2.4. Sustainable management of coasts

Question 1

How can coastal defences be categorised?

Answer 1

• Hard engineering
• Soft engineering

Question 2

Hard engineering

Answer 2

• Some physical structure has to be built and maintained
• Requires money, manpower and technology
• Protects only one part of the coast but creates problems elsewhere
• May cause harms to humans

Question 3

Soft engineering

Answer 3

• Involves proper planning management and use of the coast as well as encouraging human interference along the coast
• Involves educating people
• Environmentally friendly

Question 4

Examples of hard engineering

Answer 4

• Rip rap
• Gabion
• Groynes
• Sea wall
• Breakwater
• Revetments

Question 5

Rip rap

Answer 5

• giant boulders placed at the foot (bottom) of cliffs.
• designed to absorb the waves energy and protect the cliffs behind.
• can be effective, but does look ugly, may reduce access to the beach
• can be expensive

Question 6

Gabion

Answer 6

• boulders placed in cage
• can be installed quickly and again is fairly effective
• reduces access to the beach
• can be expensive

Question 7

Groynes

Answer 7

• designed to stop longshore drift
• protects only one part of the coast
• can be expensive

Question 8

Sea wall

Answer 8

• absorb wave energy
• sometimes they are recurved to direct the waves energy back out to sea => not effective
• can be expensive

Question 9

Breakwater

Answer 9

• Instead of breaking on the coast, waves, break on the breakwater
• are often found around the mouths of rivers and ports
• can disrupt shipping and animals

Question 10

Revetments

Answer 10

• similar to sea walls, but often built out of wood
• found at the foot of cliffs they are designed at absorb the waves energy
• require continuous efforts for maintenance

Question 11

Examples of soft engineering

Answer 11

• Dune stabilisation
• Cliff regarding
• Beach nourishment
• Beach drainage
• Managed retreat

Question 12

Dune stabilisation

Answer 12

• planting vegetation on the berm of the beach or on the dunes
• making them more stable (roots) and reducing the moisture content (root uptake)

Question 13

Cliff regrading

Answer 13

• makes cliffs less steep
• by reducing the angle you should reduce the undercutting and the risk of the cliff collapsing.

Question 14

Beach nourishment

Answer 14

adding more sand to the beach

Question 15

Beach drainage

Answer 15

removing some of the excess water to reduce stress on the cliff

Question 16

Managed retreat

Answer 16

• allowing the sea to take back land
• allowing changes to some inland ecosystems by adding salt water.