coastal landscapes Flashcards
Discordant coast example
West Cork, Ireland (headland and bay) Clear Island (detached island)
Concordant coast example
Lulworth cove, Dorest (Bay)
Croatia - Dalmatian Coastline
Baltic Sea, Germany - Haff coastline
Rock coastline example
Conochair Outer Hebrides, highest cliff in UK
sandy coastline example
Belgium 65km strech
estuarine coastline example
Severn Estuary Wales
Sand Dunes example
Braunton Burrows, UK
one of the largest systems in the UK, 400 plant species, 60 lichen species.
Conflict between nature conservation and local estate on issue of grazing
Bar example
Chesil Beach Dorset
Tombolo example
Portland Bill Dorest
Cupsate Foreland example
Dugeness Kent
Spit example
Hurst Castle, Hampshire
Define Littoral Zone
The wider coastal zone ranging from adjacent land areas to shallow offshore areas,
Closed system in dynamic equilibrium
Eleven littoral zones in England and Wales, separated by topography and landforms such as peninsulas.
Sections of a littoral zone
Backshore - above high tide, only effected by waves during storms
Foreshore- between high and low tide, main wave activity.
Nearshore- intense human activity e.g fishing, shallow water, transfer of sediment by currents (physical system)
Offshore - deep water, limited activity
Rocky coastline characteristics
Formed from cliffs of variable hardness, dominated by erosion and transportation, destructive waves (high energy coast) long fetch abrupt transition from land to sea storm conditions are common caves, arches, stacks, wavecut platform
Sandy Coastline features
Can be sandy or estuarine Gentle transition from land to sea Dominated by deposition constructive waves (low energy) short fetch beaches, bars, sand dunes, mudflats
Formation process classification
primary coasts - dominated by land processes
secondary coasts - dominated by marine based processes
Relative sea level change classification
Emergent coasts - coasts rising relative to sea level
Submergent coasts - coasts flooded by sea.
Change can be isostatic (land moving relative to sealevel) or eustatic (sea moving relative to land)
Tidal range classification
Microtidal - 0-2m
mesotidal 2-4m
macrotidal above 4m
wave energy classification
low energy - sheltered coast, low wind and limited fetch= small waves
high energy- exposed coast, prevailing winds, long fetch = powerful waves.
cliff profile definition
The height, angle and features on a cliff face.
cliff profile types
marine erosion dominated - steep face, active undercuting, limited cliff debirs, constant erosion and transportation of material away from the cliff base.
sub-aerial process dominated - gently sloping profile, accumulated debris, limited erosion at base.
Erosion resistance of rock type influences
- how reactive minerals are in rocks when exposed to chemical weathering
- clastic or cystalline
coastal accretion definition
The deposition of sediment, being stabilised by vegetation, causing the seaward growth of the coastline.
geological structure
The arrangement of rocks in three dimensions.
strata- the different layers of rock and how they relate to each other.
deformation- the degree to which rock units have been tilted/folded by tectonic activity.
faulting- the presence of major fractures that have moved rock from their original position.
freeze-thaw weathering
mechanical, water expands by 9% in volume when freezing exerting a force to widen cracks, repeated cycles.
any rocks with cracks/fissures away from salt spray, relatively uncommon in UK
salt crystallisation weathering
growth of salt crystals in cracks when sea water evaporates exerts a breaking forces.
more common in hotter drier climates
carbonation chemical weathering
the slow dissolution of limestone due to rainfall which reacts with calcium carbonate.
hydrolysis chemical weathering
the effect of water and dissolved CO2 breaks down minerals into new clay minerals and material in solution
oxidation chemical weathering
the addition of oxygen to minerals produces oxides which expand in volume contributing to mechanical breakdown. Common on iron compounds
Biological weathering
action of plants, bacteria or animals.
plant roots or rock boring (animals bores and secrete chemicals on rocks)
concordant coasts
pacific coasts
rock strata runs parallel to the coast line
Dalmatian coast line
location: Croatia
limestone was deformed by tectonic activity into s series of anticlines and synclines that run parallel to the modern coastline.
