Coasts Flashcards
(176 cards)
1
Q
what are the different sources of energy
A
-wind
-tide
-waves
-currents
2
Q
wind energy
A
3
Q
the formation of waves
A
-waves are created by energy passing through water causing it to move in circular motion
-however water does not actually travel in waves
-waves transmit energy not water across an entire ocean and if not obstructed by anything they have the potential to travel across an entire ocean basin
-waves are most commonly caused by wind
-wind driven waves are created by the frictional drag between wind and surface water
-as wind blows across the surface of the ocean the continual disturbance creates a wave crest as the wave approaches the shore disturbance to the circular motion beneath the surface leads to more horizontal wave movement and the wave breaks
4
Q
what are the two different wave types
A
-constructive
-destructive
5
Q
what are constructive waves
A
-add material to the coastline
-strong swash
-low waves with long wavelength
-formed by distant weather systems
6
Q
what are destructive waves
A
-remove material from the coastline
-strong backwash
-tall in relation to length
-causes cliff face erosion
-common during winter storms
7
Q
what are the causes of tides
A
-tides are predictable even though the time and size of them are based on the position of the sun and moon relative to earth
-get 2 high and 2 low tides a day
8
Q
what determines the amount of gravity
A
-mass
-porximity
9
Q
why are spring tides exceptionally high and neap tides low
A
-both pulling in the same plane meaning it will be a high tides
-however neap tide there is pull in one way with the sun out having different pull with the moon
10
Q
what is tidal range
A
-tidal range is the difference in height between the low and high tide marks
11
Q
spring tide
A
-increased gravitational pull
-increasing range
12
Q
neap tide
A
-sun and moon are at 90 degrees to the earth gravitational pull is less effective
-high tide is less and low tide is higher
13
Q
high energy coast
A
-no beach meaning it has never been formed due to no deposition
-destructive waves
-erosion of landforms
-rocky coastline
-contains cliffs and headlands
-erosion exceeds deposition
14
Q
low energy coast
A
-constructive waves
-beachy sand and seaweed
-strand lines show high tide lines on the beach
-large flat beach with high material meaning low amounts of erosion
-sheltered areas such as bays
-depositional landforms such as beaches and spits
15
Q
what is hydraulic action
A
refers to the impact on rocks and the sheer force of water itself (without debris) this can exert enormous pressure upon a rock surface thus weakening it
16
Q
what is wave quarrying
A
a breaking wave traps air as it hits a cliff face the air is compressed into any gaps causing huge pressures. as the water retreats there is an explosive effect of the air pressure being released which weakens the cliff face and allows storms to remove large chunks of it
17
Q
what is abrasion/corrosion
A
eroded material being thrown against the rock by the waves and also conducts erosion of wave cut platforms due to movement of material back and fourth
18
Q
what is attrition
A
rocks which are carrying out abrasion slowly worn down into smaller rounder particles
19
Q
what is solution
A
not overly common as sea water is generally alkaline rather than acidic, however where sea water interacts with freshwater supplies carbon bared rocks may be dissolved
20
Q
traction
A
large particles like boulders are pushed along the sea bed by the force of the water
21
Q
saltation
A
pebble sized particles are bounded along the sea bed by the force of water
22
Q
what is suspension
A
small particles like silt and clay are carried along in the water
23
Q
what is solution
A
soluble materials dissolve in the water and are carried along
24
Q
what is longshore drift
A
movement of material along a beach usually at the angle of the prevailing winds (90 degrees)
25
what process are marine
longshore drift, erosion, depositon
26
what processes are sub marine
weathering, mass movement and run off
27
what are the different types of weathering
-chemical
-biological
-mechanical
28
what is biological weathering
-the breakdown of rocks by organic activity is biological weathering in several ways at the coast
-thin plant roots grow into small cracks in a cliff face these cracks widen as the roots grow which breaks up the rock
-water running through decaying vegetation becomes acidic which leads to increased chemical weathering
-birds and animals dug burrows into cliffs
-marine organisms are also capable of borrowing into rocks
29
what is chemical weathering
-involves a chemical reaction where salts may be dissolved or a clay like deposit may result which is then easily eroded
