Hard Engineering Methods

Question 1

Groynes

Answer 1

Wooden walls 90° to coast to slow LSD - higher + wider beach
Adv: maintains beach size, protects coast, assists tourism, less expensive (than sea walls)
Dis: expensive (£1000/m), obstacle and unsightly

Question 2

Sea walls

Answer 2

Parallel to shore - recurved directs water back into waves/stepped breaks up waves
Adv: concrete absorbs energy, security, provides promenade, stops high water levels
Dis: most expensive (£5000/m), unsightly, difficult access, needs deep pilings, less sediment

Question 3

Rip rap

Answer 3

Concrete boulders resist erosion to break up waves + protect mass movement (cliff)
Adv: long lasting, flexible use, susceptible points - base of sea well, breakwater, groyne
Dis: £50/m3, unsightly, difficult access (dangerous), seawater moves through (erosion)

Question 4

Revetments

Answer 4

Sloped walls (wood) parallel to shoe but in front - takes force of waves (less erosion)
Adv: absorbs energy, traps sediment behind, LSD continued, linear access, cheaper
Dis: £1500/m, less access along width, unsightly, needs constant maintenance

Question 5

Offshore breakwaters

Answer 5

Boulders (parallel) in shallow nearshore - absorbs energy before foreshore
Adv: allows LSD, protects harbour entrance (calm), sheltered water areas + beaches behind
Dis: £1.2mil, unsightly (at low tide), high deposition on land = LSD, news other engineering (sea wall)

Question 6

Gabions

Answer 6

Pebbles in wire baskets tied together to make walls - absorbs energy
Adv: flexible in placement, holds back mass movement, cheap, easy to maintain
Dis: not strong, unsightly, needs frequent repairs