Coastal Defences

Question 1

Soft Engineering

Answer 1

Schemes set up using knowledge of the sea and its processes to reduce the effects of flooding and erosion. Tend to be environmentally sustainable and small scale.

Question 2

Sea Wall

Answer 2

Adv.
- Very good at dissipating wave energy
- High enough to prevent coastal flooding
Disadv.
- Expensive (£6 million per km)
- Prevents coastal habitats from receiving salt water
- Waves reflected off are destructive and erode beach

Question 3

Groyne

Answer 3

Adv.
- Stop longshore drift so protect beach for waves to break on
- Provides tourism to local area (economic)
- Cheap at £10,000 each (200m apart)
Disadv.
- Need replacing every 10 years and regular maintenance
- Creates erosion elsewhere
- Unsightly

Question 4

Rock Armour

Answer 4

Adv.
- Cheap at between £1000-4000 per km
- Easy to maintain
- Stop erosion and possible flooding by absorbing wave energy
Disadv.
- Unsightly (spoil natural appearance of coastline)
- Boulders are costly to import
- Severe storms can move them and cause more damage

Question 5

Beach Nourishment

Answer 5

Adv.
- Cheap at £3000 per km
- Attract tourists
Disadv.
- Unsustainable (expensive to maintain in long term)
- Taking material from seabed kills organisms like coral

Question 6

Dune Regeneration

Answer 6

Adv.
- Cheap at only £2000 per 100m
- Helps maintain ecosystem
- Absorb storm and wave energy by acting as a buffer between land and sea
Disadv.
- Time consuming
- Less effective
- Limited to a small area

Question 7

Marsh Creation/Managed Retreat

Answer 7

Adv.
- Vegetation stabilises mudflats so they can absorb wave energy
- Restores natural habitats (sustainable
Disadv.
- Expensive (land can be used for farming etc.)
- Ineffective in areas of high erosion as there is not time for it to establish

Question 8

Hard Engineering

Answer 8

Involves building manmade structures to reduce flooding erosion. Tends to be large scale and expensive.