Hard engineering strategies

Question 1

what is a sea wall?

Answer 1

a concrete rock wall which is placed at the foot of the cliffs or top of the beach
it aims to dissipate wave energy by providing a physical barrier to flooding by raising the height of the coastline

Question 2

what are the advantages of a sea wall?

Answer 2

• often has a promenade for people to walk along

- effective at stopping the sea

Question 3

what are the disadvantages of a sea wall?

Answer 3

• can be intrusive and unnatural to look at

- very expensive to build and requires alot of maintenence

Question 4

what are groynes?

Answer 4

Timber or rock structures
built at right angles to the waves
they trap sediment being moved along beach by LSD

Question 5

what are advantages of groynes?

Answer 5

• the built up beach increases tourist potential
• not too expensive
• work with natural processes to build up beach

Question 6

what are the disadvantages of groynes?

Answer 6

• unattractive
• short life span
• starve beaches along the shore of sediment

Question 7

what are gabions?

Answer 7

wire cages filled with small rocks built up to create walls, often built to support weak cliffs

Question 8

what are the advantages of the gabions?

Answer 8

• inexpensive and flexible
• encourages upper beach stability
• may eventually blend in with landscape as vegetation grows

Question 9

what are the disadvantages of gabions?

Answer 9

• look very unsightly to begin with

- the metal cage can rust and become broken and dangerous

Question 10

what is rock armour/rip rap

Answer 10

consists of large boulders being dumped in front of the cliffs or sea wall to take the full force of the waves

Question 11

what are the advantages of rip rap?

Answer 11

• cheap and easy to place and maintain

- often used for subathing by tourists

Question 12

what are the disadvantages of rip rap?

Answer 12

• rocks are usually from abroad or other parts of the coast so don’t fit with geology
• can be intrusive
• can be dangerous

Question 13

what are revetments?

Answer 13

wooden or rock barriers placed at foot of cliff or top of the beach
they take full force of waves

Question 14

what are the advantages of revetments?

Answer 14

• absorb wave energy through the slats
• effective for many years
• can be cheap compared to other techniques

Question 15

what are the disadvantages of revetments?

Answer 15

• not effective in storm conditions
• can make the beach inasccesible
• need regular maintenence

Question 16

what is cliff fixing?

Answer 16

iron bars are driven into the cliff both to stabalise it and absorb some wave power

Question 17

what are the advantages of cliff fixing?

Answer 17

• hidden structures

- prevents landslides / mass movement

Question 18

what are the disadvantages of cliff fixing?

Answer 18

• cliff still open to erosion
• ongoing maintanence costs
• eyesore
• expensive as uses metal bars

Question 19

what are offshore reefs?

Answer 19

force the waves to break offshore which reduces their impact on the base of the cliffs

Question 20

what are advantages of offshore reefs?

Answer 20

• allow the build up of sand dune to reduce the wave energy

- waves break further offshore and therefore reduce the erosive power

Question 21

what are the disadvantages of offshore reefs?

Answer 21

• may be removed by heavy storms

- difficult to install

Question 22

what are barrages?

Answer 22

large scale engineering involving the construction of a partly submerged wall in a bay or estuary
sluice gates control the flow of water in and out of a bay

Question 23

what are the advantages of barrages?

Answer 23

• can be used to generate hydro-electric power
• renewable
• reliable
• no fuel costs

Question 24

what are the disadvantages of barrages?

Answer 24

• very expensive to construct and maintain
• environmental impacts are considerable
• environmental impacts on habitats as water levels change

Question 25

what are the arguments for hard engineering strategies?

Answer 25

• Sloping walls absorb rather than reflect energy
• easy to repair
• cost less than the damage coastal erosion could cause to coastal communities and industry
• prevent loss of property

Question 26

what are the arguments against hard engineering strategies?

Answer 26

• expensive
• eyesore
• can cause increased rates of coastal erosion further down the coast
• hard engineering strategies have to be maintained which can cost a lot
• loss or of damage to the natural environment
• people are not compensated for any land they lose
• can trap sediment reducing sediment transfer by LSD