coastal landscapes ✓ Flashcards
what is a cliff ?
Cliffs are shaped through erosion and weathering. Soft rock erodes quickly and forms gentle sloping cliffs, whereas hard rock is more resistant and forms steep cliffs
what is the wave strength (wave speed) ?
the speed that a wave is travelling
what is the wind duration ?
the length of the time the wind has been blowing
what is fetch ?
is the distance of open water over which the wind has been blowing
what is swash ?
the movement of water and load up the beach
what is backwash ?
the movement of water and load back down the beach
what are characteristics of destructive waves ?
- are formed by strong winds that have blown over large fetch areas
- they are powerful and lead to coastal erosion
- they are tall and deep
- closely spaced and frequent
what are characteristics of constructive waves ?
- associate with light winds
- waves have less energy and encourage deposition
- they are low in height
- they are widely spaced
- break gently
what are prevailing winds ?
are the dominant wind direction in an area
what is a beach ?
- A beach is a narrow, gently sloping strip of land that lies along the edge of an ocean, lake, or river
- beaches are formed when eroded materials transported by longshore drift and deposited by constructive waves along the coastline
what is a spit ?
- a spit is a permanent landform resulting from marine deposition
- it is a long narrow accumulation of sand or swing
- with one end attached to the land and the other projecting at a narrow angle
what is a bar ?
- is a ridge or barrier of sand or shingle which stretches across a sheltered bay
- it is only able to extend across a bay die tot he absence of a river
what is coastal erosion ?
is the removal of material from the coast by wave action causing the coastline e to retreat inland
what are rising sea levels in coastal erosion ?
- have risen by 12 cm in the past 100 years
- levels are expected to rise by another 11-16 cm by 2030
- warmer climate causes sea water to expand and also causes the ice sheets and glaciers to melt
what are storm surges in coastal erosion ?
- is a large scale increase in sea level
- as gale force winds drive water towards the coastline
what are groynes in coastal erosion ?
- are built to trap sand
- removing sediment from the system results in increased erosion further along the coast
what is dredging in coastal erosion ?
- it removes sand and gravel
- which causes increased erosion from the place that the sand and gravel has been taken from
how are building coastal defences in coastal erosion ?
- they are built to reduce coastal erosion
what are examples of coastal defences ?
- sea walls
- rock armour
- groynes
- beach replenishment
- marsh creation
what are the advantages and disadvantages of sea walls ?
advantages:
- prevents flooding
- protects tourist beaches
disadvantage:
- costs a lot more money
- has to be restored in a few years
what are the advantages and disadvantages of rock armour (rip rap) ?
advantage:
- can last a long time
- relatively cheap
disadvantage:
- makes access to beach difficult
- litter is trapped
what are the advantages and disadvantages of groynes ?
advantage:
- relatively cheap
- larger beaches attract more tourists
disadvantage:
- dangerous
- impede walking a long the beach
what are the advantages and disadvantages of beach replenishment ?
advantage:
- makes beaches wider
- makes beach safer
disadvantage:
- very expensive
- removing sediment from an area might effect that area
what are the advantages and disadvantages of marsh creations ?
advantage:
- takes pressure off areas in the coast
- creates intertidal habitats
disadvantage:
- costs a lot of money
- lost land
are sea walls soft or hard engineering ?
hard
is rock armour (rip rap) soft or hard engineering ?
hard
are groynes soft or hard engineering ?
hard
is beach replenishment soft or hard engineering ?
soft
is marsh creation soft or hard engineering ?
soft
what are the effects of erosion on settlements ?
- loss of land
- damage to peoples homes
- weight of buildings makes cliffs more vulnerable to collapse
what are the effects of erosion on tourism ?
- the resorts require coastal defences which alter the visual impact
- loss of land
what are the effects of erosion on infrastructure ?
- factories located near the coast can lead to water pollution
- factories at the coast can increase air noise water and visual pollution
- creates jobs and wealth for the local economy
what are the effects of erosion on agriculture ?
- sea levels rising reduces amount of productive agricultural land
- soil come salinized
- loss of wildlife habitats
- farming has protected many coastal habitats
what is a no intervention management plan ?
- zero engagement approach
- allowing natural processes to determine the form and distribution of habitat and species, with minimized or no artificial interruption in the natural succession of vegetation.
what is a hold the line management plan ?
uses hard engineering solutions to protect the coastline from further erosion
what is a managed realignment management plan ?
It allows the shoreline to move more naturally, however this movement is managed, usually by the construction of defences
what is an advance the line management plan ?
New defences are built further out in the sea in an attempt to reduce the stress on current defences and possibly extend the coastline slightly
what physical factors affect Holderness ?
- geology - cliffs are made out of weak boulder clay
- powerful waves - faces the prevailing wind direction
- marine erosion processes - high tide crashing waves undercut the cliff foot by erosion
- narrow beaches - beaches slow waves down reducing their erosive power
what are the coastal defences used in Holderness ?
