Human causes of coastal recession - 2.8

• where is the holderness coast


  East Yorkshire
• how many miles is this stretch of coastline, and where is the start and end

  60 miles from Flamborough to spurn head (spit)
• what is the main rock that makes up this coastline

  boulder clay
• why is this coastline predominantly boulder clay


  in the last ice age, a large ice sheet travelled across the North Sea carrying debris, sand and clay. when it melted it left this sediment causing boulder clay
• what is the recession rate of Holderness coastline

  2 metres per year
• what what are three causes of coastal recession at the holderness coast


  fetch/waves, geology, sub ariel processes
• why is geology a cause of recession

  boulder clay
• what is the fetch of the waves here

  500-800km
• is the fetch big or small


  not particularly big
• if the fetch of waves at holderness isn't particularly big, why is fetch a problem

  the currents circulate from Atlantic sea to the North Sea due to north easterly winds, and the Atlantic sea has a large fetch of 5000km which makes the waves at holderness more powerful
• why are the waves powerful at the holderness coast


  -sea floor deep which reduces friction, so waves retain more energy

  -atlantic has large fetch which creates stronger waves in the North Sea
• which direction is the longshore drift


  south due to the North easterly winds
• why is longshore drift a problem

  creates narrower beaches
• what 2 sub Ariel processes affect recession hear

  mechanical weathering

  alternate wetting and drying
• what is mechanical weathering also known as

  freeze thaw weathering
• how does alternate wetting and drying cause coastal recession

  when its dry cracks in the rock form

  when it it wet rain fills the cracks which makes the cliff heavy

  this causes slumping
• why is slumping the dominant mass movement process at Holderness

  because the boulder clay lies above chalk which is permeable, so the saturated boulder clay becomes heavy and creates a curved plane, eventually slumping down.
• explain why storms are also a physical factor of erosion at Holderness

  regular storms of the North Sea due to the low pressure system creates a high tide with powerful waves
• what is the main human cause of erosion here

  costal management changing sediment balance which increases erosion in certain areas along the coastline
• outline e examples of coastal management at holderness and their impacts


  -2 rock armour groins at Mappleton has increased erosion south (eg) Golden sands caravan park has lost 100 chalets