booklet 11 - traditional management

• why should we manage the coast?

  - protect the poplulation - 16.9 million live on or near the coast

  - protect habitats and important infrastructure like the road at mapleton

  - there would be food security issues if the coast wasnt protected
• difference between hard and soft engineering?

  Hard engineering is making a physical change to the coastal landscape using resistant materials like concrete

  Soft engineering uses natural systems for coastal defences such as dune and salt mashes
• Hard engineering - groynes

  wooden/steel structures built at 90 degrees to waves. They are built to prevent/ stop LSD by tapping sediment

  Around £250 per/m
• Good points and bad points - groynes

  Very effective

  low maintenance

  durable

  
  

  look unattractive

  starves beach further down from sediment
• sea wall


  Made from concrete/ or wood, they have a recurved structure aiming to dissipate wave energy

  £2000 per/m
• Good points and bad points - sea wall

  very effective at protecting vulnerable area

  durable and long lasting

  
  

  very unnatural looking

  expensive

  will need replacing eventually
• gabions


  Mesh cages filled with large boulders and are placed in areas most effected by erosion

  £100 per/m
• Good points and bad points - gabions


  relativity cheap

  effective at doing job

  
  

  not natural

  can break easily

  need regular replacement
• revetments


  concrete/ wooden structures placed across a beach to absorb full force of wave energy

  Up to £4000 per/m
• Good points and bad points - revetments

  low maintenance

  look relatively natural

  effective

  
  

  very expensive

  can make some beaches inaccessible to tourists
• rip rap


  large boulders dumped in front of cliffs/ sea walls to take full impact of wave

  £2000-£6000 per/m
• Good points and bad points - rip rap

  effective

  varying prices

  
  

  look unnatural

  in stormy conditions waves can damage the structures
• cliff fixing


  driving iron bars into the cliff to stabilise it and so it can absorb wave power
• Good points and bad points - cliff fixing

  cheap

  reduces injury risk

  less prone to movement caused by weather

  
  

  hard to do as land is being used on top

  difficult to maintain
• offshore breakwater


  offshore sloped/ vertical walls that reduce wave energy out at sea so by the time they reach the shore they have less impact

  £3000 per/m
• Good points and bad points - offshore breakwater

  reduce the impact and levels of LSD

  provide good protection to bays

  low maintenance

  
  

  expensive

  can cause strong currents

  unnatural
• tidal barrages


  large structures built to prevent flooding in major estuaries and sea inlets - acts like a dam

  £100000 - £1 million
• Good points and bad points - tidal barrages

  effective

  helps provide a constant level of water

  
  

  expensive
• Advantages of hard engineering

  Provides a barrier to erosion and flooding

  Generally most effective technique for protecting land&property

  Creates confidence to develop land behind
• Disadvantages of hard engineering

  high costs, can still fail, ugly, disrupt ecosystems, can move the problem down the coast
• Impacts of hard engineering on coast

  - can ruin habitats

  - looks unnatural

  - can damage natural processes - interrupt coastal system, inputs outputs and processes like LSD

  - can make erosional impacts worse down other areas of coast
• Soft engineering - beach nourishment

  adding sand/pebbles to a beach to make it higher/wider.

  
  

  Pros: cheap, easy to maintain, natural, increased tourist potential.

  
  

  Cons: constant maintenance.
• Good and Bad points - beach nourishment

  Pros: cheap, easy to maintain, natural, increased tourist potential.

  
  

  Cons: constant maintenance.
• Cliff regrading and drainage

  Cliff regrading reduces the angle of the cliff to help stabilise it. Drainage removes water to prevent landslides and slumping.
• Good and bad points - cliff regrading

  cheap

  reduces injury risk

  less prone to movement caused by weather

  
  

  hard to do as land is being used on top

  difficult to maintain
• Dune stabilisation


  Stabilise dunes to help absorb wave energy prevent flooding and protect low lying areas from flooding
• Good and bad points - dune stabilisation

  sustainable

  natural

  provides habitats

  
  

  time consuming to plant

  not fully effective
• Marsh creation


  Allowing low lying coastal areas to be flooded by the sea to become a salt marsh. The salt marsh then acts as an effective barrier to the sea.

  Eg: Essex marshes
• good and bad points - marsh creation

  encourages creation of habitats

  sustainable

  coastal squeeze eliminated

  
  

  community may respond negatively

  not 100% effective

  takes time to plant and create
• What is cost-benefit analysis?

  a study that compares the costs and benefits to society of providing a public good like coastal sea protection
• Tangible and intangible costs and benefits

  categories for determining how well an organization can define the estimated costs and benefits for a project.
• Who are the different stakeholders along the coast

  - Residents

  - Business owners

  - Environmental agencies

  - local authorities

  - communities

  All in conflict as they want different things, residents and businesses may want a more long lasting solution but environmental agencies may want a more sustainable natural approach
• Holderness Coast


  Located in the North East of UK

  soft boulder clay, cliffs eroding quickly at 2m per year - fastest eroding coastline in Europe. Runs through multiple towns and goes from Flambourgh head to Spurn point
• Holderness Coast - mappleton

  Mappleton is a small village that could become lost to the sea. The road running through it, the B1242 links towns along the coastline and would have been lost to coastal erosion if protection measures were not put into place. So, blocks of granite were brought in and placed along the cliff base and 2 rock groynes were put into place costing £2 million to trap sediment moving because of longshore drift. However there are now problems further down the coast at grange farm - 1991-2022 eroded 100 m
• Holderness coast - sea defences

  At Hornsea concrete sea walls were put in place as well as groynes and rock armour. Impact - beach has been maintained at Hornsea but at Mappleton sediment starvation has been happening

  At Withernsea a straight sea wall was constructed in 1875, but it collapsed so following CBA in 1991 a recurved one was built. Waves are now nosier and views are restricted
• Essex Salt mashes


  Coastal squeeze was occurring in Essex whereby sea levels have been rising over the salt marshes causing deep water leading to erosion. Sea levels are rising at 6mm a year due to global warming
• Essex Salt marshes - abbots hall farm

  At Abbots Hall farm the sea wall was deliberately breached to be in time with spring tides. This enables seeds to be floated by each tide so a salt marshes can grow. The scheme had been highly successful as coastal flooding has reduced, new habitats created. £500000 has been saved in sea defences. Polders have been used to encourage salt marsh creation. A total of 26 now have been used to regulate tidal flow