Coastal Defences Flashcards
What are the 2 type of engineering defences
Hard engineering and soft
Hard engineering
Man-made structures built to control the flow of the sea and reduce flooding and erosion
Soft engineering
Schemes set up using knowledge of the sea and its processes to reduce flooding and erosion
Hard engineering strategies
- Sea walls
- Rock armour
- Groynes
Sea walls
A wall built at the edge of the coast line
Sea wall advantages and disadvantages
Advantages:
- Protects from flooding
- Long life span
Disadvantages:
- Expensive
- Reflects the energy of the wave back meaning
it remains powerful and overtime the wall will
erode
–> cost a lot to maintain
Groynes
A wooden barrier built at a right angles to the beach to prevent longshore drift
Groynes advantages and disadvantages
Advantages:
- Prevents longshore drift allowing the beach to
build up
- Beach is still accessible
Disadvantages:
- Unattractive
- Costly to build and maintain
Rock armour
Large boulders that are piled up on the beach
Rock armour advantages and disadvantages
Advantages:
- absorbs energy of the waves
- allows build up of beach
Disadvantages:
- expensive to obtain and transport the
boulders
Soft engineering strategies
-Beach nourishment
-Managed retreat
Beach nourishment
Replaces beach or cliff material that has been removed by erosion or longshore drift
Beach nourishment advantages and disadvantages
Advantage:
- Natural defense
- Attracts tourists
Disadvantages:
- Constant maintainance
Managed retreat
Areas of the cost that are allowed to erode and flood naturally.
Managed retreat advantages and disadvantages
Advantages:
- Encourages the development of beaches (
natural defense) and salt marshes (important
for the environment
- Cheap
Disadvantages:
- Compensation for land
