93
what happens to mangroves when it gets colder?
they can't really survive. If there is frost they will die.
94
are mangrove invasive?
usually no. however is found. on an isolated island like hawaii then they can be considered invasive
95
what are the main benefits of mangroves?
Biodiversity and carbon storage - thye have. ahigh rate of biodiversity and they provide habitats to migrating species like birds and fish, aswell as inverrtibrates and mammals
- although they only comprise 0.7% of global forest aerea, they can store up to 20bn tonnes of carbon worldwide which is 2.5 times the current greenhouse emissions. They also act as long them carbon sinks by storing carbon in the soil in which they grow. thye are more effective at this than tropical forests THEY SEQUESTER CO2 FROM THE ATMOSPHERE THROUGH PHOTOSYNTHESIS
Economic oppurtunities:
- thye have about 30,000 £ benefit per hectare per year for developing countries
- encourages productive fishing area like at the mouth of rivers - local communities
- good for tourists as there are more activities
coatal protection:
reduces wave ehight by 66% and reduces the damage caused by coastal flooding. less expensive to restore magnrove forests than build sea walls - more cost effecrtive
note they also prevent other areas from siliting up
96
what are the main threats to mangrove forests?
overfishing- when fish are harvested more than thtye are replaced
an increase in salinity in some areas
- pollution, - species are covered by oil polution and microplastics and may be ingested by fauna. Fertilisers and pestisides may also change the pH of and otxicity of mangrove habitat
- forest clearance for fuel wood and shoarcoal production of to clear waterfront for tourism, port infrastructure, leagal and illegal shrimp farmiing an dsalt harvesting
- river discharge changes and the amount of freshwater reaching mangrove habitats is reduced by dammig rivers upstreeam and by increasing irrigation for agriculture. A decrease in freshwater supply increases the salinity of the water surroudning mangrove may cause it to dry out
- soil erosion caused by deforestation increases succeptibility for sediment movement and the mangroves cant filter this - may cause silting
- climag echange - increase in sea levels and increased exctreme storm events make mangrove dforwst more vulnerabel to flooding
- loss of other marine habistats like coral reefs. this may be becase they prvide a natrual barrier from high waves and strong currents. if there are no coral reefs, then the supply of fine seddiment reduces which allows the mangrove seedling to grow. it reduces the nutrients availabel to them
97
how are mangrove coastlines protected?
by NGOS.
methods include planting new seedlings and promoting education oto higlight both their long and short term impacts.
98
what is an ecosystem service?
benefits provided by an ecosystem
99
what are some ecosystem sservices provided by coastal ecosystems?
goods: fish and shelllfish, fish meal and animal feed, seaweed for food and industrial use, salt, land for settlement and farming, construction materials such as sand and timer
services: protection from stromgs, harbours, shelter, recreational opputrtunities, biodiversitt, wildlife habitats, antural treatment of wastes
regulating : air quality, climate, water ruoff, erosion etc. aswell as disease regulation and pollination. it maintains a starte of balance which is either rlocal fr global
cultural: may include non tangible social benefits and contribtes ot a sense of place with sentimental serenity. Education, ethical values, existance values, recreation and ecotourism
provisioning: physical benefits / resourcesand goods which can be used by our ecosystem which are eitehr creeated or supplied by the ecosystem e.g., food, fibre , biomass, freshwater, matural medecines
asupporting:
closely related to regulatingg byt are key factor that run an ecosystem e.g., nutrient cycling, water cycling, photosynthesis
100
describe the distribution of mangroves:
usually beterrn 25 N and 25 S but is also prevalens inn south east asia and oceania
101
what are coral reefs?
Coral reefs are physical features of skeletons of millions of tiny animals called coral polyps and are the most diverse biiosphere on earch.
(corals are animals with symbiotic relationships with plabts and then they die, they turn into rock. 0
102
- what is a coral polyp?
millions of polyp form larger coral reefs
- each polyp extracts calcium and carbonate from sea water and turns into limestine which is laid down to create the solid foundation of the reed. it has a symbiotic relaitonship with algae.