Synclines drowned by eustatic change during Holocene when sea levels rose by over 30m.
Left anticlines as a series of long narrow island running parallel to the coast.
Synclines were previously eroded by abrasion from rivers.
Haff coastline
location: Baltic sea
Result of previous glaciers, meltwater rivers deposited material that was then transported as sea levels rose during Holocene.
Forms a parallel bar of unconsolidated sediment along the coast.
The long sediment ridges are gradually consolidated by a process of succession, being more vegetated and growing sand dunes. Lagoons form behind.
discordant coastlines
Atlantic coasts
Different rock strata intersects the coast at 90 degree angles, causes the coastline to vary.
headlands and bays
discordant coast, marine processes, differential rates of erosion,
crescent shaped bays=deposition forms beaches, may be long and narrow
headlands are resistant remaining jutting out, especially resistant remains as detached islands when the headland erodes,
concordant coasts=rock strata has a pre existing weakness.
wave refraction at headlands
In deep water wave crests are parallel.
Shallow offshore water near a headland slows a wave and increases its wave height. Erosion
In bays the wave crests curve to fill the bay and wave height decreases.
Lulworth cove
Hard Portland limestone and resistant Purbeck protect landwards less resistant rock.
Pre existing weakness (e.g tectonic fault line) has been exploited by marine erosion.
Less resistant rock eroded into coves, back of coves protected by limestone preventing further erosion inland
factors affecting cliff profiles
resistance of rock to erosion
dip of rock strata in relation to the coastline
dip
angle of the rock strata in relation to the horizontal, caused by tectonic movement.
horizontal dip
vertical or near vertical profile with notches showing differential rates of erosion within strata.
seaward dip high angle
low angle profile, vulnerable to rock slides, sloping with one rock layer facing the sea
seaward dip low angle
profile may exceed 90 degrees, areas of overhang, vulnerable to rockfalls,
landward dip
steep profiles, stable cliff with reduced mass movement, higher rates of erosion.
geological features comparison
Faults - major weaknesses, either side is heavily fractured and broken
Joints - occur in most rock, regular patterns dividing strata into blocks.
Fissures- smaller cracks in rocks, often centimetres or millimetres wide.
igneous rock
formation- crystallised magma
Very slow erosion rates
Crystalline, few joints
e.g Granite
Metamorphic rock
formation- changes in sed/ig rock structure due to high pressure/temperature
slow erosion
crystalline but show foliation, often folded and heavily fractured
e.g marble
sedimentary rock
formation- sediment that has been deposited then compressed and cemented.
fast erosion
clastic, geographically young erode faster, many bedding places and fractures.
e.g shale
unconsolidated sediment
newly deposited sediment, the easiest to erode.
permeability effect on erosion
Less resistant to erosion.
Permeable rocks allow water to flow through them.
Groundwater flow removes cement that binds sediment.
High pore water pressure, increases chance of slumping.
Springs cause surface runoff erosion.
lithology erosion exceptions
limestone- sedimentary but is crystalline so resistant
sandstone- ancient is compressed over millions of years so is resistant
igneous- recently erupted volcanic lava flows and tephra are easy to erode.
How does vegetation stabilise sediment?
Roots bind sediment together.
Provide protective layer against moving water + marine erosion.
Provide friction with wind reducing wind speed and erosion.
Succession definition
The changing structure of a plant community from initially bare sediment to diversity rich colony.
Each step is called a seral stage, results in a climatic climax community such as a psammosere (sand dune ecosystem)
Role of pioneer plant in embryo dune
Stabilise mobile sand with their roots
Reduce wind speed at sand surface allowing more material to be deposited
Add dead organic matter to the sand contributing to soil formation.
Explain the formation of waves
Friction between the wind and water causes energy to be transferred.
Generates ripples which when sustained grow into waves.
Circular particle movement in open water but no net forward movement.
Size depends on strength/duration of wind, water depth and wave fetch.
