Coastal Management πŸͺΈ Flashcards

1
Q

Why are coasts managed?

A

To protect homes, businesses and environment from erosion and flooding
Reduces social, economic and environment impacts

Money limited so not all coastal areas can be protected
Cost-benefit analysis used to determine which places are protected
Eg ones that have large populations or important transport links

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2
Q

Traditional approaches to coastal management

A

Hard and soft engineering

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3
Q

Sustainable approaches to coastal management

A

Shoreline management
Integrated coastal zone management

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4
Q

Soft vs hard engineering

A

Soft - more sustainable, less environmental damage and economic cost
Hard - unnatural and can impact environment and more expensive

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5
Q

Hard engineering strategies

A

Sea wall
Revetments
Gabions
Rock armour
Groynes
Breakwaters

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6
Q

Sea walls

A

Reflects waves back out to sea
Acts as barrier to flooding

+ creates promenade, tourism benefit
- expensive to build and maintain
- intrusive/ unnatural

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7
Q

Revetments

A

Slanted structures at foot of cliffs
Absorb wave energy when they break on it
Prevents cliff erosion

+ effective
- intrusive
- need maintenance

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8
Q

Gabions

A

Rock filled cages at foot of cliff
Absorb wave energy so reduce erosion

+ cheap
- unnatural and ugly

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9
Q

Rock armour

A

Boulders along coast or foot of cliff
Absorb wave energy
Reduce erosion

+ cheap
+ easy to build and maintain
- can shift in storms
- intrusive and unnatural

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10
Q

Groynes

A

Fences built at right angles to coast
Trap materials transported by long shore drift
Creates wider beaches so slow waves
Reduces their energy so less erosion

+ cheap
- increases erosion down coast, starved of material

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11
Q

Breakwaters

A

Boulders or concrete off coast
Force waves to break offshore
Waves energy reduced before reaching shore

+ expensive
- damaged by storms
- unnatural and intrusive to boats

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12
Q

Soft engineering strategies

A

Beach nourishment
Stabilisation
Dune regeneration
Land use management
Creating marshland
Managed retreat

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13
Q

Beach nourishment

A

Sand and shingle added from elsewhere (eg offshore)
Creates wide and high beaches
More wave energy absorbed
Reduced erosion

+ natural
+ tourism benefits
- need maintenance
- involves dredging seabed, bad for ecosystem

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14
Q

Beach stabilisation

A

Stabilises sand on beach - reducing angle, vegetation etc
Allows more deposition so wider
Absorb more wave energy
Reduces erosion

+ cheap and sustainable
+ creates habitats
- people walk on dunes and damage them

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15
Q

Dune regeneration

A

Dunes created or restored
By nourishment or stabilisation of sand
Provide barrier between land and sea to reduce flooding
Absorb wave energy to prevent erosion

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16
Q

Land use management

A

low value land in at risk areas

allowed to flood

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17
Q

Creating marshland

A

allowing land to flood
Planted vegetation on mudflats to stabilise sediment
become sat marsh
Creates barrier to reduce flooding
Absorbs wave energy and slows waves to reduce erosion

+ protects higher value land behind
- loss of and, agriculture loss

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18
Q

Managed retreat

A

deliberate flooding of certain areas to control the retreat
Breaching any flood defences in place

19
Q

evaluation of traditional approach

A

+ many methods effective

  • hard is expensive
  • often have knock on impacts on other areas
    eg groynes in Happisburgh
  • effectiveness against climate change unknown
20
Q

Aims of a sustainable approach to coastal management

A

New approaches since 1990s
- more holistic, consider entire zone, seperate managment in each cell
- more sustainable - less damage to environment

involve:
- protect people
- maintain physical environment
- sustainable in long and short term
- monitor changes to update strategy

21
Q

What are shoreline management plans?

A

Coastline split into zones by sediment cells
Different plans made for each cell, overall plan = SMP

treated as a closed system - managment largely contained within cells, have little knock on effects of other cells
- short term (up to 20yrs), medium (20-50yrs) and long (50-100yrs)

DEFRA advise whether to:
hold, advance or retreat line or do nothing

22
Q

4 SMP management options

A

Hold the line
Advance the line
Do nothing
Managed realignment

23
Q

hold the line

A

maintain current position of coastline
often uses hard engineering
when coasts are high value

rising sea levels make coastlines harder to maintain

24
Q

advance the line

A

extend coastline out to sea
build defences out to sea - eg nourishment or groynes
very expensive

effected by rising sea levels - would need to be raised later

25
Q

managed retreat

A

allowing coastline to erode and flood in managed way
eg creating salt marshes

26
Q

do nothing

A

letting nature take its course
erosion and flooding occur, cliffs retreat

often used when costal land of low value, eg fields or few houses

when cost and speed of erosion to large to manage

27
Q

how are the recommendations decided?