- thye have tentacles with nematocysts which are stinging cells and atttracts microrganisms to eat
- they havesoft tissue polyp which is liekt he oouter epidermis
- their rock like skeleton is made of limestone
- thye have a basal plate
- they have a stomach
- they have a prtoecticmechanism from potential protectors
103
describe the distribution of coral reefs
thye are located near the shore between 30 N and 30 S
104
what is the distribution of coral reefs determined by?
biotic factores like living features of an eocosystem including behaviour
abiotic factors including all the non living features such as climate, geoglogy, soil type etc...
105
what globla abiotic factors determine the distribution of coral ecosystems?
- temperature - the best conditions for a coral reef is between 23 and 25 degrees no higher tha 29 degrees
- depth of water as most reefs grow t a depth of 25 metres or less on margins of islands or continents
- light - needed for photosynthesis for the tiny algaewhich live on coral where they live in return for a place ot live, they supply corals with 98% of their total food requirement
- salinity. coral reefs are intolerant to waters less than 30-32 psu but can tolerate highly saline conditions like the red sea
106
what local abiotic factors determine the distribution of coral ecosystems?
- sediment - corals require clean water as sediment clogs up their feeding mechanisms ans reduces their feeding mechanismas and light available for photosynthesis (so there is almost always a coral reef break at the river mouth)
- wave action. this helps oxygenate water and therefore coral reefs need some wave action, byut again not too much as if it is too high they might destroy reef slike in storms
- ph - too acidic can destory the carbonate shell
- exposure for air, e.g., in low tides can limit the growht of corals
107
name the 4 different reef types
volcanic island, fringe reed, barrier reef, atoll
108
how do volcanic islands form?
an islsnd is formed bgy a volcanic cone which becomes extinct. usually due to plate techtonics
109
how do fringe reefs form?
as the island and the ocean floor subside, coral growth builds a fringing reef including a shallow lagoon beween the land and the main reef
110
how do barrier reef form?
as the subsidence continues, the fringing reed becomes a larger barrier reef further from the shore with a bigger and deeper lagoon inside
111
how do atoll form?
ultimately the island sinks below the sera, and the barrier of the reaf becomes and atoll enclosing on an lagoon.
An atoll is a ring-shaped island consisting of a coral reef that surrounds a central lagoon. These formations are typically found in warm, tropical or subtropical waters where coral reefs can thrive. Atolls develop when coral reefs build up around the top of a volcanic island or seamount, which then sinks, leaving the coral reef as a circular or oval island with a lagoon inside.
112
what are the provisioning services of a coral reef?
- good for population e.g., fishing , large scale fishing , tourism
- education and scientifit reseach
- houses lots of mairne life
113
what are the regulating services of a coral reef?
- coral grows with rising sea level and is good for marine life as it sequetes CO2
- it makes the water qualitt better throguh purification and regulation
- supports marine communities
- prevents eroision
- medivcine and new treatments
- jewelerry
- lime for cement
114
what are the supporting services of a coral reef?
- supoprts biodiverssity as it occupies 0.18% mairne environemnts buyt over 35% marine fish live there
- provided stability, resilience, habitat, breeding ground, food and nutrition
- suipplies basic food needs for licacl communities and commercial fishing e.g., 25% commercial marine food
- aquarium trade like sea hroses
- shoreline stability and reduces coastal erosion
115
what are the cultural services of a coral reef?
0 tourism (in 2000 over 250 million took a holiday to a coral reef area
- culture of local community and traditions
116
what is the relationship between algae and coral reefs
symbiotic. algae provides nutrients, food energy ansd the reef provides protection
117
where can atoll reefs be found ?
maldives
118
why are reefs at risk? natural causes
- increading populaiton on coasts may hav eindirect inmpacts
- global warming leads to increasing temperatures. this may lead ot bleaching, where the coral goes white, because the reefs have become stressed and expelled the zooanthelas which colour their tissues and provide them with nutirents. therefore thye die. moreover, increaed stress can lead to more diseases like the black and white band disease
- urchins feed on algae. if the populaiton of urchins decreases, the as a result of diesease, then the ubncontrolled growht of algae may overwhelm the cora, blocking out light
- some animals, like starfish , may kill about 85% coral building reefs
- gurricanes and creaste storm waves and destroy them.
