Coastal Defences

Question 1

Describe hard engineering

Answer 1

Uses man made structures to reduce or halt erosion
Highly effective
High cost
Have significant environmental impact due to use of concrete

Question 2

Describe soft engineering

Answer 2

Uses more natural materials to reduce erosion
Aims to complement physical environment

Question 3

Describe managed retreat

Answer 3

Allows erosion rates to carry on unchanged
Rate of erosion monitored and ways of adapting to this erosion are put in place

Question 4

Factors affecting management strategies

Answer 4

• economy
  = jobs, industry, insurance
• social
  = is coast historic, is it a home or village
• environmental
  = endangered species, nature reserves at risk, farms at risk

Question 5

List soft engineering strategies

Answer 5

Dune stabilisation
Beach nourishment

Question 6

Describe fine stabilisation

Answer 6

Marram grass planted
= roots help bind the dunes the protect land behind
= fences can be put in place to catch wind too

Question 7

Advantages and disadvantages of dune stabilisation

Answer 7

• cost effective
• creates an important wildlife habitat
• cheap
• minimal impact of natural environment
• planting is time consuming
• can easily be damaged in a storm

Question 8

Describe beach nourishment

Answer 8

Sand is added to the beach to replace material lost through erosion and transportation

Question 9

Advantages and disadvantages of beach nourishment

Answer 9

• maintains the beach which is a major tourist attraction
• blends in with rest of beach so it isn’t unattractive
• large quantities of sand needed on a regular basis
• must transport sand regularly

Question 10

Hard engineering strategies

Answer 10

Groynes
Sea walls
Rock armour
Revetments

Question 11

Describe groynes

Answer 11

• wooden fences built down beach at right angles to coastline
• stop material moving down beach by longshore drift
• work by building up amount of sand on updrift side
  = create wider beach
  = increase tourists and economy

Question 12

Advantages and disadvantages groynes

Answer 12

• builds up beach protecting cliff and increasing tourist potential
• cost effective
• visually unappealing
• deprives areas downwind of sediment increasing erosion elsewhere

Question 13

Describe sea walls

Answer 13

• protect coast using concrete, steel or stone
• protect cliffs from erosion and act as barrier to prevent flooding
• deflect wave energy back to sea
  = give people sense of security

Question 14

Adv of dis of sea walls

Answer 14

• effective erosion prevention
• promenade has tourism benefits
• visually unappealing
• expensive to construct and maintain
• wave energy reflected elsewhere with impacts on erosion rates

Question 15

Describe rock armour

Answer 15

• consists of massive blocks of natural rock piled up at base of cliff
• rocks dumped on top of each other
  = leaving gaps to let water through
• disperses energy of waves and reduces their erosion alr power
• quick to build and easy to maintain

Question 16

Adv and dis of rock armour

Answer 16

• cost effective
• rocks are sources from elsewhere so don’t fit with local geology
• pose a hazard if climbed upon

Question 17

Describe revetments

Answer 17

Wooden or concrete ramps that help absorb wave energy

Question 18

Adv and dis of revetments

Answer 18

• cost effective
• visually unappealing
• can need constant maintenance which creates additional cost

Question 19

Describe gabions

Answer 19

• wire cages filled with rocks that can be built up to support cliff
• often structured using local pebbles
• cheap to produce
• last 20/25 years
• can improve drainage cliffs