coasts L15 hard and soft engineering

Question 1

6 types of hard engineering

Answer 1

1. Groynes
2. Sea wall
3. Rock Armour
4. Revetments
5. Offshore Breakwaters
6. Gabions

Question 2

GROYNES

Answer 2

longshore drift stopped by groyne

benefits;
- deposition and beach accretion

costs;
- terminal groyne syndrome

HORNSEA

Question 3

SEA WALL

Answer 3

break wave energy

benefits;
- best one (curved)
- reflects waves back into sea

costs;
- £1000/m for straight
- £4000/m for curved

BRIDLINGTON (straight)
HORNSEA (curved)

Question 4

ROCK ARMOUR

Answer 4

breaks wave energy

benefits;
- wave energy dissipates
- no flooding

costs;
- grow oysters (bio weathering)
- stops beach
- £1350-6000 per metre

HORNSEA

Question 5

REVETMENTS

Answer 5

stone, timber, or interlocking concrete sloping structures
(permeable!!)

benefits;
fuck all?
make it seem like government cares

costs;
creates a literal RAMP TO THE CLIFF FACE?????

BRIDLINGTON

Question 6

OFFSHORE BREAKWATERS

Answer 6

rock armour but in the sea

benefits;
- forces waves to break offshore
- deposition encouraged

costs;
- can interfere with longshore drift

Question 7

GABIONS

Answer 7

rocks behind fence x

benefits:
???? covers cliff?

costs;
- has to be replaced/cleaned
- £300 per metre

Question 8

5 types of soft engineering

Answer 8

1. Beach Nourishment
2. Cliff Regrading
3. Cliff Drainage
4. Dune Stabilisation
5. Saltmarsh Coir Rolls

Question 9

BEACH NOURISHMENT

Answer 9

replace eroded beach sediment to break wave energy

benefits;
- natural sediment - looks natural, envt friendly

costs;
- £10 per metre cubed
- has to be replaced frequently
- sediment taken from elsewhere

SKEGNESS
LINCOLNSHIRE

Question 10

CLIFF REGRADING AND DRAINAGE

Answer 10

regrading; creating a new slope angle to stabilise it

benefits;
- natural looking
- remains stable as long as the base of the cliff is protected from marine erosion

costs;
- £1 million
- other defence needed to protect base

MAPPLETON
HOLDERNESS

drainage; where permeable rock is above impermeable rock - insert gravel to drain cliff quickly

benefits;
- reduces risk of mass movement after heavy rain
- not visible

costs;
- only REDUCES risk
- disturbs cohesion of rock layers

Question 11

DUNE STABILISATION

Answer 11

natural barrier to sea level rise & storm waves
monitoring and repairing them with geofabric or replanting marram grass

benefits;
- looks natural and is effective
- provides natural ecosystem

costs;
- £1000 per metre square
- needs fencing off when growing
- fragile

RICHMOND, GUERNSEY

Question 12

SALTMARSH COIR ROLLS

Answer 12

made from sustainable coconut waste product
biodegradable sea wall/dam

benefits;
- biodegradable & sustainable

costs;
- pilot project - could go wrong
- £100 each

BLACKWATER ESTUARY