- tropical stoerms bring a lot of silt, causing damage ot coral and they cant photosynthesise
- in all these cases, human actions may worsen this
119
what are the names of algae in coral reefs
zooanthelae
120
whst is coral bleaching?
- global warming leads to increasing temperatures. this may lead ot bleaching, where the coral goes white, because the reefs have become stressed and expelled the zooanthelas which colour their tissues and provide them with nutirents. therefore thye die
121
what are the human cuases of damage ot coral reefs?
- boating - anchoring can damage the reef
- dredgin harbours for mainas
- over shioshing can upset ecolofgial balaance
- reef tourism can damage the reef
- coral mining can setroy the reeff
- over exploitation of species like black coral
- changin fo land use like deforestation may lead to siltation fot he reef. reed debris mixes with sediment produced in lagoon
- coastal debvelopment may lead to polution of reefs
they can also owrsen existin gocnditions and exacerbate natural causes of reef destruction
122
what is the case study for a named coastal ecosystem?
great barrier ref
123
where is the great barrier reef? and otehr infor
- it extends over 2300 km along the NE coast of Australia and it adjascent to the queensland coastlliner.
- it runs form latitudes 10S to 24 S and ranges form coastal fringes to 250km offshore
It is a shalloe water platform on bedrock
- it is composed of 300 reef islands and 97 are permanently vegetated
- it is a global heritage sight
- it ormed in the ice age
- it is currently under threat
- it is Austrlias most valuble environmental assets
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what are the biotic characteristics of the Great Barrier Reef
- consists of 2900 separate reefs
- 940 islands
- more than 400 species of coral
- 4000 species of molluscs
- algae (zooxanthellae)
- 35 species of birds
- 800 species of starfish and sea urchins
- a large range of crustaceans, sponges, anemones, worms, sea turtles, sea mammals
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Abiotic characteristics of the GBR
- density of water in GBR changes with depth which changes the biotic components that can live in a given length
- salinity
- latitude
coral grows bet when water is 25 degrees
- platform reefs and wall reefs
- water quality – affects coral growth
- current reef system has grown on the continental shelf of Australia for the past 15000 years
- the photic zone penetrates about 20 m below the surface -> light and shallow water, allows for good coral health
126
what threat does agriculture (and aquaculture) pose to the GBR?
Aquaculture:
- illegal fishing
- overfishing
- unsustainable fishing techniques (cyanide bombing and bomb fishing)
- ‘down the chain’ technique where only one breed of fish is being killed
- commercial fishing – generates a total value of around 104$ billion in 2017
Agriculture:
- poor agricultural practices (e.g., fertilizer causing soil erosion
- steps have been taken in order to minimize the effects of agriculture and improve water quality (regulation of agricultural run off) -> due to deforestation
- bad water means sedimentation which cuts of the light and ‘suffocates’ the coral
- affects areas of reef near river mouth (local)
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what are the main threats to the GBR?
Agriculture, Aquaculture, Industrialisation & port dev., tourism, climate change, coral disease, predators, increase in micro-algae
128
what threat does industrialisation pose to the GBR?
- increasing infrastructure developments along the coast
- Developing port facilities greatly threaten reefs although It is Important to Australian economy as it is an export route for coal, liquifies gas
- now the Australian government must respond to the world heritage committee of any new coastal infrastructure projects/ developments which would impact the reef
- chemical pollution
- pressure to develop area economically
- one large even can cause a large effect on reef
- e.g., Gladstone harbor, a port expansion project which includes reclaiming an is adjacent to GBR world heritage area – they produced dredge soil (sand, rock, soil) and it has spilled into the GBR
– mainly localized to areas with large industrial Centre
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what threat does toruism pose to the GBR?
