coastal management

• hard engineering - building of entirely artificial structures using various materials to stop impact of coastal processes
• sea wall - concrete barrier built against the sea

  • curved face
  • directs wave energy back out to sea
  • built in areas where they have a 'hold the line' approach
  • reduces erosion
• pros of sea walls:

  • effective
  • sense of security
  • long lasting (50 years)
  • not very expensive
• cons of sea walls:

  • concrete material produces lots of CO2
  • ugly
  • high maintenance cost
  • can be eroded at bottom due to being hit by redirected waves
• groynes - timber or rock structures built out to sea from coast. Traps sediment from longshore drift. Sand doesn't move away. Beach remains buffer for coastal erosion
• pros of groynes:

  • wider beach
  • useful structures for fishing
  • not too expensive
  • timber can be collected from sustainable sources
• cons of groynes:

  • looks unnatural , unappealing to people walking along beach
  • starves certain areas of their sediment supply - greater rates of erosion
• rock armour - piles of rock placed at foot of cliff or edge of beach. Resistance rock like granite. rocks force waves to break , dissipates wave energy before it reaches land behind.
• pros of rock armour:

  • cheap , easy to maintain
  • looks natural
  • used for fishing - habitat
  • reduces wave energy , lower erosion rates
• cons of rock armour:

  • looks ugly
  • expensive
  • granite can't be locally sourced
  • if rocks are too small they'll be moved by the wave = defense useless
• gabions - wire cages filled with pebbles from local beach. Supports cliff whilst providing buffer against wave erosion. pebbles in cage absorb and disspate wave energy
• gabiosn can last up to 20-30 years
• cons of gabions:

  • ugly
• pros of gabions:

  • cheap + effective
  • improves drainage on cliffs
  • blends into landscape
  • pebbles can be locally sourced
• soft engineering - managing erosion by working with natural processes to help restore beaches and coastal ecosystems
• beach reprofiling = reshaping beach using existing beach material. In winter , beach is lowered by destructive waves. After storms bulldozers send sand + shingle back up the beach.
• pros to beach reprofiling:

  • looks natural
  • effective buffer for coastline
  • houses behind beach protected
• cons of beach reprofiling:

  • very expensive (£750,00 a year)
  • has to be done regularly to be effective
• beach nourishment - adding sand and shingle (dredging from seabed) to upper edn of beach to widen and thicken it. Done via transporting sand in trucks
• pros of beach nourishment:

  • wider beaches slows down waves
  • wider beach = more tourists
  • natural , blends in with environment
• cons of beach nourishment:

  • taking material from seabed can kill organisms and destroy habitats
  • costs £300,000 to hire a dredger
  • costs £500,000 habitats per 100m
• dune regeneration - restoration of sand dunes to maintain their protective position. Fences placed along dunes , traps sand , marram grass can colonise sand dunes. Build up sand dune
• pros of dune regeneration:

  • minimal impact on natural systems
  • can be constructed out of natural materials
  • controls public access to protect other ecosystems
  • protects dunes against coastal erosion
• cons of dune regeneration:

  • regular maintenance
  • not appealing
  • fences can get damaged by storms , not resistant to high energy waves
  • £400-2,000 per 100m
• dune fencing - planting vegetation to create or restore sand dunes. Marram grass has roots that holds down dunes together , prevents sand from being blown away.
• pros of dune fencing:

  • sand dunes provide barrier between land and sea
  • cheap
  • absorbs wave energy , prevents flooding and erosion
• cons of dune fencing:

  • protection is limited to a small area
  • nourishment expensive
  • dune regeneration has to be checked twice a year and have fertilisers applied
• 4 options for shoreline management plan:

  • Hold the line
  • advance the line
  • managed retreat
  • do nothing
• hold the line - maintaining current position of the coastline often using hard engineering methods
• advance the line - extending the coastline out to sea by encouraging build up of a wider beach
• managed retreat - allowing coastline to retreat in a managd way
• do nothing - allowing sea to erode cliffs , flood low-lying land and allowing existing defences to collapse
• CBA - cost benefit analysis
• CBA is used to determine the economic value of coastline to decide if intervention is needed to protect surrounding area
• EIA - environmental impact assessment
• EIA is used to assess the short + long term impacts of using management alignments on environment
• ICZM - integrated coastal zone management
• ICZM was created in 1992
• ICZM involves local communities in decision making process
• ICZM takes into consideration of social , economic and environmental impacts of coastal defenses