3.1.3.4 Coastal Management Flashcards Preview

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Flashcards in 3.1.3.4 Coastal Management Deck (42)
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1

what is the aim of coastal management?

to protect homes, business and the environment from the risk of erosion and flooding

2

how are places chosen to be protected?

cost-benefit analysis

3

what are the four options for coastal management?

Hold the line
Advance the Line
Do nothing
Manage retreat

4

what are different hard engineering strategies

sea wall
revetments
gabions
rip rap
groynes
tidal barrier

5

how do sea walls operate?

reflect wave energy back to sea, preventing erosion of the coast
acts as a flood barrier too

6

how do revetments operate?

slanted structures at the foot of cliffs to stop cliff erosion as they absorb and break wave energy

7

what are gabions and what do they do?

cages of rocks that absorb wave energy to reduce erosion

8

what is rip rap and what does it do?

boulders piled against the coastline to absorb wave energy and reduce the rates of erosion

9

what are groynes and what do they do

fences built at right angles to the coast
they trap material transported by longshore drift
which creates wider beaches which slow waves

10

what are tidal barriers and what do they do?

built across river estuaries
contain retractable flood gates that can be prevented to prevent flooding from storm surges

11

cost / disadvantage of sea walls

£6000/m
creates strong back wash which erodes under the wall
needs consistent maintenance
ugly

12

cost / disadvantage of revetments

£4500/m
less durable than sea wall

13

cost / disadvantage of gabions

cheap but ugly

14

cost / disadvantage of rip rap

£1000/m
still lets water through so some erosion still takes place
easily moved by high energy waves

15

cost / disadvantage of groynes

£1000/m
cause erosion to increase further down the coastline
last up to 40 years

16

cost / disadvantage of tidal barriers

VERY expensive
Thames barrier total construction cost was £534 million which is equivalent to £1.6 billion at 2016 prices

17

what is hard engineering?

the building of entirely artificial structures to reduce or stop the impact of coastal processes

18

what is soft engineering

strategies that work with natural features and processes

19

examples of soft engineering

beach replenishment
managed retreat
cliff regrading and drainage
dune stabilisation

20

what is bleach replenishment

sand is replaced along the beach

21

advantages and disadvantages of beach replenishment

A - makes the beach more effective at dispersing wave energy
A - attractive
D - doesn't prevent longshore drift so has to be done repeatedly

22

how much does beach replenishment cost

£300/m

23

what is managed retreat

allowing the coast to reclaim the land

24

advantages and disadvantages of managed retreat

A - allows more wetland habitats to form, natural and cheap
D - socially unfair for locals who lose land

25

what is cliff regrading and drainage

reducing the angle of a cliff to stabilise it
drains excess water

26

advantages and disadvantages of cliff regrading and drainage

A - prevents landslides and slumping, effective on clay and loose rocks
D - can dry the cliff out causing it to crumble, some homes on the cliff may have to be destroyed

27

what is dune stabilisation

planting durable vegetation with solid root system to stabilise dunes because they act like a barrier between land and sea

28

advantages and disadvantages of dune stabilisation

A - maintains natural coastal environment, cheap and sustainable
D - time consuming, can be eroded if mistreated by the public

29

why must coastal management be sustainable?

so there is little damage to people's homes and livelihoods as well as not incurring high costs

30

why is soft engineering more sustainable than hard?

because it is cheaper, takes less time and money to maintain.
it integrates with the natural environment and creates important habitats so can increase bio diversity of an area
**lower environmental impact and lower economic costs**