Y13 MB - Coastal Management

Question 1

What is coastal management?

Answer 1

Human intervention in natural processes at the coast in order to reduce rates of coastal erosion, limit the likelihood of coastal flooding and protect coastal habitats / ecosystems

Question 2

Why is coastal management so important?

Answer 2

50% of the population lives within 60km of the coast
75% of large cities are located at the coast
Erosion, flooding and habitat destruction (mangroves, sand dunes and coral reefs) are increasing due to rising sea levels

Question 3

What is the issue with protecting the coastline?

Answer 3

It can greatly impact coastal systems
As erosion of material is prevented at one area of the coast, it will increase the rate of erosion at another section of coastline

Question 4

What is the Environment Agency’s criteria on identifying sections of the coast to protect in England and Wales?

Answer 4

Number of households at risk
Likely impact on agriculture
Likely impact on environment and habitats
Whether erosion is impacting local infrastructure and transport
The cost of constructing management schemes including ongoing maintenance

Question 5

How has human intervention at the coast changed?

Answer 5

Traditionally - this involved taking action on relatively short lengths of coastline to either stop or slow down erosion usually with hard engineering strategies
Now - a more holistic approach is taken (understanding the coast as a whole and the connections within it) with a long-term view and focus on sediment cells. Aim to consider entire coastal zone and use hard AND soft engineering strategies to make a balance human needs and natural processes

Question 6

What are hard engineering strategies?

Answer 6

Making a physical change to the coastal landscape using resistant materials such as boulders, concrete, wood and metal to intercept natural processes

Question 7

What are the positives and negatives of hard engineering strategies?

Answer 7

+ Effective at protecting high-value buildings and infrastructure
+ Can use local materials to blend in with the landscape
- Usually expensive
- Can cause increased rates of erosion down the road coast
- Unnatural so undesirable to look at

Question 8

What are soft engineering strategies?

Answer 8

Work with natural processes to protect coasts which involve manipulating and maintaining natural coastal defences e.g beaches and sand dunes which can absorb wave / tidal energy

Question 9

What are the positives and negatives of soft engineering strategies?

Answer 9

+ Effective at working with the environment —> habitats and natural landscape protected
+ Short-term lower costs
- Require constant intervention
- Long-term high costs due to maintenance

Question 10

What is a cost-benefit analysis (CBA)?

Answer 10

Before a project is initiated a CBA must be carried out to ensure that the expected benefits (e.g hosing protected, value of land saved) is greater than the costs (maintenance, building costs)

Question 11

Give examples of hard engineering strategies

Answer 11

Groynes
Sea walls
Rip rap (rock armour)
Revetments
Offshore breaker

Question 12

Describe groynes

Answer 12

HE
Timber or rock structures built perpendicular to the coast along the beach, trapping sediment being moved along by longshore drift

+ Works with natural processes to build up the beach
+ Increases tourist potential
+ Not too expensive (doesn’t involve high maintenance)
- Starves beaches of sediment further down the coast
- Unnatural and can be unattractive

Question 13

Describe sea walls

Answer 13

HE
Stone or concrete walls built at the foot of a cliff or top of a beach. Usually have a curved face to reflect waves back into the sea
+ Effective prevention of erosion
+ Can have a promenade so people can walk along them
- Reflect wave energy instead of absorbing it
- Can be instructive and unnatural looking
- Very expensive to build and maintain

Question 14

Describe rip rap / rock armour

Answer 14

HE
Large rocks placed at the base of a cliff or top of a beach, forming a permeable barrier to the sea - breaks up the waves and allows the water to pass through back to the sea

+ Relatively cheap and easy to construct and maintain
+ Often used for recreation e.g fishing and sunbathing
- May appear very intrusive (look out of place with geology)
- Can be dangerous for people to climb over

Question 15

Describe revetments

Answer 15

HE
Sloping wooden, concrete or rock structures placed at the foot of a cliff or top of a beach. They break up the wave’s energy (like more gradually sloped sea walls)

+ Relatively inexpensive to build
- Intrusive and unnatural looking
- Needs high levels of maintenance

Question 16

Describe offshore breakers

Answer 16

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

+ Effective permeable barrier
- Visually unappealing
- Can be a navigation hazard

Question 17

Give some examples of soft engineering

Answer 17

Beach nourishment
Cliff regrading and drainage
Dune stabilisation
Marsh creation

Question 18

Describe beach nourishment

Answer 18

SE
The addition of sand or pebbles to an existing beach to make it higher or wider (sediment usually dredged from the nearby seabed)

+ Relatively cheap and easy to maintain
+ Blends in with existing beach
+ Increases tourist potential with bigger beach
- Needs constant maintenance due to natural processes of erosion and longshore drift
- Dredging can impact marine ecosystems

Question 19

Describe cliff regrading and drainage

Answer 19

SE
Cliff regrading reduces the angle of the cliff to help stabilise it
Drainage removes water to prevent landslides and slumping (water lubricates)

+ Can be effective on clay and loose rock where other methods do not
+ Draining is cost- effective
- Regrading effectively causes cliff retreat
- Drained cliffs can dry out and this leads to collapse e.g rock falls

Question 20

Describe dune stabilisation

Answer 20

SE
Marram grass (a pioneer species) can be planted to stabilise dunes with their roots. Areas can be fenced off so people can’t walk on the newly planted dunes

+ Maintains natural coastal environment
+ Provides coastal wildlife habitats
+ Relatively cheap and sustainable
- Time consuming to plant the marram grass
- People may respond negatively to being kept off areas

Question 21

Describe marsh creation

Answer 21

SE
A form of managed retreat by allowing low-lying areas of the coast to be flooded by the sea. This land then becomes and salt marsh

+ Relatively cheap (land reverts to its original state before management)
+ Creates a natural buffer to powerful waves
+ Creates coastal wildlife habitats
- Agricultural land is lost
- Farmers / landowners need to be compensated