- GBR attracts 1.6 million visits a year which generates around 5.5$AUD billion for the Australian economy -> negatively impacts reef (e.g., boating traffic to sensitive locations)
- loss of coastal habitat associated with coastal development
- growing general population grows as a threat (2013- 4.66 million living in Queensland)
- harvesting coral for tourist provision (destructive)
- tourists in dive boats pollute the area and divers directly impact coral
- sunscreen leaves an oily film on sea surface and adds to anaerobic stress
-Tourism is an investment in the local area - if used in the right way and people can learn about and spread awareness/donate
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what threat does climate change pose tot he GBR?
- adverse impacts of climate change includes rising sea levels
- coral bleaching and ocean acidification (due to CO2)
- declining water quality associated with increased catchment runoff
- higher UV puts stress on corals
- ocean acidifies with higher rates of CO2 which affects nutrient cycling and primary production and in turn marine species whose diminished diversity will kill corals
- severity of storms due to climate change will worsen and will damage coral structure
- lower PH also reduces in deposition of calcium carbonate, making coral more fragile, susceptible to damage
- can affect whole reed -> affects every where, coral – wide (even though latitudes affects this)
- note coral bleaching is caused by exogenous variables which means the algae leaves the coral and it becomes white (made of calcium carbonate/lime)
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Why is Holderness Coast at risk?
- The coastline is at risk because of the easily eroded and weathered ‘boulder clay’, the longshore drift, changes in sea level causing in increased erosion.
- The coast has also been reshaped by the forms of waves and tidal forces
- Powerful storms also force sediment further south – sediment removal and erosion
- the average rate of erosion is 1.7 meters a year and fluctuates due the the season and location.
- Climate change worsens the effects of erosion as the weather is more intense (rainfall, storms lead to floods and erosion)
- Coast extends over 50km southwards of Flamborough head and has narrow beaches, cliffs comprised of shingle and sand eroded from predominantly clay till
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what is the greatest threat to the GBR?
overall, the health of the reef is in decvline due to the culultive impacts of all the threats to the reeff. I suggest theat the mkain risk is climate change because it is a global issue whixch is extrelemly hard to combat. IN adfdition, climate change adffects many things including rising sea level coral belaching and pH change of oceas
133
what are some methods of prediciotn in coastal cflooding and defences
- use GIS to identify areas with low topogrpahy
- use monitoring techniques to forecast the liekyl occurence and path of tropical revolivng storm
- monitoring seismic activity to alets tho tyhe likely occurence of a stunami
- looking back at past records and identifying arras that have been floded most
134
what are come methods of prevention in coastal flooding and defences?
bulding ddefences along vulnerable. stretches of the coastline
- instaling ewarning systems like sirens
0 land use zoning to remove poeple and businesses from areas susceptible to flooding
- educating local peope on understanding the threats and how to minimise their exposure
- restoring locat ecosystems such as mangroves
- building emergcny sentres for shleter
135
name a depositional landform
spit
136
name one process or erosion that may affect cliffs at the coasrt
abrasion NOT WEATHERING
137
what does the rterm biotic mean?
a living factor that affects an ecosytstem
138
what is one landorm found on an emergent coastline
relic caves
139
Abrasion meaning
The wearing away of cliffs by sediment flung by breaking waves or rocks carried along by the river wear down the river bed and banks
140
what is an arch?
A wave-eroded passage through a small headland. This begins as a cave formed in the headland, which is gradually widened and deepened until it cuts through.
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what is attrition?
Erosion caused when rocks and boulders transported by waves bump into each other and break up into smaller pieces or rocks being carried by the river smash together and break into smaller, smoother and rounder particles
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what is a bar?
Where a spit grows across a bay, a bay bar can eventually enclose the bay to create a lagoon. Bars can also form offshore due to to action of breaking waves
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what is a beahc?