-carbonation: rain water absorbs carbon dioxide from the air into form a weak carbonic acid this results with calcium carbonate in rocks the cooler temperature of the rainwater the more carbon dioxide absorbed
-oxidation: the reaction of rocks minerals with oxygen for example iron to form a rusty red powder leaving rocks more vulnerable to weathering
-solution: the dissolving of rock minerals such as halite
30
what is mechanical weathering
-involved the break up of rocks with any chemical changed taking place
-frost shattering (freeze thaw) : occurs when water enters a crack or joint in the rock when it rains, then freezes in cold weather, when water freezes it expands this expansion applies pressure which causes the rock to widen and crack
-wetting and drying: frequent cycles of wetting and drying are common on the coast. rocks rich in clay expand when they get wet and contract when they dry this can cause them to crack and break up
-salt crystallisation: when salt water evaporates it leaves salt crystals behind, these can grow over time and exert stresses in the rock just as ice does causing it to break up salt can also corrode rock particularly if it contains traces of iron
31
types of mass movement
-soil creep
-mudflow
-run off
-landslides
-rock fall
32
what is soil creep
soil creep is a very slow movement occurring on very gentle slopes because of the way soil particles repeatedly expand and contract in wet soil particles increase in size and weight and expand at right angles when the soil dries out it contracts vertically
33
what is mudflow
a geological phenomenon thereby a wet viscous fluid mass of fine to course grained material flows rapidly and turbulently downslope usually in a drainway typically in torrential rain
34
what is run off
occurs when there is more water than land can absorb the excess liquid flows across the surface of the land and into nearby creaks, streams or ponds. runoff can come from both natural processes and human activity the most familiar type is snowmelt
35
what is landslide
a mass movement of material such as rock, earths or debris down a slope they can happen suddenly or move slowly over long periods of time when the force of gravity acting on a slope exceeds the resisting forces
36
what is rock fall
where a source of rock exists above a slope steep enough to allow rapid movement of dislodged rocks by falling, rolling, bouncing and sliding, rockfall sources include bedrock outcrops or boulders on steep mountainsides or near the edges of escarpments such as cliffs
37
what is a sediment cell
- a stretch of coastline within which sediment movement is more or less contained
-these cells are generally borderd by 2 large headlands or deep water and contain inputs, transfer and stores of sediment
-in total there are 12 sediment cells in the uk which you can divide into sub cells
-these are closed systems
38
sediment budgets within sediment cells
in theory within a sediment cell there should be a state of dynamic equilibrium between inputs via erosion and other methods and losses of material to deposition in sinks
39
sources of sediment
-river
-cliff erosion
-offshore sediment
-wind
40
rivers
-9% of all coastal sediment is from rivers
-coasts of steep gradient are likely to experience high amounts of sediment as rivers directly deposit sediment at the coast
-in some locations as much as 90% of coastal sediment comes from rivers
41
what is a concordant coastline
rocks on these coastlines run parallel to the sea and are the same rock type
42
what is a discordant coastline
rocks on these coastlines run perpendicular to the sea with different rock types
43
bedding plane
-horizontal layers of bedding
-only one recent slip not repeated
-hard sedimentary rock
44
dipping plane
-previous land slips that have repeatedly occurred
-dropped cliff top
-soft rock
-rates of 10 metres per year
45
how do wave cut platforms form
-a wave cut platform is when waves breaking at the foot of a cliff produce wave cut notches
-this undercutting is the result of erosion by waves
-as the cliff is undercut the rock above collapses and so the cliff gradually retreatsh
46
what is a spit
-a spit is a long narrow feature that extends from the mainland at the end of a drift aligned beach
47
what is the formation of a spit
-it is a depositional landform made of shingle and sand
-the process of longshore drift will move material along a coastline determined by the prevailing winds
-as the coastline changes direction the finer material will continue to be transported out to sea
-this will build upwards and outwards to develop into a permanent feature
-wave retraction and a second dominant wind direction will force the material to move in a different direction resulting in a curved end
-as low energy waves enter the area behind the spit the finer silt and mid is deposited
48
what is a compound spit
spits with barbs or hooks on their landward side
