Coastal Management

Question 1

What are the four options of coastal management?

Answer 1

1. Hold the line
2. Advance the line
3. Do nothing
4. Managed retreat

Question 2

What is the hold the line method?

Answer 2

Maintain the existing coastal defences.

Question 3

What is the advance the line method?

Answer 3

Build new coastal defences further out at sea compared to the existing defences.

Question 4

What is the do nothing method?

Answer 4

Build no coastal defences and deal with flooding and coastal erosion as it happens.

Question 5

What is the managed retreat method?

Answer 5

Allow the shoreline to move but manage the retreat so it causes the least damage possible.

Question 6

Define a sea wall and it’s cost.

Answer 6

A wall in the sea that reflects waves back to sea preventing erosion of the coast.
Also acts as a barrier to prevent flooding. Cost: expensive to build and maintain.

Question 7

Define a revetment and it’s cost.

Answer 7

A slanted structure built at the foot of a cliff. Can be made of concrete, wood or rocks. Waves break at the revetment and absorb wave energy and prevent erosion.
Cost: expensive but cheap to maintain.

Question 8

Define a gabion and it’s cost.

Answer 8

Rock filled cages built at the foot of a cliff that absorb wave energy and reduce erosion.
Cost: cheap

Question 9

Define rip rap and it’s cost.

Answer 9

Boulders piled up alone the coast that absorb wave energy.
Cost: Fairly cheap.

Question 10

Define a groyne and it’s cost.

Answer 10

Fences built at a right angle to the coast that trap material being transported up the beach by long shore drift creating a wider beach giving it more protection from erosion and flooding.
Cost: Quite cheap.

Question 11

Define breakwaters and it’s cost.

Answer 11

Concrete blocks deposited of the coast that force waves to break offshore giving it protection against flooding and erosion.
Cost: Expensive.

Question 12

Define an earth bank and it’s cost.

Answer 12

Mounds of earth that act as barriers to prevent flooding.
Cost: Quite expensive.

Question 13

Define a tidal barrier and it’s cost.

Answer 13

Structures built across a river estuary that contain retractable floodgates that can be raised to prevent flooding during storm surges.
Cost: VERY expensive.

Question 14

Define a tidal barrage and it’s cost.

Answer 14

Dams built across a river estuary that generate electricity by trapping water behind it during high tide. Controlled release of water though the turbines in the dam at low tide generates electricity and prevent flooding.
Cost: VERY expensive.

Question 15

What is a disadvantage of sea walls?

Answer 15

Creates a strong backwash that erodes under the wall.

Question 16

What is a disadvantage of revetments?

Answer 16

They create a strong backwash that erodes under the structure.

Question 17

What is a disadvantage of gabions?

Answer 17

They are ugly.

Question 18

What is a disadvantage of riprap?

Answer 18

They can shift in storms.

Question 19

What is a disadvantage of groynes?

Answer 19

The starve down-drift beaches of sand leading to greater erosion and flooding in those areas.

Question 20

What is a disadvantage of breakwaters?

Answer 20

They can be damaged easily during storms.

Question 21

What is a disadvantage of earth banks?

Answer 21

Over time will be eroded.

Question 22

What is a disadvantage of tidal barriers?

Answer 22

They aren’t cost effective being so expensive.

Question 23

What is a disadvantage of tidal barrages?

Answer 23

They disrupt sediment flow causing increased erosion elsewhere in the estuary.

Question 24

Define beach nourishment.

Answer 24

Where sand is added to the beach from elsewhere creating a wider beach and reducing erosion.

Question 25

Define beach stabilisation.

Answer 25

Reducing the slope angle of a beach and planting vegetation to stabilise the sand creating a wider beach.

Question 26

Define dune regeneration.

Answer 26

Where sand dunes are created or restored by nourishing or stabilising the sand providing a barrier between the land and sea absorbing wave energy.

Question 27

Define land use management in coastal erosion?

Answer 27

Important for dune regeneration. Dunes can be trampled and destroyed leaving the dune vulnerable to erosion. Wooden walkways across dunes or fencing them off will reduce vegetation loss.

Question 28

Define creating marshland as a method of coastline management.

Answer 28

Planting appropriate vegetation (Eg: glassworts) to stabilise sediment and the stems and leaves reduce wave speed.

Question 29

Define coastal realignment as a method of coastal management.

Answer 29

(Managed retreat) involves breaching an existing sea defence allowing the sea to flood or erode the land. Over time, vegetation will colonise the land making it a marshland.

Question 30

Which type of coastal management is more sustainable and why?

Answer 30

Soft engineering as it is cheaper and integrates with natural environments and encourage new habitats.
(Lower environmental impact)

Question 31

Define a shoreline management plan.

Answer 31

Splitting the beach into sediment cells and dividing a plan for each area with the aim of protecting important sites while minimising problems elsewhere.
Authorities can decide to hold, advance, retreat or do nothing in each cell.

Question 32

Define integrated coastal zone management.

Answer 32

A dynamic strategy that considers all elements of the coastal system (land, water, people, economy) when strategising and is subject to change. Aims to protect coastal zone naturally.
-The environment is viewed as a whole.
-Different uses are considered (tourism)
-Local, regional and national all input.