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Coastal Landscapes - Coggle Diagram

- - - - Mass movement
      - Freeze-thaw weathering
      - Salt crystallisation
    - - Actions of plants and animals - plants roots into rocks widen the rock fractures as the roots grow and expand
    - - Carbonation
      - Hydration (wetting and drying)
      - Chelation - organci acids
  - - - This is the process by which the coast is worn down by material carried by waves. Waves throw the material/particles against the rock, at slow or high velocity, causing gradual erosion
    - - Material carried by the wave bump into each other and so are smoothed and broken down into smaller particles.
    - - This process involves the force of water against the coast. The wave enter cracks (faults) in the coastline and compress the air within the crack building internal pressure within the rock. When the wave retreats, the air in the crack expands quickly causing a minor explosion of pressure. This processes is repeated continuously causing erosion.
    - - This is the chemical action of sea water. The acids in the salt water slowly dissolve rocks on the coast. Limestone and chalk are particularly prone to corrosion as their physical properties are vulnerable to chemical weathering. Igneous rocks are almost entirely chemically inert, therefore not vulnerable to this type of erosion
  - - - Shape of the cliff characteristics - effected by the geology, balance between MEP's and SAP's - inherit characteristics
- - - - Land
        
        River sediment - variety of rock types or organic matter carried from onshore sources to offshore
        
        Coastal ecosystems
        
        Resistance of rock - geological factors
        
        Steep or gentle beach gradient
        
        Presence or lack of beach - shingle
        
        Shape of the coastline - topography of land
      - Sea
        
        Local currents & longshore drift
        
        Tidal range
        
        Size & type of wave
        
        Long term changes - eustatic sea level rise
        
        Wave energy & direction - can be refracted by cliffs creating bays - famous coastal sites like Durdle Door
        
        Coral reef - natural barrier
        
        Coastal ecosystem
      - Weather and climate
        
        Temperature
        
        Stores and surges - climate change causing regular or more common storm occurrences
        
        Rainfall - average UK annual rainfall 1400mm
        
        Strong SW prevailing wind
        
        Wind strength & direction
      - Human activity
        
        Use of land for development - land use zoning in coastal locations - Dawlish Warren
        
        Exploitation of resources
        
        Intervention in natural systems - onshore and offshore
        
        Artificial barriers & sea defences
        
        Dredging offshore and port development
  - - - A source coming from the land - travels via rivers & estuaries into the ocean
    - - A source coming from the ocean
    - - Sediment consisting of fragments of rocks transported and re-deposited from other rock via rock weathering and erosion
    - - The shells and skeletons of marine organisms creating organic matter
  - - - the balance of sediment volume entering and exiting a particular section of the coast
  - - - Feedbacks are the consequences of change within an open ot closed system
      - Positive and negative feedback can lead to positive or negative multiplier effects
        
        Positive feedback mechanism
        
        acceleration and amplification of any effects within a system that have already occured
        
        Negative feedback mechanism
        
        System adjusts to the changes by reversing the effects and minimising changes
    - - Steady-state equilibrium
        
        Stayed the same over long time period - Does not deviate from the long term trend - e.g. resistant rocks, hold their natural position and withstand erosion and weathering until a certain position
      - Meta-stable state
        
        An environment switches between two or more states of equilibrium - large change caused by a trigger occurrence - stimulant e.g. tectonic activity - that causes a significant change in the equilibrium - with adjustment back to natural system
      - Dynamic equilibrium
        
        Gradual change, over long-periods of time - e.g. the response of coasts and oceans gradually adjusting to the ending of the glacial period and the changes since
  - - - Shape of beach
    - - Shape of the coastline and its orientation in oncoming waves
    - - Height and slope of the land/beach - gradient
    - - structure, composition and type of rocks
    - - Work to break down and remove the rock above high tide mark
    - - Hydraulic action, Abrasion, Attrition and Corrosion
    - - Chemical, mechanical and biological
- - - - A mudflat is defined as areas of fine sediment (muds clays and sand) exposed at low tide but covered at high tide
      - Salt marsh is a coastal ecosystem between land and open salt water that is regularly flooded by the tides
    - - Deposition builds up the dunes, mud breaks on the surface forming mudflats. Pioneer plant species like Cordgrass enter as an invasive colony to thrive on the conditions other plants don't require
      - Land builds up, less impact, with salt tolerant species growing in the environments conditions, salt is leached by rain, and marshes form
  - - - Symbiosis - the living together of organisms in close association for their natural benfit
      - Key facts
        
        Calcium carbonate - polyps excrete to form limestone structures
        
        Photosynthesis - algae do to create food
        
        23-29 degrees is ideal sea temperature for coral reefs to develop
        
        30 degrees - coral reefs can occur anywhere with the right components at 30 degrees Celsius
        
        1250 miles - length of the greater barrier reefs Australia
        
        25% of fish stocks rely on coral reefs
      - Climate affect?
        