-these can form by a different secondary wind as well as the other wind flow reacting in these hooks
49
what is a tombolo
tombolos are very similar to spits and form in the same way however they are unique in the fact they join the mainland to an offshore island via deposition
50
how do swash aligned beaches form
-when waves break parallel with the coast the movement of water and material is largely up and down the beach, producing features similar to those already seen
-bay head beaches
-bay bars
-barrier beaches
51
how do drift aligned beaches form
where waves approach the coastline at an angle the swash moves material up the beach in that direction. the backwash returns at right angles the constant repetition of this causes pebbles and sand to drift along the beach
-a spit
-recurved spits
-tombolos
52
how do beaches form
-beaches occur in the littoral zone between low and high tide
-constructive waves with their strong swash and weak backwash allow a net increase of material
-their waves are flatter and smaller than destructive waves and material spills forwards building up the beach whilst the water often percolates into the beach
53
how do different gradients occur at a beach
material at the top of the beach is of a large calibre and this supports concave slopes
54
seasonal change at a beach
-beach profile show marked short term and seasonal change
-this sweep zone variation is often related to the type of waves involved
55
ridges and runnels
-at the lower edge of beaches, sand accumulation to form longshore bars parallel to the waves
-this material has probably been combed from the beach plunging (destructive waves)
-breaks in these ridges result from rip currents which form in the strong backwash
-inland of these runnels form separating pools of standing water at low tide
-as the slope of the beach a netwrok of temporary drainage channels may also appear here in finer sandy beaches
56
what is a sand dune
an accumulation of sand blown into mounds by the wind
57
sand dune formation
1. sand accumulates on the beach from longshore drift
2. at low tide the sand dries out allowing the prevailing winds to move the loose sand up the beach
3. large inter tidal zone for sand to be dry
4. sand is transported by process called saltation
5. debris on beach traps sand
6. grass such as lyme grass grows which stabilises the dunes
58
embryo dune
-sand continuously moving; needs obstruction to break the force of the wind
-high ph over 8
-high wind speed
-lots of salty spray
-no more than 1 metre high
-80% of sand exposed
59
fore dune
-drought restraint plants colonise
-as they grow more sand is trapped and dunes increase in height
-20% of sand exposed
60
yellow dunes
-greater diversity of plants
-humus layer builds up
-pH slightly alkaline
-more shelter less salty spray
-maram grass dominates other vegetation includes moss, heather sea holly
-dunes 5-10 metres high
-80% of sand vegetated
61
grey dunes
-stable
-100% vegetation less marram grass, more sea spurge and small shrubs
-50-100 metres from the sea
-sheltered from winds
-humus darkens allowing soil to form
-water content low plants search for water
-10m high and wider
62
dune slack
-found between mature dunes and where the water table reaches the surface
-plants absorb to damp and shelter
63
mature dunes
-found 100m from shore
-of undisturbed can support shrubs, trees
-humans may plant fast growing conifers
64
what is tidal range
the difference in height between the high and low tide marks
65
what is creep
a method of transportation used by the wind for moving the largest material
66
what is a sand dune
an aeolian landforms created on flat land at the back of the beach
67
what is deposition
occurs when wind/waves lose energy and can no longer carry material
68
what is positive feedback
something which occurs and accelerates an already existing process
69
what is bedding plane
the point where layers of sedimentary rock are joined. provides a weakness for weathering and potential sliding surfaces for mass movement
70
what is a sediment cell
a closed system at the coast within which sediment is almost entirely contained
71
what is spring tide
the highest tides experienced occur when the sun and moon pull the ocean in the same plane
72
what are mudflats
are created by the deposition of dine silts and clays in sheltered low energy coastal environments such as estuaries
73
what are saltmarshes
an area of coastal grassland that is regularly flooded by seawater
74
what are factors affecting salt marsh developement
-river regime: changes in currents and volume can affect erosion
-weather; storms supply changes can enhance or diminish the available silt
-sediment supply: supply changes can enhance or diminish the available silt
-human action: commercial industrial and recreational activity can damage marsh
-sea level: rises can upset equilibrium and destroy the marshes
