2. Coastal Management Flashcards
What is a Sea Wall?
A wall built on the edge of the coastline.
Advantages:
- Protects the base of cliffs, land and buildings against erosion. Can prevent coastal flooding in some areas.
Disadvantages:
- Expensive to build.
- Curved sea walls reflect the energy of the waves back to the sea. This means that the waves remain powerful.
What is Hard Engineering?
Hard engineering options tend to be expensive, short-term options. They may also have a high impact on the landscape or environment and be unsustainable.
What are Groynes?
A wooden barrier built at right angles to the beach.
Advantages:
- Prevents the movement of beach material along the coast by longshore drift.
- Allows the build up of a beach.
Disadvantages:
- Can be seen as unattractive.
- Costly to build and maintain.
What is Rock Armour?
Large boulders are piled up on the beach.
Advantages:
- Absorb the energy of waves.
- Allows the build up of a beach.
Disadvantages:
- Can be expensive to obtain and transport the boulders.
What are Gabions?
Gabions are quite simply bundles of rocks in a metal mesh. They’re placed at the base of a cliff in an attempt to reduce the impact of waves on the cliff and prevent the cliff from being undercut.
What are Revetments?
Revetments are concrete or wooden structures that are built along the base of a cliff. They’re slanted and act as a barrier against waves not too dissimilar to a sea wall. The revetments absorb the energy of the waves, preventing the cliffs from being eroded.
What are Ripraps?
Riprap are just rocks and stones that have been out against the base of a cliff. They’re similar to gabions in their purpose, but they aren’t bound together in a mesh.
What are Breakwaters?
Breakwaters are offshore concrete walls that break incoming waves out at sea so that their erosive power is reduced to next to none when they reach the coast.
They are effective but they can be easily destroyed during a storm and they don’t look particularly nice.
What is Soft Engineering?
Soft engineering options are often less expensive than hard engineering options. They are usually more long-term and sustainable, with less impact on the environment.
What is Managed Retreat?
Is a form of soft engineering. In most cases it involves breaching an existing coastal defence, such as a sea wall or an embankment, and allowing the land behind to be flooded by the incoming tide, thus setting back the line of actively maintained coastline.
Advantages:
- It encourages the development of beaches (a natural defence) and salt marshes (important for the environment).
- Cost is low.
Disadvantages:
- Managed retreat is a cheap option, but people will need to be compensated for loss of buildings and farmland.
What is Beach Nourishment?
This is where sand and shingle are added to a beach in order to make it wider. This increases the distance a wave has to travel to reach the cliffs and so the wave will lose more energy.