UKs largest waves
Cornwall, 4000km fetch from Florida, sustained southwesterly wind.
swell waves
Gentle spilling waves, appear on the beach when wind has dropped but remaining waves gradually may their way onshore.
Waves breaking
At water depth of half the wave length the bottom of the orbital motion touches the seabed.
This generates friction slowing the wave trough.
The waves length decreases and the height increases causing waves to bunch together.
The wave crest eventually outruns the trough and the wave topples forward.
Constructive waves
spilling waves
low wave height <1m
long wave length up to 100m
gentle and flat
stronger swash than backwash deposits sediment up the beach forming a ridge or berm.
This beach morphology means most of the backwash percolates the beach
destructive waves
plunging waves wave height over 1m wave length of 20m strong backwash erodes beach material and deposits it as an offshore ridge or bar. may result in storm beaches
beach morphology
The shape of the beach including the width, slope and type of sediment found at various locations.
long term changes to beach morphology
sediment supply from rivers is reduced due to the construction of dams.
climate change influences e.g more destructive waves
interference of sediment supply along the coast due to coastal management.
when does most erosion occur?
Largest waves
Waves at 90 degrees to the cliff face
High tide
Heavy rainfall, percolation and surface runoff weakens he cliff.
Debris from previous erosion has been removed from the cliff base.
Spit
A sand or shingle ridge extending along a turn in the coastline.
Longshore drift.
Length determined by wind and secondary currents.
Winds in an opposite direction to the prevailing wind caused a recurved end landward into shallower water.
beach
A swash aligned features, wave breaks at 90 degrees to the coast moving and depositing sediment into a bay. Wave loses energy due to wave refraction
tombolo
A sand or shingle bar that attaches the mainland to an offshore island.
Wave refraction causes an area of calm water and deposition between the mainland and island.
Opposing longshore currents may play a role, making the formation similar to a spit.
Bar
A sand or shingle beach connecting two areas of land with a shallow lagoon forming behind.
Continued longshore drift extends a spit
Cupsate foreland
Roughly triangular shaped features extending out from a shoreline
Growth of two spits from opposing longshore drift direction.
Difference between weathering and erosion
Weathering is the in-situ breakdown of rocks, it is by mechanical, biological or chemical processes it does not involve any movements.
Erosion is the breakdown of rocks due to an external force which then transports the material to a new location.
plant roots
biological weathering
trees and plant roots growing in cracks and fissures forcing rocks apart, contributes to rockfalls
rock boring
Species of clams and muscles bore into fissures in rocks, may also secrete chemicals that dissolve rocks.
sedimentary rocks located in the inter-tidal zone.
Comparing types of weathering
Mechanical - exertion of a physical force
Chemical weathering - involves a chemical reaction and generation of new chemical compounds
Biological weathering - action of plants, bacteria and animals speeds up mechanical weathering.
mass movement
An umbrella term for the down slope movement of cliff material due to the force of gravity.
The sediment cell model
Coast split into eleven littoral zones
Long stretches of coastline that exist as a closed system in dynamic equilibrium
The processes or erosion, transportion and deposition balance the input/output of sediment between sources, transfers and sinks.
The boundaries are determined by topography and landforms such as peninsulas which act as natural barriers preventing the transfer of sediment between cells.
Onshore and offshore processes contribute to the sediment store.
Unlikely that they are fully closed with variations in wind speed and currents (storm) probably transferring fine sediment.
Many sub-cells of smaller scale
Gravity settling
Type of deposition
Energy of transporting water becomes too low and large sediment is deposited first.
flocculation
Type of deposition
Small particles like clay clump together sue to chemical or electrical attraction becoming too heavy to be carried in solution
longshore drift
drift aligned coasts
Prevailing wind influences swash to approach the coast at an angle.
The backwash retreats at a 90 degrees angle due to gravity.
Results in net transport across the beach when repeated in cycles
Rotational slides formation
Seaward dip in bedding plane between permeable and impermeable strata.
Weathering and cracks at the top off the cliff allow the permeable layer to become saturated by heavy rainfall.
This creates high pore water pressure on the bedding plane above the impermeable strata.