-climate: affects species types, growth rates and sea levels
-wave types: changes in direction, nature and size can affect marsh stability
-tidal regime: changes in tidal currents can increase erosion and alter spaces
75
the formation of a salt marsh
- a low energy tidal environment that is one where the seas erosional ability is limited
-this allows plant colonisation and sediment accumulation
-the plant community then undergo's a series of changes known as a succession
-these combine to create a feature that can eventually emerge above sea level and become permanent
76
what are the required conditions for mudflats and formation
-low tidal energy environment (constructive waves)
-large tidal range
-lack of human intervention
-sediment is required to form
77
how does sea level rise threaten these features
-sea levels rising too quickly for the marshes to adjust. increased incidence of storms leads to increased flooding
-affect lateral marsh growth
-deeper waters will allow bigger waves to reach to marsh causing erosion at the seaward edge
-plants which arent 100% marine and cant survive without oxygen will die due to high tide which means they are covered with water completely
78
what are pioneer species
the first plant to colonise an area. they are highly adapted and able to survive in extreme conditions e.g. eelgrass
79
what is flocculation
fine particles bind together and are then deposited
80
what is halophytes
salt tolerated plants which can deal with salt water
81
what is the process of deposition at a salt marsh
-salt marsh begins when mud and silt are deposited along a sheltered part of the coastline
-this is because rates of deposition are greater than transportation due to the lack of energy in the waves
-the deposition builds up over time meaning that the mud breaks to surface to form mudflats some plants then begin to grow
-plants begin to grow such as cordgrass these plants are known as pioneer plants which is tolerant to sea water and its long roots help to hold the mud and sediment together
82
what are key characteristics of landscsapes of deposition in the coastal zone
-low energy
-constant sediment supply
-large area of space for deposition
-constructive waves
-low tidal range
-these characteristics and conditions need to be dominant and regularly occur
83
succession on saltmarshes
-as the tidal current are slowed they begin to deposit material. this is fine grained at first and it may be encouraged by the growth of eelgrass in submerged areas
-eelgrass helps slow the currents further
-gradually uneven mud flats develop that are exposed at low tide
-these mudflats can then become colonised by pioneer plant species
-these plants are tolerant of salt the perodia soaking of the sea caused by the tides. they are known as halophytes, they include species such as glasswort and sea bite
-they gradually develop close vegetation over the mud allowing colonisation by further types of plants such as sea aster, marsh grass and sea lavender these form a dense mat of vegetation up to 15cm high
-this vegetation creates friction to slow the currents even further this causes yet more sediment to be deposited
-additionally the vegetation itself traps particles these accumulate even on the mud
-the plants also produce leaves and stalks that die and help build up the sediment level this vegetation waste can be up to 15m of dry matter per year
-these processes combine to increase the level of the mud flats by between 1mm and 30mm per year. they also provide a food supply for other channel such as small invertebraes to exploit
-as the mud level rises complex creek systems evolve that channel the flowing and which become deeper as the land rises
-eventually the land rises above sea level as new species such as rushes and reeds become established
-by the time the salt marsh succession is complete this halosere or succession also shows species zoneation which can be defined as a distinct spatial distribution
-by this stage the upper levels of marsh are rarely covered by the sea only high spring tides and storms allow them to become inundated
84
what are additional human threats are there to salt marshes
-daming rivers removes the silt and clay and deposits behind the sam
-litter dumped on salt marshes
-trampling destroys the delicate ecosystems which can be found
-flood defences
85
how might climate change influence the coastal system
-sea level rise: coastal flooding ruining vegetation and affecting human activities and villages
-higher sea temperatures
-sea becomes more acidic as temperature rises
-weathering patterns of heavy rain and strong winds
86
what is eustatic changes
a global change in the sea level resulting from a fall or rise in the level of the sea itself
87
what is isostatic change
local changes in sea level resulting from the land rising and falling relative to the sea
