Hard engineering Flashcards
What is a Sea Wall?
A wall, usually concrete, and curved outwards to reflect the power of the waves back out to sea
Sea walls are designed to prevent erosion and flooding.
What are the advantages of a Sea Wall?
Most effective at preventing both erosion and flooding (if the wall is high enough)
High sea walls can significantly reduce the impact of waves.
What are the disadvantages of a Sea Wall?
Very expensive to build and maintain, can be damaged if material is not maintained in front of the wall, restricts access to the beach, unsightly to look at
Maintenance is crucial to ensure the longevity of sea walls.
What are Groynes?
Wood, rock or steel piling built at right angles to the shore that traps beach material being moved by longshore drift
Groynes are used to manage sediment along the coast.
What are the advantages of Groynes?
- Slows down beach erosion
- Creates wider beaches
- Stops material moving down the coast
Groynes can help rebuild beaches by trapping sand.
What are the disadvantages of Groynes?
Starves other beaches of sand, wood groynes need maintenance to prevent wood rot, makes walking along the shoreline difficult
The interruption of sediment flow can impact adjacent beaches.
What is Rip-rap?
Large boulders piled up to protect a stretch of coast
Rip-rap is used to absorb wave energy.
What are the advantages of 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
Rip-rap can be a more economical solution for coastal protection.
What are Gabions?
A wall of wire cages filled with stone, concrete, sand etc built at the foot of cliffs
Gabions are a flexible and effective coastal defence.
What are the advantages of Gabions?
- Cheapest form of coastal defence
- Cages absorb wave energy
- Can be stacked at the base of a sea wall or cliffs
Their flexibility allows them to adapt to the coastal environment.
What are the disadvantages of Gabions?
Wire cages can break and need to be securely tied down, not as efficient as other coastal defences
Regular inspections are necessary to maintain their effectiveness.
What are Revetments?
Sloping wooden or concrete fence with an open plank structure
Revetments are designed to protect the coast by breaking wave energy.
What are the advantages of 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
Revetments can enhance beach stability.
What are the disadvantages of Revetments?
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
Their visual impact can be a concern for coastal aesthetics.