        Deeper water leads to reduced sunlight and poor water quality
        
        Acidification water has lower pH levels which means less calcium carbonate is absorbed so coral skeletons dissolve faster
        
        Higher sea temperatures cause coral bleeding which weakens the structure and kills them
        
        Delicate reefs structures deal with natural problems - but are damaged by human activity like anchors or plastic waste
    - - All reefs began life as polyps which attach themselves to a hard surface in shallow seas. Sufficient light for coral growth allows reefs to flourish in shallow tropical seas - calcium carbonate strengths the coral structure
      - Algae - supplies food for polyps - & polyps provide shelter for algae
    - - 60% of the population living in the coastal zones (60km) inland depend on reefs
      - Dependent for.... Fishing in LIC's - protection, act as an offshore barrier or breakwaters (natural breakwaters) which absorb 97% f wave energy & MEP's
      - Safety from storm surges
      - National income provided if countries acquire tropical reefs in their designated zone
      - Cultural importance in areas like Indonesia, Malaysia and Phillippines
  - - - Must be above 20 degrees temperature in the coldest months, average temperature at 25 degrees
      - Fine grain substrate
      - Sheltered shorelines with small tidal range and limited erosional exposure
    - - Form in intertidal zones - form in a combination of biotic processes and depositional processes
      - Roots from young mangroves bind to soft sediment in a sheltered coastal zone together
      - The presence of vegetation further slows down sediment so more is captured within the mangrove system
    - - Reduction of erosion on the coastline
      - Protect shorelines
      - Transfer sediment
    - - Hawaii is not native so looking to remove some, taking away tropical marine life habitats
- - - - Storm generated erosion
        
        Strong winds, larger than average waves make conditions extremely dangerous and harsh around exposed coastlines
        
        Tidal changes twice a day
        
        storms provoked flash floods and high energy destructive waves which can take greater amount of sediment then usual
  - - - 12 winter stroms i the UK in 2014
      - Dawlish railway was damaged by strong and high waves hitting the coastline
      - Flooding and flood defences damaged
      - Strong winds create high tides which stress the sea wall protecting coastal property
      - Strom Emma march 2018 - High tides, freezing road temperatures - eastern wind direction - 2.5 million in coastal damages
  - - - Slapton bar - continental drift has moved the landscape - sheltered coast chalk and shingle constructive waves low energy coastal environment, emergent raised beach - se level 100-120m lower - water is locked in ice - rapid sea level growth, flandrian transgression - 8 to 3000 years ago -
    - - Emergent landform
        
        Sea level is falling - relative level to the land - landforms are same as sea level - raised beach with relief cliff
        
        Raised beaches - areas of former wave-cut platforms and the beaches are at a higher level than the present sea level
      - Submergent landform
        
        Rising sea level - landforms are beneath sea level - fjord & rias
        
        Rias have a long section and cross profile typical of a river valley, usually a dendritic system of drainage. Can also be a coastal feature from rising sea level flowing into land
  - - - A bar is defined as any offshore deposition of sediment running parallel to the coast. Barrier bar, created 20 miles offshore rolled into place
      - Seasonal variations in wave type and impact on the bar
        
        In winter: there is a higher concentration of destructive waves, meaning there is more erosion of the bar - due to low pressure
        
        In summer: there is a higher concentration of beach material onto the bar - due to high pressure
      - What other factors change the landform over different time scales?
        
        medium timescales - longshore drift: the movement of sediment away and into the bar, both eroding and depositing sand into the bar - littoral drift: the movement of sediment away and into the bar, both eroding and depositing sand into the bar (but on a larger scale, and more pronounced effects)
        
        Short term - storm events - erode the bar due to MEP's and destructive waves
        
        Short ter - tides, tidal range, may either bring destructive waves which will erode the bar, whereas smaller tidal range will build up the bar
      - How was Slapton Bar created?
        