88
what are the two major factors causing sea level rise
-thermal expansion where the volume of water increases as it gets warmer
-land ice melting of glaciers and ice sheets
89
what are the characteristics of eustatic change
-actual change in the level of the sea
-global scale
-caused by either thermal expansion
-land ice melting/forming differs the sea level
-can be caused through tectonic changes
90
how do raised beaches form
-a raised beach is formed by wave action where its close to the waterline during a later period a change in sea level or an uplift of the land can put it beyond the waters reach
90
what are the characteristics of isostatic change
-shift in the level of the land
-regional change
-relative change in sea level
-caused by the compression of land by ice
-can be caused by tectonic change but less common only volcanoes but faults can push land up
90
emergent landforms/feautre
-raised beaches
-a funnel
90
submergent landforms/feature
-fjords
-dalmation coast
-rias
90
what is a raised beach
they are wave cut platforms and beaches that are above the current sea level
91
what is a funnel
a shaped estuary that occurs at a river mouth and is formed by the submergence of the portion of the river valley
92
what is a fjord
-they are steeper and deeper variants or rias that are relatively narrow
-they have a u shaped cross profile and are often found in icy sections of the world
-they are flooded glacial valleys which are really deep with a shallow mouth which is where the glacier deposited its load
-they are found in locations where current or past glaciation extended below current sea level
93
how does a fjord form
-a fjord where a glacier retreats after carrying its typical u shaped valley and the sea fills the resulting valley floor
94
what is a ria
-a river valley that has been flooded by the eustatic rise in sea level
-they are almost like a typical river valley but they have even more water in them
-the floodplain of these gets flooded altering cross profile
95
how are rias formed
-they are formed as sea level rises in warming climate
-the sea level change that caused the submergence of a river valley may either eustatic or isostatic
-as sea level rises low lying coastal environments become submerged and river valleys are drowned to form rias
96
what is the dalmation coast
-form in areas of the world where valleys lie parallel to each other
-when the valleys are flooded by the rise in sea level the tops of the valley remain above the surface of the sea and appear to be a series of islands that run parallel to the coastline
97
how does the dalamation coast form
-when the sea level rises or land subsides causing the sea to invade low lying areas
98
what are the 2 factors contributing to sea level change
-subsistence of the coastline
-increases in water volume of the ocean (thermal expansion)
99
what is subsistence
coastal areas sinking often this is due to excess groundwater extraction and has the effect of making the sea level higher
100
what is water volume
changes due to either thermal expansion or addition of extra water from land stores such as ice or glacier melt
101
coastal system climate change stats
-over 22000 years ago sea level was 140 m lower than now in present day
-there are three ice sheets in 2 places on earth, but together they contain the potential for 72m of global sea level rise
-greenland would have a 7m rise if melted
-2 in antarctica meaning 65m sea level rise
102
why does the coasts require management
-16.9 million people live within the coastal zone meaning a high fraction of the population are at risk if coastal mamagment doesnt occur
-38% of the coastal zone is covered by buildings, roads and recreation facility meaning if managmenet strategies arent out it place it can result in large economic loss
-25% of the coast is arable land which is land of significant economic farming value
103
what are the three reason for coastal management
-prevent coastal erosion
-coastal flooding
-failure of former defences
104
what are possible different soft engineering management strategies
-hold the line
-advance the line
-retreat the line
-do nothing
105
what is hold the line
maintain current defences or build new ones to ensure coastline stays where it is
106
what is advance the line
build new defences or build new ones to ensure coastline stays where it is
107
what is retreat the line
allow the coastline to retreat due to flooding and erosion but closely manage the rate and location of this retreat
108
what is do nothing
low value areas left to natural coastal processes as not deemed viable to spend on defences
109
what are factors affecting management strategy for hold the line
-high amount of tourists
-it is a fragile environment
-high land value
-coastal area of high population
-global importance from media promotion
