Physical - Coasts Flashcards
What are inputs (in terms of systems)?
Energy and matter which are added into the system
What are outputs (in terms of systems)?
The end result of a system and the aspects of energy and matter that leave. Includes:
- Sediment removed beyond local sediment cells
- Depositional landforms
- Erosion landforms
- Dissipation of wave energy
- Accumilation of sediment above the tide line
What is a system?
An assemblage of interrelated parts that work together by way of process
What is an open system? Give a geographical example.
Matter and energy can be transferred.
Eg. Coastal systems
What is closed system?
Only energy can be transferred. Eg Planet Earth
What is an isolated system?
Neither energy or matter can be transferred
What is positive feedback?
When the effects of an action are amplified or multiplied by subsequent knock-on or secondary effects. (usually bad)
What is dynamic equilibrium?
When inputs and outputs of a system are in balance with use of feedback loops
What is negative feedback?
The effects of an action are nullified by its subsequent knock-on effects (usually good)
What sort of system are coasts?
An open system whereby matter and energy can be transferred
What is aeolian transportation?
Transportation with (suspended in) wind
What is the energy source of waves?
Wind as a result of low pressure rising under high temperatures
What is fetch?
The distance wind travels across the sea (or flat expanses of land)
From what points do you measure wavelength?
From crest to crest (OR trough to trough)
What is wave frequency?
How often a wave passes
What is wave height?
The distance (height) from crest to trough
What is swash?
The movement and deposition of sediment onto a beach
What is backwash?
The erosion (including removal) of sediment from the beach into the sea.
What is wave refraction?
The slowing down of waves in one location due to shallower water causing them to curve round into areas of faster current (in deeper water)
More erosion of headlands, forming arch, stack and stump
Give some characteristics of constructive waves.
- More elliptical orbital motion
- Long wavelength
- Short wave height
- Low energy
- More swash, less backwash
Give some characteristics of destructive waves.
- Short wavelength
- Long wave height
- High frequency
- High energy
- More backwash, less swash
Give a feedback loop for waves.
- Constructive waves build up a beach (with swash), steeper profile
- Steeper beach causes waves to become more destructive
- Destructive waves have more backwash, so beach is eroded and becomes shallow
RESTARTS
What is a spring tide?
Extremely high or low tides
Under what conditions do spring tides occur?
Sun and moon are parallel, causes larger ‘bulges’ of water due to more gravitational pull
Under what conditions do neap tides occur?
Sun and moon are not in alignment, so the water bulges are less big
Why are high tides helpful?
- The rise in sea level also rises the sediment suspended within it
- Builds up a bank of shingle to rear of shore and offshore
- Replenishes salt marshes with salty water
What is the tidal range?
The total area/distance tides affect a coastline (between HWM and LWM)
What are the 3 types of ocean current?
- Literal drift
- Rip currents
- Up welling
What are rip currents?
- Very strong currents moving away from a coastline
- Occurs due to a breaker zone or headland, forcing water to increase in speed
- Very localised
What is upwelling?
A type of current caused by the movement of cold water from the ocean floor to the surface. Replenishes nutrients and contributes to global ocean currents
What global ocean current affects the UK?
The gulf stream
Name the 6 major sources of sediment into coastal areas.
- Glaciers
- Off shore
- Cliff erosion
- Rivers
- Wind
- Literal drift
Why are rivers a source of sediment?
Deposit sediment in mouth of estuaries before being worked by tides
How do glaciers act as a source?
Glaciers calve out valleys, pic up and carry rocks in the process
What are components in systems?
Parts of a system which are all involved in its process
What are coastal system stores?
A non-permanent place where sediment is kept in system
What are coastal system sinks?
A (hypothetically) permanent place where sediment is kept forever. MORE DEPOSITED THAN RELEASED
What is a sediment cell?
- A stretch of coastline usually bordered by two headlands which acts as a (more closed) system
- Only a model, rarely actually acts as a separate system
How many sediment cells are there on England’s coastline?
11
What is accretion?
The build up of material
What is meant by a “Sediment budget”?
A combination of wave, current and tidal action which forms a beach or other prepositional landform. Includes losses and gains
What are “losses” in a coastal system/ sediment budget?