The zone of deposited material that extends from the low water line to the limit of storm waves. The beach or shore can be divided in the foreshore and the back-shore
144
what is beach nourishment
The addition of new material to the beach artificially , through the dumping of large amounts of sand or shingle.
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what is a cave?
A large hole in the cliff caused by waves forcing their way into cracks in the cliff face.
146
what is chemical weathering?
The decomposition (or rotting) of rock caused by a chemical change within that rock; sea water can cause chemical weathering of cliffs.
147
what is a cliff?
A steep high rock face formed by weathering and erosion along the coastline.
148
what is deposition
Occurs when material being transported by the sea is dropped due to the sea losing energy.
149
what is dune regeneration
Action taken to build up dunes and increase vegetation to strengthen the dunes and prevent excessive coastal retreat. This includes the re-planting of marram grass to stabilise the dunes, as well as planting trees and providing boardwalks.
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what is erosion?
The wearing away and removal of material by a moving force, such as a breaking wave.
151
what is erosion?
The wearing away and removal of material by a moving force, such as a breaking wave.
152
what is a gabion?
Steel wire mesh filled with boulders used in coastal defences.
153
what is a groyne?
A wooden barrier built out into the sea to stop the longshore drift of sand and shingle, and so cause the beach to grow. It is used to build beaches to protect against cliff erosion and provide an important tourist amenity. However, by trapping sediment it deprives another area, down-drift, of new beach material.
154
what is hard engineering?
The use of concrete and large artificial structures by civil engineers to defend land against natural erosion processes.
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what is a healdand and bay?
A rocky coastal promontory made of rock that is resistant to erosion; headlands lie between bays of less resistant rock where the land has been eroded back by the sea.
156
what is hydraulic power?
The process by which breaking waves compress pockets of air in cracks in a cliff. The pressure may cause the crack to widen, breaking off rock.
157
what is a landscape
An extensive area of land regarded as being visually and physically distinct.
158
what is longhsore drift?
The zigzag movement of sediment along a shore caused by waves going up the beach at an oblique angle (swash) and returning at right angles(backwash). This results in the gradual movement of beach materials along the coast.
159
what is managed retreat?
Allowing cliff erosion to occur as nature taking its course: erosion in some areas, deposition in others. Benefits include less money spent and the creation of natural environments. It may involve setting back or realigning the shoreline and allowing the sea to flood areas that were previously protected by embankments and seawalls.
160
what is mass movement?
The downhill movement of weathered material under the force of gravity. The speed can vary considerably.
161
what is rock armouer?
Large boulders dumped on the beach as part of the coastal defences.
162
whart is a sand dune?
Coastal sand hill above the high tide mark, shaped by wind action, covered with grasses and shrubs.
163
what is a sea wall?
A concrete wall which aims to prevent erosion of the coast by providing a barrier which reflects wave energy.w
164
what is slumping?
Rapid mass movement which involves a whole segment of the cliff moving down-slope along a saturated shear-plane or line of weakness.
165
what is sliding?
Occurs after periods of heavy rain when loose surface material becomes saturated and the extra weight causes the material to become unstable and move rapidly downhill, sometimes in an almost fluid state.
166
what is soft engineering?
Managing erosion by working with natural processes to help restore beaches and coastal ecosystems.
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what is a spit?
A depositional landform formed when a finger of sediment extends from the shore out to sea, often at a river mouth. It usually has a curved end because of opposing winds and currents
168
what is a stack?
An isolated pillar of rock left when the top of an arch has collapsed. Over time further erosion reduces the stack to a smaller, lower stump
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what is transportation
movement of eroded material
170
what is a wave cut platform?
A rocky, level shelf at or around sea level representing the base of old, retreated cliffs.
171
what is a wave?
Ripples in the sea caused by the transfer of energy from the wind blowing over the surface of the sea. The largest waves are formed when winds are very strong, blow for lengthy periods and cross large expanses of water.
172
what is mechanical weathering
Weathering processes that cause physical disintegration or break up of exposed rock without any change in the chemical composition of the rock, for instance freeze thaw.