-if the land has international importance
-if the area has high amounts of service industry
110
what are factors affecting management strategy for advance the line
-high amount of tourists
-high land value
-coastal area high population
-if the land has international importance
-global importance from media promotion
-if thr area has high amounts of service industry
111
what are factors affecting management strategy for retreat the line
-high amounts of tourists
-low land value
-low economical importance
112
what are factors affecting management strategy for do nothing
-low value land
-low economical importance
113
cost benefit analysis for coasal management
- a cba is carried out before a coastal mangament project is given the go ahead
-costs are forecasted and then compared with the expected benefits which can be in two types of tangible factors and intagible factors
114
what are tangible factors
where costs and benefits are known and can be given a monetary value
115
what are intangible factors
where costs may be difficult to assess but are important
116
what tangible factor which are assessed
-flood defences of already existence
-roads and infrastructure
-buildings with businesses
-houses
-land/farm use
117
what intangible factors are assessed
-wider environmental factors
-historical change
-cultural factors/heritage
-visual impacts
-personal attachment
-scientific value
-archaeological value
118
what is soft engineering
works with nature and natural systems to protect the coast
119
what is hard engineering
making a physical change to the coastline using man materials and or structures
120
what are different hard engineering defences
-sea walls
-groynes
-gabions
-revetments
-barrages
-offshore reefs
121
what are sea walls
stone or concrete walls at the foot of a cliff or at the top of a beach . they usually have a curved face to reflect wave energy and the waves back to the sea
122
what are advantages of sea walls
-effective prevention of erosion
-they often have a promenade fir people to walk along
123
what are disadvantages of sea walls
-they reflect wave energy rather than absorbing it
-they can be intrusive and unnatural looking
-they are very expensive to build and maintain
124
what are groynes
timber or rock structures built at right angles to the coast. they trap sediment being moved along the coast by longshore drift building up the beach
125
what are advantage of groynes
-work with natural processes to huiild uo the beach, which interacts tourist potential and protects the land behind it
-not too expensive
126
what are disadvantages of groynes
-starve beaches further along the coast of fresh sediment often leading to increased erosion elsewhere
-unnatural and can be unattractive
127
what are gabions
they consist of metal cages containing rock. gabions are usually constructed at the base of a cliff to absorb wave energy and reduce erosion.
128
what are advantages of gabions
they absorb energy of waves which allows a build up of a beach
129
what are disadvantages of gabions
-they can be expensive to obtain and transport the boulders
-can look unattractive
130
what is revetments
sloping wooden or conrete or rock structures places at the foot of a cliff or at the top of a beach they break up the waves energy
131
what are advantages of revetment
they are relatively inexpensive to build
132
what are disadvantages of revetment
-intrusive and very unnatural looking
-they can need a high level of maintane
133
what are barrages
partly submerged structures containing sluice gates that control the tidal flow of the sea and river water from land
134
what are advantages of barrages
-generate electricity
-create new habitats for wildlife
135
what are disadvantages of barrages
-alter natural sediment transport patterns and reducing the availability of habitats for coastal wildlife
-impact of water quality
136
what are offshore reefs
a partly submerged rock barrier designed to break up the waves before they reach the coast
137
what are advantages of offshore reefs
an effective permeable barrier
138
what are disadvantages of offshore reefs
visually unappealing and a potential navigation hazard
139
what is beach nourishment
the addition of sand or pebbles to an existing beach to make it higher or wider. the sediment is usually dredged from the nearby sea bed
140
what are advantages of beach nourishment
-relatively cheap and easy to maintain it looks natural and blends in with existing beach
-it increases tourist potential by creating a bigger beach
141
what are disadvantages of beach nourishment
-needs constant maintenance because of natural process of erosion and longshore drift
142
what is dune regeneration
marram grass can be planted to stabilise dunes areas can be fenced in to keep people off the newly planted dunes
143
what are advantages of dune regeneration