When sediment is deposited in a sediment sink
What can cause an upset in coastal systems?
Storms and river floods. Also, and increasingly so, human activity is a factor
Give an example of how human activity has disrupted a system. What happened their?
Hallsands, Devon
- Offshore dredging ocured in 1895, under government orders
- Beach subsided and retreated, much less wide
- Storms caused more and more damage until it was abandoned in early 20th century
Give an example of a regional study into coastal erosion conducted by the USGS.
The south Carolina Coastal Erosion Study
What was the main objective of the South Carolina Coastal Erosion study?
To determine the geologic and oceanographic processes that control sediment movement along the region’s coastline. Allowed for projections to be made
What is a wave-cut notch? How is it formed?
Where the cliff overhangs. Formed when softer bands of rock are eroded with harder rocks laying on top of them. Eg: Clay eroded laving Limestone over the top. Depends on LITHOLOGY
.
What affects the resistance of different types of rock to weathering?
The materials in the rock, the coherence of the materials and how compressed the constituent materials are
What is the difference between weathering and erosion?
Weathering: The disintegration of rock slowly, in situ
Erosion: The subsequent removal of rock
Give some example of physical weathering.
- Exfoliation (heated by sun)
- Freeze Thaw
- Wind power
- Hydrolic power
- Expansion of wet rocks
Give some example of chemical weathering.
- Crystallisation with salt
- Carbonation (dissolved by acid rain + sea water)
- Oxidation of iron-containing rocks
Give some example of biological weathering.
- Plant roots
- Excavation of nests/burrows by animals
What is a rockfall?
Cliffs undercut, overhangs form and fall down after time under gravity (often in storms)
What is a landslide?
Heavy rainfall can cause rocks and other sediment to loosen, starts slow, increasing in speed
What is a Runoff?
The movement of water over land. At the coast this is often a stream which causes vertical erosion
What are mudflows?
Soils become incredibly saturated after a long duration of persistent, heavy rainfall. Surface becomes fluid and flows downhill - depends on angle of hilside
What is slumping/rotational slip?
Soft rocks (or clay) slide over harder rocks, so soil slides down a concave slope. Common on glacial deposits
What soil creep?
The very slow movement of soil down a shallow slope, likely to the the result of saturated soils
What role does weathering and erosion play in a coastal system?
By removing material away from a source and depositing at a sink offshore (such as offshore bar) the force of the waves is reduced so less erosion occurs
What is hydraulic action?
The force of water/waves creating negative pressure, ripping off pieces of rock. Very strong, no debris involved
What is cavitation?
The expansion of a small crack in rock (as a result of freeze thaw) by hydraulic action
What is abrasion?
Sand suspended within the water wears away rock faces (sand papering effect), common on wave cut platforms
What is wave quarrying?
Combination of cavitation and hydraulic action. large waves in a storm enter gaps in the rock under extremely high pressure
What is corrosion? (weathering)
Calcium-rich rocks like limestone are dissolved
What is attrition?
Rocks suspended in the sea are slowly broken down/rounded by clattering together frequently
What is the term used to describe material transported in the wind?
Aeolian transportation
What is marine transportation?
Movement of material in the water
What is the movement of sediment along a coastline called?
Littoral drift
What are the two types of aeolian transport?
- Surface creep (rolling along the surface
2. Saltation (picked up in wind)
What are the 4 types of marine transportation?
- Traction (large rocks rolling along sea bed)
- Saltation (particles bouncing on sea bed)
- Suspension
- Solution (solutes dissolved in water)
What causes coastal deposition?
Low energy environments where the effects of waves, storms and tides are reduced
How do some coastal engineering strategies cause +ve feedback loops?
By reducing the effects of erosion or LSD at a particular location the effects are magnified elsewhere on the coastline where energy is highest
What type of ecosystem are sand dunes?
A psammosere ecosystem
What are inputs to sand dunes?
Sand, onshore prevailing winds, long tidal range, pioneer species and obstacle to trap sand
Outline the formation of sand dunes.
