2.11.B Hard engineering

Question 1

hard-engineering

Answer 1

this involves building structures along the coast

Question 2

groynes

Answer 2

timber or rock structures built at right angles to the coast

they trap sediment being moved along the coast by longshore drift and build up the beach

Question 3

PROS of groynes

Answer 3

the built-up beach increases tourist potential and protects the land behind it

relatively inexpensive - £5,000 to £10,000 each (at 200-metre intervals)

Question 4

CONS of groynes

Answer 4

-groynes starve beaches further along the coast of fresh sediment because they interrupt longshore drift –> increased erosion elsewhere

unnatural and rock groynes are unattractive

Question 5

example of groynes

Answer 5

MAPPLETON

two rock groynes were built in 1991
at Cowden (3km south of Mappleton), the resultant sediment starvation caused erosion of the cliffs to increase from 2.5m a year to 3.8 between 1991 and 2007)

Question 6

seawall

Answer 6

made of stone or concrete at the foot of a cliff or at the top of a beach
usually, have a curved face to reflect waves back into the sea

Question 7

PROS of a seawall

Answer 7

often have a long promenade for people to walk on

effective prevention of erosion

Question 8

CONS of a seawall

Answer 8

they reflect wave energy rather than absorbing it

they can be intrusive and unnatural looking

(the most expensive coastal defence) - build & maintain (£6,000 a metre)

Question 9

rock armour

Answer 9

large rocks placed at the foot of a cliff or at the top of a beach
forms a permeable barrier to the sea, breaking up the waves

Question 10

PROS of rock armour

Answer 10

• relatively cheap and easy to construct and maintain (about £50 per m^3)

Question 11

CONS of rock armour

Answer 11

can be very intrusive

rocks can be dangerous

Question 12

example of a seawall

Answer 12

WITHERNSEA

a straight sea wall was built was 1875 but over time, wave energy scoured the base of the wall, causing it to collapse

Question 13

offshore breakwater

Answer 13

a partly submerged rock barrier designed to break up the waves before they reach the coast

Question 14

PROS of offshore breakwater

Answer 14

an effective permeable barrier

Question 15

CONS of offshore breakwater

Answer 15

visually unappealing

costly, between £1 million and £2 million