Coasts

• eustatic sea level rise: results in a global change, due to an alteration in volume of global sea water
• isostatic sea level rise: change on a local scale, glaciers make continents sink or rise (by melting)
• isostatic rebound: when a glacier melts and the continent rises
• The hockey stick debate: trend in global temperatures last 100 years- is it unprecedented or within range expected by natural variation?
• reliable evidence for climate change only arounds for last 150 years, before that: ice cores, tree rings
• Kiribati:

  • 33 islands in Pacific
  • most places less an 1 meter above sea level
  • may disappear in 50 years
  • rising sea levels are contaminating groundwater sources and affecting crop growth
  • president bought 20km2 of land on Fiji will be used for agriculture and fish farming projects
  • government has launched 'migration with dignity' to allow people to apply for jobs on neighbouring islands
  • if islands sink, population will become environmental refugees
• The Sundarbans:

  • Bangladesh
  • 3 rivers in delta- The Ganges, Brahmaputra, Meghna
  • sand dunes and new islands created
  • education for: eco-friendly farming, preparing for natural disasters, water sanitation, water-borne diseases
  • new salt-tolerant rice varieties
  • building multi-purpose cyclone shelters
  • rainwater tanks in at-risk areas
  • natural challenges: coastal flooding, cyclones, salinity of soil, human-eating tigers
  • mangroves provide shelter against: winds, tsunamis, erosion
• The Holderness coastline:

  • Eastern England- sediment cell 2
  • 2 headlands- Flamborough Head in North and Spurn Head in South
  • chalk (resistant) and boulder clay from ice sheets (less resistant)
  • LSD and prevailing winds move north to south
  • Flamborough Head- wave cut platforms, stacks, caves
  • Bridlington Bay- beaches, sea wall, groynes
  • Hornsea- gabions,
  • Withersea- groynes and sea wall
  • Skipsea- gabions
  • Mappleton- groynes and revetments
  • Spurnhead- groynes and rip rap
• Mudflats:

  • develop on shorelines which are sheltered from powerful waves
  • are low lying areas of land made of silt and clay- submerged at high tide
  • formed when river flows into estuary- river brings fine sediment which settle out of suspension by flocculation, particles then sink
  • UK example: Camel Estuary
  • Contrasting example: Korea's wester coast
  • Plants: eel grass (slows current and leads to deposition), glasswort, seabite, and spartina
• Halosere: the vegetation succession that develops on mud flats
• Halphytes: plants toleratant to salinity, and being submerged

  e.g grasswort, seabite, spartina
• Beach nourishment- soft engineering

  • sediment added to existing beach
  • cheap maintenance, looks natural, increase tourism as bigger beach
  • needs constant maintenance due to erosion
  • £300,000/100m
• cliff regrading and drainage- soft engineering

  • reduces angle and drains to stabilise
  • can be effective on rock where other methods won't work
  • drained cliffs can dry out- rock falls
  • cost is variable
• dune stabilisation- soft engineering

  • marram grass planted
  • maintains natural environment, cheap, sustainable, provides habitats
  • grass takes time to grow
  • £200-2000/100m
• marsh creation- soft engineering

  • form of managed retreat, allows low-lying coastal land to be flooded
  • relatively cheap, creates natural buffer
  • agricultural land lost- compensation needed
  • coast varies depending on size of land
• 4 types of soft engineering:

  1. beach nourishment
  2. cliff regrading and drainage
  3. dune stabilisation
  4. marsh creation
• groynes- hard engineering

  • timber or rock structures at 90 degrees to coast
  • works with natural processes and builds up coast- increases tourism
  • starve beaches down coast- unattractive
  • £5,000-10,000 each at 200m intervals
• sea wall- hard engineering

  • curved face to reflect energy
  • promenade- used for recreation and effective prevention
  • energy reflected not absorbed
  • expensive- £6,000/m
• Revetments- hard engineering

  • wooden, concrete, or rock structures
  • slope up towards cliff and break wave energy
  • intrusive and unnatural
  • high levels of maintenance
  • up to £4,500/m
• offshore break water- hard engineering

  • partially submerged rock barrier
  • effective permeable barrier
  • potential navigation hazard
  • £10,000-300,000/100m
• Rip rap/ rock armour- hard engineering

  • large rocks at foot of cliff
  • permeable barrier- break up waves but allow some water
  • can have recreational use, relatively cheap, easy to maintain
  • intrusive and looks out of place
  • £100,000- 300,000/ 100m
• Lyme Regis- hard engineering case study

  • Doset
  • managed retreat not possible as nowhere to retreat to
  • £30million
  • Cobb road widened, strengthened and stabilised; land behind beach stabilised; new drainage systems to reshape parkland
  • rock armour added, 2 new jetties, new sea wall, new beaches replenish
  • consequences- town will lose 2 carparks (less tourism), 2 new park and ride schemes, beach huts closed for 1 1/2 summer seasons
  • more people visited to see works
  • only time will tell if it was worth it as it only prevents very slow changes
• Cuckmere Estuary- soft engineering case study

  • let current defences be breached, land will revert back to salt marsh
  • old defences needed replacing, will cost £20 million
  • lower estuary will flood- earth bank built to stop inland from flooding
  • footpaths moved or raised
  • area will be monitored to make sure no billing becomes at risk
  • Advantages- creates 200 acres of salt marsh, area will look more natural, forms natural flood defence, sustainable
• Coastal squeeze: when sea level rises, gets pinned against sea wall and get deeper, increases erosion
• Outline characteristics of constructive waves 


  constructive waves are flat and gentle

  they have low frequency

  swash is greater than backwash

  carries material up beach and deposits it
• input: material or energy moving into the system

  e.g precipitation
• output: material or energy moving from the system to the outside
• energy: power or driving force e.g energy in flowing water
• stores/components: individual elements or parts of a system e.g beach
• flows/transfers: links or relationships between components
• dynamic equilibrium: when there is a balance between the inputs and outputs
• closed system: transfers of energy (not matter) in and out of the system
• open system: matter and energy transferred in and out of the system
• atmosphere: layers of gases surrounding the earth
• lithosphere: the crust and upper mantle
• hydrosphere: water at or near the Earth's surface
• Biosphere: all living matter
• Cryosphere: water locked in ice
• Positive feedback: A feedback loop that amplifies a change in a system.
• negative feedback: a system that responds to a change in the environment by nullifying the change