-maintains a natural looking coastal environment
-provides important wildlife habitats
-relatively cheap and sustainable
144
what are disadvantages of dune regeneration
-time consuming to plant marram grass
-people may respond negatively to being kept off of certain areas
145
what is managed retreat
the controlled flooding of low lying coastal areas. if an area is at high risk of erosion, managed retreat would be an option. it occurs where the land is of low value e.g farm land
146
what are advantages of managed retreat
-cheap
-creates a salt marsh which can provide habitats for wildlife and a natural defence against erosion and flooding
-from the creation of salt marshes it supports many species by having a diverse ecosystem
147
what are disadvantages of managed retreat
-land is lost as it is reclaimed by the sea
-owners of the land would require compensation
148
what is land use management
they allow the planning and management of land types to determine which areas of land should he chosen for which uses of land
149
what are advantages of land use management
-permits the development of societies through managing land use
-maintains the environment and its natural resources
150
what is do nothing
the easy option to deal with the effects of flooding and erosion as they come or just ignore them. this generally happens in areas where theres no people and so nothing of 'value' to protect
151
what are advantages of do nothing
-the risk if flooding and the impacts of flooding arent reduced
152
what is SMP
shoreline management plans
153
what is ICZM
integrated coastal zone management
154
what are SMP aims
-promote long term mangement policies into 22nd century
-assess the risk associated with coastal evolution
-address risks in a suitable way
-ensure management plans comply with nature conservation
-provide policy for coastal mangement
-assess risks to developed natural and historic environments
-plans are schemes constantly reviewed
155
what is ICZM's
-created the following 1992 earth summit, ICZM's aim to focus on the fact that coastal zones are some of the most economically valuable yet ecologically sensitive places on earth. they aim to work with multiple stakeholders to manage the coast
-for them to successful it must adhere to the principles that define sustainability and act upon them in ways that are intergrated
156
what stakeholder groups are involved in ICZM
-coastal residents
-council
-government
-local businesses
-environmental groups
-neighbouring coastal residents
157
SLAPTON SANDS
158
slapton background info
-slapton sands is a shingle barrier beach which along with blackpool sands, beesands and hallsands makes up the area of start bay along the south coast of devon
-the bay is an exposed position and faces southeast meaning the influence of incoming waves in sediment levels and transport is large
-along the coast its exposed to waves coming from the south which has the common trend of pushing seidment northwards
-slapton is located in sediment cell 6 which stretches along the south west coast from lands end to portland bill
-the village of torcross is located in the southern end and the back of slapton ley which is the largest natural lake in the south west england
-slapton ley is separated from the sea by a narrow shingle bar it si entirely fresh water
-the stretch of coastline is known for coastal landsforms caused by erosion, transportation and deposition which attracts many students to the area for analysis and data recording
-over the years many coastal defenmces have been constructed over many years starting in 1917 and most recently in 2017
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timeline of coastal management
-concrete sea wall (1917): a wall capped with a concrete rip 143m ling was constructed north of torcross
-rock revetments (1979): a 795m long rock resentment was constructed north of torcross
-torcross sea wall phase 1 of 3 (1979-1980): the torcross sea wall was first consrtructed in 1979, with three principle elemnts of 6m steel sheet piled toe with concrete capping beam, 5m reventment with a recurved sea wall
-concrete armourflex blockwork (1980s): 330m of 'armour flex' blockwork was installed in fron of the middle car park - however the blockwork suffered from storm damage meaning that the blockwork remains in poor conditions
-torcross sea wall phase 2 of 3 (2000): the seawall was later modified by the envrioment agency
-reactive road realignment (2001-2002) severe storms in jan 2001 caused a reduction in the crest within of 5m over length of 100m. the erosion undermined a 200m length of the A379 north of the junction with sands road resulting in temporary closure
-beach recycling (2005-2009) : in 2005 a number of bastions were installed along the back of the beach to protect the car park and monument area with the placement of beach material over the bastions