Marine erosion exploits weaknesses in geological structure (fissures) undercutting the cliff.
This generates instability, the whole cliff starts to pivot and rotate around a surface failure point.
currents
Flows of seawater in a particular direction due to wind and water density, may be continuous or sporadic.
define mass movement
An umbrella term for the downslope movement of rock and soil due to the force of gravity
how is mass movement classified
speed of movement
type of material
Rotational slides overview
Generally sedimentary rock or unconsolidated sediment
difficult to manage due to multiple causes
deep failure in cliff slowly moves a large volume of material
Rockfall
Dislodged by mechanical weathering or hydraulic action
undercutting/wave cut notches leads to large rockfalls
large and rapid
generally horizontal dip
Topple
influenced by geological structure
steep seaward dip and undercutting
Translational slide
low angle seaward dip prevents rockfall
materials slide down towards the sea
more rapid and downwards than rotational slides.
Flow
clay and unconsolidated sediment
heavy rainfall and high tides cause rock to become saturated
lose cohesion and flow downslope
enhanced greenhouse effect
cause of anthropogenic climate change
Thicker layer of greenhouse gases caused by human activity absorbs infrared radiations and re-radiates as thermal radiation.
Sea level rise, warming temperatures.
Bangladesh impact from climate change
Three major cyclones since 1970 costing £3.5 billion and killing 554,000/
30-70% of the country is flooded each year
2050 17% of land is expected to be underwater displacing 35 million
1/3 of country works in agriculture. saltwater intrusion is expected to decrease rice production by 28%.
Bangladesh climate management
Switch to aquaculture- shrimp and crab farming
Building over 200 new cyclone shelters
Developed weathering forecasting and early warning system
Florida impact from climate change
located in “hurricane valley”
2018 Hurricane Michael first category five storm since 1992.
Only 2% of coral reef remains, threatens 70,000 jobs and biodiversity.
Rate of sea-level rise doubles every seven years.
Miami $15 billion of property could be underwater by 2050,
Florida climate change management
State wide construction code since 1992
“Noahs Ark” collecting and preserving coral chunks
Spends 50 million annually on beach erosion including beach nourishment.
Maldives impact from climate change
2100 77% of Maldives expected to be underwater
Tourism to coral reef supplies 70% of GDP
Water shortages due to saltwater contaminating supply.
Maldives climate change management
Capital City Male is ringed by 3m high seawall
Building of an artificial island from coral sediment costing US$32 million
What is a delta?
A deposition of sediment at a river mouth caused by decreased water energy in stagnant sea water.
Particles clump together by flocculation
Why is the Nile Delta important?
41% of Egypt’s population (40 million)
Fertile soil supports 63% of agricultural land
85% water resources
Over 500 plant species and important route in bird migration
Why is the Nile Delta densely populated?
Fertile soil and less arid environment compared to rest of Egypt.
Mediterranean Sea ideal location for trade in landlocked Africa
Ports and industry, rapid urbanisation around historical fishing and farming industry.
How have humans exacerbated the Nile Delta sinking?
1960s Ethiopia Dam, decreased sediment renewal by 98%.
Economic and demand pressure caused switch to aquaculture, purposely flood land, over 8,000 hectares of land is devoted to fish production.
Urban area grown by 60% annually in early 2000s increased soil erosion
Egypt’s second largest producer of natural gas, drilling through sand layers increases subsidence
Environmental impacts of climate change in the Nile Delta
Warmer climate will increase algae blooms and eutrophication, reducing biodiversity. Home to 500 plant species.
Economic impacts of climate change in the Nile Delta
Saltwater intrusion decreases soil fertility, agriculture expected to decrease by 47% by 2060.
Also causes water shortages only 660cm3 of freshwater per person per year.
Social impacts of climate change in the Nile Delta
increased risk of flooding 2015 flash flood killed 60.
Town of el-max neighbourhood forced to migrate due to risk of flooding.
Shanghai threat from climate change
17.5 million could be displaced
One of the worlds biggest trading ports.
