Hard Engineering Flashcards
Define hard engineering.
Making physical changes to the coastal landscape using resistant materials like concrete and wood.
What does hard engineering involve?
Working against the nature.
Each strategy is large scale and costs a considerable amount of money.
Name 8 examples of hard engineering?
Seawalls. Rockarmour. Gabions. Revetments. Groynes. Cliff fixing. Offshore reefs. Barrages.
Name 3 disadvantages to hard engineering?
Structures are expensive to build and maintain.
Defence in one place may have serious consequences in other areas on the coastline.
Structures are unattractive.
Name 2 advantages of hard engineering?
Often more effective.
Job opportunities.
What is a sea wall?
Physical barrier to flooding.
Recurved walls dissipate wave energy as they throw waves back out to sea into the path of the next incoming wave, reduces wave impact.
What is rock armour?
Large boulders dumped in front of cliff or sea wall to take full force of waves.
Rocks angular in appearance to present large surface area to waves, gaps allow water to filter through.
What are gabions?
Small boulders contained within steel wire-mesh cages to take wave impact.
Can be joined together to form large structures.
Can support weak cliffs
What are revetments?
Concrete or wooden structures placed along coastline to take full force of water and absorb energy.
What are groynes?
Wooden, stone or steel breakwaters built nearly at a right angle to waves.
Control LSD by trapping sediment to create higher and wider beaches.
What is cliff fixing?
Often done by driving iron bars into cliff face, to stabilise it and absorb wave power.
What are offshore reefs?
Partly submerged rock barrier.
Forces water to break offshore, reducing impact on base of cliff.
What are barrages?
Large structures built to prevent flooding on major estuaries.
Acts as dam across estuary prevents incursion of seawater.
Sluice gates control water flow
Generate tidal power
Positive sea wall ❌
Stop sea
Promenade
Sea wall disadvantage 🧟♂️$$€€
Intrusive
Expensive
Maintainence
Cost sea wall
£6000 a metre
Groynes advantage
Build up beach
Tourists
Protect land behind
Groynes diadvantage
Starve beaches
Problem shifted
Intrusive
Mappletone
Groyne cost
£5000 - £10,000
Rock armour advantage
Easy to contruct
Fishing
sunbathing
Rock armour disadvantage
Rocks usually from other areas - abroad.
Intrusive as don’t fit in with normal geology
Dangerous
Rock armour cost
£100,000 - 300,000 for 100 metres
Gabion advantage
Not that expensive
Upper beach stability
Gabion disadvantage
Unsightly
Rusty metal cages
