Coastal Management Flashcards
What does the Hold the line strategy entail?
Maintaining the existing coastal defences.
What does the Advance the line strategy entail?
Building new coastal defences further out to sea than the existing line of defence.
What does doing nothing entail?
Building no coastal defences, and deal with erosion and flooding as it happens.
What does the Retreat the line strategy entail?
Building no coastal defences, but move people away from the coast.
What is a sea wall?
A wall which reflects waves back out to sea, it prevents erosion of the coast and is also a barrier to flooding.
What are the disadvantages of a sea wall?
They are expensive to maintain and maintain. It also creates a strong backwash which erodes under the wall.
What is a revetment?
Revetments are slanted structure built at the foot of cliffs. They can be made from concrete, wood or rocks. Waves break against them, they absorb the wave energy and prevent cliff erosion.
What are the disadvantages of revetments?
They are expensive to build and also create a strong backwash
What are gambions?
Gambions are rock filled cages. A wall of gambions is usually built at the foot of cliffs. They absorb wave energy and reduce erosion,.
What is riprap?
It is boulders piled up along the coast. The boulders absorb the energy reducing erosion.
What are the disadvantages of riprap?
They can shift in a storm
What are groynes?
Groynes are fences built at right angles to the coast. They trap sediment transported by longshore drift. It creates wider beaches giving greater protection to the coast.
What are the disadvantages to Groynes?
They starve down beaches of sand. Thinner beaches dont protect the coast as well. Terminal groyne syndrome
What are breakwaters?
Breakwaters are concrete blocks or boulders deposited off the coast. They force waves to break offshore. The waves energy is then reduced by the time it reaches the shore.
What are the disadvantages of breakwaters?
They can be damaged in a storm.