-bartons construction and beach recycling (2015); after the 2014 storm the back levels in front of the torcross defences did not recover as quickly as anticipated - this meant further action was required included the deposition of shingle from strete gate to torcross and the construction of six shingle bastions
-concrete seawall repairs (2016): following winter storms in 2015/2016 a section of the concrete sea walll required to be repaired as north of the slipway was severely damaged snd collapsed - fixing the sea wall cost a further 2.4 million however the reapair meant a reduced risk of flooding to 51 properties
-torcross sea wall phase 3 (2016): in 2016/2017 pilling and reinforced concrete capping beam added to the site along torcross sea wall frontage
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what are the main processes and evidence of them at slapton
-deposition: the formation of a bar creating a lagoon behind slapton sands barrier beach
-erosion: the evidence of stacks and stumps at 'two stones' and 'damming beggers
-erosion: the formation of wave cut platforms through hydraulic action and abrasion
-transportation: bar widens as we move northwards
-marine fransgression: the sediment on slapton sands
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ODISHA
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where is odisha located
located in the northern hemisphere in the east of india in the continent of asia
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what is odishas unique ecology
-odisha coastal zone has a wide variety of marine flora and fauna including mangroves, sea grasses, slat marshes etc
-large stacks of fish, marine mammals, reptiles and olive ridley turtles
-the chilka lake bird sanctuary boasts over 150 migratory and resident species of birds
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what are the dominant processes occurring in odisha
-opptunities of offshore oil and natural gas as well as sea bed mining
-the coast is lergely accreting with 36.8% eroding and 14.4% stable
-depostional rate is 46.8% highest occur in the mangrove forest
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odishas sediment
-35% of the coastal stretch contains minerals and heavy metal deposits
-erosion provides iomportant imuts of sediment that once transferred along the coast by waves, tides and currents is deposited to form beaches, dunes and barrier beaches
-rivers provide important transfers of sediment into the region in forming deposits
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managing odisha coast
-the odisha coast has recently developed an ICZM project to coordiante the actvities of the various stakeholders and promote the sustainable use of the coasts natural resources while maintaining the natural enviroment
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what is the aim of the project
-establish sustainable levels of economics and social activity
-resolve environmental, social and economic challenges and conflicts
-protect the coastal environment
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what are the issues trying to be resolved
-coastal erosion associated oceanfgrpahic processes
-biodiversity conservation
-livelihood security
-pollution and environmental quality management
-conservation of cultural/archaelogical assets
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who are involved in this project
-ministry of forest snd enviroment
-indian goveremnt
-the world bank
-goverment of odisha
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what are the proposed plans of the project
-the assessment and control of coastal erosion
-the development of ecotourism
-planting or replanting mangroves
-building cyclone shelters
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mangroves
-50 years ago coastal villages in odisha had an average width of 5.1km of mangroves protecting them
-todal an avergae of 1.2km are found
-they absorb strom surges with dense roots to help bind and build soils
-they ahve above ground roots, slow down water flow, encourage deposition of sediment and therefore reduce erosion
-parts of mangroves have been reclaimed for cultivation fuelwood and timber as well as for large scale shrimp farming
-bhitatkarikas delicate ecosystem is facing a major threat from the alteration of fresh water inflow due to construction of hydrological structures upstream
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turtles
-every year hundred and thousands of endangered olive ridley turles come to nest on some of odisha beaches
-the turtles hjowever arw at risk from uncontrolled fishing in prohibited areas and intesive tourism
-their mass nesting site on gahirmatha coast has been gradually shifting norhtward over the ladt 20 years due to coastal erosion
