Holderness coast - case study

• Holderness coast, Yorkshire:

  • stretch over 50 km, from the Chalk cliff at Flamborough through Holderness to spurn Head.
  • combination of clay geology and high energy environment one of the most rapidly eroding coastlines in Europe
• Physical factors:

  weather - winter storms produce stronger waves and higher sea levels. The rain intensifies sub-aerial processes. The saturated clay cliffs suffer increased runoff leading to slumping.
• Physical factors:

  waves - dominant waves from the north east which is also the direction of the direction of the largest fetch. Destructive waves erode the beaches. Long shore drift then carries this sediment southward. Tides and low energy environment of spurn head allow sediments to collect forming a spit, mud flats and sand dune.
• Physical factors:

  geology - the two main rocks are chalk and boulder clay. The more resistant chalk have survived large scale erosion and this has created classic features. The boulder clay are easily eroded and their retreat has formed the bay of Holderness.
• features and processes:

  • chalk headland and cliffs near flamborough
  • retreating clay cliffs of Holderness bay
  • 6km spit at spurn head
• Flamborough head:

  headland - arch, stack and wave cut platform

  chalk is resistant to erosion and have a distinctive lithology

  horizontal bedding planes - where they assist in the formation of wave cut platforms increasing abrasion.

  wave refraction - further concentrations waves on headlands allowing caves to develop progressively into arches, stacks and stumps
• Holderness cliffs:

  • formed by material left by ice sheets
  • retreating at 1.8 metres each year
  • sub-aerial processes - rainwater enters the clay & weight of water causes material to slide seawater. Removal of vegetation & increased urbanisation can accelerate these effects causing slumping.

  cliff top housing or hotels make matters worse. At cliff root the dine clay is easily removed by waves & estimated that LSD carries half a million tonnes each year in suspension. Little material to form beaches & protect cliffs.
• Spurn head:

  • sediments deposited here where the winds and river estuary have a large but fragile spit (6km)
  • currently growing at 10cm each year, winter storms are threatening to cut through narrow neck and detach from mainland
  • spit is also the site of sand dune and salt marsh ecosystem
• human factors:

  presence of people - turns physical processes into hazards and threatens life and property. Increased population levels due to retirement and the development of leisure and holiday facilities have occurred around Bridlington. The risk of erosion have been much greater at Easington where the gas terminal is under threat.
• human factors:

  interfering with natural processes - such as LSD or implementing defence strategies can have adverse effects. Downward drift impact of groynes at Hornsea, prevents building beaches elsewhere. Rapid erosion rates may be due to sediment starvation.
• human factors:

  global warming - indirect human impact are creating a rise in sea level and increase storminess. Areas such as Spurn head are at greater risk in such conditions, from both coastal flooding and erosion.
• hard engineering:

  • 11.4km of 50km coastline is currently protected by hard engineering
  • Bridlington protected by a 4.7km sea wall as well as groynes
  • easington gas station protected by revetments
  • spurn head protected by groynes and ripraps
• existing schemes are not sustainable:

  • groynes trap sediment, increasing width of beach. Increases erosion down drift.
  • protection is leading to formation of bays causing increased pressure and eventually the cost of maintaining sea denfences will be too high
• Managed retreat - relocating caravan parks further inland and allowing the land they are on to erode. However, there are issues surrounding how much compensation businesses will get for relocating and relocation isnt always possible