A

cost-benefit analysis

costs - money and physical impacts
vs
benefit to population and environment

benefits must outweigh the costs

28
Q

factors considered in a CBA

A

social - how it will affect the people, safety

economic - impact of tourism, cost of defences, value of land protected

environmental - impact on ecosystems

29
Q

What is integrated costal zone management?

A

whole sections of the coast managed together
manages wider coastal zone (eg land, water, people and economy)
- recognise cells interact, reduced impacts on next cell
- aims to be sustainable in long and short term

Aims:
- manage flood and erosion risk
- coordinate activities to be more sustainable
- manages natural resources

It is integrated - brings together all involved in development and use of coast, many stakeholders involved

30
Q

evaluation of ICZMs

A

+ more sustainable in protecting coast
+ have less impact of other parts

relocation may be need where defences too expensive or ineffective
- can’t protect all

create conflicts
- people disagree about choices
eg farm owners attached to land left to erode

future sea level rise creates uncertainty on effectiveness of plan

31
Q

location of Norfolk Coast

A

east Norfolk
includes
- Bacton (+ gas terminal)
- Happisburgh - 1400 people
- Sea Palling - 650 people
- Winterton

32
Q

geology of Norfolk coast

A

glacial till and layers of silt, clay and sands
deposited by advancing ice in glacial period

unconsolidated and soft rock
= low, unstable and vulnerable cliffs
Happisburgh cliffs - 6-10m

33
Q

coastal process in east Norfolk

A

high rates of erosion - 2m per year
- high energy waves (due to fetch)

frequent mass movement - landslides and slumping
- especially in winter when runoff makes cliff less stable

drift aligned = longshore drift
- sediment moves south
- creates narrow beaches, vulnerable

history of flooding in Happisburgh
- due to low pressure storms over North Sea = high waves and storms
- worsened by rising sea levels

34
Q

why is Norfolk vulnerable to erosion? + in future

A

geology
- soft, unconsolidated rock cliffs
- glacial till
= erosion
vulnerable slumping after heavy rain

long fetch from north sea
- destructive waves

drift aligned = longshore drift
- creates narrow beaches, less protected

erosion and flooding increased by climate change
- rising sea levels
- increased storm events
- heavier rainfall = more slumping

35
Q

traditional approach in Norfolk

A

developed 1950s after floods

groynes
- trap LSD sediment to widen beach, protect
- moved issue to Sea Palling, south of Happisburgh, starved of sediment
wooden revetments and rock armour
- absorb wave energy to protect from erosion

change in government policy stopped funding
- road to sea eroded
- storm destroyed 300m revetments

36
Q

why was the traditional approach unsustainable?

A

cost of maintaining defence to high due to:
- geology
- storms and fetch of North Sea
- frequent surges
- rising sea levels

37
Q

sustainable approach in Norfolk

A

1996 SMP6 to manage coast as a unit

stakeholders - environmental agency and north Norfolk district council, local residents

38
Q

why was SMP6 more sustainable?

A

environmentally sustainable
economically justifiable
holistic and integrated - not piecemeal
long term - next 100 years

39
Q

approach in Bacton

A

hold the line
using hard engineering strategies
- maintain sea walls
- new rock armour
- gryones to maintain beach and absorb wave energy

reason:
protect gas terminal - national importance and creates jobs

but expensive
trapping sediment starves coast to the south

40
Q

approach in Happisburgh

A

managed retreat

reason:
higher relief then Bacton, less flood risk
small population - 1400
surrounded by low value agricultural land
- cost benefit analysis, new defences not justifiable

unpopular with locals
- financial losses as house prices fallen
- land and agriculture lost

41
Q

approach in Sea Palling

A

hold the line

reason:
protect low lying Norfolk Broads behind - environmental benefits
and economic benefits
- 7 million visitors a year making Β£400 million for local economy

orignal plan - advance the line
offshore reefs made to break waves before coast - reduced energy
- starved areas south - Winterton

42
Q

approach in Winterton

A

do nothing
despite:
Area of Outstanding Natural Beauty snd nature reserve - environmental impacts
reefs at Sea Palling reduced sediment supply to area

reason:
village 1km from sea
no direct threat

43
Q

evaluation of SMP6

A

+ more sustainable management
+ involves local people and groups more
+ more holistic and long term

  • removal of old defences to allow coast to retreat
    people feel they are bing left to fend for themselves = conflicts
  • increasing costs due to climate change, increased erosion so more defences needed