management of coastlines

Question 1

Evaluate Sea Walls;

Answer 1

Reflect wave energy
£6000 per metre
Effective in high-risk locations
Expensive maintenance
Can be eroded
Increases system output of energy

Question 2

Evaluate Groynes;

Answer 2

Low wall that traps sand
Costs £10,000
Effective on a local scale but require maintenance
Affect sediment budget

Question 3

Evaluate Revetments;

Answer 3

Sloping concrete wall laid along coast
£2000 per metre
Low maintenance but obtrusive
Disrupts sediment budget

Question 4

Evaluate offshore breakwaters;

Answer 4

Barrier located below low-water mark
£5000 per metre
Waves break earlier reducing the input of wave energy but increasing deposition

Question 5

Evaluate rip raps;

Answer 5

Interlocking boulders that break up waves
£3500 per metre
Protect beach from erosion - waves more destructive

Question 6

Evaluate beach nourishment;

Answer 6

Coastal sediment added from elsewhere
£3000 per km of sediment
Maintains beaches for tourists but needs to be annually

Question 7

Evaluate cliff regrading and drainage;

Answer 7

Cliff made more stable and re vegetated
In-cliff drainage reduces pore-water pressure
£1m per 100m
Can disrupt local areas

Question 8

Evaluate dune stabilization;

Answer 8

Dunes held together with fencing or marram grass
Cost £400-£2000 per 100m
Cost effective in long term

Question 9

Evaluate marsh creation;

Answer 9

Low lying coastal areas flooded to become marshes
£5000 to £10,000 per hectare
Cheap and creates habitats