- Large tidal range exposed at low tide, wind blows sand inland
- An obstacle traps the sand so it builds up on the windward side
- The leeward side of the obstacle is sheltered so further sand is deposited
- Land is warmer than sea, causing lower pressures - aiding further deposition
- Sand progressively builds up and becomes fixed in place by pioneer species
What are “mobile dunes”?
The fore and yellow dune, move over time - hence the term moblie
What re the youngest dunes in sand dune succession?
Embryo dunes (<5 years old)
What measures are used to prevent footfall on sand dunes?
Dune fences can be erected
How do plant roots aid the sand dune ecosystem?
They retain water as it is a very dry, well-drained environment
How much sand is exposed on a healthy dune?
10-25%
Name some plant species found on sand dunes.
- Sand Sedge
- Sea Buckthorn
- Maram grass
- Reedbeds
- Heathland species
- Alder Carr
- Xmas trees are sometimes added for stability
What are blowouts in dunes?
Wind carves out a depression in dunes (promoted by footfall/animals weathering). Forms a dune slack
What are the dunes furthers from sea called?
Mature dunes. No longer interfered by coast
How old are most mature dunes?
400 years old
Name some threats to sand dunes.
- Agriculture
- Wildfires
- Interception of LSD, prevents transportation of sand, narrower beach
- Trampling by humans and sometimes animals
Name some management strategies for sand dunes.
- Education (leaflets by national trust)
- Signposting to prevent trampling
- Planting of maram grass + xmas trees
Give an example of sand dunes.
Studland, Dorset
How old are some of the dunes at Studland?
700 years old
What type of plant is maram grass?
A xerophyte, thriving in low water avaliablity
What is the term used to describe sand dunes in dynamic equilibrium?
Plagioclimax
What does inundation mean?
Flooding of inland areas with sea water, becoming area of sea
What is an ecosystem comprised of salt-tolerant species called?
A halosere ecosystem
How do mudflats form?
- Sea water and fresh water meet at the sea
- Velocities cancel out
- Particles suspended in the water flocculate (join together)
- Particles are deposited at the intertidal zone
- Halophytes colonise the area, securing the sediment
How do salt marshes form?
- Creeks form on mudflats where the current is strongest
- Leaves areas with higher ground, less effected by currents
- Pioneer species colonise, slow down current more, causing more deposition
- Land begins to be raised up over years
Give some examples of plant species present on salt marshes.
- Eelgrass
- Grasswort
- Sea blite
Of sand and shingle which forms shallower beaches? Why?
Sand (<5 degrees). Becomes compact when wet
Of sand and shingle which absorbs more wave energy? Why?
Shingle. It has much more large gaps between them so hydraulic action is absorbed, energy dissipates. Does also reduce backwash, forming steeper beaches.
What are drift-aligned beaches?
Beaches orientated parallel to direction of LSD, 45 degrees to prevailing wind direction, sediment travels along the beach. If coastline changes direction forms spits + tombolos
Why is equilibrium vital on drift-aligned beaches?
Without a continuous supply of sand they are more prone to erosion (less sediment inputted)
How do swash-aligned beaches vary with drift-aligned beaches?
- Orientated parallel to oncoming waves
- On irregular coastlines where headlands funnel waves
- Rare, examples include Lulworth Cove
What are ridges and runnels? How are they formed?
- Runnels are depressions in beach cross sections with water still present within them at low tide
- Ridges are located either side of runnels
- Formed by sediment deposited when current looses energy after being eroded from beach in backwash
What are berms?
Small ridges form near HWM of beach, built up by waves
What are cusps on beach profiles?
Small indentations beneath berms due to backwash
Give an example of an exemplar beach cross-section
Harlech beach, north Wales
Give a global example of a beach
Cox’s Bazar, Bangladesh
Give some facts on Cox’s Bazar Beach.
- 2nd longest uninterrupted beach in world
- 120km long, drift-aligned beach
- Human impacts from tourism threaten future
Give a UK example of a beach
West Wittering
In what ways is west wittering unique?
Litteral drift runs east to west (not west to east like much of southern UK
What was the speed of LSD at W Wittering in 2017?
2.7m/s
On what type of coastline do spits form?