- hard engineering methods
- such as groynes
- creates increased erosion south of Mappleton
what landforms are found on a discordant coastline ?
headlands and bays because it alternates between hard and soft rocks
what landforms are found on a concordant coastline ?
coves because outer hard rock provides a barrier to erosion outer rock can be punctured leaving softer rock to be eroded creating a curve in the rock creating a cove
how does a concordant coastline erode ?
- bands of differing rocks run parallel to coast
- outer harder rock provides barrier
- harder rock can be punctured
- leaving softer rock exposed
how does fetch affect the rate of erosion ?
longer fetch and stronger winds means stronger waves increasing the rate of erosion
how do destructive waves shape the coast ?
there is little sediment due to strong backwash which takes away most of the sediment
how do constructive waves shape the coast ?
more sediment due to weak back wash which leaves more sediment
how do storms affect the rate of erosion ?
storms makes more water which increases the amount of water hitting the rocks increasing the rate of erosion and the strong winds also increase the strength of the waves increasing the rate of erosion
how does the rate of erosion differ in the summer and the winter ?
rains more in the winter and it is more windy so there is an increase in the rate of erosion
how do prevailing winds affect the rate of erosion ?
prevailing winds make the rate of erosion higher on the side that is hit by the wind
how does erosion create headlands ?
- bands of soft rock such as clay and sand are weaker and can be eroded quickly
- this forms bays
- hard rock such as chalk is more resistant to erosion
- when softer rock is eroded inwards the hard rock sticks out into the sea forming a headland.
how does erosion create bays ?
- bands of soft rock such as clay and sand are weaker and can be eroded quickly
- this forms bays
- bay is an inlet of the sea where the land curves inwards
how does erosion create wave-cut platforms ?
- sea attacks the base of the cliff between the high and low water mark
- wave-cut notch is formed by erosional processes such as abrasion and hydraulic action
- dent in the cliff usually at the level of high tide
- the notch increases in size cliff becomes unstable and collapses creating a retreat in the cliff face
- backwash carries away the eroded material leaving a wave-cut platform.
how does erosion create cliff ?
- soft rock erodes quickly and forms gentle sloping cliffs
- hard rock is more resistant and forms steep cliffs
how does erosion create caves ?
- cracks are widened in the headland through the erosional processes of hydraulic action and abrasion
- the waves continue to weather away at the crack it begins to open up to form a cave.
how does erosion create arches ?
cave becomes larger due to being constantly weathered away and eventually breaks through the headland to form an arch
how does erosion create stacks ?
the base of the arch continually becomes wider through further erosion until roof becomes too heavy and collapses into the sea. This leaves a stack
how does erosion create stumps ?
the stack is undercut at the base until it collapses to form a stump.
how has urbanisation changed the coast ?
as more buildings and houses are being built closer to the edge of the coast coastal defences are being built altering where the sea is most powerful making different sites at a higher risk of damage
how has agriculture changed the coast ?
- emissions are polluting the coastal areas
- use of pesticides is harming species that live on the coast
how has industry changed the coast ?
factories and tourist attractions are being put in coastal areas polluting the areas
how has coastal recession made an impact on people ?
less land for people to build on and homes have to be abandoned and can’t be sold because they won’t be bought
how has coastal recession made an impact on the environment ?
reduces species and loss of habitats
what are the disadvantages of the soft engineering offshore reefs ?
- needs to be constantly replaced.
- the sand has to be brought in from elsewhere.
how has coastal coastal flooding made an impact on the environment ?
leads to loss of habitats for species reducing biodiversity and the food chains in that area
what are the disadvantages of the soft engineering offshore reefs ?
- needs to be constantly replaced.
- the sand has to be brought in from elsewhere.
what are the advantages of the soft engineering offshore reefs ?
- the natural marine ecosystem is only partly disrupted.
- dunes are allowed to stabilise onshore.
- rocks create a new intertidal habitat for marine wildlife.
what are the disadvantages of the soft engineering offshore reefs ?
- may cause a navigation hazard.
- can create an eyesore at low tide.
- can disrupt the recreational use of the beach, for example the use of jet skis.
how can hard and soft engineering change costal landscapes ?
can make areas further downstream more at risk of floods
where is Holderness located ?
coastal area in north-east England in Yorkshire
what is the significance of the location of Holderness ?
one of the most vulnerable coastlines in the world
retreats two metres a year
what is Holderness’ background ?
rapid erosion cliffs retreat up to 1.9 metres per year
what were the impacts on people’s lives in Holderness ?
- homes near cliff risk falling into sea
- property prices have fallen rapidly was worth £250,000 now worth £1
- accessibility affected because roads near the cliff tops risk falling in sea
- businesses at risk
- gas terminal is at risk only 25 metres from cliff edge
- 80,000 m2 farmland lost a year
