3.2.3.4 Coastal management Flashcards
Explain sea walls
Aim to absorb wave energy, often recurved to throw the wave back to prevent erosion.
Positives of sea walls
- protect important areas effectively
Explain rock armour (rip rap)
Large boulders piled up around the coast to absorb wave energy
Negatives of sea walls
- any gaps will be quickly eroded by hydraulic action
- very expensive (£800-£1500 per metre)
- creates a strong backwash which erodes under the wall
Positives of rock armour (rip rap)
- relatively cheap (£300 per metre)
- can use local debris
- some environments allow it to look natural
Negatives of rock armour (rip rap)
- rocks can shift in storms
- visually unattractive
Explain gabions
Cages filled with rocks which allow waves to percolate, reducing erosion
Positives of gabions
- very cheap (£10 per square metre)
Negatives of gabions
- metal cages fail quickly
- visually unattractive
Explain groynes
Fences built perpendicular to coasts which reduce longshore drift
Positives of groynes
- healthier beaches slow waves and reduce erosion
- increased tourism due to nicer beaches
Negatives of groynes
- cost £200,000 per groyne
- starves down-drift beaches of sediment
Explain beach nourishment and beach stabilisation
Replacing lost material to create wider beaches.
Also reducing the gradient of beaches to promote constructive waves and encourage sand dunes
How can organisations implement sand dune regeneration
- replanting vulnerable areas with pioneer plants
- providing boardwalks for tourists
- providing information about the potential damage trampling causes
Explain managed retreat
- allowing the sea to flood low value land
- this can create marshland which becomes a natural buffer
Advantages of soft engineering over hard engineering
- more sustainable
- a lot cheaper
- integrated with natural environment
Advantages of hard engineering over soft engineering
- provides a short term solution
- more resistant to larger storm events
Explain shoreline management plans (SMPs)
- a plan for how the coastline of one sediment cell should be managed
- a cost benefit analysis and land use management of this area
- based on the principle that intervention will be self contained within the cell
What are the 4 options to consider for each SMP
- hold the line (maintain the current position of the coastline)
- advance the line (extending the coastline out to sea)
- managed retreat (allowing the coastline to retreat and create natural environments)
- do nothing
Explain integrated coastal zone management (ICZM)
- the process which brings together all people involved in the development, management and use of a coastline
- a more holistic overview of the coastal area
What is the aim of ICZM
To establish sustainable levels of economic and social activity