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what is the other case study for coastal managemenrt (developing country)
Odisha India
174
why is the coastline at odisha india at risk
- there are 6 major deltas which are bellow sea level meaning they are prone to storm surges which is worsened by rising sea levels, which make it more vulnerable
- extreme tidal variations mean some parts of the year are more vulnerable than others
- human destruction of mangroves has made the locaiton more vulnerable
- cyclones cause flooding e..,g 2013 cyclone Phailin
- erosion mean sit is more at risk
only 14.4% of the coastline is stbale and so many people may be affected
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what are the impacts of coastal flooding in Odisha india?
- many if not most communiyies live on the coast and coastal flooding can displcae them
- damage to infrastructrtue
- damage chances of huge ecnonmic potential and offshore wind could be negatively affected by flooding
-35% coast has heavy metal and mineral deposits which may be damaged due to flooding (+ offshore oil and fgas oppurtunities)
- touristy areas destroyed, fishemran boats destrowyed
- ports which are vital fort he econnomy are destroyed
- agricultureal lands and chemicsld may leach into water
-community loss
- people evacuated form area sof risk during cyclones where 44 people died, 500,000 had of crops detroyed and economy losses close to 7,000,000 use in oct 2013 Phailin cyclone
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what attempts have there been to manage the coatline in Odisha India?
- sea walls, break weaters, rock armour and more to protect the infrastrucutr elike ports. however htis also nefativeyl impacts erosion in other areas and can exacerbate it
- relief supplies are organised before the storm
- conduting staged evacuations in themes vulnerable areas
- highliy localised strategies did more harm than good
- Odisha IC2M project aims to coordinate activities for various stake holders and promote sustainable use of coast's natural environment, protecting it from the coastline and conserving biodiversity aseell as assessing vulnerability to disaster, building cyclone shelters for stormn surges
- helping cultivate mangroves (chzrities, NGOs state_ which reduces storm wave power and the effects and training locals to gorw mangrove nuyrserys
- bettew rmonitoring nad notifying of warnigng and early warnign sysdtems
177
what is the coastal management case study in the uk? why is this coast at risk?
holderness coast-NE England
- easily eroded material adn longshore drift
- the coast has been reformed by forms of waves and tidal forces
- powerful storms push sediment further south
- av erosion is 1.7. m a year but s=fluctuates due to seasons
- climate change sis worseing the effects of erosion as the weather is more intense and there is more severe rainfall and lieklihood of floods and coastal erosion
- the coasdtline extends over 50km southwrds of Flambororugh head- there ar enarrow beaches, cliffs compromised of shingle and sand eroded form preodminanalty clay till
178
what are the impacts fo coastal erosion at holderness coast?
- 1.7. m erosion a year on average- tourist areas such as coastal towns and caravan are afected
-farmers are affected by erosion and coastal plans that woudl increase erosion int hat area
- SMPs can negatively impact environment and lead to a lsoss of habitat
- conflics between local residents
-0 damages to local infrastructure and transport
- derctruction to habitats
- can leasd to a lack of housing and homeless
179
what are the attempts to manage th ecoadtline and what are the costs and benefits of these strategies?
- the central government is responsible to funding under the DEFRA (department of environment, foor and rural affairs)
- DEFRA supervises schemes carried out by local authorities, which have been encouraged to make/develop lonf term plans called shoreline management plans (SMPs) which ttempt to reduce risks to people and natrural environment
the most common ones are do noting
in bridlington thye have high masonry, sea walls, groynes, in honsea they have soncrese seawalls and gorwns aswell as rock armour
in mappeleton they have soncrese seawalls and gorwns and revetments and in withrnsea they have timber groynes and soncrese seawalls and gorwns
180
what are the diff types of flooding?
tsunami, storm surge, climate change,
181
expalin tsunamis. how does forecasting reduce the impact of flooding and what strategies ar eused to prevent it?