        The bar at slapton sand has formed over long-term movements of land and sea. Its low energy coastline has caused the sediment to build up and toll into a bar formation. Rapid sea level growth post glacial times has caused the coastal landforms many dynamic changes. Known as Flandrian transgression. Eustatic sea level rise, flandrian transgression - long term median term
      - Key facts
        
        86% on average percentage of the bar contains quartzite and flint geology
        
        9km length of slapton bar
        
        1917 - Hall sands devastated by storms
        
        A379 - diversion of road would increase commuting time to approximately 1hr and 20 mins, a significant difference to normal journeys
    - - The A379, built along the bar, faces flash floods, storm surge erode, loss of the bar. Rising sea levels, erosion of the shingle
    - - Rock armour, sea wall, used at tor cross, provides protection from destructive waves. Impact of LSD and deposition, changing beach profile in some spots. maintaining the A379, not defending vulnerability of the coastline
- - - - Coastalisation has happened for many different reasons. Towns and cities often develop around trade and industry. World trade has led to the development of important ports because the sea is a natural transport route. This is utilised by industry, which imports raw materials and exports end products. Industry also often requires large amounts of water for cooling purposes and there is a plentiful supply at the coast. Marine resources can also provide the basis for recreation and employment. Coastal sites are often attractive places to settle. For similar reasons, naturally beautiful sites are prime locations for tourist development. The climate at the coast if often pleasant. However, remote coastal sites are useful too. They are often used for more sensitive operations, such as nuclear power and military bases. Coastal land can be ideal for agriculture becasue it is often flat and fertile.
    - - 60% of the global population live on the coast
      - 60km - live within 60km of the coast
      - 2/3's of the worlds largest cities are located on coastal areas
      - 25% of the English coastline has been developed
    - - Coastal processes
        
        Exposed beaches with long fetch creates surfing waves attracting active leisure pursuits e.g. Slapton body boarding etc e.g. Sennen Cove cornwall
        
        Coastal deposition in estuaries by long-shore drift can make harbour entrances difficult to navigate & require dredging e.g. Poole Harbour Dorset. This material is then used for beach nourishment for the tourist beaches of Bournemouth
        
        Deposition of beaches - creates tourist attraction e.g. Dawlish Warren
      - Coastal landforms
        
        Beautiful & dramatic coastal scenery attracts sightseers, walkers, active leisure pursuits like coasteering e.g. Jurassic Coast
        
        Estuaries rias etc provide sheltered harbours for trade e.g. Humber estuary, East Yorkshire, & Exe Estuary Devon
        
        Flatter land encourages development for farming, tourism, industry, energy production, transport and housing e.g. Exe estuary and Port Talbot Wales
  - - - Seasonal employment, tourism exceeding carrying capacity, litter, ocean pollution, sustainability? and disruption to transport links
    - - Cost of coastal defences - key idea; humans have built on as if it were static, but the dynamic environment changes, managed retreat, lost of flat building land, seasonality of tourism, loss of coastal footpaths
  - - - Management needed?
        
        Transporting of sediment - long shore drift - west to east
        
        MEP - eroded the neck of the spit - destructive waves, storms, eustatic sea level rise and climate change causing changes to the beach shape
      - Dawlish Warren 2014 to 2017 transformations
        
        Replenishing beach hoping that visitor numbers will rise again to 1/2 million a year. Stop the end of spit from detaching - increase flood risks, needing to stop sediment loss from dunes and marshes
        
        2017 defence scheme
        
        Geo-tubes at the neck of of the spit - 7m down, buried with and and plats covering it as beach nourishment
        
        A 'concrete mattress' was implemented along the dunes to protect them from tidal flooding or storm events - a storm larger than usual displaced part of it - so it was ineffective - and it was an unappealing feature of the beach
        
        Advance and hold the line via beach nourishment
        
        £12 million total cost on re-nourishing the beach with sediment supplies
        
        Removal of gabions and replacement with flexible revetment mat
        
        2 to 3 months of dredging and pumping from pole sands in the estuary
      - Managing via land zoning
        
        Dawlish Warren is divided into 3 sections - the honeypot site, buffer zone, and natural zone
        
        Dawlish Warren's honeypot site is an area of valuable properties like cafe's, shops and leisure activity sites, the £8;£1 costs of property worth to coastal expenses sums up why the Honeypot zone is greater defended than the other zones. The main investment of concrete defences like revetments, sea walls is to protect the large income source for DW's businesses
        