On drift-aligned coasts at the point where a concordant coast turns discordant
Why do spits not cross an entire estuary (forming a bar)?
Too deep and currents are strong and persistent
What are the two types of sand spit?
Simple spits and compound spits
What are the differences between simple and compound spits?
Compound spits have minor spits to the landward side and multiple recurved edges which mark the old position of the spit. Simple spits do not
Give a global example of a spit.
Farewell Spit, NZ
Where is Farewell spit located?
Northernmost point on New Zealand south island
How long is Farewell spit?
26km long
What is the sediment source for Farewell spit?
Sediment from the erosion of cliffs further along the coastline. The spit is a sediment sink
What type of spit is Farewell Spit, NZ?
A compound spit with minor spits and mudflats on the landward side of it. Obstacle to boats and whales
What is a UK example of a simple spit?
East Head
What is the name of the saltmarsh at west Wittering?
Snowhill Creek
What are tombolos?
A spit that joins an island to the mainland
What are the 3 ways Tombolos could form?
- LSD
- Deposition on the leeward side of the island (nearest land) - a shaddow effect
- Migration of offshore bar inland (chesil beach)
What is the “tombolo equation”?
Tombolo will form if:
(Distance from mainland) / (Width of island) <1.5
D / W < 1.5
What is a global example of a Tombolo?
- Scotts Head, Dominica. Formed by LSD method
- Major tourist attraction
What is a UK example of a Tombolo?
Chesil Beach
Also Vatersay, Outer Hebrides
What “type” of tombolo is Chesil beach?
An offshore bar which migrated inland an is technically a barrier beach
What is a bar?
A band of sand which separates the sea from a lagoon
What are the two ways that an offshore bar can form?
- LSD moving across a cove/bay with no current from landward side
- Onshore migration due to sea level rises after the ice age
Give a UK example of a bar.
Slapton Sands, Devon
How did the bar at Slapton Sands form?
By an onshore migration of an offshore bar
What rare plant species is only found at Slapton Sands?
Strapwort
Why is it important that the bar at Slapton Sands is preserved?
If it is eroded the sediment will be stored elsewhere in the cell and will not return (as Littoral drift is not an input)
What is a barrier beach?
An elongated bank of deposited sand/shingle which lies parallel to the coastline. NOT submerged at high tide (differentiating it from a ridge on a beach)
How do barrier beaches form?
- Sand gets deposited offshore as a result of rip currents loosing energy OR a Spit which gets breached
- More material get continually deposited on the bar
- Builds up until it is an island which is always above water line
- Sand is deposited by Aeolian deposition
- Forms sand dunes
What is a global example of a Barrier Island/beach?
Venice Lido, Italy
How did the Venice Lido form?
A breached bar
How long is Venice Lido?
20km long with 3 settlements. Protects Venice Lagoon
What threatens Venice Lido barrier island (and indeed whole of Venice Lagoon)?
Dredging of Venice harbour has caused underwater subsidence, upsetting dynamic equilibrium
How do humans impact salt marshes?
- Increased development near the sea since the 1800s
- Sea walls upset dynamic equilibrium indefinitely
What is a useful adaption of Cordgrass for salt marshes?
- Glands secrete salt to minimise dehydration
- 2 root system to secure mud
- Used for land reclamation in china
What happened to cordgrass in the 1950s which threatens salt marshes?
It began to decline rapidly and reasons are unclear
How many Laver snails are there per square metre of mud in Chichester Harbour salt marsh?
- Provides food for predators like wading birds
What are more recent human impacts on salt marshes?
- Oil spills
- Agricultural pollution leading to eutrophication
- Dredging removes sediment from sources so less inputs
- Swash from fishing and leisure boats (chi harbour has “reduce your swash” on the side of boats to stop this
.
How do headlands and bays form?
- Discordant coastline with regularly varying rock bands (lithology)
- Softer rocks eroded more quickly than hard rocks
How do coves form?
- Concordant coastline with hard rocks nearest the sea
- Crack in the hard rock is opened up by cavitation, wave quarrying and hydraulic action
- Soft rocks become exposed after a while and then erode more rapidly
Give an example of headlands and bays in the UK.