Current threats from erosion in the Nile Delta
saltwater intrusion, damages soil conditions agriculture expected to decrease by 47% by 2060.
water shortages only 660cm3 per person per year, expected conflict.
Alexandria expected to be underwater, citadel foundation eroding.
2015 flash flood killed 60 people
warmer water = aglae blooms and eutrophication.
How does wind direction effect recession?
changes daily, dominant wind determines wave direction and produces the largest waves.
longer fetch provides larger waves.
Maximum erosion is produced by the most dominant waves with the longest fetch.
Wind direction example
Land’s End Cornwall,
prevailing wind from Atlantic Ocean, comes from the SW over a large fetch producing large destructive waves.
How does tides effect recession?
At high tides the sun and moon are aligned so stronger gravitational pull.
At low tides the sun and moon are perpendicular to each other.
Four times a year the moon is closer to earth producing larger tides.
Higher tides exposes more of the cliff to marine processes and increases the frequency of destructive waves.
How does weather systems affect recession?
Seasonal weather patterns are based on high pressure and low pressure areas.
At low pressure air masses are at different temperatures, rising air rapidly creates strong winds and waves.
High pressure creates calmer conditions and smaller waves.
In winter the difference in temperature between the poles and the equator is at its greatest, this creates stronger low pressure conditions. Faster winds speeds more destructive waves and coastal recession.
Weather system example
North Atlantic UK anticlockwise spirals of winds.
How does sub-aerial processes affect coastal recession?
Weathering and mass movement accelerate coastal recession.
More strongly linked to seasonal climate changes.
Mass movement deposits material at the base of the cliff which can be removed by longshore drift exposing the base of the cliff.
Weathering produces weaknesses in the cliff strata that can be exploited by marine processes
Sub-aerial processes examples
French side of the English Channel, cliff failures due to weathering.
North Norfolk, sea wall defences useless. Heavy rainfall saturates the cliff causing high pore water pressure and slumping. Clear scars and terraces are left across the promenade
Impacts of global warming on coastal recession.
More heat in the atmosphere intensifies low-pressure systems causing stronger winds and larger waves.
Increases the intensity of tropical storms and storm surges.
Every 1cm in sea-level rise accounts for 1m horizontal erosion.
Unbalances dynamic equilibrium of sediment cells.
Increased winter conditions and erosion.
Holderness erosion rates.
Fastest erosion rates in the UK, 1.25m a year
low elevation zones statistic
By 2060 12% of the worlds population will live in low elevation coastal zones.
Local factor one making population vulnerable
Land reclamation- the Netherlands.
Half the Netherlands is below sea-level.
Drain wetlands to make usable for agriculture and other development.
Increases vulnerability to sea level rise and storm surges.
Coastal dikes built around the reclaimed land could fail, put area at higher economic risk due to tulip fields.
Local factor two making populations vulnerable
Mangrove removal - Java
30 million people suffer from coastal flooding in 3000 villages.
Mangroves removed for aquaculture development and groundwater extraction prioritising economic growth
Mangroves would act as a natural buffer against marine erosion, reduce wave height by 40% over 100m due to friction.
Stabilise and trap sediment.
Global factor making populations vulnerable
Increased storm surges.
A storm surge is a temporary increase in sea-level rise due to wind pushing water on land and changes in atmospheric pressure during tropical storms.
In 1990 200 million people lived in areas vulnerable to storm surge flooding
North sea storm surges
1953 2000 killed in Netherlands, 300 in Uk from2-3m surges.
Built Thames storm surge barrier to 1 in 1000 year standard.
36 hours warning system.
2007 storm surge in Norfolk, 4m surge breached sea-walls damaged conservatories and holiday accommodation. 700 evacuated.
Bangladesh storm surges
1971 cyclone 3.8m storm surge.
1988 flood covers 3/4 of the country .
Bay of Bengal number one global surge hotspot.