        The buffer zone is the beach expanding off the honeypot site, where the main capacity of people are required to be. In the buffer zone is some revetments, groynes and beach management plans like dune paths and located benches. The buffer zone is the main dune ecosystem, therefore it must be protected, but mainly protected from people and tourists humanly eroding/damaging the dunes like blowouts
        
        The natural end zone, consisting of the vulnerable neck of the spit, is mostly off bounds to people and dogwalkers. It is the separated natural habitat that needs to naturally re-grow and live without human interference
- - - - Dorset cliffs consists of a mixture of compositions
        
        Clays & sand (soft), chalk (hard), clays & sand (soft), limestone (hard)
        
        Creating Sharland Bay, Ballard Bay, Swanage Bay, Durlston Headland
        
        Called a discordant coastline
        
        Discordant as the bays and headlands create a varying line of the coast - concordant are straight e.g. cliff faces at the ocean edge
      - Old Harry's Rocks
        
        Chalk stump at the end of Ballard headland (Ballard Down), East Purbeck, Dorset. Discordant coastline of headlands & bays, dictates the wave refraction activity
- - - - Metamorphic rocks
        
        Examples - slate, marble & schist
        
        Resistant to erosion, often folded, heavily fractured, erosion can be exploited in fractures where its weakest in the rock formation
      - Sedimentary rocks
        
        Example - sandstone, limestone & shale
        
        moderate to fast eroding, young rocks tend to be weaker and easily eroded
        
        Sedimentary or clastic rocks, erode faster than crystallised rocks - clastic vs metamorphic & igneous
      - Igneous rocks
        
        Example - granite & basalt
        
        Slow erosion, inter-locking crystals make strong rock formation, few joints, limits weaknesses, hence it takes long-term to erode
- - - - Load is bounced along the sea bed, current cannot keep the larger and heavier sediment afloat for long periods - e.g. small pieces of shingle or large sand grains
      - Sand particles - sized
    - - Small particles are carried in water e.g. silts and clays, which can make the water look cloudy - currents pick up large amounts of sediment in suspension during a storm, when strong winds generate high energy waves
    - - Minerals are dissolved in sea water and carried in solution. The load is not visible, can come from cliffs made from chalk or limestone, and calcium carbonate is carried along in solution
      - Chemical compounds in solution
    - - Pebbles and larger sediment are rolled along the sea bed
      - Rolled and bounced larger pebbles
  - - - Gravity settling - sediment sorting - occurs when the energy of transporting large sediment will be deposited first.
      - Flocculation - depositional process for small particles, clay, suspended in the water, particles clump together due to electrical and chemical attraction while reacting with he saltwater
  - - - Cliff system
      - Long shore drift
      - River sediment (fluvial)
      - offshore (marine movement of sediment)
    - - beach sand and shingle
        
        Sandy caostline - small pebbles covering a coastal area
      - Spit
        
        Sand or shingle beach ridge expending beyond a turn in the coastline - long shore drift - current spreads out and loses energy
        
        example - Spurn head - Yorkshire
      - Bar / barrier beach
        
        sand or shingle connects two areas with a shall water lagoon between them. Spit grows so long it extends across a bay, closing it off and forming a barrier bar beach
        
        example - Chesil beach Dorset
      - Tombolo
        
        Sand or shingle bar that attaches the coastline to an offshore island creating calm water and deposition between the island and coastline
        
        Example - St Ninians tombolo Shetland
      - Cuspate foreland
        
        Roughly triangular shaped features extending out from a shoreline - affected by LSD
        
        Example - Dungeness Kent
- - - - The gravitational pull of the moon - gravity - pulls low tide and high tide
      - spring tides are at the maximum tidal range - pulled across the width of the earth - while neap tides are smaller bulges of gravitaional pull rom the vertical sides of the earth - is weaker
      - Tidal frequency
      - Semi diurnal tides and diurnal tides
        
        Semi - 2 high tides and low tides
        
        Diurnal - 1 high tide & low tide
      - Tidal range
        
        Micro tidal / mesotidal and macro tidal
      - Tides push sediment into estuaries during high tides, and move sediment off the beach or out of estuaries in dropping tides - either deposit or withdraws sediment from the shoreline
    - - onshore - more energy - sediment pushed towards the shoreline - movement of swash and backwash and longshore drift
      - offshore - more energy away from the beach - sediment is pulled away from the coast - rip currents
      - River - transport river sediment and fresh water into the coastal zone where it is deposited into the sea