high energy and low energy coastlines

• high energy coastline


  saltburn to flamborough head
• key stats and ideas about saltburn to flamborough head

  60km long coastline

  flamborough head = chalk/glacial head

  north york moors = sandstone/limestone

  discordant coastline
• energy flows in high energy coastline

  dominant wave direction is north and northwest - fetch is 1500km

  LSD occurs southwards

  areas of weak lithology experience erosion rates of 0.8m/year

  areas of stronger lithology experience erosion rates of 0.1m/year
• geology at saltburn to flamborough head

  chalk headland = strong lithology

  bays either side = clay

  saltburn = limestone and sandstane

  horizontally bedded
• sediment sources at saltburn - flamborough head


  River Esk at Whitby supplies limited amounts

  sediment from subcell 1d which comes from nearshore areas driven onshore by historic sea level rise
• net increase of sediment between 2008 and 2011 at saltburn


  9200 metres cubed
• cliffs at saltburn - flamborough head


  horizontal bedding = vertical cliff face

  cliffs at FB made of chalk = strong lithology

  cliffs between Robin Hood's bay and Saltburn are higher and have a stepped profile due to varied geology of more resistant sandstone and limestone, and less resistant clay and shale
• shore platforms at saltburn to flamborough head

  Robin Hood's bay

  platform has width of 500 metres
• headlands/bays at saltburn - flamborough head

  discordant planform

  robin hood's bay and filey bay

  Ness point and Flamborough head - chalk
• beaches at saltburn - flamborough head

  Scarborough and Filey bay
• modification of saltburn to flamborough head

  minutes - mass movement/cliff erosion

  daily - tidal changes = temp micro features e.g., cusps

  seasonal - winter = more destructive waves = increased erosion

  decade - development of erosional and depositional landforms e.g., spits and headlands

  millenia - development of wave cut platforms
• low energy coastline


  nile delta - egypt
• key ideas - nile delta

  2 main distributaries = rosetta and damietta

  arcuate delta

  deposition > erosion rates for 3000 years
• conditions under which nile delta forms

  nile = vast sediment load

  small fetch due to internal mediterranean sea - 750km

  gently sloping continental shelf

  warm climate favouring vegetation growth

  minimal tidal energy = minimal erosion
• formation of nile delta

  nile transports large sediment load

  heavy particles settle to sea floor rapidly and meet saline sea water

  silt/clay particles flocculate on continental shelf

  delta builds up

  colonised adding stabilisation
• key landforms of nile delta

  promontories from river mouth

  burullus spit

  bar

  beaches

  Abu Qir bay

  sand dunes

  lagoons
• interrelation of landforms at rosetta promontory

  deposition where nile meets med. sea

  longshore drift and ocean currents move sediment east = deposition

  formation of bar across Burullus lagoon
• interrelation of landforms at damietta promontory

  build up of fluvial sediment by Nile

  erosion from north west winds

  material transported east by longshore drift to Port Said, building up spits and bars across Manzala Lagoon

  formation of salt marshes due to sheltered water
• interrelation of landforms across whole coastline at nile delta


  onshore winds have blown sand inland to create sand dunes

  low tidal range = erosion more concentrated = not a lot of sand is wet from tides = wind is able to pick it up and transport sand
• influence of human activity on nile delta

  construction of Aswan dam causing decreased fluvial deposits

  north west facing beaches are eroded due to lack of sediment

  accelerated erosion and coastal retreat - 148m/year in some areas
• seasonal changes in interrelation

  winter winds = stronger = more extreme waves removing sediment from delta front creating underwater sand bars (negative feedback)
• some landforms of nile delta are less interrelated


  west of Abu Qir headland, bars are more influenced by local rip currents than LSD

  east of Abu Qir headland, bars heavily influenced by eastward moving LSD currents
• modifications of nile delta

  daily - little change due to minimal wave energy

  seasonal - increase in wind energy = destructive waves e.g., 4-8m of erosion at Abu Qir

  millenia - aswan high dam resulting in overall net erosion, 10% of water in Lake Nasser evaporates per year - required for flocculation, construction of Grand Ethiopian Renaissance dam = lower levels of sediment yield