- dense techtonic plates slide beneath plates containing continents. from time to time this can cause rock to fracturea dn this can lead ot an earth quake. this spreads vibrations througg the fouend and th eactual movemenr can cuase underwater rock layers to suddenly push sea upwartds.
this causes waves to spread and these waves contain tremendous amounts of energy (up to 8kmh)
as tthey draw closer, the friction with the ocean cuases them to slow down but gian height and thehy can demolish buuildings, flip vehicles, and wash poeple out to sea
182
name a tsunami warning system
recorder on seabed moniters changes in pressure. it can detect tsunamis s small as one cm. the acoustic links tramits data to ground stations. monitoring siemic activity can also indicate tsunami occurence
- helps people get out of way
- warning apps and monitoring
183
what strategies are used to prevent tsunamis?
- apps eg.g, Yurekuru notifies you of outbreak of tsunami
- signs near hazard zone
- installing warning alarms
- lookin back on past record tha thave been flooded most
- sea walls and other defences
184
expalin storm, surges. how does forecasting reduce the impact of flooding and what strategies ar eused to prevent it?
-tropical storms e.g.,g hurricane
- an abnormal rise of water generated by a storm e.g., fropm wind. they occur during tropical cyclones , intense storms, typhoons, hurricanes
- storm track monitoring cna forecast rhe likely occurence and path of tropical revolving storm NOAA and lead ot accurate evacuation
- interactive maps can track active tropical storm
- flood forecast
prevention:
- sea walls and flood defences
-flooding 0 making plans for floods and emergency kits
- uilding emergency shelters for people
- land use zoning to remove peope and business' susceptible to flooding
- thames has been one of the largest moveable flood barriers ot the world (up to 520 m long)\
- information
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expalin climate change. how does forecasting reduce the impact of flooding and what strategies ar eused to prevent it?
- (eustatic change-change in vol of water)
- glaciers and ice sheets worldwide are melting and adding warter to the ocean and as the water wrms the volume expands
- this happens on a globakl scale
model projec tions and hazard mapping:
- maps and plotting where previous accidents were
- forecasts and monitoring
0 measuring risk factors globally and humidity
- landslides and soil heave and storm damage
-assessing which areas need protection
building and design planning:
- floating homes (rise in sea)
- building homesfurther away from fcoasts and flod resitant, (stilts)
- spreading information about rising sea levels
- riasing roads (helpsdrain water and reduces tidal flooding)
- defences against floods and levees
- house on stilts
- wetlands
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how can you protecr. property from flooding?
- glass = water prood
- concrete front support - wont decay and more reistant to strong waves
- stilts protects propwerties from rising sea and prevents flood water from getting in and they have deep foundations
- shelving keeps objects away from water
- water proof coating
and prevents water damage and mould
- drains and pipes let water out
- flood guard and raised threshold stops waterf rom getting in ass it acts as an obstacle
- no fitted carpets prevents water soaking into fabtis
- high up water sockets prevents fires etc
187
what are sea walls?what are the pros and cons?
Concrete walls that are placed at the foot of a cliff to prevent erosion. They are curved to reflect the energy back into the sea.
Advantages
Effective at protecting the base of the cliff. and most effective at preventing both erosion and flooding if the wall is high enough. Sea walls usually have promenades so people can walk along them.
Disadvantages:
Waves are still powerful and can break down and erode the sea wall.
Expensive - approximately £2,000 per metre. and difficult to maintain.
restricts access to beach and perhaps ugly
188
what is rock armour?pros and ocns? what is another name for rock armouus?
AKA RIP RAP
Large boulders placed at the foot of a cliff. They break the waves and absorb their energy.
Advantages
Cheaper than a sea wall and easy to maintain.
Can be used for fishing.
abrsorbs energy from the base of cliffs
Disadvantages
They look different to the local geology, as the rock has been imported from other areas.
The rocks are expensive to transport.
boulders can be eroded or disloged during heavy storms
189
what are fgabions? pros and cons?
Gabions
Rocks are held in mesh cages and placed in areas affected by erosion.
Advantages
Cheap - approximately £100 per metre.
