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Coastal Management Strategies, image, image, image, image, image, image,…
Coastal Management Strategies
Hard Engineering
Sea walls
:check: Prevents erosion
A permanent concrete wall that reflects wave energy back out to the sea
:check: Very effective
:red_cross: Expensive to build and maintain
:red_cross: Can create a strong backwash which erodes and damages the wall
:red_cross: Limits tourism and access to the beach
Groynes
Wooden/concrete fences built at right angles to the coast. They trap material being moved by longshore drift, allowing beaches to develop.
:check: Cheap to build
:check: Having a beach slows down waves and reduces their energy, protecting the coast
:red_cross: Starves beaches further along the coast so can cause erosion problems elsewhere along the coastline
Gabions
Rock filled wire cages, often stacked or built as a wall
:check: Absorb wave energy so reduce erosion
:check: Cheap
:check: Effective
:red_cross: Some people think they are an eyesore
Rock armour
Boulders/ concrete blocks that are placed at the foot of cliffs/ the back of the beach
:check: Absorb wave energy so reduce erosion
:check: Cheap
:check: Effective
:red_cross: Some people think they are an eyesore
Soft Engineering
Dune regeneration/ fencing
Fencing / marram grass planting / stakes / tree trunks to help stabilise dunes
:check: Sand dunes provide a barrier between the land and the sea so they absorb wave energy and prevent erosion
:red_cross: Not as effective as hard engineering
:red_cross: Need to be regularly maintained and managed
Beach nourishment/ replacement
Sand and shingle is added to beaches from elsewhere to replace material lost to longshore drift
:check: Encourages tourism
:check: Cheap
:red_cross: Needs to be done regularly to maintain beaches long term
:check: Large, wide beaches are very effective at reducing wave energy
Case Study (Lyme Regis)
Location
Lyme Regis is a small coastal town on the south coast of England
It is located on the 'Jurassic Coast'
It is a popular tourist destination
Reasons for managing the coastline
Much of the town is built on unstable cliffs
The coastline is eroding very rapidly
Many properties have been destroyed/damaged
The sea walls have been breached many times
Aims
To provide long term coastal protection and reduce the threat of landslips
Conflict prevention
Consultation meetings
Public were kept informed before and during the construction work
Outcomes
:red_cross: Negative
Increased visitor numbers have led to litter and conjestion
New defences have 'spoilt' the natural landscape
The new sea wall may interfere with coastal processes and affect neighbouring coastlines
Stabilising cliffs will prevent landslips that may have revealed important fossils
:check: Positive
New beaches have increased tourism
The new defences have worked
The harbour is now better protected, benefitting boat owners and fishermen
Actions
Phase 1 (1995)
New sea wall and promenade constructed
Cliffs stabilised
Hundreds of large nails were used to hold the rocks together
Improved drainage and re-profiled the slope of the beach
Phase 2 (2005 - 2007)
Construction of new sea walls and promenades
Creation of a wide sand/shingle beach to absorb wave energy and increase the use of the shore.
Extension of rock armour to absorb wave energy and help retain the new beach
Phase 3 (not undertaken)
The initial plan was to help prevent landslips and coastal erosion
However the costs outweighed the benefits
Phase 4 (2013 - 2015)
A new 390m sea wall in front of the existing wall to provide additional protection
Extensive nailing, piling and drainage to provide cliff stabilisation
