🏖️3.1.3.4 - Coastal Management Flashcards
How many people lived within the coastal zone in 1999?
16.9 million
How much of UK manufacturing lies close to the coast?
40%
How much of coastal land is built on?
30%
What are the reasons for coastal management?
Coastal Erosion
Coastal Flooding
Failure of previous defences
What is hold the line?
Maintain current defences
What is advance the line?
Build new defences seaward of existing line
What is managed retreat?
Allow the coastline to retreat due to flooding and erosion but closely manage the rate and location of the retreat
What is ‘do nothing’?
Low value areas left to natural coastal processes as not deemed viable to spend on defences
What are the social factors taken into account?
Number of residents
Use of the land
Who is impacted if it is damaged
Effect of downdrift land
What are the economic factors taken into account?
Value of land
Coast of defences
Cost of maintenance
Value of business and connections in the area
What are the environmental factors taken into account?
Impact on surrounding land
Current state of the coast
Habitats and environment concerned
Unique landforms
What are the political factors taken into account?
What are the alternatives?
Objections/opinions
Likelihood of success
Taking into account opinions of stakeholder
What is tangible cost benefit analysis?
When costs and benefits are known and can be given as a value
What is intangible cost benefit analysis?
Where costs may be difficult to assess but are important (eg visual impact)
What are the steps in cost benefit analysis?
Where is the issue? What are causes and effects? Who is affected? What should be done? Is solution technically viable and environmentally acceptable? What is cost benefit? etc.
What are sea walls?
Concrete or stone walls at the foot of a cliff, or at the top of a beach. Usually have a curved face to reflect waves back to sea
What are the advantages of sea walls?
Protects high value land
Can prevent flooding
What are the disadvantages of sea walls?
Eyesore to the locals and tourists
Expensive to build and maintain
Produce strong backwash, undercutting it
What are groynes?
Timber or rock structures built at right angles to coast. Trap sediment being moved along the coast by longshore drift, building up beach
What are the advantages of groynes?
Very effective for building beach
Prevents sediment moving by LSD
Allows a natural defence to build up
What are the disadvantages of groynes?
Remove a lot of sediment from downdrift
Other beaches left vulnerable to erosion
What are gabions?
Bundles of rock in mesh cages at base of cliff to reduce impact of waves and prevent cliffs being undercut
What are the advantages of gabions?
Cheap to build and maintain
Difficult to erode
What are the disadvantages of gabions?
Not very effective
Unsightly, unnatural appearance
Ongoing maintenance required
What are revetments?
Sloping wooden, concrete or rock structures placed at the front of a beach. Break up the waves energy
What are the advantages of revetments?
Effective in reducing erosion
Little maintenance once built
What are the disadvantages of revetments?
Expensive to build
What are barrages eg. the Thames Barrier?
Big, retractable walls built across estuaries that can be used as floodgates to prevent storm surges
What are the advantages of barrages?
Very effective
Prevent flooding
Can be used to generate energy for commercial use
What are the disadvantages of barrages?
Very expensive
Can alter habitats and ecosystems
What are offshore reefs?
A partly submerged rock barrier, designed to break up waves before they reach the coast
What are the advantages of offshore reefs?
Effective at reducing wave energy
What are the disadvantages of offshore reefs?
Can be easily destroyed by a storm
Don’t look very nice
Contaminate local water supplies
What is beach nourishment?
The addition of sand or pebbles to an existing beach to make it higher or wider. Sediment usually dredged from nearby seabed
What are the advantages of beach nourishment?
Structures behind beach are protected from erosion
Effects of erosion lessened
Looks natural
Tourist friendly areas
What are the disadvantages of beach nourishment?
Can kill other wildlife
Very expensive
Has to be repeated and maintained
What is dune regeneration?
Marram grasses are planted to stabilise dunes and more sediment is added to build the dunes up again
What are the advantages of dune regeneration?
Provides a barrier between lands and sea, wave energy absorbed
Stabilisation is cheap
Creates habitats
What are the disadvantages of dune regeneration?
Limited to small areas
Very expensive
What are the advantages of managed retreat?
Reduces flooding of land
Fairly cheap
Little maintenance
Creates beaches and salt marshes
What are the disadvantages of managed retreat?
Political disagreements over land
Can lead to habitats being destroyed
Compensation for farming
What is land use management/zoning?
The process of dividing the coastal area into zones for particular use, to reduce coastal vulnerability
What is SMP?
Shoreline Management Plans
What is ICZM?
Integrated Coastal Zone Management
What is the UK coastline divided into?
22 Shoreline management plans due to limited budget
What are the aims of SMPs?
Promote long term management
Assess risk associated with coastal evolution
Address risks in a sustainable way
Ensure management plans comply with nature conservation
Provide policy for coastal management
What are the aims of ICZMs?
To focus on the fact that coastal zones are some of the most economically valuable yet ecologically sensitive places
Aims to work with stakeholders
Optimal balance between environmental protection and development of economic and social sectors
What are the stakeholder groups involved in ICZMs?
Coastal residents
Local council
Tourism Businesses
Fishermen
Universities/NGOs
Why are coastal residents stakeholders?
They live and work in the area and it may involve them and their land
Why are local councils stakeholders?
They may be funding part of the project or it may occur on their land
Why are tourism businesses stakeholders?
Much of local income may come from tourism so businesses would be affected
Why are fishermen stakeholders?
Those involved in aquaculture may be involved because it is the land they work on
Why are universities/NGOs stakeholders?
Are those which may provide information or important decisions
2 Main Aims of Management Strategies
Defend and mitigate against impacts of flooding
Protect and mitigate against impacts of erosion
Advance the Line
Build defences seaward of existing line
Managed Realignment / Retreat the Line
Allow retreat but closely manage its rate and location
Do Nothing
Low value land left to natural processes
For a management strategy to pass a CBA, how much does £1 spent have to protect?
£7
Sea Wall Disadvantages
Reflects energy, doesn’t absorb it
Unnatural looking
Expensive to build and maintain- gaps exploited by hydraulic action
Rip Rap / Rock Armour Advantages
Absorbs large amounts of energy
Rip Rap / Rock Armour Disadvantages
Not always same lithology as surrounding area- unnatural
Cliff Fixing
Iron bars in cliff face
Stabilises it
Absorbs wave energy
Cliff Fixing Advantages
Prevents mass movement
Hidden structure, natural appearance
Cliff Fixing Disadvantages
Cliff still eroded overtime
Overall conclusions about Hard Engineering
Long lasting and effective over planned lifespan
Expensive to build and maintain
Impact other coastal areas
Eyesore, spoils landscape and habitats
Land Use Management Disadvantages
Potential loss of tourism
Do Nothing Advantages
Natural
Fairly cheap
Sediment moves downwind, benefits other areas
Do Nothing Disadvantages
Compensation
Habitat loss
Overall conclusions for Soft Engineering
Works with the environment
More sustainable
Arguably less effective
Shoreline Management Key Points
22 in UK, roughly align with cells
Long term management
Live documents- reviewed and updated
Research for future strategy development
Policy and agenda for coastal defence management
Integrated Coastal Zone Management Key Points
Can adapt to change- closely monitored
CBA- economically viable
Constant information collection- continually improved
‘Live’ sheets, improvements logged for future reference
Cycle for Integrated Coastal Zone Management
Planning (CBA)
Decision Making (stakeholders consulted)
Manage, Monitor, Implement
Information Collection (improve)
When was Integrated Coastal Zone Management created?
1982 Earth Summit
Main focus of Integrated Coastal Zone Management
Community involvement
