Management

• The aim of any coastal management is to protect the environment but mostly people from the impacts of erosion and flooding
• Not all coastal areas can be protected or managed as there are economic constraints
• Hard engineering methods


  • Sea Wall
  • Groynes
  • Rip-rap
  • Gabions
  • Revetments
  • Off-shore barriers
• Hard engineering


  • Involves building some form of sea defence, usually from concrete, wood or rock
  • Structures are expensive to build and need to be maintained
  • Defences work against the power of the waves
  • Each type of defence has its strengths and weaknesses
  • Protecting one area can impact regions further along the coast, which results in faster erosion and flooding
  • Used when settlements and expensive installations (power stations etc) are at risk: the economic benefit is greater than the costs to build
• Sea Wall


  A wall, usually concrete, and curved outwards to reflect the power of the waves back out to sea
• Sea Wall


  • Most effective at preventing both erosion and flooding (if the wall is high enough)
  • Very expensive to build and maintain
  • It can be damaged if the material is not maintained in front of the wall
  • Restricts access to the beach
  • Unsightly to look at
• Groynes


  Wood, rock or steel piling built at right angles to the shore, which traps beach material being moved by longshore drift
• Groynes


  • Slows down beach erosion
  • Creates wider beaches
  • Stops material moving down the coast where the material may have been building up and protecting the base of a cliff elsewhere
  • Starves other beaches of sand. Wood groynes need maintenance to prevent wood rot
  • Makes walking along the shoreline difficult
• Rip-rap


  Large boulders are piled up to protect a stretch of coast
• Rip-rap


  • Cheaper method of construction
  • Works to absorb wave energy from the base of cliffs and sea walls
  • Boulders can be eroded or dislodged during heavy storms
• Gabions


  A wall of wire cages filled with stone, concrete, sand etc built at the foot of cliffs
• Gabions


  • Cheapest form of coastal defence
  • Cages absorb wave energy
  • Can be stacked at the base of a sea wall or cliffs
  • Wire cages can break, and they need to be securely tied down
  • Not as efficient as other coastal defences
• Revetments


  Sloping wooden or concrete fence with an open plank structure
• Revetments


  • Work to break the force of the waves
  • Traps beach material behind them
  • Set at the base of cliffs or in front of the sea wall
  • Cheaper than sea walls but not as effective
  • Not effective in stormy conditions
  • Can make beach inaccessible for people
  • Regular maintenance is necessary
  • Visually unattractive
• Off-shore barriers


  Large concrete blocks, rocks and boulders are sunk offshore to alter wave direction and dissipate wave energy
• Off-shore barriers


  • Effective at breaking wave energy before reaching the shore
  • Beach material is built up
  • Low maintenance
  • Maintains natural beach appearance
  • Expensive to build
  • Can be removed in heavy storms
  • Can be unattractive
  • Prevents surfing and sailing
• Soft engineering methods


  • Beach replenishment
  • Dune regeneration
  • Cliff re-grading
  • Managed retreat
• Soft engineering


  • Works with natural processes rather than against them
  • Usually cheaper and does not damage the appearance of the coast
  • Considered to be a more sustainable approach to coastal protection
  • However, they are not as effective as hard engineering methods
• Beach replenishment


  Pumping or dumping sand and shingle back onto a beach to replace eroded material
• Beach replenishment


  • Beaches absorb wave energy
  • Widens beach front
  • Has be repeated regularly which is expensive
  • Can impact sediment transportation down the coast
  • Removing material from the seabed damages fragile ecosystems such as corals and sponges
• Dune regeneration


  Planting vegetation helps to create or stabilise sand dunes and beaches
• Dune regeneration


  • Reduces wind erosion
  • Sand dunes act as a barrier between the sea and land
  • The wave energy is absorbed, preventing erosion and flooding
  • Cheap method of stabilising dunes
  • Hard to protect larger areas of coastline cliffs with this method
• Cliff re-grading


  The angle of a cliff is reduced to reduce mass movement
• Cliff re-grading


  • Prevents sudden loss of large sections of cliff
  • Regrading can also slow down wave cut notching at base of cliffs as wave energy is slowed
  • Does not stop cliff erosion
• Managed retreat


  Existing coastal defences are abandoned or removed, allowing the sea to flood inland until it reaches higher land or a new line of defences
• Managed retreat


  • No expensive construction costs
  • Creates new habitats such as salt marshes
  • Disruptive to people where land and homes are lost
  • Saltwater damages existing ecosystems
  • Cost of relocation can be expensive
  • Compensation to people and businesses may not be paid
• Most coastal managers aim to use a combination of methods depending on the value of what is being protected, known as Integrated Coastal Zone Management (ICZM)
• Cliff re-grading


  • Prevents sudden loss of large sections of cliff
  • Regrading can also slow down wave cut notching at base of cliffs as wave energy is slowed
  • Does not stop cliff erosion
• Managed retreat


  • No expensive construction costs
  • Creates new habitats such as salt marshes
  • Disruptive to people where land and homes are lost
  • Saltwater damages existing ecosystems
  • Cost of relocation can be expensive
  • Compensation to people and businesses may not be paid
• Integrated Coastal Zone Management (ICZM)


  A range of methods are used depending on the value of what is being protected
• Coastal cells


  Sections of a long coastline that are managed separately to identify erosion and flooding risks
• Coastal cells


  • Allows resources to be allocated effectively to reduce the impacts of these risks
  • The 'cost to benefit' is easier to calculate
• Shoreline Management Plans (SMP)


  Set out an approach to managing a coastline from flooding and erosional risk
• Shoreline Management Plans (SMP)

  • Aim to reduce the risk to people, settlements, agricultural land and natural environments (salt marshes etc.)
• Coastal management approaches


  • Hold the line
  • Advance the line
  • Managed realignment or retreat
  • Do nothing
• Hold the line


  Build and maintain coastal defences so the current position of the shoreline remains the same
• Advance the line


  Build new defences to extend the existing shoreline
• Managed realignment or retreat


  Some or all coastal defences are removed, allowing the coastline to move naturally
• Do nothing


  The coast is allowed to erode and retreat landward, no investment is made in protecting the coastline or defending against flooding
• Decisions about which coastal management approach to apply are complex and depend on various factors