Hurricane Sidr 3,000 dead
Shanghai storm surges
Japan 2 million people live below sea-level
20th century land subsided by 2.8m
Kiribati overview
Settlement beginning 2000 years ago 33 atolls, 21 inhabited only 6m above sea level GDP £1,685 (LIC) Fear cultural extinction of loss of land, first ever climate change refugees
Causes of problems in Kiribati
from 1993 sea levels have increased by 3mm per year
Global average temperatures have risen by 0.85 degrees in 100 years
Frequent cyclones damage atolls
Increase in wave height with king tides due to storm surges.
Economic impacts of sea-level rise in Kiribati
Loss of vegetation due to coastal erosion
Loss of agricultural sales from coconut trees, papaya trees etc.
Agriculture makes up 25%of GDP.
Environmental impact of climate change in Kiribati
coral bleaching, making atolls unsustainable
King tides polluting fresh water sources, salt water intrusion makes drinking water and agriculture unusable.
Social impacts of climate change in Kiribati
Could disappear within 30 years
Rapid urbanisation to capital city half the population live here, large sewage disposal and water pressure.
Tebunginako 200m lost to sea displaced people from traditional homes.
Displacement from global warming statistic
1.7 million people in the Pacific alone could be displaced by 2050 because of rising sea levels associated with climate change.
Economic losses of coastal recession and flooding
In developed countries
Miami £15 billion property could be underwater by 2050.
Australia a 1m sea rise would flood 5 power stations, 75 hospitals and £87 bn worth of commercial property.
Infrastructure and property expensive to repair.
Economic losses of coastal recession and flooding
In developing countries.
San Fernando expected to loes 123,000m2 of beach with £95,000 tourist revenue per year.
Nile delta agriculture to decline by 47% by 2060, main source of employment.
Social losses of coastal recession and flooding in developed countries
North Sea 3m strorm surge in 1957 killed 2000 in the Netherlands and 300 in the UK.
Hurricane Sandy 350,000 homes were destroyed in new Jersey, mainly insured losses of £70 billion
Shanghai could be underwater by 2050, displacing 17.5million.
Social losses of coastal recession and flooding.
In developing countries
Typhoon Haiyan 2013, 6 million people displaced from Philippines, 20 000 travelled to capital city.
Vietnam 70% at risk of flooding, 2020 two consecutive floods displaced 90,000 people.
Environmental refugees.
Kiribati
Fairbourne Wales
Louisiana, US
Tuvalu Pacific Ocean
Fairbourne Wales
Environmental refugees
decomission of village expected to start in 2045, will displace 850 residents
housing prices decreased by 40%
Only 3m above sealevel
Louisiana US
Native American tribe lost 98% of land to Gulf waters
Only 60 members remain.
Fear cultural extinction
Tuvalu Pacific Ocean
Produce less CO2 than a small American town
average atolls only 2m above sealevel
5,000 left homes, travel to New Zealand
Mitigation and adaptation in developed countries
Florida £50 million a year on beach nourishment.
Netherlands Deltawerken project, spent £3 billion on the construction of dams and flood gates to control storm surges.
London Thames Barrier 1 in 1000 year standard, prevents greater london floodplain from flooding.
Mitigation and adaptation in developing countries
Maldives built three meter seawall around capital city Male, Mangroves for the Future education scheme
Bangladesh 200 new cyclone shelters
What is sustainable coastal management?
Managing the wider coastal zone,
considers economic livelihoods and social wellbeing
Ensures safety from coastal hazards
Minimises environmental and ecological hazards.
What is a shore line management plan?
A method of sustainable coastal management. Considers: Cost analysis Environmental impact assessment Feasibility Risk Assessment Resident attitudes
What is hard engineering?
Form of coastal management, aims to stop or alter physical processes to prevent coastal erosion.
What is soft engineering?
Form of coastal management, aims to work with natural processes to reduce coastal erosion and flood risk.
Physical risks at the Holderness coast
Weather - winter storms and heavy rain saturate cliffs
Waves- north east long fetch, destructive waves, longshore drift and suspension
Geology- chalk resistant headlands, boulder clay easily eroded Holderness bay
Human risks at the Holderness coast
People - large retired population, increase in holiday and leisure facilities.
