management for coast methods Flashcards
5 types of hard engineering
- revetments
- gabions
- groynes
- sea walls
- rock armour
aim of revetments
porous design made to absorb wave energy
strenghts of revetments
easily masde and cheaper than sea walls
weakness of revetments
life span limited
gabions aim
rocks held in wire cages to absorb wave energy
gabions strengths
cheap
gabions weakness
small scale
groynes aims
prevent longshore drift
groynes strength
relatively low cost and are easily repaired
weakness of groynes
cause erosion on downdrift side, interrupt sediment flow
rock armour aim
large rocks at base of cliff to absorb wave energy
rock armour strength
cheap
rock armour weakness
unnatractive and may be removed in heavy storms
sea walls aims
curbed walls designed to reflect wave energy
sea walls strengths
easily made,
sea walls weakness
expensive, and foundation can be undermined
3 types of soft engineering
offshore reefs
managed retreat
beach nourishment
offshore reefs aim
Waste materials, e.g. old tyres weighted down, to reduce speed of incoming wave
strength of offshore reef
Low technology and relatively cost-effective
offshore reef weakness
long term impact unkown
beach nourishment aim
sand pumped from sea bed to replace eroded sand
beach nourishment strength
looks natural
beach nourishment weakness
short term and expensive
managed retreat aim
coastline allowed to retreat in certain places