Absorbs wave energy.
can be stackes at the base of a sea wall or cliffs
Disadvantages
Not very strong. - cages maky break and must be tied down.
not as efficient as othe rmethods
Looks unnatural.
190
what are groynes? pros and cons?
Groynes
are wooden or rock structures built out at right angles into the sea.
Advantages
Builds a beach - which encourages tourism.
They trap sediment being carried by longshore drift. and slows down longshore drift
Disadvantages
By trapping sediment it starves beaches further down the coastline, increasing rates of erosion elsewhere.
They look unattractive.
starves other beaches of sedement
wooden groynes need maintanence so they dont rot
makes walking along the coast more difficult?
191
whar is soft engineering?
Soft engineering
does not involve building artificial structures, but takes a more sustainable and natural approach to managing the coast. Each strategy has its advantages and disadvantages for use.
192
name some soft engineering strategies. what are they, what are their pros and cons?
beahc nourishment - Sand is pumped onto an existing beach to build it up.
Advantages:
Blends in with the existing beach. Larger beaches appeal to tourists.
absorbs wave energy
Disadvantages:
Needs to be constantly replaced.
The sand has to be brought in from elsewher - expensive
can impact sediment transportation downt he coast and removing material can damaege fragiel ecosystems like coral
Reprofiling - The sediment is redistributed from the lower part of the beach to the upper part of the beach.
Advantages:
Cheap and simple. Reduces the energy of the waves.
Disadvantages:
Only works when wave energy is low. Needs to be repeated continuously.
dune nourishment - Marram grass/vegetation planted on sand dunes stabilises the dunes and helps to trap sand to build them up. reduces wind erosion
Advantages: Relatively cheap.
Maintains a natural-looking coastline. act as a barrier between sea and land and it prevents erosion and flooding. it is cheap methos of stabilising dune
Disadvantages: Can be damaged by storm waves.
Areas have to be zoned off from the public, which is unpopular
hard to prtoedt larger areas with this mehtod.
cliff regrading - andle fo a cliff is reduced to reduce mass movement pros 0 prevents sudden loss of large sections of clidd and can slow down wave cut notching at bqase of cliff as the energy of wave is slowed
- hoevfrer it doesnt stop cliff erosion
manaeged retreat - Existing coastal defences are abandoned or removed, allowing the sea to flood inland until it reaches higher land or a new line of defences
pros- No expensive construction costs. Creates new habitats such as salt marshes
cons- Disruptive to people where land and homes are lost
Saltwater damages existing ecosystems
Cost of relocation can be expensive
Compensation to people and businesses may not be paid
193
what are hard engineerign stategies?
Hard engineering involves building some form of sea defence, usually from concrete, wood or rock
Structures are expensive to build and need to be maintained
Defences work against the power of the waves
Each type of defence has its strengths and weaknesses
Protecting one area can impact regions further along the coast, which results in faster erosion and flooding
Hard engineering is used when settlements and expensive installations (power stations etc) are at risk: the economic benefit is greater than the costs to build
194
name the hard engineering strategies:
sea wall, groyens, rip rap, gabions, revetments, off shore barriers,
195
name some soft engineering methods:
- brach rpelenisment, dune regenration, cliff regrading, managed retreat
196
what are revetments? pros and cons?
Sloping wooden or concrete fence with an open plank structure
pros- Work to break the force of the waves
Traps beach material behind them
Set at the base of cliffs or in front of the sea wall
Cheaper than sea walls but not as effective
cons- Not effective in stormy conditions
Can make beach inaccessible for people
Regular maintenance is necessary
Visually unattractive
197
off shor barriers - what are they? pros and cons?
Large concrete blocks, rocks and boulders are sunk offshore to alter wave direction and dissipate wave energy
pros - Effective at breaking wave energy before reaching the shore
Beach material is built up
Low maintenance
Maintains natural beach appearance
cons- Expensive to build
Can be removed in heavy storms
Can be unattractive
Prevents surfing and sailing
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