Interfering with natural processes- sediment starvation effect.
Global warming - rise in sea levels and increased strominess
Holderness cliffs
Include Hornsea and Mappleton
bolder clay, easily permeable, slip planes and slumping
stabilising vegetation has been removed for urbanisation.
Hornsea
Holiday resort with promenade and hotel frontage
Repair and new groynes costing £5.2 million, replanted sand dunes and raised seawall.
+ve low lying coastal development continued
-ve sediment starvation at Mappleton
Mappleton
1988 Cliff Road falling into sea
1991 £2.1 million EU funding for rock groynes, revertments, cliff nourishment and degrading.
+ve allowed development of car park of toilet
-ve early signs of slumping
-ve groynes undermined, eroding of car park
-ve sediment starvation, defences not strong enough.
Easington
Natural gas terminal provides 24% of North Sea Production.
£4.5 million scheme including rock armour and cliff re-profiling
protects national interest not village, conflict with local environmental groups due to surrounding wildlife habitats.
Spurn Head
managed retreat,
could not afford to protect spit, abandoned in 1995
+ve reduced local authority costs
-ve loss of heritage site
-ve lifeboat men and coastguard homes may be displaced.
Sustainable coastal management
Developing countries
The Maldives
97% of inhabited islands experience erosion
Conflict- money being concentrated on capital Male and fishing communities not remote areas or commercial business.
Mangrove for Future - education on protecting and importance of mangroves
The Global Environmental Facility - small grants given to help develop farming and fishing.
Sustainable coastal management
Developed countries
Essex
The Essex Wildlife Trust purchased Abbots hall for £645,000.
Allowed to turn into salt marsh by managed retreat as cheaper than protecting.
-ve Fisherman concerned about damage to oysters
-ve RSPB concerned about change to bird habitats.
What is a shoreline management plan also known as?
Integrated Coastal Zone Management (ICZM)
key idea of a ICZM
Considers the whole coastal zone including rivers.
Considers human activity including economic benefit.
Aims to improve the quality of life but also be environmentally appropriate.
Rio Earth Summit 1992
Prioritised coastal erosion as a global issue for sustainable development.
Believed issues are better handled when all citizens are involved.
Invested $13 billion into protecting and managing the oceans.
Types of shoreline Management plan
Hold the line
Advance the line
Managed retreat
Do nothing
Factors to consider when managing the coast.
Economic feasibility Environmental sensitivity Land use and value Impacts on coastal processes in the entire sediment cell Political, social and economic reasons.
The promontory effect Norfolk.
Failed to consider long term impact on the sediment cell.
Protection of headlands causes more pronounced headland extension in the future will block long shore drift in the future.
Summary of Norfolk shoreline management plan
Managed retreat and realignment.
Some hold the line.
Organised by Norfolk district council and environmental agency in 2004.
Happisburg Norfolk
Losers
Suffer cliff undercutting and collapse
1996 did not qualify for hold the line funding under DEFRA so no active intervention.
2025 expected the lose 25 homes, caravan park and have no access to the beach or lifeboat.
Overstrand Norfolk
Losers and Winner
rotational slides and slumping
1996 DEFRA hold the line funding
2004 changed to hold the line until defences fail then managed retreat
2055 expected to lose 135m including 55 homes, school and cromer golf club.
Conflict over cost analysis with locals valuing the land at £90 million and the council at £8 million.
Sea-palling Norfolk
Winners
1953 extensive storm surge and flooding
Environmental agency aims to protects Hampstead Marshes and Broads National Park
1990s £11 million spent on offshore rock reef and seawall.
Ecological and economic significance benefits small population.
Porlock Bay SMP
1996 Sea wall broke causing extensive flooding.
Decided to do managed retreat
-Farmers no insurance
-Locals, bus route cut in two
+ environmentalists recreate tidal habitat and encourage salt marsh plant/ insects
+local council saves money.
Minehead SMP
cost of further flooding estimated at £21 million.
Spend £12 million on hard engineering strategy e.g seawall and rock armour.
+protects Butlins holiday resort opened in 1962.
