Y13 MB - Coastal Management Flashcards
What is coastal management?
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
Why is coastal management so important?
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
What is the issue with protecting the coastline?
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
What is the Environment Agency’s criteria on identifying sections of the coast to protect in England and Wales?
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
How has human intervention at the coast changed?
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
What are hard engineering strategies?
Making a physical change to the coastal landscape using resistant materials such as boulders, concrete, wood and metal to intercept natural processes
What are the positives and negatives of hard engineering strategies?
+ 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
What are soft engineering strategies?
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
What are the positives and negatives of soft engineering strategies?
+ 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
What is a cost-benefit analysis (CBA)?
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)
Give examples of hard engineering strategies
Groynes
Sea walls
Rip rap (rock armour)
Revetments
Offshore breaker
Describe groynes
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
Describe sea walls
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
Describe rip rap / rock armour
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
Describe revetments
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