Swanage bay, Purbeck
- Bay is clays and sandstones
- Durlston head to south is limestone
- The forehead to the north is chalk
What is a UK example of a cove?
Lulworth cove
- Hard Portland Limestone eroded, exposing softer sandstones
- Climate change storm intensity increase is likely to erode more portland limestone, opening up the cove and threatening human settlements
What is a global example of a cove?
San Francisco Bay
- Hard rocks have been eroded
- Sea inundated the lower river areas after ice age, forming Rias
How does a wave cut platform form?
- Cliff is eroded (specific terms needed) in storms
- Undercut, leaving a wave-cut notch
- Notch collapses under gravity, cliff retreats
- Wave cut platform forms at a 5 degree angle
- Abrasion makes platform smooth
How do wave cut platforms create a negative feedback loop?
- Platform gets longer
- Waves break sooner, energy dissipates
- Cliff is eroded less, in the mean time the wave cut platform is eroded
- Takes time for cliff to erode again, closer to dynamic equilibrium
.
What is a UK example of a wave cut platform/cliff?
Seaford head
How are caves formed?
Cavitation and hydraulic action opening up a crack in a cliff (crack formed by freeze thaw)
How are Geos formed?
Caves on cliff made of softer rocks collapse under gravity. Creates an indent
How are blowholes formed?
A cave erodes upwards in storms under high pressure
How are arches formed?
A cave is eroded through a headland by hydraulic action
How are stacks and stumps formed?
- Arch is eroded and undercut, collapses under gravity, forming a stack
- Stack eroded in storm forming a stump
How many stumps are there at Old Harry Rocks?
- Used to be more and old maps suggest that the arch used to be higher
How high could sea levels rise between 1990 and 2090?
18-59cm
What part of the UK coastline will climate change sea-level rise affect the most?
The south coast of England because of isostaic rebound in Scotland is causing the south to sink, magnifying the effect.
In what way does sea level rise affect fresh water supplies?
The rise in sea levels above the water table will lead to aquifer contamination with salt water which is inedible
What are the effects of coastal sea level rise?
- Inundation of sea inland areas, creation of new rias
- Contamination of fresh water aquifers
- Low lying areas of habitation evacuated
- Landforms submerged and destroyed
- Loss of coastal farmland due to salty conditions and frequent flooding
What percentage of Bangladesh will be flooded by a 440mm sea level rise?
11%
What percentage of the world’s population live within 100km of the coast?
44% - Major cause for concern with climate change
Name 3 coastal landforms of submergence.
- Rias
- Fjords
- Dalmatian coastlines
What is isostatic change?
- Ice, which previously pushed down on land with weight melts
- Sea levels rise up
- Land rises up after weight taken off it, so sea levels fall RELATIVE TO LAND
- Called isostatic rebound
What is eustatic change?
Ice from glaciers melting causing sea levels to rise globally
What are rias?
Sea inundates low-lying areas inland due to eustatic change (sea level rise)
Give a UK example of a ria.
Chichester harbour, the Solent
Give a global example of a ria.
Ria del Arosa, Spain
What are Fjords?
- A long, narrow arm of sea formed by submergence
- Steep sides, >200m high
- Shallowest near mouth (threshold) where glacier once ended
- Caused by both isostatic and eustatic changes
What is an example of a fjord?
Sognefjord, Norway
What is a dalmatian coastline?
- Sea inundates valleys on a concordant coastline
- Islands form, running parallel to the old coastline with ‘sounds’ between them
What is an example of a dalmatian coastline?
Croatia dalmatian coastline, famous limestone islands with historic cities like Dibrovic on them
Name some coastal landforms of emergence.
- Raised beaches
2. Raised wave-cut platform
How are raised beaches and wave-cut platforms formed?
By isostatic rebound in previously glaciated areas, land rises relative to the sea
What is an example of a raised beach?
The king’s cave, Isle of Arran (partly due to isostatic rebound but also tectonic uplift)
What are raised beaches?
Beaches which are higher than previous HWM as a result of isostatic rebound. Relic caves, where beach fills a cave, may be present
What are raised wave-cut platforms?
