holderness

• The Holderness Coast is one of Europe’s fastest eroding coastlines. The average annual rate of erosion is around 2 metres per year. 

  The main reason for this is because the bedrock is made up of till (soft clay). This material was deposited by glaciers around 12,000 years ago.

  The coastline stretches along the coast of the East Riding of Yorkshire, known as Holderness, from Flamborough Head (chalk) in the North, to Spurn Head in the south. 

  Since Roman times, the Holderness Coast has retreated 4 km – at least 29 villages have been lost to the sea
• Spurn Head represents a temporary sediment store or sink. 

  It is 3 miles long. On reaching the River Humber estuary, the deposited sediment grows out to form a narrow finger of new land. It has a curved tip as a result of wave action. 

  A salt marsh has formed on the inside of Spurn (Spurn National Nature Reserve, near Kilnsea). This is because the area is sheltered and the low energy environment results in sediment (flocculation) being deposited by the Humber Estuary.
• • Spurn Head is very narrow for much of its length and has frequently been breached and destroyed by major storms. Evidence suggests that the feature has gone through a number of cycles of growth and decline, lasting on average about 250 years. 
  • Following a massive breach in 1849, groynes and revetments (wooden barriers) were built to stabilise the spit. 
• Unable to afford the maintenance costs of the spit, the Trust had to allow some of the sea defences to fall into disrepair. When the largest tidal surge in 60 years hit Spurn Head in 2013, the defences could not cope- buildings were destroyed and the access road swept away.

  In subsequent years, when military forts were established at Spurn Point, the Royal Engineers took over the task of maintaining coastal defences. In the 1950s the military left, and in 1960, the spit was bought by the Yorkshire Naturalists' Trust.
• What was the scheme at Mappleton?

  • In 1991, sea defences were built in order to protect the village and B1242 main road
  • £2 million project
  • Two large rock groynes 
  • Revetment consisting of large granite boulders
  • Defended 450m along the shoreline
  • Cliff gradient was reduced artificially 
  • Vegetation was planted on the cliffs to stabilise (reduce mass movement)
• • The construction of the rock groynes has created a larger, higher sandy beach for Mappleton. 
  • High tide waves do not reach the base of the cliffs along the seafront at Mappleton
  • Erosion has slowed to a point where it is no longer a threat to the settlement. 

  Rock armour revetment has been very effective in protecting the cliff to the southern end of the settlement. They have been successful in restricting waves from attacking the base of the cliffs here.
• • Cliff stabilisation has had a positive impact in managing the threat of mass movement. There is no evidence of slumping along the area of cliffs where the angle of the slope has been reduced and vegetation has been planted over the last 25 years since they were modified. 
  • As a result of the coastal scheme at Mappleton no properties have been lost to the sea and the B1242 remains safe from the risk of erosion.
• • Owing to the limited beach material, waves reach the base of the cliffs even during neap tides. This has led to increased rates of erosion and an increase in slumping. 

  Erosion rates have increased from 1.7 (+/-) 0.6 m/yr to 3.3 (+/-) 0.8 m/yr . In some places erosion exceeds 10 m per year. 
• The process of longshore drift continues to transport materials away from the beach to the south of Mappleton but is not replenished as it is trapped by defences at Mappleton. Beaches to the south have very little sediment and during low tide expose a combination of sand and clay boulders that have been eroded from the cliffs. This process is called terminal groyne syndrome and happens frequently when groynes are stopped.
• The area directly south of the village now suffers from an even greater rate of erosion. As the movement of sediment has been disrupted due to the construction of the stone groynes material previously feeding the beaches to the south of the Mappleton is restricted. 
• future of holderness

  • The rate of future sea level rise is expected to accelerate. 
  • DEFRA have stated that they expect a total rise in sea level of just under 1 metre by 2105 for this area. 
  • The medium prediction for sea level rise along the Holderness coast is about 30 cm in the next fifty years (6 mm/year). This rate is higher than 1-2 mm/years that have occurred in the previous 100 years. 
  • It is likely that climate change will also bring about increased storminess.
• • The SMP for Holderness for the next 50 years recommends ‘holding the line’ at some settlements (e.g. at Bridlington, Withernsea, Hornsea, Mappleton and Easington Gas Terminal) and ‘doing nothing’ along less populated stretches. 
  • Managed realignment has been suggested, e.g. relocating caravan parks further inland and allowing the land they are on to erode. This would be a more sustainable scheme as it would allow the coast to erode as normal without endangering businesses. 
  • Stop trying to protect Spurn Head from erosion - do nothing became the new strategy. 
• Easington Gas Terminal is currently protected by rock revetments, and the SMP recommends that these defences are maintained for as long as the gas terminal is operating.