Wave cut platforms which have raised up above HWM after tectonic uplift or glacial melting (isostatic rebound)
What is an example of a raised wave-cut platform?
Isle of Portland, Dorset
Give 2 example of social sustainable coastal management.
- Public meetings
2. Education on different types of protection
What is a holistic approach to coastal management?
Where all stakeholders, environment and effects on the coastline are all taken into account
What are the 5 environmental methods of coastal management?
- Hold the line
- Advance the line
- Managed retreat
- Do nothing
- Adaptive retreat (used by Chichester harbour conservancy)
What government department provides funding/bids for coastal management?
DEFRA
Department of Environmental, Food and Rural Affairs
What is the ICZM?
Integrated Coastal Zone Management
Established in 1992 at UN Rio summit
How many people live near coast in Europe?
200 million
What does the IPCC stand for?
Intergovernmental Panel on Climate Change
What coastal management (national level) has the UK adopted?
SMP
Shoreline Management Plans
How many islands are there in Kiribati?
33
What “type” of island are there in Kiribati?
Low-lying sand, coral and mangrove atolls, most places only 1 metre above sea level
What did president Tong of Kiribati do in 2014?
Purchased 20km squared of land in Fiji for migrants to go to
Why is Kiribati experiencing sea level rise at nearly 4 times the rate globally?
It is close to a subduction zone, so the islands are sinking relative to the water anyway
How much has Australia donated to Kiribati to restore its economy?
A$44 million
What is the definition of hard engineering?
Making a physical change to a coastline with the use of resistant materials like concrete, wood, stone + metal
Give 5 examples of hard engineering strategies.
- Revetments (sloping wooden/concrete structures)
- Offshore reefs
- Sea walls/rock armour
- Gabions/cliff fixing
- Groynes
What is a social benefit of hard engineering?
Protects areas of habitation for 100s of years, used for leisure
What is a social cost of hard engineering?
Upsets the sediment cell dynamic equilibrium so the problem is moved on to somewhere else on the coastline
What is an economic benefit of hard engineering?
Lasts a long time so although initial coast is high doesn’t need replacing. Payback time is short
What is an environmental benefit of hard engineering?
Can be used to protect SSSIs or special areas. Rip rap creates a new habitat for wildlife
What is an environmental cost of hard engineering?
An eye sore to insiders and outsiders
What is an economic cost of hard engineering?
Initial cost is very high. Money lost with less tourism
What is a social benefit of soft engineering?
Protects areas of population whilst maintaining a good sense of place - attractive
What is an environmental benefit of soft engineering?
Less interference with the environment and less adverse effect on the coastal system and cells
What is an economic benefit of soft engineering?
Can attract tourists and investment due to being attractive
What is an environmental cost of soft engineering?
None except disruption during planning and construction
What is an economic cost of soft engineering?
Large projects like beach nourishment cost a lot
What is a social cost of soft engineering?
Doesn’t last as long and less safe than hard
Why were shoreline management plan established (SMP)?
The 11 sediment cells in Eng and Wales do not line up with local authority boundaries
When was the Shoreline Management Plan (SMP) established?
In 1995 to have an integrated system in place to avoid poor management
How many Shoreline Management Plans (SMP) are there in the UK?
22
Chichester harbour is SMP 13
What do Shoreline Management Plans set out to do?
- An integrated systems approach
- Work with all local authorities they encompass
- Identify a sustainable approach to manage flood and erosion risks
- Incorporate short and long-term plans
What is managed realignment?
When the coast is allowed to do erosion or flood but it is controlled by humans
Under what conditions is “Hold the line” or “advancing the line” used?
On high value coastlines;
Housing, towns,major industries, sometimes on rare ecosystems
What is an example of hold/advancing the line?
Palm island, Dubai
Why was the Integrated Coastal Zone Management (ICZM) created by the UN in 1992?
To coordinate global government policies on coastlines with nature protection, agriculture, fisheries, offshore energy and tourism taking priority
What did the EU establish in 2013 to work alongside the ICZM?
The Maritime Spatial Planning (MSP)
What is an example of a managed realignment scheme?
Abbot’s Hall Farm, Blackwater estuary, Essex
How much land did Abbot’s Hall Farm scheme cover?
280 hectares, among the largest in EU
When did Essex wildlife trust buy Abbot’s Hall Farm?
In 2000
What was the aim of the managed realignment at Abbot’s Hall farm?
- Provide leisure
- Farming
- Conservation of habitat
- Proved that hard engineering is not always required on a coastline
When was work completed on Abbot’s Hall Farm?
October 2002
What conditions did the contractors at Abbot’s hall farm have to meet?
- Counter-walls to protect nearby farms
- Environmental assessment
- Archaeological surveys
Why was Abbot’s Hall Farm managed realignment used?
WWF and Wildlife trust presented evidence to UK government over concerns for loss of salt marsh habitats in the 1990s
What is coastal squeeze?
Sea walls (as a result of advancing the line) are closer to the sea, causing salt marsh to be eroded due to stormy weather
How much do sea walls cost for every metre?
£6000/m
How much does a single wooden groyne cost?
£5000
How much does beach nourishment cost per sq metre?
Up to £5000 per sqm
What percentage of Chichester harbour is protected?
90%
By how much has the hinge at east head moved in the last 300 years?
70 degrees clockwise in the last 300 years, could be effected by the groynes
What is the population of West Wittering village?
4,500
What happened to east head spit in October 2004?
It was breached in a storm
What sediment cell is Chichester Harbour in?
Cell no. 5 (Selsey Bill - Portland Bill
Who are the stakeholders in Chichester Harbour?
- Residents
- Businesses
- National trust
- MOD on Thorney island
- Wildlife
What coastal management strategy is being used at Chi harbour?
Adaptive management
Why is adaptive management being used at chi harbour?
A fragile environment with plant species and lots of population. Some areas like Thorney island need hard engineering whilst West Wittering does not.
What is the purpose of adaptive management at Chichester harbour?
Controls coastal processes like erosion whilst keeping it a natural process, so dynamic equilibrium is not upset
When were the groynes at WW first built?
In 1840s, replaced every 100 years, coating £1 million each time
What were the benefits of groynes at WW?
Made beach wider
What were the costs of groynes at WW?
Prevents literal drift, possibly caused East Head to breach in 2004
When was sand dune stabilisation used at WW?
2004
How much did the sand dune stabilisation at WW cost?
£4.5 million, lasts approx. 70 years
What did sand dune stabilisation at WW involve?
Sand and shingle taken from hook of the spit and added to the neck along with boulders
What was a benefit of sand dune stabilisation at WW?
- Sand dunes and spit protected
- Snowhill creek saltmarsh protected
- Visitor numbers increased again
Was was a cost of sand dune stabilisation at WW?
Very expensive, costing £4.5 million
Where are the Sundarbans?
Southern Bangladesh/India, net to bay of Bengal
21 degrees north, 88 degrees east
How far away are the Sundarbans from Dahka, the capital of Bangladesh?
240km
What type of landscape are the sundarbans?
A delta landscape of multiple river systems and estuaries
How many people live in the sundarbans?
3.8 million
Where does the sediment regularly deposited in the sundarbans come from?
- Himalayas (as glacial material in rivers)
- From southern India every year in the monsoon, builds up big dunes
What type of plants live in the Sundarbans?
Halophytes (salt loving)
What is the name of the grass responsible for stabilising mud in the Sundarbans called?
Sea grass
What is a major benefit of mangrove forests in the Sundarbans? (tsunami)
30 mangrove tress per 0.01 hectares reduces the force of a tsunami by 90%
What is a major adaption of the black mangrove?
All excess salt is transported to one leaf which subsequently falls off
Give an example of a fish in the sundarbans.
Tarpen (which can breath oxygen to catch smaller fish in low spring tides)
What is good about butress roots in mangrove forests?
- Protect small fish by acting as a cage
- Filters water
- Secures soil
How do the mangrove forests of the sundarbans help in the carbon cycle?
They are a very large carbon sink
Name three rivers which flow to the Sundarbans.
Brahmaputra
Meghna
Ganges
Why is the ecological importance of the sundarbans an opportunity?
- Fish can be caught
- Salt-tolerant rice can be grown
- World heritage site brings in tourists
How is the opportunity surrounding the ecological significance of the sundarbans limited?
India and Bangladesh have deforested some parts for salt, which destroys . Upsets dynamic equlibrium
What is wood used for by residents of the sundarbans?
Construction because it is the only building material. An opportunity, especially because the locals sustainably source wood by only cutting one branch at a time
How is the opportunity of wood used in the sundarbans limited?
Currently wood is sustainably sourced from trees by the locals, however if the population increases, more wood will be required. Governments are felling trees on mass scale for salt farming
How does education in the sundarbans act as an opportunity?
More young children will gain knowledge about the international importance of the sundarbans in terms of ecosystems and natural coastal defences
What percentage of children currently go into higher education in Bangladesh?
Only 0.7%, very low. So is education in the sundarbans really an opportunity?
How much is each hectare of the sundarbans worth?
$12,000
What are the problems with shrimp farming in the sundarbans?
- Mangroves removed
- Pollution
- Invasive species introduced
- Ecosystems damaged
- TNCs only, not effecting local economy much
What cyclone hit the sundarbans in 2007?
Cyclone Alia, with wind speeds of 100km/h
How many people are killed by tigers each year in the sundarbans?
20
What is a major problem with coastal flooding in the sundarbans?
More trees destroyed, could lead to positive feedback
What is the problem with dredging in the sandarbans?
Islands in the sundabans are unstable and have started to subside
How have crops been adversely affected in the sundarbans?
- Higher salt levels have caused some plant species to die
- Cyclones can decimate rice crops
What is the definition of resilience?
The ability to recover quickly from difficulties in the current environment. E.g Mangrove forests in the sundarbans provide a high level of resilience against winds, floods and tsunamis
How much CO2 do the sundarbans (net) take in each day?
4 tonnes
What is the dinition of mitigation?
Reducing the severity of known impacts
What is a major concern with deforestation in the sundarbans?
The countries forests could disappear completely by 2020 at the current 2% rate
How many saplings were there planted in 2015 in the sundarbans?
50,000. A good mitigation strategy (afforestation)
What adaption strategy was adopted in 1986 to stop tiger attacks?
Masks were worm on the back of heads as tigers attack from behind - had a temporary effect
What is the definition of adaptaion?
A strategy adopted to try and change against the effects of something.
When did cyclone Aila hit the sundarbans?
In 2009
How many people died in cyclone Aila?
190, 4 million affected
What have the sundarbans national cyclone risk mitigation programme (NCRMP) done to reduce the effects of cyclones?
1,000 cyclone shelters constructed in 2015
How are the sundarbans adapting to food shortages?
New salt-tolerant varieties of rice are being used which can remain submerged for 2 weeks
How have the sundarbans adapted to salt water inundation of fresh water supplies?
Storage tanks have been installed in areas most likely to be effected by salt water innundation
How have the sundarbans adapted to the higher frequency of flooding?
- Water-tight bags have been distributed to store important belongings and papers during floods
What is the definition of sustainable development?
Allowing for social, economic and environmental growth for future generations of a community without jeopardising the concerns of the current generation
When was bangladesh’s Integrated Coastal Zone Management (ICZM) established?
in 2005
What are the 4 pillars of sustainable socioeconomic development?
Pillar 1: Vulnerability reduction
Pillar 2: Poverty reduction
Pillar 3: Biodiversity conservation
Pillar 4: Institutional change
What are the 6 opportunities for sustainable development in the sundarbans?
- Bottom-up developments
- Food security
- National + int government scheme implementation
- Solar panels
- Planting of salt-tolerant plant species
- Ecotourism
Give an example of bottom-up development in the sundarbans.
Construction of 10km of brick roads by Bengal women
Give an example of food security in the sundarbans.
Oxfam and 5 other NGOs have helped to improve food security in Khulna
Give an example of government schemes implemented in the sundarbans.
World bank “a resilient future for the sundarbans” project, 4 pillars
Give an example of solar pannels in the sundarbans.
- 5 million households used to not have any power
- Power provided by 1000s of solar panels
Give an example of ecotorism in the sundarbans.
Passur river, 150m from sundarban forest
